close

Вход

Забыли?

вход по аккаунту

?

LABORATORY AND FIELD STUDIES ON THE RETENTION AND CONTROL OF CERTAIN PROTECTIVE COPPER FUNGICIDES

код для вставкиСкачать
The Pennsylvania State College
The Graduate School
Department of Botany
Laboratory and Field Studies on the Retention’ and
Control of Certain Protective Copper Fungicides
A Dissertation
by
Harold James Miller
Submitted in Partial Fulfillment
of the requirements
for the degree of
Doctor of Philosophy
May, 194-2
: .,V-
Approvedi
Plant Pathology
0MXJU >JT,
»
Head, Department of Botany
A ckn owledgement s
The author wishes to express his sincere, appreciation,
particularly to Dr. D. E. II. Frear and Dr. II. W. Thurston who
contributed many valuable suggestions and criticisms during
the planning and execution of the experimental work and pre­
paration of the manuscript.
The author also especially wishes
to thank Dr. S. E. A. McCallan of the Boyce Thompson Institute
for so kindly determining the Tenacity Coefficients of the
materials used in 1940 and 1941.
An appreciation is also
extended to J. Duaine Moore, Albert Hildebrand, Harry Keil,
Bernard Trabin, Irving -Wiion
and Paul Crum who rendered
technical assistance in preparation of the data and to Dr.
Nelson Shaulis for many helpful suggestions in preparation of
the manuscript.
846540
ii
Table of Contents
A cknowledgements
1
List of tables
iv
List of figures
vii
Introduction
1
Literature Review
6
General methods of laboratory testing
Methods of laboratory determinationof retention
6
10
Laboratory studies on retention of copper
fungicides
12
Studies on retention of copper fungicides in the
field
15
Correlation between laboratory and field studies
of retention
19
Theories of retention
23
Factors concerned in weathering
23
Summary of literature review
25
Experimental Procedure
25
Object
25
i
Outline of experiments
26
List of materials used
27
Ron-commercial materials
Commercial materials
Methods
27
_
28
30
Laboratory spraying
30
Field spraying
32
Determination of copper
32
iii
Method, or sampling in field.— 1938
33
Method of sampling in field— 1939, 1940, 1941
34
Method of determination of areas
. 35
Preliminary Experiments
J
37
Retention on apple leaves
37
Retention on apple fruits
-
41
Retention on cherry leaves— 1938
41
Retention on Pyralin plates
43
Correlation Experiments
48
Changes in experimental technique
’
48
Correlation studies in 1939
50
Effect of lead arsenate on retention on plates
66
Results of weathering Pyralin plates in the
field in 1939
66
Correlation studies in 1940
Correlation studies in 1941
69
*
81
Retention of copper in treatments applied only
after harvest
95
Relation of rainfall and time to weathering of
copper spray residues on cherryleaves
97
Discussion of correlation studies
101
Summary
109
Conclusions
111
Bibliography
113
Iv
List of Tables
1.
Composition of spray mixtures and schedule of
application on Gano apple.
Criswell orchard--
1938
.
38
Per cent copper remaining
on apple leaves— 1938
39
3.
Per cent copper remaining
on apple fruit— 1938
42
4.
Composition of spray mixtures and schedule of
2
applications on cherries (Montmorency).
Blue
Ribbon orchards--1938
5.
6
.
7.
Per cent
copper remaining
44
on cherry leaves— 1938
Retention on Pyralin plates--1938
47
Composition of Spray mixtures and schedule of
applications on cherries (Montmorency).
Blue
Ribbon orchards— 1939
8
.
45
Retention on cherry leaves.
51
Mg.
copper per
square meter remaining at date of sampling.
Average of six rep>licates— 1959
9.
53
Retention on Pyralin plates in mg. copper per
square meter--1939
10
.
Retention on cherry leaves.
55
Per cent copper
remaining at date of sampling.
Average of six
replicates— 1939
11
.
56
Analysis of variance of per cent copper remain­
ing on leaves— Aug. 7, Aug. 22, and Oct. 2,
12
.
Retention on Pyralin plates.
1939
57
Average per cent
remaining; two runs (five plates per run)--1939
58
13.
Indices of retention and control--1939
61
14-.
Effect of lead arsenate on retention of copper
V
on Pyralin plates
15.
67
Retention on Pyralin plates weathered in
field— 1939
16.
68
Composition of spray mixtures and schedule of
applications on cherries (Montmorency) .
Blue
Ribbon Orchards— 1940
17.
Retention on cherry leaves,
71
mg. copper per
square meter remaining at date of sampling*
Average of six replicates— 1940
18.
72
Retention on Pyralin plates in mg. per square
meter— 1940
19.
Retention on cherry leaves.
73
Per cent copper
remaining at date of sampling.
Average of six
replicates— 1940
20
.
74
Analysis of variance of per cent copperremain­
ing on leaves— Aug. 28, Sept 20,
21
.
22.
Retention on Pyralin plates.
!
remaining--1940
*
andOct. 9, 1940
Average per cent
76
Indices of r.etention, tenacity coefficient,
LD50, and control— 1940
23.
78
Composition of spray mixtures and schedule of
applications on cherries (Montmorency).
Blue
Ribbon Orchards— 1941
24.
75
Retention on cherry leaves.
82
Mg. copper per
square meter remaining at date of sampling*
I
25.
Average of six replicates— 1941
85
Retention on Pyralin plates in mg. per sqLiare
I
meter— 1941
36
vi
26.
Retention on cherry leaves.
Per cent copper
remaining at date of sampling.
Average of six
replicates— 1941
27.
87
Analysis of variance of per cent copper remain­
ing on leaves— Aug. 25, 1941, Oct. 10, 1941, and
Nov. 3, 1941
28.
Retention on Pyralin plates.
88
Average per cent
remaining— 1941
29.
Indices of retention, tenacity coefficient,
LD50, and control— 1941
30.
96
Rainfall data and sampling dates— 1939, 1940, and
1941
32.
90
Retention on cherry leaves of treatments with
only one application (after harvest)— 1941
31.
89
98
Days weathering, total rainfall, and average
amount of copper remaining on the samplings in
1959, 1940, and 1941.
99
!
vii
List of Figures
t
1.
Laboratory spray apparatus
30
2.
Leaf measuring apparatus
3.
Retention on apple leaves
4.
Retention
on cherry leaves
5.
Retention
on leaves and plates; leaves remaining—
'
36
i
-
1939
6
.
7.
Retention
.
46
62
on leaves and plates— 1939
63
Retention (amount of copper) and leavesremaining—
1939
8
40
64
Retention on leaves and plates, tenacity
coefficient— 1940
79
9.
Retention
on leaves and plates— 1940
80
10.
Retention
on leaves and plates, tenacity
coefficient; disease— free leaves--1941
11.
Rainfall and time in relation to copper remaining
91
100
INTRODUCTION
The need, for reliable laboratory methods of testing
fungicides is recognized by almost every worker in the field
of plant pathology.
The large amount of published data on
this subject testifies to the demand for information on the
fungicidal properties of materials before they are actually
used in the field.
Wallace, Blodgett, and Hesler (109) as
early as 1911 pointed out the need for laboratory testing as
follows:
"An entire season is required to get results from
a single set of experiments (in the field); we must, therefore*
expect that progress in the discovery of new fungicides or
beneficial modifications of old ones will be slow until some
method is adopted whereby the fungicidal properties of various
substances can be studied in the laboratory .11
The develop­
ment of many new compounds, particularly organics and 'teubstitute" copper materials to .replace Bordeaux mixture which
have been shown to have fungicidal value, has stimulated the
demand for methods which would more accurately predict the
performance of new materials, in the field.
For the determination of the fungicidal properties of all
classes of fungicides four general types of methods have been
used.
They are as follows:
1. The fungous spores are suspended in a liquid prepara­
tion of the fungicide, removed at different times,
and placed on a suitable medium to determine If growth
takes place.
2. The fungicide is Incorporated with a nutrient medium
and growth, of spores or mycelium on this is tested*
3. The spores are suspended in a hanging drop pre­
paration of the fungicide, placed over water in a
moist chamber and percentage germination noted.
4. Glass slides (or other surfaces) are sprayed (or
dusted) with the fungicide, and allowed to dry.
Then drops of spores are added and germination
determined after holding for a suitable interval
in a moist chamber or the slide is subjected to a
"rain test" and the amount of fungicide remaining
determined chemically or by using spore germination
tests.
The first three of these might be further grouped as a
type in which the properties of a fungicide are determined
without.any drying process while the fourth type does allow
for the evaporation of the water.
Fungicides are commonly divided into eradicant and pro­
tective types.
As Wallace, Blodgett, and Hesler (109) pointed
out, the fungicidal properties of a protective fungicide
should be determined after the material has dried since it
must always exhibit these properties in the field after drying
has taken place on the foliage.
The eradicant type does not
necessarily need to possess this property after drying since
the killing of the fungus takes place while the fungicide is
still suspended or dissolved in the liquid (or gaseous) state.
Since the fungicides used in this study are all protective, no
further consideration will be given to the first three types
of laboratory tests as they do not allow for any dryin
of the
material before determination the fungicidal properties*
Dis­
cussions of methods will be limited to this fourth type and
references to fungicidal properties will be confined to those
influencing the protective value.
It will be noted that the fourth type suggests that more
than one factor should be evaluated since it refers to a “rain
test” .
Horsfall, Marsh, and Martin (52) list in more detail
the factors that determine the protective value of a fungicide
as follows:
(a) fungicidal value; (b) initial retention; (c)
tenacity; and (d) miscellaneous factors such as phytocidal
action, cost, etc., which limit the range of usefulness of the
fungicide.
Fungicidal value is usually determined by lab­
oratory tests of toxicity to spores of various fungi.
Initial
retention and tenacity also are amenable to fairly simple
methods of laboratory testing.
Since the studies reported here are confined to the fac­
tor listed by Hors fall, et al (52) as
11tenacity",
a considera­
tion of terms used in this connection seems desirable.
Several
i
terms have been used to refer to the fact that fungicidal
materials having protective value tend to remain on the foliage
and fruit surfaces for a relatively long period of time fol­
lowing their application.
"Adhesiveness" and "adherence" have
been employed quite commonly to express this fact but their
I .
use in this connection does not seem quite desirable.
defines "to adhere" as follows:
a glutinous substance does."
Webster
"to stick fast or cleave, as
Adhesive Is stated to be usually
confined to the physical and adherence to the figurative sense.
This suggests that adherence should not be used in this
4
connection.
Adhesiveness sums to imply the presence of a
glutinous material which is certainly not true for most pro­
tective fungicides except where a sticker material is some­
times added.
Recently ‘'tenacity” has been commonly used to refer to
this concept.
Its use was probably first introduced by Fajans
and Martin (18) who used It in preference to “adherence" which
they state to imply a “mechanical sticking" which may not be
Involved at all in this phenomenon.
Webster defines tenacity
as; "the state of being held fast or being inclined to hold
fast; resistance to rupture; cohesveness as distinguished from
brittleness, fragility, or mobility."
The implication of a
definite molecular cohesion as being the force responsible
does not seem to be directly applicable to this process either
since no convincing proof exists as to what attracting force
>
is involved.
"Retention" has been used by Frear and Worthley (23) to
refer this phenomenon.
It is defined by Webster as, "a ret­
aining or holding fixed in some place or position; state of
being kept in place."
The element of time is implied in the
term retention and it is this property of protective fungi­
cides to remain on a plant surface for a given period of time
that we are concerned with In this concept.
From these defii
nitions it would seem that "retention" Is preferable to
"tenacity" or the derivatives of "to adhere".
Deposition has been used to refer to the concept of the
actual process of depositing the spray material during the
period of its application and retention to the property of the
5
material which causes it to remain in place longer than the
few minutes required, for deposition (Frear and Worthley, 23)•
These two terms will be used in this discussion in preference
to the terms "initial retention" and "tenacity" used by
Horsfall, et al in referring to the factors influencing pro­
tective value.
The Importance of the retention factor in Influencing
the protective value of fungicides has been receiving consi­
derable attention in recent years.
Relatively poor protective
value of a copper material, for example, has been explained
as being due to poor retention as compared to a material of
a high protective value such as Bordeaux Mixture.
Millardet
and David (82) as early as 1886 first suggested the importance
of sticking (retention) as a factor influencing the protective
value of copper fungicides as a result of experimental obser­
vations on the performance of various modifications of Bordeaux
mixture on grapes.
Several workers, Including Kadow (56),
Daines (10), Marsais and Se'gal (76), and Hamilton (35) have
suggested that retention may be the variable factor which
would explain the differences in control and Injury resulting
from different copper fungicides commonly used on fruits.
The
studies reported here were undertaken to evaluate the reten­
tion factor both In the laboratory and field and to evaluate,
if possible, its relative importance in determining protective
value•
I
6
LITERATURE REVIEW
GENERAL METHODS LABORATORY TESTING:
The first designed attempt
to test protective fungicides in the laboratory utilizing
fungous spores to measure toxicity is generally credited to
Reddick and Wallace (98) in 1910.
Burrill (7) published in
1907 the results of one experiment with Glomerella cingulata
in which he dried Bordeaux mixture on cover slips and tested
its toxicity against that organism.
Reddick and Wallace were
!
the first to describe a method for comparing the toxicity of
I
different materials and mixtures of materials after they had
been allowed to dry which is a process, of course, to which
all protective fungicides are subjected in the field.
Wallace,
Blodgett, and Healer (109) utilized this method which they
describe in detail, in tests of lime sulphur preparations.
In
this method glass microscope slides were placed side by side
on a flat surface and one-half of each covered with paper
which is to be used a check.
The material was sprayed on
with a hand atomizer of the deVilbiss type and an attempt was
made to spray the slides as uniformily as possible.
It was
necessary to keep the material thoroughly mixed so that it
would not settle out of suspension in the atomizer. Drops of
/
suspensions of Venturia inaequalis, Sphaeropsis malorum, or
Sclerotinia sp. spores were then placed on the sprayed and
unsprayed area after the mixture had dried.
The slides were
held in petri plates over water and the percentage germination
determined after a given time.
They noted a great variability
in the germination of the spores even in the check half.
This
7
method did not involve any test of retention.
This is funda­
mentally the method that was to be later used with slight
modifications by Schmidt (100), Doran (14, 15), Holland, Dun­
bar, and Gilligan (46), Lee and Martin (60), Goodwin, Martin,
and Salmon (23), Horsfall (48), Horsfall and Heuberger (50),
McDaniel (74), Wilcoxon and McCallan (112, 114), McCallan and
Wilcoxon (64,
6 6 ),
Butler and Doran (8 ), Taubenhaus, Boyd and
Gelber (106), Boyd (5), Davies and Adams (11), Heuberger and
Adams (43), Adams and Priode (1), Plakidas (97), Howard (55),
and Peterson (95)•
McCallan (61) published a detailed account of this method
and the importance of the following factors:
clean glassware;
source of spores; age of culture; kind of water; concentration
of spore suspension and oxygen relations; temperature; light;
time; application of the fungicide; and methods of recording
results.
He also describes a method of dusting the slides to
compare different dusting materials which has also been used
by Kightlinger (59), Wilcoxon and McCallan (113), and Tauben­
haus (104, 105).
Dimond et al (13) has discussed in detail the
interpretation of data obtained by this method.
Method or manner of spraying and equipment used has been
suspected of causing a large amount variability in this pro­
cedure.
Horsfall, et al (49, 51) describe a method of enclos­
ing the spray cone coming from the atomizer in a cylinder and
placing the slide to be sprayed at the end of this tube.
Exposure, was governed by a clamp on the air hose attached to
the atomizer.
They state that this avoids the loss of any
solid particles by evaporation of the water in transit from
atomizer to slide which is related to the dew point of the
atmosphere.
McCallan and Wilcoxon (71, 72) ran replicate
uniformity tests with free hand atomizer spraying, atomizer
)
attached to air hose; horizontal sprayer; and a settling tower*
The settling tower consists of a*closed chamber in which the
spray is atomized upward and allowed to settle on slides at
the bottom of the chamber.
They state that error is at a
minimum with the settling tower.
A slight modification of
this method was used by Henry and Wagner (39) .
Gornitz (29)
developed an apparatus for dusting slides or individual
detached leaves essentially similiar to a settling tower*
Amount of dust settling on the surface of slide or leaf was
weighed automatically as the dust settled by means of an arm
attached to a modified balance arrangement.
Evans and Martin
(16) describe an atomizer which is in two parts to permit
adjustment.
The amount of spray deposited on a glass plate
is controlled by a pendulum arrangement.
A sliding shutter
to control deposit ivas used by Heuberger and Horsfall (45) •
Other phases- to be examined as sources of error were:
methods of obtaining spores (McCallan and Wilcoxon, 69; Peter­
son, 95); species of fungus (McCallan, Wellman, and Wilcoxon,
63); nozzle setting (Horsfall et al, 51); variation in spore
germination (McCallan and Wilcoxon, 65); freeing of spores
from adhering nutrients by centrifuging (McCallan and Wilcoxon,
69); and different transfers of the fungus (McCallan and
Wilcoxon, 70)•
Several different types of surfaces have been used.
Young and Beckenbach (117) state that glass slides were very
9
comparable to foliage without giving any data.
Evans and
Martin (16) tried glass plates dipped into one of the follow­
ing:
cellulose nitrate; butyl acetate; cellulose acetate; or
shellac.
Fajans and Martin (18) and Martin (81) used paraffin
wax, cellulose acetate (or nitrate) and resin.
The cellulose
nitrate is stated to be comparable in ease of wetting with
potato leaves.
Horsfall et al (51) state that glass slides
give some variation in the amount of spreading and suggest the
Lise of cellulose nitrate.
Heuberger (41) used both plain
glass slides and slides coated with cellulose nitrate.
Williams (115) states that shellaced glass slides wet simili­
ar ly to foliage surfaces.
Weber and McLean (110) used waxed
glass plates.
Worthley and Frear (116) state that cellulose nitrate
plates were comparable to leaf surfaces.
Kehlhofer (57) used detached leaves and glass plates which
were sprayed in the laboratory.
Marsh (77) described a method of spraying the material to
be tested on an apple leaf attached to a twig.
The spore
suspension is placed and percentage germination noted.
Higher
germination resulted on the leaves than on cellulosed slides
in the case of certain materials.
Goodwin, Salmon, and Ware
(27) sprayed the material to. be tested on one of two paired
leaves and then placed zoospores of Pseudopernospora hnml ~1i
on them to determine germination.
Plakidas (97) placed
conidia of Mycosphaerella fragariae on strawberry leaves
sprayed with Bordeaux mixture and determined germination.
Howard (55) sprayed materials to be tested on excised tomato
leaves held in sand.
The germination or spores of Alternarla
solani was then noted on these leaves.
Hamilton (34) used
potted apple trees sprayed on a turntable from an atomizer.
Fungicidal value was determined by artifically inoculating
the leaves with apple scab.
This is an improvement of the
method described by Keitt and Jones (58).
Hoskins and co-workers (54, 2, 40), Borden and Hensill
(4) and Upholt (103) used a method for determining the amount
of oil deposited from a given mixture involving spraying the
material on bottles coated with beeswax with a positive dis­
placement type sprayer.
Dawsey, Cressman, and Hiley (12)
used mica plates coated with paraffin and the same type of
sprayer.
MacCreary (73) used this type of sprayer to spray
apple and peach fruits on a rotating turntable.
Pierpont
(96) atomized the spray solution on fruits of apple, peach
and grape on a rotating turntable in a study of the effect of
rosin residue emulsion on lead arsenate deposits.
Goldsworthy and Green (26) developed a so-called dynamic
system for determining toxicity in which spores are exposed to
a continually changing supply of copper ions.
METHODS OF LABORATORY DETERMINATION OF RETENTION:
Guillon
and Gourand (33) first studied the retention of certain copper
preparations on glass plates in 1898.
They used artifical
rain in the laboratory and analyzed for copper remaining.
Kehlhofer (57) in 1907 used both detached leaves and
plates in the laboratory which were subjected to an artificial
I
rain. Amount of copper remaining was determined chemically.
Probably the most common method of determining how much
fungicide will be removed by water from a given surface is by
dipping as described in detail by Heuberger (41, 42).
The
sprayed (or dusted) slides are dipped or agitated in water for
a given period.
This has been used by Young and Beckenbach
(117), Davies and Adams (11), Heuberger and Adams (43),
Williams (115), Montgomery and Moore (84) and Goodwin, Salmon,
and Ware (27).
Another method commonly used is to sprinkle
water on the slides (Wilcoxon and McCallan, 113; McCallan and
Wilcoxon,
68;
Marsh, 77; Gornitz, 29; and Schmidt, 101, 102)
or atomize it on (Marsh, 78; Heuberger, 41; Fajans and Martin,
18; Hamilton, 34).
Boyd (6 ) exposed slides outside for given
periods.
Determination of the amount of fungicide remaining has
been made biologically by determining spore germination on
the washed spray film (Boyd,
6
; McCallan and Wilcoxon,
68
;
Hamilton, 34; Goodwin, Salmon, and Ware, 27; Marsh, 77, 78;
Montgomery and Moore, 84; Davies and Adams, 11; Heuberger and
Adams, 43; Heuberger, 41, 42).
Determination by weighing wa.s
used by Wilcoxon and McCallan (113) and Gornitz (29) with
dusts and a direct chemical analysis by Young and Beckenbach
(117), McCallan and Wilcoxon (6 8 ), Nikitin (90), Boyd (5),
Martin (79) Williams (115), Schmidt (100, 102).
Gornitz (29) used detached grape leaves which he dusted
with weighed amounts of the fungicide and determined its
effect on Plasmopara vitioola before and after a rain test.
Hamilton (34) described a method in which he atomized
water on previously sprayed trees while they were rotated on
0
a turntable.
Amount or spray remaining was then determined
by artificially inoculating the leaves with apple scab.
Hamilton and Weaver (36) improved.this technique by using
sporidia of Gymnosporangium junlperi-virgin!anae and leaving
half of each apple leaf
as an unsprayed check. This method
is further discussed by
Hamilton and Mack (37).
Nikitin (89, 91) described a method of determining
retention from the behavior of copper materials during electrodiaiysis.
He states (90) that retention on the diaphragm
I
was correlated with, retention of materials on glass plates
i
subjected to a rain test in the laboratory.
Pierpont (96) used a Friend type spray gun with 250
pounds pressure to wash fruits of apple peach, and grape on
a rotating turntable.
Lead residue remaining was determined
by chemical analysis.
LABORATORY STUDIES ON THE RETENTION OF COPPER FUNGICIDES;
Millardet and David (82) first noted in 1836 that cupric stea
tite showed high retention on grape leaves which they attri­
buted to its fineness.
Their conclusions were based on
observation only.
Another early investigation of retention of copper fungi
cides was made by Kehlhofer (57) in 1907 on glass plates and
grape leaves subjected to laboratory "rain".
Soda Bordeaux
was found to show higher retention than ordinary Bordeaux
mixture by chemical analyses.
Sugar reduced the retention of
Bordeaux.
McCallan and Wilcoxon (6 8 ) found by spore germination
13
tests and chemical analysis of washed glass slides that
Bordeaux mixture, Cuprocide, and Copper Oxychloride had a
higher retention than copper oxalate and basic copper sulphate*
Results were somewhat variable with the different species of
fungi.
Correlation between chemical analysis and spore germi­
nation tests of retention was high with certain species of
fungi.
Heuberger (41, 42), using spore toxicity tests only,
found Bordeaux mixture, red copper oxide and yellow copper
oxide to show a high retention; Basicop and Compound "A" to
have an intermediate rating; and Copper Hydro "40", Coposil
and Z0 to have a relatively low retention.
The retention is
expressed as a "tenacity coefficient" which is the ratio of
the inhibiting power of unwashed to washed slides.
The same
author (42) in a review of tenacity of fungicides has dis­
cussed the role of particle size, particle shape, and nature
of particle surface, as well as solubility in. determining
retention.
He does not quote extensive data as to the relative
importance of these factors, however.
Davies and Adams (11) have studies the effect of spreaders
on the retention as determined by spore toxicity tests after
laboratory washing of glass
3 liaes
and found that bentonite
increased the retention of Z0 and Coposil while Wyojel and
Kaolin,^ which are special forms of bentonite, reduced it.
Young and Beckenbach (117) found bentonite and Wyojel to
increase retention of basic copper sulphate, basic copper
chloride, and copper phosphate, using chemical analysis of
deposits on glass slides before and after a rain test.
14
Boyd (5) reported that all the following spreaders
increased retention of Cuprous oxide-Lethane Spreader, Areskaji
Aresklene, SS-3, wettable sulphur, Corikal N powder, Igepon T
powder, Kayso, dry Aresket,. and dry Ortho spreader.
The
residue on the slides was analyzed chemically after a period
of laboratory washing with water.
Montgomery and Moore (84) found that a Bordeaux mixture
containing
0
.6 ,^ copper was still highly toxic to spores after
two hours of laboratory washing while a
0
.
3
$
Bordeaux mixture
showed lower retention.
Marsh (78) found that cottonseed oil and white oil
emulsion would increase retention of cuprous oxide.
Sulphite
lye reduced retention of cuprous oxide, cuprous iodide, and
Bordeaux mixture using laboratory v/ashing of both leaves and
slides.
Retention was determined biologically*
Fajans and Martin (IS) determined by chemical analysis
the effect on retention of a whole series of spreaders and
stickers on cuprous oxide and cuprous iodide after laboratory
rain tests.
In general it was found that supplements of a
high surface activity decreased retention while methyl
cellulose did not.
A paraffin surface gave materials a higher
retention rating than cellulose ..nitrate.
The same workers
(19) found that petroleum oil increased retention of cuprous
iodide on glyptal resin surface if concentration of sulphite
lye emulsifier was not too high.
retention.
Cottonseed oil also increased
"Agral S. R.n had no effect v/hile gelatine gave
only a slight increase in retention.
obtained on cellulose nitrate surface.
The same results were
fleuberger (42) pointed.
out also that spreaders and wetting agents reduced retention*
STUDIES ON RETENTION OP COPPER FUNGICIDES IN THE FIELD:
Field
tests on retention of copper fungicides have not been very
extensive and much of it lias been done without allowing for
normal variation in field sampling.
This will be discussed
more fully later.
One of the earliest papers on retention of copper materi­
als;, in the field was published by Girard (24) in 1892 who
studied various modifications of Bordeaux mixture*
He was
impressed by the observation that blight followed the washing
off of the copper on potato leaves.
The potato plants were
subjected to artificial rain In the field and the amount of
copper remaining determined by chemical analysis.
He found
that a slow, light rain over a long period would remove more
copper than a short fast rain even though the amounts of
water applied were approximately the same.
Perraud (93, 94) also did some early work on retention
In the field after, periods of natural rainfall on grapes.
Chemical analysis of leaves and fruit were made at two periods
to determine the amount remaining.
Among the stickers he
tested with Bordeaux were starch, dextrin, egg powder, and
dried blood, all of which were ineffective.
Postive results
were obtained with resin, soap, potassium silicate, molasses,
gum tragacanth and glue.
The work of Magie and Horsfall (75) on relative retention
of certain copper fungicides has been quoted extensively.
ranked materials only from chemical analyses of the leaves
They
16
after different periods of weathering as to their relative
retention on apple and cherry leaves as follows (in descending
retention); cuprous oxide plus cotton-seed oil; Bordeaux
mixture plus cotton-seed oil Bordeaux mixture; cuprous oxide;
copper oxychloride; copper phosphate; copper-ammonia-silicate
plus cotton-seed oil; and copper-ammonia-silicate.
No data
are given as to whether these differences are significant or
not.
Daines (1 0 ) found that field determinations of copper
residues of a number of copper materials on cherries showed
that high retention was generally correlated with good con­
trol of leaf spot and that lack of injury was correlated with
poor retention.
Daines and Martin (9) added certain metals
above copper in the electromotive series to Bordeaux mixture
on Golden Delicious apples (leaves and fruit) and found that
/
they did not reduce the retention but did decrease injury
while zinc sulphate and wettable sulfur decreased retention
without reducing the injury caused by the Bordeaux.
Kadow, Hopperstead, and Goodwin (56) in a study of Bitter
rot control by various copper fungicides on apples found
(based on calculations from their residue data) some correla­
tion between retention as shown by analysis and control of
the rot, but there were several exceptions which might be
due to the fact that only one determination of copper was
made after a two week period of weathering.
Their data indi­
cate that Orthex reduced retention of Bordeaux mixture and of
Compound "A" while a rosin sticker (GSS) did not alter reten­
tion of either.
Compound A showed lowest retention.
Copper
17
Hydro "40" and Oxo-Bordeaux with. Orthex showed retention
almost equal to Bordeaux while Basicop, ZO and Coposil with
Orthex were intermediate between these and Compound A»
Copper phosphate-bentonite-lime mixture showed retention of
about the same as ZO.
No comparison of ZO, Basicop, Coposil,
Oxo-Bordeaux, and Copper Hydro 1140" without oil was made.
Deposition of Bordeaux mixture was almost six times that of
i
some of the insoluble coppers.
No figure is given as to
statiscal significance of differences.
Hartman (38) studied the retention of certain insoluble
coppers on apple and cherry foliage by chemical analysis.
Retention on both fruits was approximately the same order of
ranking.
Cuprocide 54Y showed highest retention.
Copper
Hydro 1140" was second in retention but this ranking was
reversed on apples.
Copper phosphate and Bordow were next
with approximately equal retention on cherries and variable
results on the apple varieties.
The. order of decreasing
retention of the remaining materials on cherries was as fol­
lows:
Cupro-K ZO; Copper Compound A, and Basicop.
no retention on apples in the case of Cupro-K,
Copper Compound A.
There was
Bordow,. and
Again these data on retention are based on
only one sampling after a two week period of weathering.
figures are given for statistical significance.
No
Data on leaf
spot control are sketchy but apparently Bordeaux mixture and
Cuprocide which showed high retention gave excellent control
while' Basicop which had low retention gave poor control.
Copper Hydro "40" showed some leaf spot although retention
seemed to be better.than Bordeaux mixture.
Fajans and Martin (IS) tried Cuprous oxide with, various
supplements against potato blight (Phytopht hora infestans) and
tried to correlate control with retention of copper on the
leaves as determined by chemical analyses.
The authors state
that correlation is high, but several discrepancies are
explained by the effect of the supplement on spreading or on
fungicidal effeciency.
and best control.
Petroleum oil showed highest retention
Agral 2 (an alkylated naphthalene sul-
phonate) was lowest in retention and next to poorest in blight
control.
Sulphite lye, lime, lime casein, cottonseed oil,
Sulphonated Lorol, methyl cellulose, gelatine, and cuprous
oxide alone varied rating based on control compared with a
rating based on retention.
The authors give figures for
significance both in blight control (data and retention data.
Four replicate analyses were made per treatment giving data
susceptible to analysis of variance.
Samples were not kept
separate from each of ten blocks in the field, however.
The
leaflets from these ten blocks were mixed and four samples of
50 discs (one disc per leaf) were obtained from a total of
200 leaflets per plant.
Four different samplings were taken
and a grand average of the amount retained in each treatment
for all the samplings was made to get an estimate of retention
The same authors noted an effect of supplements on initial
deposition.
Green and Goldsworthy (32) determined the effect of the
following adjuvants on retention on Kieffer pear leaves of
copper phosphate-bentonite-lime mixturej aromatic sulphonate,
synthetic resin mixture, fish oil soap, and cotton-seed oil.
19
The fish oil soap increased retention while the others had no
effect.
The authors state the following in a discussion of
copper residue data:
"one very ohjectionable feature of the
figures obtained in 1935 is their lack of concordance".
Only
one sample per treatment was taken on a given date in, 1936.
Duplicate samples were taken in 1937.
The authors noted
considerable discrepancy between duplicates, however.
Hamilton (35) states that retention and control of scab
on apple foliage showed a high degree of correlation in the
case of Coposil,
copper phosphate mixture, red copper oxide,
and Bordeaux mixture.
tion.
Injury is also correlated with reten­
Ho data on retention are given.
Pajans and Martin (19) studied the effect of oil supple­
ments on the retention of cuprous oxide and found the oil
Increased retention but that too much emulsifier of the
sulphite lye type counter-acted this effect.
Increased retention but "Agral S. R." did not.
Cottonseed oil
Ho repli­
cations were made In these tests.
Martin (80) found that where the amount of copper retained
was the same with different supplements in Bordeaux mixture,
there also was no difference in control.
CORRELATION BETWEEN LABORATORY AND FIELD STUDIES OF RETENTION:
Some fine early work on correlation of laboratory and field
determination of retention was done by GullIon and Gouirand
(33) in 1898.
Glass plates were sprayed in the laboratory
and subjected to artificial rain.
Comparisons were made as
to the relative retention after different lengths of time of
20
preparation of Bordeaux mixture and various modifications
using other materials besides lime and stickers with, the regu­
lar copper-lime mixture.
These same materials in exactly the
i
same formulas were placed on grape leaves (by placing small
drops directly on the leaf surface) in the same way as they
were placed on the glass plates.
and washed with the
the.glass plates.
The leaves were detached
same kind of artificial rain as used on ■
The amount
cally on both surfaces.
remaining wasdetermined chemi­
The conclusion was that older pre­
parations are retained more poorly on both surfaces.
Plates
and leaves subjected to natural rain are stated to give the
same results although no data are presented.
Actual order of
retention on plates varied some from that on leaves.
No data
are given as to the original amount of copper on either sur­
face and the assumption apparently is made that approximately
the same amount was
placed on each plate or leaf.
It is
interesting to note
that this very early work in the lab­
oratory involved a careful comparison with field results
i
in which more variables were kept constant (formulas and
' '
!
materials, rain, and analytical method) than has been the case
in most work following this that has been found recorded in
the literature reviewed here.
Heuberger (41, 42) states that results on retention of
certain copper sprays studied by him and expressed as "ten­
acity coefficient" as determined on glass slides gave the
same order of rating as the field analyses on retention of
Magie and I-Iorsfall (75) .
He further (42) states that oil
increases retention of copper compounds in both field and
21
laboratory tests.
Spreaders and wetters both reduce retention
in both types of tests.
Heuberger and Horsfall (44) report that laboratory tests
on toxicity only showed that yellow cuprous oxide was better
than red and that field data on control of Diplocarpon rosae
and Alt.ernaria solani also showed that the yellow form was
better than the red.
Fajans and Martin (18) found a fair degree of correlation
between laboratory and field results on both deposition and
retention of cuprous iodide and cuprous oxide as influenced
by vari us supplements.
lows;.
They summarize the results as fol­
"the laboratory method provides an assessment of effect
upon tenacity (retention) applicable to field conditions with
a high degree of accuracy though, as was expected, the actual
percentage figures have no quantitive significance".
The same
authors (19) also found that laboratory results as to the
increase in retention caused by oil was borne out in field
studies on retention of red cuprous oxide on potatoes.
The
effect of sulphite lye in reducing retention by the petroleum
oil sticker in the laboratory was found not to hold true in
the field where no effect was noted.
Cottonseed oil increased
retention in the field and laboratory.
Montgomery and Moore (84} point out that the ratio of
actual quantitative amounts required to inhibit spore germi­
nation in the laboratory and to control disease in the field,
varies for different fungicides.
Marsh (78) using toxicity tests on leaves in the labora­
tory found that quantitative results as to amount required 'for
inhibition were directly applicable to the field.
Petroleum
oil-sulphite lye emulsion does not reduce the fungicidal value
of lime sulphur in the field as it did in the laboratory.
He
points out that deposition in the laboratory is kept low to
study the effect of several supplements on the same amount of
deposit of a fungicide while spraying in the field continues
up to the point of run-off which will give a higher deposit of
fungicide with some supplements than with others.
This is
advanced as an explanation for lack of correlation between
certain laboratory results and control of a disease in the
field.
Williams (115) found a good correlation between laboratory
analyses of sulfur dusts remaining after weathering on shel­
lacked slides and field analyses of dusts on apple leaves.
Percher (92) indicated that he obtained a correlation
i
between laboratory and field results on tenacity of certain
copper materials.
Worthley and Prear (116) in a comparison of deposition
and retention of lead arsenate and various adjuvants on
Pyralin plates in the laboratory and on apple fruits and
leaves in the field, noted that a high error appeared in the
field data.
They also suggested that previous applications
on the fruit and leaf surface may influence the retention
while the plates in the laboratory are only sprayed once.
They found correlation with some of the treatments and none
with others.
They state that laboratory results are to be
used with caution in predicting the effect on deposition and
retention of lead arsenate with various stickers in the field.
I
23
THEORIES OP RETENTION:
Relatively little is to be found in
the literature concerning the forces involved in the retention
of a spray or dust on a leaf surface.
Hooker (47) prepared a
copper hydroxide which he stated to possess a positive charge
on the particles which would he attracted to the negatively
charged leaf surface.
He stated that this material gave good
control of scab and blotch on apple at a weaker concentration
t
of copper than that contained in a 3-5-50 Bordeaux mixture.
Mud in the spray water was suggested as a factor tending to
neutralize the charge on the copper hydroxide particles.
Moore (85, 86) determined that the leaf exhibited a
negative electrostatic charge.
He prepared a basic calcium
arsenate which he stated to have a retention on cotton leaves
many times that of ordinary neutral calcium arsenate.
Borchers and May (3) also discuss the possible role of
electrical charges on the retention of dusts.
Gortner (30) discusses this further, stating that ordinary
commercial arsenicals are positively charged.
a negative charge.
The leaf carries
Negatively charged particles would not be
retained at all according to this author.
Hoskins and Wempler (53) studied the deposition of lead
arsenate in the laboratory In relation to electrostatic charge.
He suggested that the charge on the leaves changes during
spraying.
The authors could not be certain of the role of the
charge in deposition and retention.
FACTORS CONCERNED IN WEATHERING:
Very little is known con­
cerning the relative importance of various factors in weather-
24
ing such rainfall,_mechanical action, etc*
Kehlhofer (57) very
early suggested that factors tending to reduce the amount of
copper on plant surfaces could he divided into:
such as wind and rain, and (2) chemical.
(1) mechanical,
He found the carbon
dioxide dissolved in distilled water used to soak sprayed
plates in the laboratory reduced the copper much more than
pure distilled water.
Ammonium nitrate solution did not reduce
it much more than distilled water.
Fajans and Martin (19) suggested that lack of rain ac­
counted for almost complete removal of certain copper compounds.
Green and Goldsworthy (32) suggest that the scouring
effect of two leaves rubbing together is a factor in the
removal of spray residue.
This is considered to be less severe
when water is present.
Weathering of sulfur has been rather clearly shown to be
independent of rainfall after initial loss since volatili-
li
zation occurs according to Thatcher and Streeter (107) and
White (111).
Hamilton (35) noted the large amount of sulfur removed
by initial rain but that later rain did not remove the same
proportion.
He also showed that increase in fruit size was
a large factor in reducing the sulfur residue per unit area.
Rainfall has been shown to be relatively unimportant in
weathering of lead arsenate on apple fruits and that growth
probably accounts for most of the reduction according to Frear
and Worthley (23) and Fahey and Rusk (17).
Frear and Yiforthley
(23) also found no loss on the lower leaves during periods of
excessive rainfall.
25
SUMMARY OP LITERATURE:
It is evident from the references
cited that many detailed studies of copper fungicides have
"been made in the laboratory.
Most of the work has been con­
centrated on toxicity studies to determine what compounds
have fungicidal value.
Much of this work has been sponsored
by commercial interests and has consequently not been fully
reported in the literature.
As the results of these tests
were carried to the field many compounds have been found to
give poor control in spite of favorable ratings in the lab­
oratory.
This has- lead to a re-examination of the accuracy of
laboratory procedures and a realization of the large amount
of error involved as shown by replicate tests.
Much careful
work has been recently conducted to correct this as already
noted.
Also it has become evident that fungicidal value was
just one of the important factors determining protective value
of a fungicide, particularly copper.
Retention has been shown
to account for the lack of control with some of the compounds
tested.
EXPERIMENTAL PROCEDURE
OBJECT:
Since a large proportion of the laboratory testing
of copper fungicides has been devoted to determinations of
toxicity only, it seemed desirable to investigate the import­
ance of retention in relation to the protective value of these
materials.
It soon became evident that laboratory testing was
not completely accurate and that field data on retention was
26
needed since little can be round reported in the literature on
retention on fiolage or fruit.
It was necessary therefore to Improve the accuracy of the
laboratory method as much as possible.
Correlation with field
data is a necessary part of the determination of this accuracy
and it was hoped that improvement could also be made in the
methods involved in obtaining this field data.
After obtaining
these two types of data it was thought It should then be
possible to ascertain if any correlation existed between the
behavior in laboratory and field tests and, If possible, to
estimate the degree of this correlation.
OUTLINE OP EXPERIMENTS
I• Pr eliminary
1. Laboratory studies
a. Retention of different commercial materials
b. Effect of varying lime on retention of tank-mix
copper phosphate
c. Effect of bentonite on retention of commercial
copper phosphate
d. Effect of length of time of drying on retention
of Cuprocide "54"
2. Field Studies
a. Apple
(1) Pruit
(2) Leaves
b. Cherry leaves
II. Correlation studies
1. 1939
27
a. Field data on cherry leaves
(
b. Laboratory data
2. 1940
a. Field data on cherry leaves
b. Laboratory data
(1) Treatments comparable to field data
(2) Effect of Lead arsenate on Retention
3. 1941
a. Field data on Cherry leaves
(1) Data comparable to lab. tests
(2) Additional Plots with only one application
b. Laboratory data
LIST OF MATERIALS USED
Non-commercial materials
Bordeaux Mixture:
Prepared by the instant Bordeaux method as
described by Schneiderhan (103).
First figure in formula
i
indicates amount of copper in lbs. and second, the amount
of lime.
Hydrated Lime:
Fresh hydrated spray lime was used always.
Dolomitic lime was obtained from Woodville, 0.
Copper Phosphate-Bentonite-Lime: 1 Prepared according to Roberts,
et al (99).
See also Goldsworthy (25) and Green (31).
Tank-Mix Copper Phosphate:
Required amount of copper sulphate
was dissolved in the tank as in the preparation of
Bordeaux mixture and the sodium phosphate was added.
After thorough mixing the lime was added.
28
Commercial Materials
Name
Probable Composition
Bordeaux (Dry) Bordeaux mixture (12.5/a Cu)
Company
Grasselli Chem. Co.
Bordow
Cu-mg complex (12.5# Cu)
Do we Chem. Co.
Basicop
Basic copper sulphate
(52# Cu)
Sherwin Williams Co.
Basic Copper
Arsenate
Cu-arsenate complex
Sherwin Williams Co.
Goposil
Copper-ammonium Silicate
(20# Cu)
California Spray
Chem. Co.
Copper “A ”
(Compound 11A 11
Copper oxychloride
(45# Cu)
Grasselli Chem. Co.
Copper Hydro '^ C ’Copper hydroxide (26# Cu)
Chipman Chem. Co.
Corona Lead
Arsenate
Lead Arsenate
Pittsburg Plate Glass
Co.
Copper oxide
Cupric oxide (75# Cu)
Harshaw Chem. Co.
Cuprocide 54
Cuprous oxide (86# Cu)
Rohm & Haas Co.
Cupro-K
Copper oxychloride
(24# Cu)
Rohm & Haas Co.
Cuprous oxide Yellow cuprous oxide
(Cup? ocide '^Y1*)
(85# Cu)
Rohm & Haas Co.
Nopco
Potash Fish Oil soap
National Oil ftoducts Go.
Rosin emulsion
Miller Chem. Co.
Orthex
Sulphonated Oil
Cal. Spray Chem. Co.
S. E. C. Oil
Cottonseed oil emulsion
Rohm & Haas Co.
Nufilm
Soya bean flour
Soya Flour
(Duspray #100)
Central Soya Co.
i
Spralastic
Oil emulsion and fish
oil soap
Sherwin Williams Co.
Summermulsion
Oil emulsion
Sherwin Williams Co.
Spred-Rite
Fish oil soap
Sherwin Williams Co.
Tenn.
Basic Copper Sulphate
(26# Cu)
Tennessee Copper Co.
" 26"
29
Tenn. "34"
Basic Copper Sulphate
(54$ C{
u)
ZO
Copper Zeolite (25$ Cu)
Tennessee Copper Co.
Perrautit Co.
All materials were secured fresh each season since the
composition of some commercial materials is often changed
from year to year.
The exact nature of the copper compound
in these "commercial coppers” is either not known or usually
/
not published b y the company since they are all patented
products.
METHODS
Laboratory spraying:
The machine used for the spraying and rain
tests has been described b y Worthley and Frear
illustrated in figure 1.
(116)
and is
It consisted of a turntable made of
heavy plywood 48 inches in diameter which was rotated at a
speed of 14 revolutions per minute by means of a reducing gear
connected to a constant speed motor of the synchronous type.
Twenty-four blocks were set on the outer periphery of the turn­
table with surfaces beveled to a 45 degree angle to hold the
5 by 5 Inch Pyralin plates which were attached b y means of
push pins.
The spray from an atomizer type spray gun is
directed at right angles to this beveled surface./
The atomizer
Is held on a support about 24 inches from the turntable.
spray is drawn up. from a container
The
(usually a 600 cc beaker)
and sprayed on to the plates as the turntable rotates a given
number of revolutions to give a constant dosage.
The atomizer
was always flushed out first before actually spraying of the
plates began.
Air pressure on the 1939,
1940, and 1941
Pig. 1.
Laboratory Spray Apparatus
31
experiments was maintained at 120 pounds per square inch..
the preliminary experiments 40 pounds pressure was used.
In
The
room in which spraying was done was kept at nearly constant
humidity and temperature.
The materials were weighed in quantities equivalent to
the field formulas so that a 500 cc of suspension was prepared.
Agitation was maintained b y means of a variable speed labora­
tory stirrer.
Celulose nitrate plates ("Pyralin" manufactured by E. I.
DuPont de Nemours & Co.)
.0125 inch thick were used in all the
experiments after cellulose acetate plates were found unsatis­
factory.
They were cut 5" x 5" and finally trimmed to 10
square centimeters just before analysis of the copper was made.
After preliminary testing it was decided to divide the
twenty sprayed plates obtained during one spray operation, Into
four groups of five plates each.
One group (designated as A)
was analyzed to give the estimate of the original amount on
the plates.
The remainder (in all work except in the pre­
liminary laboratory studies made In 1938) were held at least
\
two weeks after being sprayed and then placed back on the turn­
table for the rain test.
This was done because results re ­
ported elsewhere In this paper showed that some materials did
not give the same retention If washed immediately as compared
with those allowed to dry for a given period.
Two hundred and
fifty cubic centimeters of distilled water was atomized on the
plates as they were rotated.
Five plates were then removed
(designated as '*B” ) and 500 cc of water atomized on the remain­
ing, ten.
Five more plates v/ere removed (designated as "C")
32
and 1000 cc more of water was atomized on tlie plates.
last group was designated as nD".
This
Thus the total amount of
water sprayed on each group was as follows:
A
B-C-D
Field Spraying:
Hone
250 cc
750 cc
1,750 cc
All spraying in the field was done with a
single nozzle spray gun.
All the cherry and apple trees used
were of a small enough size that adequate spraying could "be
accomplished from the ground by working all around the tree.
A ten sixty-fourths disc was used in the gun.
A truck-mounted Friend sprayer was used and pressure was
maintained between five
and six hundred pounds.
was always made to getthorough
the trees.
An
attempt
coverage without "drenching"
In the plots in 1939 calling for double dosage the
tree was sprayed once in the regular manner and then immedi­
ately sprayed a second time in the same way.
Determination of Copper:
The method used for analyzing deposits
on the plates has been described by Frear (21).
The copper
was removed from the Pyralin plates by washing thoroughly In
hot 1 + 1
nitric acid.
The washings were made alkaline with an
excess of ammonia and diluted to a suitable volume in a
volumetric flask.
To this 1 cc of a
1
%
sodium diethyl dithio-
carbamate was added and the amount of the resulting color was
determined with a photocolorimeter.
For the plates analyzed
prior to 1940 the home-made photocolorimeter described by
Frear and Haley (22.) was used.
For those analyzed in 1940 and
33
1941 an Evelyn photocolorimeter was employed.
The copper in the field samples of leaves in 1938, 1939,
and 1940 was determined electrolytcally according to the method
of Frear (20)•
The ground leaves (5 gms) were ashed at 500° C.
and the ash dissolved in nitric acid.
The amount of copper
deposited on the electrodes from this solution was determined
"by direct weighing.
The whole unground samples of leaves
collected in 1941 were ashed and dissolved as before.
This
solution was then made alkaline with an excess of ammonia and
the amount of copper determined colorimetrically as described
above for the Pyralin plates using the Evelyn photocolorimeter.
The apple fruits in 1938 were washed with 3 per cent b y
volume hydrochloric acid to remove the copper residue.
This
was freed from organic matter by digestion with nitric and
sulfuric acids.
This solution was then made alkaline with an
excess of ammonia and the copper determined with sodium diethyl
dithiocarbamate in the photocolorimeter.
Methods of Sampling in Field— 1958:
i
Apple leaves v/ere selected
from terminal growth only and all sampling was done from the
ground.
An attempt was made to select leaves of approximately
the same age and care was' taken to avoid the younger leaves on
the terminal which might not have received all the cover sprats.
I
Enough leaves were taken from each of the six blocks in each
treatment to make a total of 100 at each sampling date per plot.
Apple fruit samples were selected from the top and bottom
of each block in the treatment.
Thirty apples were obtained
from the top station and thirty from the bottom in each plot.
34
These were placed In Mason jars and taken Into the laboratory
for washing with the acid*
Cherry leaves in 1938 were selected at random from each of
the nine blocks.
Sampling was all done from the ground*
Fif­
teen leaves were taken per tree to give a total of 135 leaves
per treatment*
Both apple and cherry le aves were dried, ground, and
placed in vials after measurement.
Method of Sampling in Field— 1959, 1940, 1941:
For reasons
which will be discussed later the method of sampling the cherry
leaves was changed after 1938.
Samples were kept separate from
each tree to give six from each treatment.
One hundred eighty
leaves were obtained for each sample in order to have suffi­
cient quantity for analysis by the electrolytical method used
in 1939 and 1940.
In 1941 only fifty leaves were obtained
per sample since analyses were made with photocolorimeter.
They were measured, dried, ground and placed in vials just as
the other leaf samples.
Leaves were taken from spurs only in
order to avoid sampling leaves occuring on terminals which
might not have been old enough to receive all of the four
sprays.
Most of the spur leaves received the petal fall spray
and certainly all received the shuck fall and following sprays*
Method of determination of Areas:
Apple fruit areas were
determined by measurement of transvere and vertical axis of the
fruits immediately after washing.
Average diameter was used
in the formula for determining the surface area of a sphere.
Measurement of leaf areas was done photoelectrically*
In
35
the 1938 and 1939 samples of apple and cherry leaves, the
apparatus described by Frear (20) was used.
The amount of
light cut off by the leaves is measured with a photoelectric
cell.
Light was supplied in the apparatus by alternating
current which fluctuated considerably so that the original
reading (from which per cent light cut off is caculated) varied
while a reading was being taken of a given lot of leaves.
In
order to avoid this error a machine was built in 1940 utilizing
direct current from storage batteries and a more sensitive
microammeter for the weaker light.
This entirely eliminated
fluctuations in the source of light and was used for measure­
ment of the 1940 and 1941 samples of leaves.
This apparatus
is illustrated in figure 2.
In this method standardization curves are made from the
percentage light cut off by leaf discs of known areas.
These
leaf discs are cut directly from a composite sample of the
leaves being measured in order to eliminate variations that
might possibly be introduced by varying opaqueness of a leaf
at different times of year.
From the per cent light cut off
by a given lot of leaves the area then can be read off directly
The curve is almost a straight line so very few points are
needed to draw it.
The area of eight to fifteen leaves can be
determined at one time depending on their size.
All copper analyses were calculated as milligrams per
square meter.
per leaf.
Leaf area caculations were based on two surfaces
-Fig* 2* Leaf Measuring Apparatus
w
0)
37
PRELIMINARY EXPERIMENTS
RETENTION ON APPLE LEAVES:
The schedule of* copper applications
on apples in 1938 is given In tahle 1.
follows:
Samples were taken as
after 1st copper spray and "before second spray; after
last copper spray and at the end of 42, 67, and 90 days of
weathering after this.
The results are tabulated In table
2
and shown graphically in figure 3.
'Vi,
An inspection of the graph indicates the large amount of
variability in the data obtained on the apple foliage.
phosphate-bentonite-lime mixture, for example,
Copper
apparently had
the highest percentage copper remaining on June 7.
Yet on
July 8, it dropped to the lowest and was at an Intermediate
point on Oct. 5.
It is hardly concievable that the retention
of a material would change so at different times through the
season and it is certainly more probably that this is an exam­
ple of the variability in samples due to the difficulty of
obtaining uniformlly sprayed leaves or to the washing off from
upper leaves to lower ones as has been noted with lead arsenate
(Frear and Sforthley, 23)•
Since samples from the six blocks
in each treatment were combined no estimate could be made of
the amount of error Involved.
The retention of Bordeaux mixture and tank-mix copper
phosphate and copper Hydro 40 appeared to be higher than most
of the other materials.
Any other conclusion as to compara­
tive retention of the materials Is precluded by the large amount
variability In this data.
38
Table 1
Composition of spray mixtures and
schedule of applications on Gano apple
Criswell Orchard--1938
Plot No.
1
Materials
Amounts per 100 gallons
Bordeaux 2-6-100
C opp er sulpha t e
Hydrated lime
Lead arsenate
2 pounds
6
«
fi
3
3
Basic Copper arsenate
3
4
Copper Phosphate
Hydrated lime
Bentonite
Lead arsenate
4
Basic Copper Sulphate
Hydrated lime
Metalic zinc
Lead arsenate
■la
3
JL
2
3
Coposil
Hydrated lime
Lead arsenate
2
3
3
8
Tank mix Copper phosphate
Copper sulphate
Disodium phosphate
Hydrated lime
Lead arsenate
Copper Hydro 40 (New formula)
Lead arsenate
8
4
3
Cupro K
Lead arsenate
Applications— 1st
2nd
3rd
(No
ii
it
it
it
ti
ii
ii
it
it
it
2
ii
2
it
JL
ii
2
3
ii
2
3
ii
i
10
it
2
3
ti
TI
II
Cover— May 21
Cover--June 7
Cover--(lead and lime alone) June 16
additional covers applied)
All sprays before the cover applications were uniform lime
sulphur•
Table 2
Per Cent*Copper Remaining on Apple Leaves— 1938
Treatment
No. Material
Sampling Date
6/7
7/18
8/12
10/5
5 Basicop
52.4
44.9
26.0
16.3
10 Cupro-K
48.5
53.4
27.2
23.3
3 Basic Copper Arsenate
31.2
47.2
45.0
27.6
4 Copper Phos.-Bentonite-Lime
80.9
38.7
30.7
29.0
6 Coposil
50.3
55.9
41.3
32.9
8 Tank-Mix Copper Phosphate
74.7
54.6
45.3
36.1
1 Bordeaux 2-6-100
53.7
72.3
52.1
37.1
9 Copper Plydr o 1140"
37.8
64.7
50.4
53.1
-*The amount of copper which, remained on June 7 is expressed
as the percentage of the amount found just after the first
copper spray. The amount remaining at different periods of
weathering after the last spray is expressed as percentage
of the copper that was present just after the last appli­
cation of copper materials.
100
70
60
COPPER
40
HYDRO 4 0
BORDEAUX * 2 - 6 - IOO
TANK-MIX COPPER PHOS.
COPOSIL
COPPER PHOS. - BENT. - LIME
BASIC COPPER ARSENATE
C U P R O -K
%
COPPER
REMAINING
80
30
BASICOP
DATE
FIG.3
RETENTION
ON
OF
SAMPLING
A PPLE
LEAVES -
1938
~y
/
41
RETENTION ON APPLE FRUITS;
Th.is study was made on the same
trees as were used In the foliage retention studies.
of treatments is given in table 1.
Schedule
Samples of fruit were taken
immediately after the last copper spray was applied and after
the periods of weathering noted in table 3.
The copper found
after these periods of weathering is expressed as the percent­
age of the original amount that was present just after the
I
application of the treatment.
It Is to be noted that all the percentage figures of
amounts remaining are lower at all three dates than those for
the apple leaves in table 2.
The explanation, of course, Is
that the growth of the apple fruit accounted for a large
reduction in per cent of copper remaining per unit area.
A
comparison of the Individual materials on any one of the dates
shows very little difference in retention.
The last sampling
(October 5) showed copper arsenate to have weathered off more
than any other, but differences between the other materials
are probably not significant.
Possibly the only conclusion
that can safely be drawn from this experiment is that the
growth of the fruit was the biggest factor in reducing the
amount of copper per unit area.
RETENTION ON CHERRY LEAVES— 1938;
treatments is given in table 4.
Full schedule of copper
Four applications were made
according to the recommended schedule.
as follows;
Samples were collected
After 1st and before 2nd Spray; after 2nd and be­
fore 3rd spray; after 3rd and before 4th spray; 29 days after
4th spray; 71 days after 4th spray.
The amount of copper
42
Table 3
Per Cent*Copper Remaining on Apple F r ui t— 1938
Sampling Date
Treatment
7/18
8/12
10/5
1. Bordeaux 3-6-100
13.2
13.2
11.7
3. Basic Copper Arsenate
21.7
13.3
7.1
4. Copper Phos.-Bentonite-Lime
16.7
14.0
11.5
5* Basicop
22.4
13.1
12.0
6 • Coposil
20.7
14.2
13.8
8. Copper Phosphate, Tank-Mix
23.6
13.4
12.7
9. Copper Hydro "40M
19.6
12.8
11.4
17.9
13.2
10.3
Number Material
•
o
H
Cupro-K
*-The amount of copper remaining after the different periods
of weathering is expressed as the percentage of the amount
that was present after the last application of copper materials.
remaining after a weathering period is expressed as, in table
5, a percentage of the amount found in the sample taken just
after the last previous spray.
The original amount was thus
taken at the start of the weathering period*
These results are presented graphically in figure 4.
The
first impression one gets from the examination of these curves
is again one of some confusion due to the extreme variability
in data of this type*
With only two exceptions the Bordeaux
mixture and tank-mix copper treatments showed a greater per­
centage remaining after the different periods of weathering
than any of the substitute copper materials.
The retention of
these tank-mix type materials was consistently higher, but there
seems to be no constant difference between these three treat­
ments.
Cupro-K with oil and lime showed a higher retention
than Cupro-K alone.
The percentage remaining just before the
4th spray in the case of Basicop is out of line from the curve
based on the other samples and illustrates the variation which
occurred in the samples.
RETENTION ON PYRALIN PLATES:
Results of preliminary studies
in 1938 on the retention various copper materials on Pyralin
plates are given in table 6. •
;
No attempt was made to
obtain the same deposit with the different materials and they
were not applied at equivalent copper contents. Neither were
the materials all used in the same formulas that were used in
the field.
The difference in retention obtained by washing immediately
with water or allowing the plates to hang for five days before
44
Table 4
Composition of* spray mixtures and schedule
o.f applications on cherries (Montmorency)
Blue Ribbon 0rchards--1938
Plot
Treatment and Materials
Amount
2
Bordeaux 6-8-100
3
Copper Ph.osph.ate
Hydrated lime
Bentonite
4 gals.
8
4
4
Tank-mix copper phosphate
Copper sulfate
Sodium phosphate (Dibasic
Hydrated lime
6
6
1.5
Tank-mix copper phosphate
(Half-strength)
Copper sulfate
Sodium phosphate
Hydrated lime
3
3
0.75
5
6
Basicop
Hydrated lime
Zinc (powder)
per 100
3
8
1
i
7
Cupro-K
3
8
Cupro-K
Hydrated lime
Pish Oil (Nopco)
3
. 3
1 pt.
Lead Arsenate at rate of 2.5 lbs-100 in Petal Pall and
Shuck Pall and Pink fruit applications.
Applications:
Petal Pall— May 2
Shuck Pall— May 17
Pink Fruit— June 10
Post Harvest— July 13
:
45
•1
Table 5
Per cent1-'copper remaining on cherry leaves— 1938
Sampling Date
Treatment
5/14
6/10
7/13
8/11
9/23
7. Cupro-K
22.1
26.2
53.1
48.7
33.9
6. Basicop
17.2
39.3 101.1
66.2
36.5
8. Cupro-K oil + lime
23.7
40.6
63.2
7,0.1
38.2
5. Tank-Mix Cu Phos (-J-)
58.4
84.5
99.2
83.6
42.4
3. Copper Phos-Bentonite-Lime 29.2
29.9
67.2
56.5
43.7
4. Tank-Mix Copper Phosphate
45.2
56.4
82.1
80.8
57.0
2. Bordeaux 6-8-100
24.0
78.1
75.2 106.9
77.6
No.
Material
^Amount found on May 14 Is expressed as percentage of the
amount on May 2.. Amount on June 10 Is expressed as percent­
age of that on May 17. Amount on July 13 is percentage of
that on June 10 (after the spray application).
Amounts Aug.
11 and Sept. 23 are expressed as percentages of that on July
13 (after the spray application).
r
i
46
m
z§':-
1001
90
80!
S
BORDEAUX *
'•»
T A N K -M IX
6
100
70
j$&
■iris’.
$V^f
i
£30
20
a
«t
Jcj^v
#
*? £-
■jfCfStiV*
^1I'
W
nt
j|
i|
j
S;
*
P
Iff
iV-'t?'
ill
P HO S.
COPPER
PHO S. > 4 - 6 - 4 .
•T A N K -M IX C O P P E R P H O S . fife S T R E N G T H )
-C U P R O -K ♦ O IL + L IM E
•B A S IC O P
■ C U P R O -K
F,40
. -
CO PPER
o 50
P E R IO D
FIG A
RETENTION
OF
W E A T H E R IN G
ON
CHERRY
LEAVES - 1 9 38
1
1
47
Table
Retention on Pyral in Plates— 1938
Original
amTt
mg/M2
Treatment
Bordeaux 4-12-100
Bordeaux 2-6-100
remaining after
No.
3rd
1st
2nd
Runs
Wash Wash Wash
A . v e > %
48.0
24.8
105.1 105.6 105.3
92.7 88.7 89.8
3
9
18.1
30.8
17.0
46.6
21.5
16.1
28.3
100.0
97.6
99.4
86.7
91.2
78.3
66.4
5
2
3
1
5
1
2
Yellow Copper Oxide *-6-1.8-100
Red Copper Oxide *-6-1.8-100
Purple Copper Oxide *-6-1.8-100
22.2
20.3
18.7
105.0 102.7
106.7 101.9
100.5 86.6
Prepared Copper Phosphate 1.6-300
Prepared Cu Phos 1.6-100, Lime
3.2-100, Bentonite 1.6-100
19.2
78.6
16.2
43.2
Basicop 1-g— 3-100
Copper Hydro 1140" 2-100
Basic Copper Arsenate 3-100
Basicop 1.5-100 Zn -|--100
Basicop 1.5-100
Dry Bordeaux (G-rasselli) 8-100
Coposil 2-3-100
Cooper Hydro "40u 3-100
ZO 3.2-100
Cupro-K 2-100
Coposil 5.3-100
38.3
30.0
50.6
24.6
23.5
40.9
13.6
46.1
20.1
30.6
20.3
100.5
85.9
92.1
87.8
72.3
42.8
80.0
54.0
50.7
73.3
46.8
21.8
65.1
47.2
41.3
2
20.0
38 ..6
34.0
20.5
56.9
31.4
12.0
31.8
19.1
10.5
21.5
17.0
2
2
Tank-Mix
CuS04
2-100
2-100
2-100
4-100
2-100
2-100
2-100
Copper
Na2HP04
2-100
2-100
2-100
4-100
2-100
4-100
2-100
Phosphate
Lime
0.2-100
£-100
3.2-100
3.2-100
0.2-100
None
None
Cuprocide 1154" 1.4-100
Washed after 5 days
Cuprocide 1154” 1.4-100
Washed immediately
Cupro-K 4-100Yi/ashed after 5 days
Cupro-K 4-100 Y/ashed immediately
■K-Samples from J. W. Heuberger
96.6 104.4
96.3 98.4
98.8 92.9
92.7 91.6
88.8 91.2
71.4 69.6
64.3 61.4
97.3
94.0
46.5
1
2
1
62.0
42.7
2
31.5
31.5
2
79.2 40.4
2
62.8 39.0
2
73.5 36.6
2
46.7 28.5
1
35.3 27.7
3
34.7 25.2
3
39.7 21.4
2
28.2 17.8
3
26.4 15.9
4
37.6 14.1 ■ 2
21.2 ■ 12.3
2
48
11weathering11 is shown with Cupro-K and Cuprocide 54 in table 6.
Allowing them to remain unwashed Tor five days increased reten­
tion particularly with Cuprocide 54.
In all the tests made
after the series in table 6 two weeks were allowed to elapse
between time of spraying and the washing process.
An examination of the data in table 6 reveals the fact
that Bordeaux mixture and tank-mix copper phosphate with lime
were retained very v/ell after the periods of washing.
When
lime was omitted from the copper phosphate retention was some­
what lower.
Yellow and red copper oxide were retained as well
as Bordeaux mixture.
much poorer retention.
The purple form of the oxide showed
All the remaining copper materials
showed poorer retention than Bordeaux mixture.
The effect of
bentonite added to a prepared copper phosphate seemed to be a
slight reduction In retention.
There was probably little
significant difference between the other materials.
CORRELATION EXPERIMENTS
CHANGES IN EXPERIMENTAL TECHNIQUE:
The field results on reten­
tion on both apple and cherry In 1938 left much to be desired
In the way of consistent data from which one could draw
unquestionable conclusions as to significant differences between
materials.
Apparently variation could not be satisfactorily
eliminated by the methods of sampling utilized.
Since Improve­
ment could not be made In the technique of obtaining uniformly
sprayed leaves, it became evident that a method would have to
49
be evolved to evaluate this variability so that allowance could
be made Tor it in determining significant differences.
Fortun­
ately, statistical methods of analysis are available by which
this can be accomplished.
As the single tree plot lay-outs in
the fruit spray experiments were replicated at least six times
and randomized in each replicate such an analysis would be
permissable if samples were collected from each tree and
analyzed separately for copper.
It was decided to do this in
the following years work.
The 1938 data also revealed the fact that cherry leaves
were much less variable than apple.
Also fruit data on apples
was found to be complicated by the growth factor.
Thus it
appeared that cherry foliage would be better to work with
than either the apple leaves or fruit.
.It was also decided
that samplings after the last spray would be more reliable
since the original amount would remain the same and several
samples could be obtained after varying periods of weathering
on a deposit.which would not be altered by subsequent spray
applications.
One factor which could cause additional vari­
ation would thus be eliminated.
Sampling was confined to spur
leaves which had ceased growth by the time of first sampling.
Results on Pyralin plates showed that differences in
retention between various copper materials could be demons­
trated by this type of laboratory test.
These differences
seemed to be of the same order as obtained by other workers
whose results are reviewed in the literature.
question which logically presented itself was:
results correlate with field results?
The next
How do these
50
In attempting to answer this question it soon became
evident that no comparison could be made unless the materials
were applied in exactly the same formulas in both laboratory
and field.
Laboratory work was then planned to use the same
concentrations of the same materials as were to be used in the
field in 1939 and following years.
CORRELATION STUDIES IN 1939:
The copper retention studies on
cherry;leaves were confined to samples taken after the last
spray which is applied immediately after harvest.
Since this
Is ordinarily during the latter part of July, a long period of
weathering remains until the leaves fall about the middle of
November.
This also coincides with the period when leaf-spot
development reaches a peak and some materials fail to give
adequate control.
Thus it would seem that control might be
related to retention during this period of almost four months
when no additional sprays are applied.
Schedule of materials and concentrations for each treat­
ment as used in 1939 is given in table 7.
Three sprays were
applied before harvest in addition to the one following
harvest.
The amounts of copper in milligrams per square meter
i
found on each sampling date Is given in table 8.
In table 10
the copper found on the three sampling dates which followed a
weathering period are expressed as percentage of the amount
present immediately after the last spray.
Several points of interest are to be noted In table 8
giving the amount of copper found on the various treatments at
the first sampling.
In treatment 4, copper phosphate-bentonite-
51
Table 7
Composition of spray mixtures and schedule
or applications on Cherries (Montmorency)
Blue Ribb on 0rchards--1939
Plot H o .
Amount per 100 gallons
1
Basicop (Slierwin Williams)
H y d r a t e d lime
Zinc (metallc)
2
Bordeaux 1-2-100
3
Cupro K (Rohm & Haas)
Hydrated lime
3 lbs.
3 lbs.
4
Copper Pb.osph.ate
Hy dr a t e d lime
Bentonite
Copper hydro 40 (Chipman)
Hy d r a t e d lime •
4
8
4
3
3
7
Bor do w
4 lbs •
8 (Double dosage)
ZO
5
Lime
Spralastic
9 (Double dosage)
10
C u Phos.
Lime
Spralastic
1
(Emulsified)
Tank-mix phosphate
Copper sulphate
Dis od iu m phosphate
Hyd ra te d lime
l|rlbs.
3^ lbs.
lirpts.
2 lbs.
5 lbs.
6 lbs.
Copper phosphate (Monsanto)
Half cf plot #4 (2-4-2—100)
12
Basicop (Sherwin Williams)
as in plot fjpl--om.it zinc
14
lbs^
lbs.
Ibs^
lbs.
lbs.
2 lbs.
4 lbs.
(Emulsified) 1 q t .
11
13
3 lbs.
8 lbs*
1 lb.
"ZO" (Permutit)
H y d r a t e d lime
Orthex
3 lbs.
3 lbs.
1 pt.
'
Y e l l o w Cuprous oxide
(R. & H 54Y)
Hy dr a t e d lime
1
,
1 lb.
3 lbs.
17
Harshaw Chem. Co*
Cuoric oxide
Lime
'
1 lb.
3 lbs
Applications Petal Fall--May 12
Shuck Fall— May 24
Pink Fruit— June 21
Post Harvest--July 25
Hote— Lead arsenate at rate of 2^--100 in all three sprays
before harvest.
I
53
Table 8
Retention on cherry leaves.
Mg. copper per
square meter remaining at date of sampling.
Average of six replicates— 1939
Treatment
No.
Date Sameling
7 / 2 5 ^ 3/7 ®
Material
48.0
47.6
38.3
29.1
21.7
17.2
12.6
5.8
3. Cupro-K 3-3-100
44.3
41.6
37.7
23.3
4. Copper Phos-4 Bentonite-4, Iime- 8
80.9
78.4
54.4
37.1
5. Copper Hydro 1140"
29.7
36.7
26 •6
13.4
7. Bordow 4-100
16.6
17.9
10.0
4.8
8. Z0 l|r-3-100 + Spralastic
16.7
13.0
10.2
4.2
9. Copper Phos + Spralastic
42.8
49.4
40.5
35.3
• •
o H
H
Tank-Mix Copper Phosphate
38.2
31.7
30.4
20.6
H
Copper Phos-2 Bentonite-2, Lime--4 40.3
31.6
27.5
20.1
. 45.9
46.1
29.8
20.8
13. Z0 3-3-100 + Orthex
20.1
22.3
9.8
5.8
14. Yellow Copper Oxide
24.5
25.2
11.3
7.8
17. Cupric oxide
Average/
(1)
No
(2)
13
(3)
28
(4)
68
36.6
36.2
34.0
35.2
31.6
26.5
18.3
17.6
i;
Basicop 4- Zn
8 / 2 2 ® 10/^4)
2. Bordeaux 1-2-100
12. Basicop 3-8-100
'
weathering
days after post harvest spray
days after post harvest spray
days after post harvest spray
54
lime mixture was applied at twice the concentration of plot
11 and the actual amount of copper found was twice as much.
Use of zinc with Basicop in plot 1 did not result in a higher
deposit of copper over treatment 12 where Basicop was used alone.
Spraying with double dosage and half the concentration of ZO in
plot eight did not give a deposit equal to treatment 13 where
it was used at twice the concentration with normal dosage.
The
use of Spralastic with copper phosphate (plot 9) at double
dosage also did not result in an increased copper deposit over
a normal application with bentonite (plot 11)•
The analysis of variance of the percentage copper remain­
ing given in table 10 at the different sampling dates is
compiled in table 11.
In no case is the error for replicates
significant, indicating that the method of sampling used in
this year materially reduced the error Involved.
High signifi­
cance Is indicated at all three dates among the different
treatments.
Results of retention tests in the laboratory are given in
actual amounts of copper residue per square meter of surface
In table 9 and as per cent of the original in table 12.
Doubl­
ing the dosage practically doubled the actual copper deposit
in the case of ZO and copper phosphate on the plates.
The
deposit with Basicop was the same with and without zinc.
Some comparisons between laboratory and field results on
retention can be made from tables 10 and 12 which give the per­
centage copper remaining after weathering in the field of the
leaves and washing of the plates in the laboratory.
It will
be noted that Bordeaux mixture, tank-mix copper phosphate, and
55
Table 9 ’
Retention on Pyralin plates In mg. copper per square meter.
Each amount is average of two runs of five plates per run-1939
Treatment
No.
Material
Total Water Sprayed on Plates
None 250 cc 750 cc 1750 <
1. Basicop + Zn
49.4
47.4
43.3
36.6
2. Bordeaux 1-2-100
15.5
15.5
15.8
15.3
3. Cupro-K- 3-3-100
30.2
27.0
24.0
21.9
4. Copper Phos-4 Bentonite-4, Lime-8 60.9
58.2
52.1
35.0
5. Copper Hydro 1140'*
33.4
26.5
21.0
16.5
7. Bordow 4-100
28.3
18.9
11.3
7.2
8. ZO r|--3-100 f Spralastic
41.6
35.6
25.9
18.7
9. Gu Phos. + Spralastic
87.4
69.5
44.9
30.0
29.6
28.8
25.8
25.9
11. Copper Phos-2 Bentonite-2, Lime-4 42.8
42.9
32.7
26.8
12. Basicop 3-8-100
47.9
45.0
40.6
32.4
13. ZO 3-3-100 f orthex
48.8
42.5
26.1
14.0
14. Yellow Copper oxide
16.0
14.6
13.9
13.6
17. Cupric oxide
24.3
20.4
13.4
10.5
Ave. 13 & 8
45.2
39.1
26.0
16.4
10. Tank-Mix Copper Phosphate
56
Table 10
Retention on cherry leaves.
Per cent copper remaining at
date of sampling.
Average of six replicates— 1939
Treatment
No.
Material
Date Sampling
8 / 7 t1 ) 8/22(2 )10.2(3 )
102.56
80.29
61.45
2. Bordeaux 1-2-100
SO. 01
60.94
27.71
3« Cupro-K 3-5-100
94.12
35.52
53.05
4. Copper Phos-4 Bentonite-4, Lime-8
96.96
67.92
46.10
5. Copper Hydro "4011
128.96
92.09
45.12
7. Bordow 4-100
110.93
62.39
29.65
8. Z0 1-g— 3-100 + Spralastic
79.70
62.32
25.30
9. Copper Phos + Spralastic
116.55
95.96
82.43
10. Copper Phos., Tank-Mix
83.31
81.36
53.48
11. Copper Phos-2 Bentonite-2, Lime-4
79.63
69.24
50.49
101.37
66.21
45.80
13. ZO 3-3-100 + Orthex
99 .<58
49.40
27.79
14. Yellow Copper .oxide
107.59
47.71
32.30
17. Cupric oxide
95. 54
89.98
50.91
L. S. Diff.
(20:1)
23.39
18.65
11.28
(100:1)
31.48
24. 57
14.86
1. Basicop + Zn
12. Basicop 3-8-100
(1) 13 days after post harvest spray
(2) 28 days after post harvest spray
(3)
68 days after post harvest spray
57
Table 11
Analysis of variance of per cent
copper remaining on leaves
Source of
Degrees of
Variation
freedom
Sum of
squares
Mean
P
square
August 7, 1939
Total
83
Treatments
13
Replicates
5
1,779.4
355.9
65
29,321.7
451.1
Error
48,086.9
16,985.8
1,306.6
2.90**
August 22, 1939
Total
83
Treatments
13
Replicates
5
999.1
199.8
65
17,830.8
274.3
Error
37,522.0
j
18,692.1
1,437.9
5.24**
October 2, 1939
Total
83
26,098.0
Treatments
13
19,464.8
Replicates
5
112.1
65
6,521.1
Error
-”-*C-reat er than odds of 100:1
j
1,497.314.9**
22.4
100.3
Table 12
Retention on Pyralin plates. Average per cent
Ipp
remaining; two runs (five plates per run)-1939
>r~»
^
£
Treatment
Total Water Sprayed on
W
No.
t•
[
Material
250 cc
750 cc 1750 cc
1. Basicop + Zn
96.1
.87.8
74.1
2. Bordeaux 1-2-100
99.7
101.6
98.8
3. Cupro-K 3-3-100
84.3
72.6
63.7
4. Copper Phos-4 Bentonite-4, Lime-8
95.6
86.0
58.1
5. Copper Hydro 1140"
79.0
62.9
49.2
7. Bordow 4-100
67.05
40.0
25.3
8. ZO lijr-3-100 + Spralastic
79.4
68.5
44.8
9. Copper Phos. + Spralastic
79.2
50.6
34.2
97.2
87.3
87.8
100.4
76.4
62.8
12. Basicop 3-8-100
84.5
71.1
54.3
13. ZO 3-3-100 + Orthex
87.1
54.4
28.6
14. Yellow Copper oxide
91.1
86.9
85.4
84.2
55.2
43.4
10. Tank-Mix Copper Phos.
11. Copper Phos-2 Bentonite-2, Lime-4
17
Cupric oxide
Cuprocide 54Y showed no loss of copper in the laboratory rain
but that retention in the field was not nearly so good.
Bordow
and ZO, on the other hand, showed about the same percentage
loss on the Pyralin plates as on the leaves in the field.
The
retention of the copper phosphate-bentonite-lime mixture was
in almost the same proportion in the laboratory as in the field
at the lower concentration but the initial loss of the higher
concentration (4-4-8) was much greater for the first and second
weathering periods on the leaves.
Copper phosphate was retained
better on the leaves with Spralastic than with bentonite.
The
laboratory test showed the formula with Spralastic to be very
poor.
Correlation of retention in the laboratory and field
with other materials under test in 1939 does not appear to be
very good.
Another method which has been used to correlate laboratory
and field results is to determine how the ranking of the various
materials compares in the two types of data.
However, in order
to do this it is necessary to have a single figure representing
retention in the field or laboratory.
Since the data tabulated
here involves four separate analyses on both plates and leaves
it is either necessary to take one of the sets of analyses for
each surface and compare them or to obtain some kind of average
figure for such a comparison.
Consideration of retention and
control in the field, of course, indicates that the latter is
a function of the amount of copper remaining over the whole
period and that the amount remaining in the earlier part of the
season would be more important because an early start of a
disease would be prevented by an initial high retention.
On
60
the other hand, one would most certainly give a higher rating
to a material which was retained well throughout the season
than to one in which retention was high only in the first part
of the weathering period.
These important points made it seem
desirable to obtain one figure which would reflect retention,
particularly in the field, over the whole weathering period.
The only way to do this very readily was to obtain a figure
representing relative area beneath a curve based on percentage
copper remaining per unit of rain fall in the field or amount
of water sprayed on the plates in the laboratory.
To obtain
this the percentage copper remaining was multiplied by inches
of rain, in the case of field data, and by liters of water, in
the plate data, for each of the three periods in both sets of
figures.
These were added together to give what might be
called an "index of retention".
Time of weathering was not
used since no time element was considered in the laboratory
after the first washing.
These sums are contained in table 13.
Inches of rain multiplied by the actual amount of copper is
also included for comparison.
Percentage leaves remaining on
the lower branches is also given.
These were calculated from
the number of leaves remaining between two tags.originally
marking fifty spur leaves at five different stations.
Counts
were made at the time of last sampling.
Here, again, it is difficult to compare the general rank­
ing of the materials in the field with that In the laboratory.
To facilitate such a determination of any possible correlations
of ranking these data are shown graphically In figures 5, 6,
and 7.
Treatment numbers are plotted on the horizontal axis
61
Table 13
Indices of retention and control--1939
Treatment
No.
1
Leaves
Material
Plates
Inclie s Incbes ^Sleaves-Js- liters
xMgs.*- Remaining x
x
411. 5 194.7 76.5
142.0
2. Bordeaux 1-2-100
240.5
50.3 50.7
174.5
3. Cupro-K 3-3-100
330.3 167.3 67.5
121.1
4. Copper Rios.-4 Bentonite-4, Lime-8
332.6 267.0 67.9
125.0
5. Copper Hydro ,f40"
381.3 111.3 62.3
100.5
7. Bordow 4-100
270.3
43.7 65.7
62.1
8. ZO 1-g— 3-100 + Spralastic
232.3
38.1 70.9
99.0
9. Copper Plios. -f Spralastic
522.6 222.4 71.5
79.3
Tank-Mix Copper Pbos.
370.4 140.8 76.5
155.8
Copper Pbos.-2 Bentonite-2, Lime-4
339.4 135.1 61.7
126.1
12. Basicop 3-3-100
331.9 150.1 77.9
1 1 1 . 0
13. Z0 3-3-100
238.4
50.1 61.1
77.6
14. Y e l l o w Cu Oxide
260.9
61.6 68.8
151.7
17. Cupric Oxide
378.8 135.1 60.3
92.0
•
O
H
1. Basicop + Zn
1 1 .
f
Ortbex
L. SIg. Diff.
(100:1)
16.9
(20:1)
12.7
-5s-See test p60 for explanation of bow tbese Indices were
determined.
i
62
I**
' # 1
x zi x
j!*!!
% LEAVES
I\
W
/
A
^
\
REMAINING
\.
X L .- PLATES
O<
0o
X
Oo
TREATM ENT
FIG.J RETENTION ON LEAVES AND PLATES - LEAVES
REMAINING - 1939
INCHES R AIN
S88
888
f
f
%
X
L. -
%
X
IN C H E S
R A IN
IN C H E S
R A IN
MG. X
/
TREATM EN T
FIG.6 RETENTION ON LEAVES AND PLATES - 1939
P LA TE S
200
REMAINING
LEAVES
8 0 - 1 4
MG. X RAIN -LEAVES
64
%
LEAVES
R E M A IN IN G
o
(0
o
i
n
MG.
9
5
3
17
10
II 4
12
7
14
2
13
e
TREATM ENT
FIG .7 RETENTION (AMOUNT OF COPPER) AND LEAVES REMAINING - 1 9 3 9
X
IN C H E S
R A IN
65
and the different estimates or indices of retention are plotted
on the vertical axis.
Percentage leaves remaining is also
plotted on this axis.
It is evident that the three curves are not correlated
very well in figure 5.
In other words, estimates of retention
obtained from tests on plates In the laboratory did not seem to
predict very accurately the retention on the leaves In the
field since there seems to be very little correlation.
Only a
slight correlation appears between laboratory field estimate's
of retention and the number of leaves remaining.
Since the
percentage of leaves remaining is a reflection both of control
of leaf-spot and lack of injury, one could not logically assume
that there would be a very direct relationship with retention.
An Index of retention based on milligrams of copper on the
leaves is plotted in figure
6
ing on the leaves and plates.
between any of them.
with that for percentage remain­
Little correlation is evident
In figure 7 the actual copper and per­
centage leaves remaining are given and some correlation is to
be noted.
Since the materials were not applied in formulas of
equivalent copper content, a better correlation would be
expected with actual than percentage copper remaining provided,
of course, that defoliation was a result of leaf-spot and not
injury.
Although no counts were made it can be definitely
stated the loss of leaves in 1939 was pratically all due to
leaf-spot.
In order to compare more accurately these Indices of
retention in laboratory and field, correlation coefficients
were calculated.
The correlation between the percentage copper
66
remaining on leaves and on the plates was —
correlation at all.
.121
indicating no
The correlation coefficient between per­
centage copper remaining on the leaves and the number of leaves
remaining was 4- .378 which is not significant.
The best
correlation coefficient was found between the index based on
actual amount of copper and per cent leaves remaining which
was + .417 which is still not significant.
EFFECT OF LEAD ARSENATE ON RETENTION ON PYRALIN PLATES:
Since
lead arsenate was applied in all three sprays before harvest
in 1939 it seemed desirable that some attempt be made to
evaluate the effect of this material on retention of copper on
the Pyralin plates.
Bordow and Copper Hydro 40 were tested
for retention with and without the lead.
table 14.
Results are given in
Retention of Bordow was increased somewhat by the
addition of lead arsenate although the percentage remaining
after the last washing was nearly the same as without the
lead.
Copper Hydro 40 -was not retained as well where lead
arsenate was added.
RESULTS OF WEATHERING PYRALIN PLATES IN THE FIELD IN 1959:
In
order to obtain a more direct comparison between the retention
of copper materials on Pyralin plates and on leaves the sprayed
plates were taken directly to the field.
One set of 15 plates
for each of eleven out of the fourteen treatments listed in
table 7 was placed In the cherry orchard on wooden supports so
that they were-held at approximately a 45° angle.
Five additi­
onal plates for each treatment were kept in the laboratory for
analysis as to the original amount on the plates.
The plates
67
Table 14
Effect of lead arsenate on retention of Copper on Pyralin plates
g?otal Water Sprayed on
Material
250 cc
750 cc
<
%
.
1750 cc
%
x L.
*
Copper Hydro 40 3-3-100
79.0
62.9
49.2
100.5
Copper Hydr o 40 + Lead
83.9
56.7
36.7
86.1
Bordow 4-100
67.0
40.0
25.3
62.1
Bordow ♦ L ead
92.7
51.7
27.3
76.3
6B
Table 15
Retention on Pyralin plates weathered in Pield--1939
%
No-
Treatment
Material
Date of Sampling
8/7
8/22
10/2
7.6
None
None
None
3- Cupro-K
12.6
1.8
tt
4. Copper Phos. 4-8-4
30.2
None
it
5- Copper Hydro 40
18.9
»
7• Bordow
14.0
it
21.1
15.4
tt
tt
6.1
1.1
it
ti
12. Basicop
35.5
20.0
tt
it
13. ZO
21.0
None
tt
tt
8.3
1.2
tt
it
11.2
0.4
tt
tt
2. Bordeaux 1-2-100
10- Tahk-Mix Copper Phos.
11- Copper Phos. 2-4-2
14. Yellow Copper oxide
17. Cupric oxide
7/25
ti
it
it
I
69
were put in the field on the same date that the original leaf
samples were taken.
One set of five was removed from the
supports on each of the la^st three sampling dates.
Thus the
plates were actually exposed to the same weathering conditions
as the cherry leaves.
The results are tabulated in table 15.
It is evident from
this table that the type of weathering to which the leaves
were subjected in the field completely removed all the materials
from the plates much sooner than it did from the leaves.
None
of the treatments had any copper remaining on the plates at
the time of the third sampling on Aug. 22 which covered a
period of rainfall totaling 1.98 inches.
After the first
weathering period on Aug. 7 during which there was a rainfall
of only
0.66
inches the amount of copper retained was not
sufficient to give any accurate measure of retention.
J
A measurement of the actual amount of water reaching the
plates during washing was made during some later laboratory
tests in 1940 and found to be only 0.28 inches with the total
of 1750 cc water sprayed on the plates.
This amount removed
more than 80 per cent of the copper in some cases as is shown
in table
6
.
Therefore the actual amount of water required to
wash off a large proportion of the copper from the plates is
much lower than the rainfall necessary to remove an equivalent
amount from leaves in the field.
CORRELATION STUDIES IN 1940:
Cherry leaf samples for analysis
were taken in the same way as in 1939.
Studies on retention
j
were confined to Bordeaux mixture, two formulas of tahk-mlx
copper phosphate, and a commercial copper fungicide called
70
Tennessee 26 which, was used with several stickers as well as
alone*
A complete schedule or treatments is given in table 16*
The regular schedule of three sprays before harvest and one
after was followed.
Amounts
in table 17.
of copper remaining at each sampling date is given
It is to be noted that the amount of copper
found on the Bordeaux and two tank-mix copper phosphates plots
in the first sampling was slightly higher than the Tennessee
26 alone even though the formula for the latter contained onethird more actual copper.
This is probably a reflection of
the better retention of Bordeaux mixture from earlier appli­
cations.
Tennessee 26 had a higher deposit where stickers
were added than where it was used with lime only.
The percentage copper remaining after the three periods
of weathering is given in table 19 and the analysis of variance
in table 20.
It Is readily seen that highly significant
differences as Indicated by the P value was again evident
among the treatments applied.
The P value for replicates is
significant In the last two samplings only.
Some comparisons of retention on Pyralin plates and leaves
can be made directly from tables 19 and 21 which give the per­
centage remaining after weathering of the leaves In the field
and washing of the plates in the laboratory.
It is again
evident that Bordeaux mixture and the tank-mix copper phos­
phates were
retained very well on the plates
on the leaves was not nearly so good.
but that retention
Percentage copper
retained on
plates with all the Tennessee 26 formulas was much
higher than
that on the leaves.
71
Table 16
Composition of spray mixtures and schedule
of applications on cherries (Montmorency)
Blue Ribbon 0rcliards--1940
Plot
Material
Amount per 100 gallons
2
lbs
4
11
Tank-mix copper phosphate
CUSO 4
Trisodium Phos.
Hydrated Lime
2
2
11
3
11
Tennessee "26"
Hydrated lime
3
3
Tennessee 1126"
Hydrated lime
Orthex
3
3
11
1
pt ■
13
Tennessee "26"
Hydrated lime
Hufilm
3 lbs
3 11
1 pt.
14
Tennessee "26"
Hydrated lime
Spralastic
3 lbs
3 lbs
1 pt •
15
Tennessee "26"
Hydrated line
Summermul si on
Spred-rite
3 lbs
3 it
1 pt.
1 pt.
22
Tank-mix Copper Phosphate
Copper sulfate
Disodium Phosphate
Hydrated lime
2
2
lbs
3
ti
Bordeaux mixture--CUSO 4
Hydrated lime
1
7
1
11
12
Applications:
Note:
11
it
11
tt
ti
Petal Fall--May 21
Shuck Fall— June 3
Pink Fruit— June 21
Post Harvest— Aug. 8
Lead arsenate in all three applications before harvest
at rate of 2 lbs. per 1 0 0 gallons.
72
Table 17
Retention on cherry leaves.
Mg. cooper per
square meter remaining at date of sampling.
Average of six replicates— 1940
Treatment
Wo.
Material
Date of Sampling
8/8
CO 8/28(2) 9/20$)
10/9&)
1. Bordeaux 2--4-100
38.7
39.2
28.4 15.1
7. Tank- Mix Copper Phosphate
40.6
36.6
27.2 15.7
11
. Tenn. “26" 3-3-100
36.5
23.9
16.5
12
. Term. "26" + Orthex
43.6
32.6
24.7 10.3
40.3
22.7
18.3
4.7
46.7
29.5
19.6
7.2
15. Tenn. "26" + Summermulsion & Sptred-RLte 45.4
A
2 2 . Tank- Mix Copper Phosphate
44.7
36.3
27.6
10.6
35.4
29.7 13.5
Ave •
32.0
24.0 10.4
13. Tenn.
1126"
f Wufilm
14. Tenn. "26" f Spralastic
42.1
(1 )
(2 )
(3)
(4)
Wo weathering
2 0 days after post harvest spray
43 days after post harvest spray
62 days after post harvest spray
5.9
73
Table 18
R e t e n ti on on Pyralin plates In mg. per square meter--1940
Treatment
Wo.
Total Water Sprayed on Plates
Material
. Bord 2-4-100
None 250 cc 750 cc 1750 cc
Wo. Runs
Averag
21.8
21.4
22.0
21.5
3
20.3
21.2
21.1
21.0
2
Tenn. "26" 3-3-100
35.2
30.1
22.5
18.2
2
. Tfenn "26" + Orthex
35.8
32.6
26.5
22.4
2
13. Tenn."20f+ Nu fi l m
30.1
28.3
24.4
19.6
2
14. T e n n . "20"+ Spralastlc
35.5
32.0
24.5
18.8
2
15. Tenn. ”20' + SummerM u l sl on & Spred-Rite
35.5
34.9
29.6
25.1
2
22.0
21.9
22.1
22.2
2
Ave . 1, 7, 22
21. 5
21.5
21.7
21.6
Ave . 11,
34.4
31.6
25.5
20.8
1
7. Tank-.Mix Copper
Ph.osph.ate
•
H
H
1 2
22
. Tank-Mix Copper
Phosphate
12, 13, 14, & 15
i
74
Table 19
Retention on cherry leaves.
at date of sampling.
Average of six replicates-— 1940
Treatment
No.
Per cent copper remaining
Material
1. Bord 2-4-100
Sampling Date
8/2$-) 9 / 2 0 ® 10/9(3)
100.52 72.87 38.22
7. Tank- Mix Copper Phosphate
91.25 67.51 38.13
45.16 16.05
11
. Tenn. "26" 3-3-100
66.12
12
. Tenn. " 26" + Orthex
74.76 57.19 23.30
13. Tenn. "26" + Nufilm
56.40 45.56 11.67
14. Tenn. "26" + Spralastic
73.85 49.13 18.07
15 • Tenn. "26" + Snmmer-Mulsion Spred-Rite 79.80 60.77 23.29
22
. Tank-■Mix Copper Phosphate
Least Sig. Diff.
79.58 66.54 29.80
(100:1)
16.14
13.26
9.41
(20:1)
12.05
9.90
7.03
(1) 20 days after post harvest spray
(2)
43 days after post harvest spray
(3)
62 days after post harvest spray
75
Table 20
Analysis of variance of per cent
copper remaining on leaves
Source of
Degrees of
Variation
freedom
Sum of
squares
Mean
P
square
August 28, 1940
Total
47
12,221.6
Treatments
7
7,939.0
1,134.1
Replicates
5
1,115.1
223.0
35
3,167.5
90.5
Error
12.53**
2.46
September 20, 1940
Total
I
Treatments
47
7,627.9
7
4,744.8
Replicates
5
989.3
35
1,893.3
Error
677.8
197.8
12.5**
3.7**
54.1
October 9, 1940
Total
47
5,543.0
Treatments
7
4,089.2
584.2
21.96**
Replicates
5
522.7
104.6
3.93**
55
931.1
26.6
Error
,---"-GREATER THAN ODDS
f
OP 100:1
I
76
Table 21
Retention on Pyralin plates. Average per cent remaining-1940
Treatment
Ho.
Material
Water Sprayed on Plates
250 cc
750 cc 173Doc
99. 8
101.5
100.1
101.6
101.2
100.9
11. Tenn. "26" 3-3-100
85.7
63.9
51.8
12.
Tenn. ” 26”
+ Orthex
90.9
73.8
62.4
13.
Tenn. ”26"
+ Nufilm
94.1
81.1
65.1
14.
Tenn. "26"
+ Spralastic
90.2
69.0
53.0
15.
Tenn. "261' + Summer-Mulsion Spred-Rite 98.2
83.3
70.6
99.6
100.3
101.6
1. Bord. 2-4-100
7. Tank-Mix Copper Ph.osph.ate
22. Tank-Mix Copper Phosphate
77
To compare the ranking of the materials by the two methods
the so-called indices of retention for laboratory and field
were prepared as described in the discussion of the 1939 data*
These are tabulated in table 22.
Number of leaves remaining
is given but since statiscal analysis showed no difference in
these averages no attempt made to graph them.
fficients-”- are also given in this table.
sented graphically in figures
In figure
8
8
and
9
Tenacity coe­
These data are pre­
.
it is readily evident that laboratory tests
on plates failed to reveal any differences in retention between
Bordeaux mixture and the two tank-mix copper phosphates (plots
1, 7, 22)•
However, field studies showed Bordeaux was retained
the best, with the trisodium phosphate giving a better retention
than the disodium form in the tank-mix copper phosphate.
Retention of Tennessee 26 alone and with each of the stickers
except Nufilm (plot 13) was of the same order of ranking in
laboratory and field.
Nufilm ranked higher than Tennessee 26
alone or with Orth-ex or Spralastic on the plates but retention
with Nufilm was lowest of any in the. field.
The Spred-rite-
Summermulsion (plot 15) was the best sticker, Orthex (plot 12)
was second, and Spralastic (plot 14) was only slightly better
than the material alone.
Retention based on actual copper
remaining, in figure 9, shows the same ranking as that based
on percentage copper retained which is a reflection of the fact
that the original amounts at the first sampling were not
^-Determined through the kindness of S. E. A. McCallan.
It is
a ratio toxicity to spores of Sclerotinia fructicola spores
before and after a rain test.
Table 22
Indices of* retention, tenacity
coefficient, LD50, and control— 1940
Treatment
No.
Material
Leaves
ELates
Inches Undies ^Leaves Iitor*s
x
x Mg.*«-Remaining x
%
1. Bord.
2-4-100
7. Tank- M i x Copper Phos.
T.C.^ LD50-1
- *
759.4 296.5 71.3
175.8
.555 .19
709.7 287.0 68.5
176.9
.465 .23
448.2 163.0 70.2
105.8
.190 .35
11
. Tenn.
12
. Tenn. "26" + Orthex
548.6 239.6 72.8
122.1
.235 .36
"26" + Nufilm
392.3 157.4 72.8
129.2
.170 .33
14. Tenn. "26" + Spralastic
497.6 198.9 71.0
110.1
.085 .30
15. Tenn. 1126" + Summerm u l s i o n Spred-Rite
577.2 262.6 72.5
136.8
.070 .24
623.8 279.0 72.3
176.7
.410
L. S. Diff . none
(2 0 :1 )
.209
15. Tenn.
22
"26" 3-3-100
McCall an
. T ank- M i x Copper Phos.
.21
■*See p 60 for explanation of how these indices were determined.
+LD50 is the concentration of the material permitting
germination of the spores of Sclerotinia fructicola.
Tenacity coefficient is the ratio of the LD50 concentra­
tion before and after a rain test.
3
0
%
/
% X L . - PLATES
-•
T E N A C IT Y
0.1
110
400
0.2
130.
500
0.3
150
600
0.4
170
700
0.5 - TENACITY COEFFICIENT
190 - HU
- PLATES
800 - % X INCHES RAIN
79
X IN C H E S
0.0
90
300
%
22
TR EA TM EN T
FIG.? RETENTION ON
LEAVES ANO PLATES - TENACITY
COEFFICIENT -
C O E FFIC IE N T
1940
RAIN
80
2«I
- jS
X
I
j!
I
S*
i
?S8
PLATES
% X I N C H E S R A IN
M G . X I N C H E S R A IN
22
TREATM ENT
FIG. f
RETENTION
I
ON LEAVES
AND
P LA TES - 1 9 4 0
greatly different.
Tenacity coefficient tests (as determined b y McCallan)
separated Bordeaux mixture and the tank-mix copper phosphates
as showing a higher retention which was correlated with the
results on Pyralin plates.
The order of retention of these
three materials was the same as the field results showed.
The direct copper analysis on Pyralin plates failed to reveal
this.
However, the tenacity coefficient ranked plot 15 lowest
while it was highest of any of the Tennessee 26 plots on leaves.
Retention of Tennessee 26 alone (plot 11) and with Nufilm
(plot 13) was higher than with Spralastic (plot 14) as determi­
ned by tenacity coefficient.
Retention on leaves, however,
ranked Spralastic higher than the other two.
A correlation coefficient caculated between the index of
percentage remaining on leaves and on plates was found to be
+ .841.
6
.
This confirms the h igh correlation evident in figure
The coefficient between percentage retained on leaves and
the tenacity.coefficient was + .808 which is almost as good as
the actual analysis method.
Correlation coefficient between .
retention -determined by actual analysis and the tenacity
coefficient (retention determined by toxicity tests) was f .85,
indicating that the two methods gave fairly comparable results.
CORRELATION STUDIES IN 1941:
in 1941 Is given in table 23.
The schedule of spray applications
All formulas except Bordeaux
were caculated to give an approximate concentration of threefourths of a pound of actual copper to one hundred gallons of
water.
Bordeaux at 2-8-100 contained only one-half pound of
82
Table 23
Composition or spray mixtures and schedule
of applications on cherries (Montmorency)
Blue Ribbon Orchards— 1941
Plot No.
2
.
Materials
Lime Sulphur (Before harvest)
Bordeaux 2-8-100 (Post harvest)
Amount per
IQO gallons
* A
2 gals.
3-
Bordeaux 2-8-100
4.
Cupro-K
Lime
3
3
lbs.
lbs.
5.
As plot 4 plus S. E. C. oil
1
pt.
Tennessee 1126"
Lime
3
3
lbs •
lbs .
Tennessee "26"
Lime (Dolomitic)
3
3
lbs .
lbs .
8
Tennessee "34"
Lime
2i lbs.
3 lbs.
9.
Copper Hydro "40"
Lime
3
3
.
Copper "A"
Lime
lit lbs •
3 lbs .
11
.
Coposil
Lime
3-g- l b s .
3 lbs .
12
.
Bordov/
Lime
6
3
lbs .
lbs.
15.
Tennessee "26"
Lime
Spralastic
3
3
1
lbs.
lbs •
qt.
16.
Tennessee "26"
Lime
Soya flour
3
3
x
lbs .
lbs.
lb.
Copper "A"
Lime.
8
6
.
7.
.
10
18.
20
.
(Apple)
Tennessee "26"
s.
(same as plot 6)
lbs.
lbs.
■ lbs.
lbs.
83
21.
Lime sulphur
(In four applications "before harvest)
Bordeaux 2-8-100 (Post Harvest)
2
^gals •
22.
Lime Sulphur (Before Harvest)
Tennessee ,126M (Post Harvest)
Lime
2
3
3
gals .
lhs
l"bs •
Applications:
Note:
Petal Pall--May 5
Shuck P a l l — M a y 19
Pink Fruit--June 17, 18
Pre-Harvest (Plot 21 only)
Post Harvest--Aug. 1
.
July 17
L e a d arsenate at rate of 2-100 In Struck Pall and
Pin k Fruit.
Plot 21 also received lead arsenate In
Petal Pall.
84
copper to the hundred.
The regular number or applications
were made except to plots 2, 21, and 22 which, received a spray
of copper only after harvest.
The data on these plots are
tabulated and discussed separately.
Sampling was done in the
same way as in 1939 and 1941.,
The amount of copper per square meter remaining is given
in table 24.
The copper found at the first sampling date
indicated that there was considerable variation in the amount
on the leaves in spite of the equivalent copper formulas.
Bordeaux mixture was, for example, nearly as high as the
average although the actual copper concentration applied was
lower.
This fact is most probably a reflection of the better
retention of the deposit from the three previous sprays in the
case of Bordeaux and some of the other treatments and must be
considered in relating control to copper retained as will be
discussed later.
In table 27, the analysis of variance of the percentage .
copper remaining after the three periods of weathering is
given.
These are caculated from the figures entering into the
averages in table 26, none of the errors for replicates are
significant and the treatment differences at all three periods
are highly significant.
Retention on Pyralin plates in milligrams of copper is
given in 25 and as percentage in table 28.
A comparison of
the percentage remaining on the plates with the percentage
copper retained on the leaves after different periods as given
in table 26 shows that Bordeaux mixture again failed to give
as high retention in the field as in the laboratory.Of the
85
Table 24
Retention on cherry leaves*
Mg* copper per square
meter remaining at
date of sampling*
Average of six replicates— 1941
Treatment
No.
Material
Date of Sampling
s/i c1 ) 8/25(2) 10/10 (3) ll/3(
38.4
25.8
15.5
11.4
4. Cupro-K
40.0
20.1
14.0
10.2
5* Cupro-K + S. E. C. oil
47.5
29.5
20.1
17.9
6. Tenn* ” 26”
42.2
17.3
15.2
10.2
7. Tenn. ”26” + Dolomitic Lime 45.3
19.5
13.4
9.7
8. Tenn ”34”
40.9
18.7
14.2
13.0
9. Copper Hydro ”40”
53.2
20.5
15.0
16.4
33.3
11.3
7.5
8.0
li. Coposil
35.0
12.4
9.9
8.1
12. Bordow
41.7
14.7
13.2
8.6
15. Tenn. ”26” + Spralastic
53.7
22.8
13.0
12.9
16* Tenn. ”26" + Soya Flour
46.7
15.7
15.1
10.2
, 33.5
11.5
9.8
8.2
48.3
17.1
12.4
10.7
42.8
18.4
13.8
11.1
H
CD
•
•
o
H
3. Bord. 2-8-100
Copper A. lir-3-100
Copper A. l2”8~10°
20. Tenn. "26"
•
Ave.
(1)
(2)
(3)
(4)
No
25
71
95
weathering
days after post harvest spray
days after post harvest spray
days after post harvest spray
86
Tatle 25
R e t e n t i o n on Pyralin plates i n mg. per square m e t e r — 1941
Treatment
No.
Material
3- Bord.
2-8-100
IbfcalWater Sprayed cn Plates No. Runs
None
250cc 750 cc 1750 cc
Averaj
18.0
17.5
15.9
16.0
2
4. Cupro-K
20.3
18.6
12.8
10.0
3
5. Cupro-K + S. E. C. oil
28.5
25.7
23.3
24.1
2
6. Tenn.
"26"
30.6
24.7
17.1
13.4
3
7. Tenn.
"26" -f Dolomlticlime 33.7
22.1
17.3
13.5
2
8. Tenn.
"34"
29.2
22.8
20.9
16.1
2
33.9
26.2
17.8
12.0
2
25.1
17.6
11.6
7.9
2
ii. Coposil
28.4
21.2
15.5
9.1
2
12. E ord o w
31.9
2 o .9
18.4
15.6
2
9. Copper H y dro "40"
•
o
H
Copper A. llf-8-100
15. Tenn.
"26" + Spralastic
35.8
19.6
18.5
13.5
2
16. Tenn.
"26" + Soya Flour
27.8
16.8
11.5
10.2
2
23.3
15.7
10.4
6.7
2
18. Copper A. 1-g— 8-100
I
87
Table 26
Retention on cherry leaves#
at date of sampling.
Average of six replicates— 1941
Treatment
No.
Per cent copper remaining
1 1 / 3 (3)
3. Bord. 2-8-100
68.1
41.1
30.0
4. Cupro-K
50.3
35.5
25.6
5. Cupro-K + S. E. C. oil
62.8
42.7
37.0
6. Tenn. ”26”
41.3
36.3
24.4
7. Tenn. ” 26” -f Dolomitic Lime
43.1
30.0
25.6
8. Tenn. ”34"
45.4
34.2
31.5
9. Copper Hydro ”40”
38.4
28.2
30.8
34.5
22.6
24.0
ii. Coposil
35.7
28.4
23.5
H
to
35.3
32.1
20.6
15. Tenn. ”26” + Spralastic
43.2
34.0
24.3
16. Tenn. ”26” + Soya flour
33.5
32.7
21.9
Copper A. lir-8-100
34.7
29.5
25.0
Tenn. ” 26”
35.6
25.7
22.2
•
•
10/10(2)
o
H
8/25 C1 )
• •
CO o
H CO
Material
Date of Sampling
Copper A. lg— 3-100
Bordow
L. Sig. Diff.
(100:1)
8.42
7.81
6.41
(20:1)
6.34
5.88
4.82
(1) 25 days after post harvest spray
(2)
71 days after post harvest spray
(3)
95 days after post harvest spray
1
88
Table 27
Analysis of variance of* per cent
copper remaining on leaves
Source of
Degrees of
Variation
freedom
Sum of
Mean
squares
F
square
August 25, 1941
l
Total
83
10,946.5
Treatments
13
8,830.9
679.3
21.7**
r
Replicates
Error
5
82.7
16.5
65
2,032.9
31.3
October 10, 1941
Total
83
4,094.7
Treatments
13
2,276.2
1,750.9
Replicates
5
207.2
41.5
65
1,611•3
24.8
Error
70.63**
November 3, 1941
Total
83
2,850.5
Treatments
13
1,604.9
123.5
Replicates
.. 5 -
100.5
20.1
1,145.3
17.6
.
Error
.
.
65
**Greater tiian odds of 100:1
j
7.91**
1.14
89
■ Table 28
R e t e n t i o n on Pyralin plates.
A v e r a g e per cent r e m a in in g— 1941
Treatment
Total Water S p r a y e d on
M a t er ia l
1750 cc
250 cc
750 cc
3. B o r d e a u x 2-8-100
97.1
88.4
89.9
4. Cu p r o - K
92.6
63.9
50.1
5. C u p r o - K -f S. E. C. Oil
90.5
82.0
84.3
6. Tenn.
"26"
83.1
56.9
44.1
7. Tenn.
" 2 6 “-Dolomitic Lime
65.7
51.5
40.2
8. Tenn.
"34"
78.8
72.3
54.6
9. Copper H y d r o "40"
77.3
52.5
35.6
Copper A lg-3-100
70.2
46.0
31.5
11. Coposll
74.3
54.5
32.3
12. B o r d o w
75.6
57.5
48.7
54.2
51.9
37.8
60.3
- - 41.2
36.5
55.5
37.0
23.7
H
O
•
No.
15. Tenn.
"26" + Spralastic
16. Tenn.
"26" + S oy a Flour
18. Cop p e r "A" 1^-8-100
- —
90
Table 29
Indices of* retention, tenacity
coefficient, LD50, and control— 1941
Treatment
Leaves
Plates
leaves
Inches Inche s vdth no liters*
X
x Mgs.-* Leaf-Spob
x %
McCallan'
%
Material
T
J
LD504
&
322.3
122.0
98.0
158.4
.570
.15
4. Cupro-K
252.4
100.7
33.8
105.3
’•o45
.44
5. Cupro-K +
S. E. C. Oil
326.4
154.7
56.2
147.9
.240
.59
6. Tenn.
223.6
93.7
72.7
93.4
.150
*46
7. Tenn. "26"
D o l o m i t i c .Lime
224.9
96.9
76.7
82.4
.135
.32
8. Tenn. "34"
251.6
103.8
88.9
110 .5
.310
.36
9. Copper Hydro "40" 222.4
118.6
82.6
81.2
.305
.59
187.6
61.7
68.2
72.1
.185
.35
11. Coposil
196.2
68.2
54.7
78.2
.140
.37
12. Bordow
191.8
79.6
82.2
95.9
.255
.22
15. Tenn. "26" +
Spralastic
226.7
119.9
86.7
77.4
.185
.44
16. Tenn. "26" +
Soya PIour
190.3
88.8
78.6
72.2
.330
.47
198.4
65 .6
50.7
56.1
.085
.30
189.6
91.2
73.5
93.4
.150
CD
o
•
H
5. Bord. 2-8-100
H
•
No.
1126"
Ccpper A lg— 3-100
Copper Al^— 8-100
20. Tenn. "26"
J_t. S I g . DIff . (100:1) 25.9
(20:1)
19.4
.231
-*See p 60 for explanation of how these Indices were determined,
+LD50 is the concentration of the material permitting
germination of the spores of Sclerotinia fructicola.
Tenacity coefficient Is the ratio of the LD50 concentra­
tion before and after a rain test.
b
0
%
f
f
% X L. - PLA TE S
TENACITY COEFFICIENT
%
%
X
TREATMENT
RAIN
D IS E A S E -F R E E LEAVES
MO. X
FIG.tO RETENTION ON LEAVES AND PLATES
TENACITY COEFFICIENT ; DISEASE-FREE LEAVES - 1 9 4 1
IN C H E S
INCHES
RAIN
92
proprietary materials Copper "A" in plots 10 and 18 had about
the same percentage retained on both leaves and plates*
Again no comparison is very readily made until a single
figure is obtained as an estimate of retention both in the
laboratory and field.
These indices are given in table 29.
graph prepared from this table is given in figure 10.
A
Control
expressed as the percentage of leaves on lower branches free
of leaf— spot is given since data were taken in such a way as
to se£>arate disease control and injury.
Tenacity coefficients
as determined by Dr. McCallan are also tabulated.
Plot 20 is
a duplicate of plot 6 in the field and the same data are used
for bo t h plots in the graph of retention on plates.
A survey of the curves readily shows a similiarity among
them indicating a good correlation between the different
methods of ranking the materials.
Retention dn Pyralin plates
I
and tenacity coefficient seems to be well correlated with
retention on leaves.
Certain exceptions occur but some of
them are to be found where the differences between treatments
were small In all three estimates of retention.
Leaf-spot
control Is fairly well correlated with these retention Indices.
Control of leaf-spot is also correlated with the curve based
on actual copper.
Bordeaux mixture
retention and control on the leaves.
h igh in the laboratory tests.
likewise high for this plot.
(plot 3) was high in both
This material was also
The tenacity coefficient was
Tennessee 34 (Plot 8) Is high. In
retention both on leaves and plates and Is second highest In
control.
It was also better than Tennesse.e 26 In retention o n
leaves and plates and in control. 1 Treatments 10 and 18 are
Interesting In that they are both Copper A with different
amounts of lime*
Retention on the leaves was about the same*
Plot 10 is the lowest of any treatment in retention a nd number
18 was but slightly higher.
In the laboratory tests.
Retention was also low for b o t h
Control on plot 18 where eight- pounds
of lime was u s e d was second from the lowest and on 10 with
the regular three pounds of lime, it ranked only f ifth above
the treatment giving least control which indicates a correlation
with r e t e nt io n on these plots.
Tennessee 26 with Spralastic
(plot 15) was higher i n retention on leaves than plot 16 where
Soya flour was used.
This plot was also slightly higher than
Tennessee 26 (6 and 20)
Increase
1940.
in retention which is in line with the
in retention resulting when Spralastic was u s e d in
Control was also correspondingly higher.
Bot h lab­
oratory tests predicted Copper Hydro 4Q (plot 9) to be lower
in r et ention than Tennessee 34 (plot 8).
This was confirmed
in percentage copper remaining on the leaves as well as in
control.
Labora to ry tests all showed little difference in
retention between Tennessee 26 with, dolomitic lime (plot 7)
and plot 6 where the regular high calcium lime was used.
Little difference also appears in the. retention and control
in the field.
Coposil was not greatly different in retention
from copper A in b ot h laboratory tests and also on the leaves.
Control— was .about the same as the average of the two plots of
copper A.
Co rr el at io n coefficients tended to confirm these evident'
correlations.
Highest value was found for the correlation
bet we en percentage copper retained on leaves and on the Pyralin
94
plates wh.±ch. was + .902.
Tenacity coefficient when correlated,
with percentage remaining on leaves gave a value of + *603.
This estimate of retention also gave a correlation coefficient
of + *679 with, the index obtained with the pyralin plates*
Both of these values are highly significant*
Actual amount
remaining showed a coefficient of correlation with control of
only + *232 while the value for percentage retained correlated
with control was only -f .089. Neither of these are significant.
Since the treatments had a different deposit at the beginning
i
of the sampling period it would be naturally expected that conI
trol would be better correlated with actual copper rather than
per cent copper.
A large discrepranacy was found in Cupro-K with and with­
out oil (4 and 5) where the copper deposit was relatively high
yet control was significantly lower than any other treatment
in the case of plot 4.
Treatment 5 also averaged lower than
all other plots except two.
here.
No explanations seems available
LD 50 values as determined b y Dr. McCallan did not
indicate any lower toxicity for Cupro-K but,
showed a higher value than the average.
on the contrary,
Laboratory tests,
both on Pyralin plates and in tenacity coefficient shoived
Bordow (plot 12) to be high in retention.
failed to confirm this,
A
s p e c i a l
Retention on leaves
although control was among the highest.
point worth further consideration is the line
plotted in figure 10 from the .retention on leaves based on
nercentage values.
Plot 6 which was Tennessee 26, was the same
treatment exactly as plot 20.
Yet the difference between these
two values covers the range of differences of all the treatment
numbers between them on the horizontal axis except 8, 10» and.
15.
This certainly would imply that there was no significance
in the differences in retention of these other treatments
since they are less than that between the same treatment.
Yet
some of the control differences were significant when compared
with the least significant difference value.
However,
the
curve based on actual copper shows that treatment 20 and 6
were nearly the same and that differences between any of the
other treatment numbers were greater than that between these
two except 6 and 7.
This would certainly suggest that percent­
age evaluation of retention on leaves was misleading.
This is
another point related to the fact already noted which indicates
that actual copper deposits were not uniform on the leaves at
the start of the weathering period and that control was related
to this original amount as well as to that remaining after
weathering.
RETENTION OF COPPER IN TREATMENTS APPLIED ONLY AFTER HARVEST:
The data for these plots are given in table 30.
The original
amount of copper found was in approximately the ratio of actual
copper in the formula since Tennessee 26 had one-third more
then the Bordeaux plots, copper remaining on the second sampling
date after weathering was, however,
approximately equal in the
three treatments and this was maintained through the remaining
weathering periods.
The same trend is found in the data
expressed as percentage and the index of retention based on
these figures showed that Tennessee 26 was much lower.
~ It is Interesting to compare the actual amount of copper
9#
Table 30
Retention on cherry leaves on treatments with,
only one application (after harvest}— 1941
Treatment
M g s . Cu Remaining on
8/1
8/25
10/10
2. Bord 2-8-100
24.6
13.6
9.8
7.5
69.9
21. Bord. 2-8-100
27.7
12.4
8.1
7.0
63.5
to
to
•
No. Material
Inches
x Mgs •
43.7
11.8
8.0
7.8
63.5
Term. "26"
11/3
^ Cu Remaining on
laches
x
%
11/3
8/25
10/10
2. Bord 2-8-100
55.6
39.5
30.4
284.7
21. Bord. 2-8— 100
45.6
30.3
25.7
233.4
22. Tenn.
31.0
19.4
19.4
162.0
"
2
6
"
97
on the first sampling date on the Tennessee plot with that
treatment
(6 and 20) in tahle 24 where three additional
applications preceded the one after harvest.
These amounts
were found not to "be much different where the single application
of the copper material was made.
Bordeaux was much lower
after a single application* however, which confirms the assump­
tion previously made as to the fact that Bordeaux was retained
better from these early applications than the substitute coppens.
RELATION OF RAINFALL AND TIME TO 'WEATHERING OF COPPER SPRAY
RESIDUES ON CHERRY LE AV E S :
Total rainfall data were recorded
for all the weathering periods studies in 1939,
1940,
and 1941
from a rain gauge located directly In the block of trees In
which the sampling was done.
summarized in table 32.
cally in figure 11.
These data are given table 31 and
The data in table 32 are shown graphi­
The amount of copper remaining plotted
against rainfall is shown as the continuous line and the amount
of copper plotted against time shown as the broken line in the
same graph.
Distribution of rain in relation to time is shown
in the histograms for each of the three years.
A n Inspection, of the graphs for each of the three years
Indicates a rather close correlation between the two curves.
This would certainly indicate a relationship between rainfall
and the loss of copper.
It Is reasonable to assume that copper
loss due to weathering factors other than rain,
mechanical abrasion, would be constant,
line relationship to time.
such as
thereby giving a straight
Instead, however,
the time curve
more or less parallels the curve for rainfall indicating the
98
Table 31
Rainfall data and
sampling dates — 1939,
1959
Date
Original Sample
2nd Sampling
Rain for
tills period
7/25
7/26
7/27
7/29
8/3
8/7
3rd Sampling
Rain for
this period
4th. Sampling
Rain for
this period
Inches
0.0
0.18
0.14
0.15
0.03
0.18
1941
Date
Inches
Date
Inches
8/8
0.0
8/14
8/19
8/20
8/25
8/27
8/28
8/1
0.09
0.58
0.02
1.12
1.75
0.14
0.0
3/12
8/15
8/19
8/23
8/25
0.36
0.55
8/28
3.70
0.13
0.01
0.05
0.58
0.55
9/2
9/7
9/15
8/22
2.30
0.38
0.12
9/20
0.29
0.92
0.04
0.25
0.44
0.04
0 •93
0.91
0.05
9/21
9/26
10/3
10/3
2.96
8/27
9/4
9/5
9/6
9/11
10/3
2.80
0.60
1.83
1.49
.98
1.08
10/11
10 /16
10/20
10/22
10/27
ll/l
11 /2
10/1
10/9
3.87
0.03
0.22
0.25
0.09
0.51
0.54
0.91
11/3
4.90
j
0.07
0.03
0. 30
0.18
0.20
0.05
10/10
1
1.32
1.24
0.26
0.55
8/25
0.66
8/24
9/4
9/7
9/9
9/12
9/13
9/29
9/30
10/1
and 1941
1940
8/7
8/13
8/16
8/17
8/18
8/19
1940,
2.55
99
Table 32
Days weathering, total rainfall, and average amount of
copper r em aining on the samplings in 1939, 1940, and 1941
1st
Sampling
2nd
Sampling
Wea the ri ng
■
'
3rd
Sampling
4th
Sampling
•
1939
0
13
28
68
1940
0
20
43
62
1941
0
25
71
95
Ave .
0
19.3
47.3
75.0
1939
0
0.66
1.98
5.85
1940
0
3.70
6. 50
1941
0
2.96
4.04
6.59
Ave,
0
2.44
4.17
7.85
of R a i n
11.1
Re m a i n i n g
1939
36.2
35.2
26. 5
17.6
1940
42.1
32.0
24.0
10.4
1941
42.8
18.4
13.3
11.1
Ave.
40 .4
28.5
21.4
13.0
100
40
M
G
. C
U PER
1941
30
AVERAGE
DAYS \
RAIN
I
N
C
H
E
S
INCHES) RAIN
DAYS
25
MG. C
U P
E
R Mz
OF YEA RS
1 9 3 9 , 1 9 4 0 , 9 1941
95
DAYS
1939
1940
30
20
iDAYS
DAYS
RAIN
RAIN*
RAIN
IN C H E S
INCHES
0.66
OAYS
DAYS
F IG M
R A IN F A L L
A N D T IM E IN
R E L A T IO N T O
COPPER
R E M A IN IN G
101
effect of the precipitation factor on the loss of copper from
the leaves in the field.
A grand average for the three years
given in the same figure shows that the curve for time follows
that for rainfall in these years.
The fact that rain removes more copper in one season than
in another is indicated by a comparison of the 1939 and 1940
curves with that for 1941.
It took approximately twice the
amount of rainfall to remove half the deposit in 1939 and 1940
as was required to remove this amount in 1941.
A much shorter
period of time was Involved in the removal of this initial
amount In 1941 Indicating that other weathering factors could
not have been operating as long.
The residue remaining in
1941 after the large loss during the first weathering period
was retained very well since the long time and heavy rains in
the remainder of the v/eathering period removed a much smaller
amount •
DISCUSSION OP CORRELATION STUDIES
The correlation between retention on plates in the lab­
oratory and on cherry leaves in the field was iound to be very
good in 1940 and in 1941.
Laboratory tests would seem to have
rather accurately predicted the retention in the field.
How­
ever, 1939 results were negative and there appears to be no
ready explanation.
The only difference in method in 1940 and
1941 as compared to 1939 was the use of the Unproved photo­
electric leaf-measuring apparatus which eliminated current
102
fluctuations*
This fluctuation might have introduced, enough
error in leaf measure me nt s in 1939 to obscure differences in
copper analyses w h e n expressed as milligrams per un i t of area.
Control
data u s e f u l for comparison with r e t e n t i o n data
were o b t ai ne d for only two years since that for 1940 was not
significant.
Th ese data seemed to "be "better correlated w ith
actual amount of copper ret ai ne d than with percentage.
It is
doubtful if pe rc en ta ge copper r em aining would ever correlate
well w i t h control on any leaf surfaces sprayed in the field
since there is n o way to obtain an absolutely u n i f o r m deposit
on all the leaves or all the surface of any one leaf.
amount r e t a i n e d is,
of course,
Actual
a reflection of b o t h the
original
amount a p p l i e d and the r e t e n t i o n property of the spray
material.
The difficulty In correlation with control develops
as a result the fact that there Is no wa y of separating the
relative effect of these two variables.
A n o t h e r difference between l a b o ra to ry and f i e l d spraying
which Martin
(79) has poin te d out Is the fact that m a n y leaves
on a tree are sprayed u n t il run-off occurs while ordinarily,
spraying of plates In the laboratory is stopped before run-off
takes place.
This was done in these studies In order to obta in
a u n i f o r m deposit o n the plates.
The fact that previous sprays were applied to the leaf
surface b e fo re r e t e nt ion studies were started m a y possibly be
considered as a factor tending to introduce v ar ia bi li ty In the
field data w h i c h would not be found In the la bo ra to ry tests.
This has b e e n suggested b y W o r th le y and Prear
(116)
as b e i n g
one r e a s o n w h y laboratory and field tests of deposition and
103
retention of* lead arsenate residues did not correlate too well*
However,
variability in spray deposit on leaves would tend to
be m uch higher witb only one application*
This was evident in
the analyses for individual replicates in treatments 2, 21,
and 22 in 1941 where only one copper application was made*
Variation was m u c h larger in these treatments than where three
copper sprays preceded the post-harvest application.
This is
also indicated b y the fact that the standard error of the mean
for the three applications in plot 6 was 1.96 while that for
plot 22 with only one copper spray was 7.18.
Another factor w hich m a y have introduced some error in the
retention studies on cherry leaves was the loss of leaves due
to leaf-spot or injury.
Defoliation due to disease would
naturally occur first on leaves with a lower copper residue.
The net effect of this would be a larger percentage of leaves
with a h i g h copper residue.
Injury would probably have some­
what the opposite effect by causing defoliation of leaves with
a high copper residue.
Injury,
of course,
develops only with
i
certain materials.
Some injury was evident in. 1939, but none
was observed on any copper treatments in
1940 and
1941 after
the retention studies were started.
A consideration of the type of surface on a cherry leaf
reveals a striking difference between it
used In the laboratory.
and the plate surface
The upper surface of the
leaf Is
relatively smooth while the lower surface is hairy.
Retention
on b o t h leaf surfaces Is Important in disease control.
The
chemical nature of the cuticle layer is relatively obscure and
probably changes during the course of the season.
104
The laboratory tests of* retention reported liere Involve
a test of the amount remaining after being subjected to a "rain
test1'•
As n o t e d In the literature review this is all that
weathering tests consist of in the ordinary laboratory determi—
nations of detention*
However,
this is probably only one of
the m a ny factors involved in weathering in the field*
ical abrasion,
Me ch a n ­
alternate wetting and drying during day and
nights when dew settles, h i g h and low temperatures,
and sun­
light are among the m a n y factors which could concievable be
involved in the loss of copper from the leaves.
Differences
in the i n t e ns it y of rainfall is also an important variable in
the field.
E v e n the rain test u se d in these studies was not
comparable to r a i n in the field as already noted.
A consideration of all these factors which are different
in laboratory and field suggests that a correlation would not
necessarily be expected and that there is no reason to assume
that the two types of surfaces would show the same order of
retention.
Therefore,
it seems especially important to have
data w h ic h does indicate a h i g h correlation between the two
methods.
The importance of retention differences found in 1940 on
the leaves seems to be slight when there was no significant
differences b e t w e e n the number of leaves remaining on the vari­
ous treatments.
The differences in control which were signifi­
cant In 1939 and 1941 did, h o w e v e r , indicate some r e l a t i o n to
i
retention and consequently emphasize the importance of this
factor in determing the protective value of the copper fungi­
cides used.
1
105
The laborato ry method, u s ed in this work involved, a
deter mi na ti on of* the copper residue by chemical analysis.
In
order for the actual copper to bear any direct r e l a t i o n to
control,
a u ni t of copper must exhibit the same t o x i c i t y in
all the different
copper compounds.
However this is not n e c e s ­
sarily always true since different compounds are k n o w n to have
different t o x i c i t y in the laboratory before the residue is sub­
jected to any sort of weathering test.
Iieuberger
Horsfall
(49)
and,
(42) b o t h discuss this point and the former very
d e f i n it el y states that chemical analysis should not b e substi­
tuted for the biological assay method of spore toxicity tests
before and after r ain test,
in estimating retention.
However,
chemical analysis was deliberately u s e d in this study of
correlation b e t w e e n laboratory and field retention in order to
avoid the v a r i a bi li ty involved In spore toxicity determinations.
Also,
since chemical analysis offers the only praticable w a y
of de te rm in ing ret en ti on in the field It was thought the same
m e t h o d sh ou l d be u s e d In the laboratory In a correlation study
of this type.
The better agreement betw ee n retention on leaves
and plates as determined b y chemical analysis than that determi­
ned b y b i o l o g i c a l assay expressed as tenacity coefficient seem
to justify this precaution in 1941.
The two correlation
coefficients were about the same, however,
Iieuberger
(41, 42)
In 1940.
attempted to justify the v a l i d i t y of
his l a b o r a t o r y results o n retention as determined b y the b i o ­
logical a s s ay m e th od b y comparison with a set of f i el d data
on the same compounds as determined b y chemical analysis of
the res id ue s
after weathering.
This would not seem quite
IQS
logical if* the chemical method did not give an accurate measure
of retention as Horsfall states
(4&) .
Heuberger
(42) also
states that the biological assay method offers a way of deter­
mining the actual amount of copper before and after weathering
in addition to the toxicity of the compound under test and adds
that this m u s t assume that the weathering test does not change
the chemical in any way*
This would seem to be another way
of saying that weathering does not affect the deposit other
than removal of a given unit of the toxicant and therefore
!
chemical analysis before and after weathering should give the
/
same ratio of retention as the biological method.
of course,
position,
it is reasonable to assume that some change in com­
su c h as has been noted in lead arsenate on the leaves
where the arsenic troxide/lead ratio changes
Worthley,
Actually,
(Frear and
'23 ) , does take place especially in the .field.
Martin (80),
for example, has noted changes occurring in a
film of B o r d e a u x mixture on a leaf due to carbonation and other
factors.
Therefore,
retention as determined by the biological
assay m e t h o d only determines the ratio of toxicity before and
after weathering.
This might not show a relation to actual
amount of the fungicidal ingredient,
such as copper,
and there­
fore could not reaspnably be called a measure of retention in
such cases.
It is difficult to find reported data on the compounds
tested for r e t e n t i o n in this study.
Heuberger
(41, 42)
states
that Soya flour does not increase retention and this was found
.
_
m
„ m
+--eu^ TQ 4 1
true
for
Te nnessee 26 in
t
-in w cuprouscl oxiae
de
also
reports yello
results.
The same author
x
to
shown a h i g
uu have
ua
& h re ten—
107
tion which is in accord with, laboratory results in 1939
although field data did not confirm this.
He found that copper
zeolite (ZO) showed low.retention which is in accord with
results in 1939 in both laboratory and field and with those of
IvIcCallan and Wilcoxon (653) in the laboratory as determined by
chemical analysis.
The low retention of Bordeaux mixture in
the field in this year, 1939 does not agree with results
published elsewhere or those obtained in 1938, 1940, and 1941.
No explanation can be offered other than that the weak formula
(1 pound copper sulphate to the 100 gallons) might not have
been stable in the field.
Magie and Horsfall (75) found that
emulsified cotton-seed oil increased retention of cuprous
oxide and copper-ammonia-silicate which is in accord with the
results on Cupro-K in 1941 (S. E. C. oil in plot 5).
Hartmann
(38) found Bordeaux mixture, Copper Hydro 40, and copper
phosphate to show a higher retention on cherry leaves than ZO
and Bordow which correlates with the 1939 data.
Cuprocide 54Y
was high and Basicop low which is Just the reverse of the
results reported here.
Cupro-K and Compound A were lower in
retention than Bordow and all three were lower than Bordeaux
mixture and Copper Hydro 40 which is the same as found in the
1941 results.
Comparison of these results with published data
on these compounds with trade names is likely to be misleading
since it is known that such compounds are often changed as to
method of manufacture, type of diluent and particularly the
kind of wetter or spreader which is sometimes added.
The
spreader might be added one year and then omitted the next.
This type of supplement would be expected to materially affect
108
retention since a wetting and spreading agent should certainly
facilitate removal by water during a rain.
The question as to how accurately laboratory tests will
predict field performance is always raised when a new material
shows promise in laboratory studies.
Horsfall (49) states
that there is no evidence that the host plant alters the
relative ranking of materials.
Martin (79), on the other hand,
has pointed out the importance of the host plant in changing
the protective value of a fungicide.
Also, the failure of many
new compounds to give control in the field testifies to the lack
of precision of laboratory tests in actually predicting field
performance.
Results found in this study certainly would
indicate that the host plant and weathering factors in the
field do alter the ranking materials in some instances from
that found in the laboratory.
Thus laboratory results in 1940
predicted Efufilm to increase retention of Tennessee 26, yet
field results showed this material to reduce retention.
In
general, the results of this study and those reported by
others have shown that laboratory techniques are capable of
selecting a high percentage of the materials as being high or
low in retention which are confirmed by field studies.
How­
ever, the fact that there are some few descrepancies indicates
that this technique cannot entirely replace field testing.
In
other words, laboratory testing enables one to select a group
of materials in which some will also perform v/ell in the field.
Yet, there is not certainity that all of them will give control,
nor is one sure that some which fail in laboratory tests (such
as Spralastic in 1940) would not show promise in field tests.
109
Laboratory testing offers a reasonably certain way of selecting
a few out of tlie many available compounds which would warrant
further trials in the field*
The chance, would be taken, of
course, that some good ones would be missed.
In this way
laboratory studies certainly would be a valuable adjunct to
field experimentation on protective fungicides.
SUMMARY
Methods were developed for determining the retention of
protective copper fungicides on Pyralin plates in the labora-^
tory and on leaves and fruit in the field.
After preliminary
studies, experiments were so planned that a direct comparison
between laboratory and field retention determinations could
be made.
Control data were also taken for estimating the
importance of the retention factor In determining the pro­
tective value of the copper fungicides used In this study.
Bordeaux mixture showed higher retention than any of the
commercial substitute copper materials on apple leaves in 1938
and on cherry leaves in three, out of the four years studies.
Lower retention was found In 1939 on cherry leaves where the
weak concentration of 1-2-100 was used.
Tank—mix copper phosphate also gave high retention on
apple and cherry leaves In 1938 and on cherry leaves in 1939
and 1940.
A higher retention on leaves resulted In 1940 when
It was prepared with trisodium phosphate than with disodium
phosphate.
110
Cupro-K showed a better retention on cherry leaves when
used with fish oil in 1938 and S. E. C. oil in 1941.
Better
control of leaf-spot also resulted in 1941 where S. E. C. oil
was used*
Tennessee 26 was tested with a number of stickers and
showed a higher retention on cherry leaves when used with
Orthex,
Spralastic,
and a Spred-rite-Suramermulsion mixture*
Lower retention than when used alone was found with Nufilm and
Soya Floor.
Tennessee 34 showed higher retention than the
Tennessee 26 copper.Dolomitic lime did not affect it.
Same
order of retention was noted in the laboratory except with
Wufilrn which increased retention of Tennessee on the Pyralin
plates.
Copper A was found to be low in retention on cherry
foliage as were also Coposil and Bordow.
Copper "A" was also'- ''
i
low in control.
used with it*
ZO was also low even though stickers were
,
The correlation coefficient between retention on Pyralin
plates and on leaves was + *841 in 1940 and + *902 in 1941*
slight negative correlation was found in 1939.
A‘
Where control
data were available in 1939 and 1941, a better correlation was
found between control and actual amount of copper than between
control and the percentage of copper remaining indicating the
relation of amount of copper to control.
The tenacity coef­
ficient showed a high correlation with the retention on Pyralin
plates but the correlation with retention on leaves was lower
than that obtained with Pyralin plates in 1941 and about the
same in 1940.
Ill
Correlations between laboratory and field data were not
loossible to make in 1938 since different formulas of materials
were used in the two methods of determining retention.
Weathering in the field was found to be entirely too
severe for-the copper deposits on plates.
All the materials
weathered off at a much greater rate than comparable treatments
on leaves.
The large amount of variability in the field data on
leaves and fruit in 1938 made it impossible to make many signi­
ficant conclusions as to the relative retention of various
copper substitutes for Bordeaux mixture.
Six replications in
1939 and following years were found adequate for estimating
this error so that allowance could be made for it in determining
significance of differences.
Amount of rainfall seemed to be slightly better correlated
with the rate of removal of the deposit by weathering in the
field than with the length of time it was exposed in the field.
CONCLUSIONS
It was concluded that laboratory determinations of reten­
tion fairly accurately predicted the field performance of the
copper materials used in this study.
noted, however.
Some exceptions were
It seems fairly evident that laboratory tests
could very well predict some materials to be promising which
would not perform well in the field and they could also often
fail to select materials that might very well prove promising
in field tests.
Likewise, laboratory tests could not replace
112
the field tests as the final criterion of the real protective
value even if the injury factor could he evaluated by such
techniques.
However, the accuracy of laboratory tests in the
studies reported here in predicting retention in the field
certainly indicates the value of such tests as a means of
selecting materials which would warrant field trials.
The
value of laboratory studies as an adjunct to field experi­
mentation on protective fungicides is amply demonstrated.
I
113
BIBLIOGRAPHY
1.
2
Adams, J. P. and Priode, C. N. Fungicide No. 66*
Peninsula Hort. Soc. 25:40-45. 1935.
.
Trans*
Ben-Amot , Y. and Hoskins, W. M. Factors concerned In
deposit of sprays. III. Effects of wetting and em­
ulsifying powers of spreaders.
Jour. Econ. Ent.
30:879-886. 1937.
z
3.
Borchers, F. and May, E. Methoden zur Prufung von Pflanzenschutzmltteln. VIII. Betrachtung und TJntersuchungen tlber die ph.yslkallsch.en Eigenschaften staubformiger Pflanzenschutzmlttel. Mitt. Biol. Reichsanst.
Land. u. Forstw. 50:5-55. 1935.
4.
Borden, A. D. and Hensill, G. S. A. method of studying
comparative oil deposits of proprietary oil emulsions.
Jour. Econ. Ent. 27:838-41. 1934.
5.
Boyd, G. T.
Studies on spreader materials.
In Fiftieth
Ann. Rept. Texas Agr. Exp. Sta. 1937:111-lT^.
6.
Boyd, G. T. The effect of weathering on the toxicity of
copper sprays to spores of Actinonema rosae. In Fifti­
eth Ann. Rept. Texas Exp. Sta. 1937:112.
7.
Burrill, T. J. Bitter rot of apples, in 111. Agr. Exp.
Sta. Bull. 118:553-608. 1907.
8
.
9*
10
Butler, .0* and Doran, W. L.
Spray solutions and the con­
trol of apple scab.
N. Hamp. Agr. Exp. Sta. Bull. 36.
1928.
Daines, R. H. and Martin, W. H. Reduction of Bordeaux
mixture Injury by the use of amendments.
(Abstract)
Phytopath. 27:126. 1937.
.
Daines, R. H. Two years experiments in the control of
cherry leaf spot (Coccomyces hi emails) • (Abstract)
Phytopath. 29:5-6. 1939.
.
Davies, F. A. and Adams, J. F. The Influence of spreaders
and stickers In relation to the fungicidal effeciency
of insoluble copper spray films.
Trans. Peninsula
Hort. Soc. 26:32-39. 1936.
11
1 2 . Dawsey, L. H., Cressman, A. W., and HIley, J. The rel­
ative quantities of oil deposited upon paraffin-coated
plates and upon plant foliages by oil sprays.
Jour.
Agr. Res. 54:387-398. 1937.
13.
Dimond, A. E., Horsfall, J. G., Heuberger, J. W., and
Stoddard, E. M. Role of the dosage— response curve In
the evaluation of fungicides.
Conn. Agr. Exp. Sta.
Bull. 451. 1941.
114
14.
Doran, V/. L. Laboratory studies of the toxicity of some
sulphur fungicides. N. Hamp. Agr. Exp. Sta. Tech..
Bull. 19. 1922.
15.
Doran, Wm. L. Toxicity studies with, some copper fungi­
cides.
Phytopath. 13:532-542. 1923.
16.
Evans, A* C. and Martin, H. The incorporation of direct
with protective insecticides and fungicides.
I. The
laboratory evaluation of water-soluble wetting agents
as constituents of combined washes.
Jour. Pomol.
13:261-292. 1935.
17.
Fahey, J. E. and Rusk, H. W. Effect of fruit growth and
weather on deposits of insecticides on apples in
southern Indiana.
Jour. Econ. Ent. 33:505-511. 1940.
18.
Pagans, E. and Martin, H. The incorporation of direct
with "protective insecticides and fungicides.
II. The
effects of spray supplements on the retention and
tenacity of protective deposits.
Jour. Pomol. 15:1-24.
1937.
19.
Fajans, E. and Martin, H. The incorporation of direct
with protective insecticides and fungicides.
III.
Factors affecting the retention and spray residue of
emulsions and combined emulsion-suspensions• Jour.
Pomol. 16:14-38. 1938.
i
.
20
Frear, D. E. H.
Photoelectric apparatus for measuring
leaf areas.
Plant Physiology 10:569-574. 1935.
21
D. S. H. Determination of small amounts of copper
. Frear,
In spray residues.
Ind. Eng. Ghem. 11:494. 1939.
22
.
Frear, D. E. H. and Haley, D. E. A simiplified method
for the rapid determination of lead reasidues on apples.
Penna. Agr. Exp. Sta. Bull. 304. 1934.
23.
Frear, D. E. H. and Worthley, ,H. N. Deposition and reten­
tion of sprays on apples. Penna. Agr. Exp. Sta. Bull.
344. 1937.
24.
Girard, A. Recherches sur 1/adherence aux feuilles des
plantes, et notamment auz feuilles de la pomme de
terre, des composes, cuiriques destines
combattre
leurs maladies.
Compt. Rend. Acad. Sci. 114:234—236.
1892.
Goldsworthy, M. C. Fungicide (U. S. Patent No. l,954,rZL>)
U. S. Patent office, off. Gaz. 441:360. 1934.
?
25.
26.
Goldsworthy, M. C. and Green, E. L. Effect of low con­
centrations of copper on germination and growth of
conidia of Gcleroti-nia fructicola and Glomerella oingulata. Jour. Ag. Res. 56:489-506• 1938•
115
27.
Goodwin, W., Salmon, E., and Ware, W. M. The action of
certain chemical substances on the zoospores of
Pseudoperonospora humlll.
Jour. Ag. Sci. 19:185-200.
1929.
28.
Goodwin, W., Martin, H., and Salmon, E.
The fungicidal
properties of certain spray-fluids, VI.
Jour. Agr.
Sci. 20:18-31. 1930.
29.
Gornitz, K. Methoden Zur Prufung von Pflanzenschutzmitteln.
IV. Heue Apparate und Methoden.
Biol.
Reichsanst. Land u. Porstw. Mitt. 46:5-59. 1933.
30.
Gortner, R. A.
Outlines of biochemistry 1938.
2nd Ed.
XX + 1017pp.
New York and London:
John Wiley and
S ons.
31.
Green, E. L.
Spray material (TJ. S. Patent no. 2,004,783.) .
U. S. Patent Office, Off. Gaz. 455:459. 1935.
32.
Green, E. L. and Goldsworthy, M. C. The copper content
of residues from sprays containing adjuvants.
Phy­
topath. 27:957-970. 1937.
33.
Guillon, G. M. and Gourand, G,. Sur l^adherence des
bouilles cupriques utilisees pour combattre les mala­
dies cryptogramiques de la Vigne. Compt. Rend. Acad.
Sci. 127:254-256* 423-424. 1898.
34.
Hamilton, J. M.
Studies of the fungicidal action of cer­
tain dusts and sprays in the control of apple scab.
Phytopath. 21:445-524. 1931.
35.
Hamilton, J. •M.
Studies on apple scab and spray materials
for its control in the Hudson Valley.
N. Y. (Geneva)
Agr. Exp. Sta. Bull. 227. 1935.
r
36.
Hamilton, J. M. and Yfeaver, L. 0. Methods for determin­
ing the effectiveness of fungicides against apple scab
and the Cedar-apple rust fungi.
(Abstract) Phytopath.
30:7. 1940.
37.
Hamilton, J. M. and Mack, G. L.
New and improved methods
for study of fungicides.
Farm Res. N. Y. (Geneva)
Agr. Exp. Sta. 8:10, 13. 1942.
38.
Hartmann, II. T. Tests with new copper,* fungicides with
special reference to injury, tenacity to foliage, and
d warf in g effect.
Proc. Amer. Soc. Hort. Sci. 38:
148-152. 1941.
39.
Henry, B. W. and Wagner, E. G. A rapid method of testing
the effects of fungicides on fungi in culture.
Phyto­
path. 130:1047-1049. 1940.
116
40.
Hensill, G. S. and Hoskins, W. M. Factors concerned in
the deposit of sprays. I. The effect of different
concentrations of wetting agents.
Jour. Econ. Ent.
28:942-950. 1935.
41.
Heuberger, J. W. A laboratory biological assay of ten­
acity of fungicides.
Phytopath. 30:840-847. 1940.
42.
Heuberger, J. W. Tenacity of protective fungicides.
Chron. Botanica 7:9-10. 1942.
43.
Heuberger, J. W. and Adams, J. F. The influence of lead
arsenate and lime on the fungicidal toxicity and ad­
herence of wettable sulfur sprays.
Trans. Peninsula
Hort. Soc. 26i 68-70. 1936.
44.
Heuberger, J. V/. and Horsfall, J. G. Yellow cuprous
oxide as.a fungicide of small particle size, (abstract)
Phytopath. 29:9-10. 1939.
45.
Heuberger, J. W. and Horsfall, J. G. Relation of particle
size and color to fungicidal and protective value of
cuprous oxides.
Phytopath. 29:303-321. 1939.
46.
Holland, E. B., Dunbar, C. 0., and Gilligan, G. M. The
preparation and effectiveness of basic copper sul­
phates for fungicidal purposes.
Jour. Ag. Res. 33:
741-751. 1926.
47.
Hooker, H. D. Colloidal copper,hydroxide as a fungicide.
Xnd. Eng. Chem. 15:1177-1178. 1923.
48.
Horsfall, J. G. A study of meadow-crop diseases in New
York.
New York (Cornell) Agr. Exp. Sta. Mem. 130.
1930.
49.
Horsfall, J. G. Biological assay of protective fungicides.
Chron. Botanica 6:292-294. 1941.
50.
Horsfall, J. G. and Heuberger, J. W. Relation of color
to fungicidal value of insoluble copper compounds.
(Abstract) Phytopath. 30:11. 1940.
51.
Horsfall, J. G ., Heuberger, J. W., Sharvelle, E. G., and
Hamilton, J. M. A design.for laboratory assay of
fungicides.
Phytopath. 30:545-563. 1940.
52.
Horsfall, J. G., Marsh, R. W., and Martin, H. Studies
upon the copper fungicides. IV. The fungicidal value
of the copper oxides.
Ann. Appl. Biol. 24:867-882.
1937.
'
-
53.
Hoskins,'W. M. and Wampler, E. L. Factors concerned in
the deposit of sprays. II. Effect of electrostatic
charge upon the deposit of lead arsenate.
Jour. Econ.
fent. 29:134-143. 1936.
>
■f
117
54.
Hoskins, V/. M. and Ben—Amotz, Y. Tlie deposit of aqueous
solutions and of oil sprays. Hilgardia 12:83-111.
1938.
55.
Howard, P. L. The value of testing fungicides in the
laboratory before use in the field. Proc. Am. Soc.
Hort. Sci. 37:409-414. 1939.
56.
Kadow, K. J*, Hopperstead, S. L., and Goodwin, M. W.
Will insoluble copper sprays control bitter rot under
conditions favorable to the disease? 1938 Results.
Trans. Peninsula Hort. Soc. 23:99-102. 1938.
57.
Kehlhofer, W. XJber die Ausfuhrung und die Ergebnisse
von Haf tf estigkeitsversuchen Rupf erhaltiger Bekampfungsmlttel gegen die Peronospora. Zeitschrift f.
Pflanzenkrankh. 17:1-12. 1907.
58.
Keitt, G. 7«. and Jones, L.'K. Studies of the epidemi­
ology and control of apple scab. Wis. Agr. Exp. Sta.
Res. Bull. 73. 1926.
59.
Kightlinger, C. TJ. Preliminary studies on the control
of cereal rusts by dusting. Phytopath. 15:611-613.
1925.
60.
Lee, H. A. and Martin, J. P. A method for testing in
vitro the toxicity of dust fungicides to fungous
spores.
Phytopath. 17:315-319. 1927.
61.
McCallan, S. E. A. Studies on fungicides. II. Testing
protective fungicides in the laboratory. N. Y.
(Cornell) Agr. Exp. Station Mem. 129:8-24. 1930.
62.
McCallan, S. E. A., Wellman, R. H . , and Wileoxon, P.
The different toxicity ratings of compounds by dif­
ferent fungi and experiments in spore-germination
tests of fungicides.
(Abstract) Phytooath. 31:16.
1941.
63.
McCallan, S. E. A., Wellman, R. H., ana Wilcoxon, P.
An analysis of factors causing variation in spore
germination tests of fungicides.
III. Slope of toxi­
city curves, replicate tests, and fungi. Contrib.
Boyce Thompson Inst. 12:49-78. 1941.
64.
McCallan, S. E. A. and Yfilcoxon, F. The fungicidal
action of sulphur. II. The production of hydrogen
sulohide by sulphured leaves and spores and Its toxi­
city to spores. Contrib. Boyce Thompson Inst.,3:1338. 1931.
65.
McCallan, S. E. A., and Wilcoxon, F» The precision of
spore germination tests. Contrib. Boyce Thompson
Inst. 4:233-243. 1932.
118
66*
McCallan, S. E. A. and Wilcoxon, P. The form of the
toxicity surface for copper sulphate and for sulphur,
In relation to conidia of Sclerotinia americana.
Contrib. Boyce Thompson Inst. 5s173-180. 1§33.
67.
McCallan, S. E. A. and Wilcoxon, P. Fungicidal action
and the periodic system of the elements. Contrib.
Boyce Thompson Inst. 6:479-500. 1934.
68
.
McCallan, S. E. A. and Wilcoxon, P. Laboratory com­
parisons of copper fungicides. Contrib. Boyce Thomp.
Inst. 9:249-263. 1938.
69.
McCallan, S. E.
tors causing
• fungicides.
Boyce Thomp.
70.
McCallan, S. E. A. and Wilcoxon, P. An analysis of fac­
tors causing variations in spore germination tests of
fungicides.
(Abstract) Phytopath. 29:16. 1939.
7 1.
McCallan, S. E. A. and Wilcoxon, P. . A comparison of
methods of laboratory spraying for the testing of pro­
tective fungicides.
(Abstract) Phytopath. 30:16. 194&
72.
McCallan, S. E.
tors causing
fungicides.
Thomp. Inst.
73.
MacCreary, D. The effeciency of certain proprietary oil
emulsions, Volck and Orthol-K, for control of the
oriental fruit moth. Del. Agr. Exp. St a. Bull. 184.
1933.
74.
McDaniel, A. S. Colloidal bentonite-sulfur. A new
fungicide.
Ind. Eng. Chem. -26:340-345. 1934.
75.
Magie, R. 0. and HorsfaTl, J. G-. Relative adherence of
cuprous oxide and other copper fungicides.• (Abstract)
Phytopath. 26:100—101. 1936.
76.
Marsais, P. and Sdgal, L. Contribution a letude de
Inaction anticrytogamique du cuivre. Rev. Vitic.,
Paris. 88:285-287. 1938
77.
Marsh, Q. W. Notes on a technique for the laboratory
evaluation of protective fungicides.
Trans. Brit.
M y c . Soc. 20:304-309. 1936.
78.
Marsh, R. IV. Some applications of laboratory biological
tests to the evaluation of fungicides. Ann. Appl.
Biol. 25:583-604. 1938.
A. and Wilcoxon, P. An analysis of fac­
variation in spore germination tests of
I. Methods of obtaining spores. Contrib.
Inst. 11:5-20. 1939.
A. and Wilcoxon, P. A n analysis of fac­
variation in spore germination tests of
II. Methods of spraying. Contrib. Boyce
11:309-324. 1940.
119
79.
Martin, H. Tlie laboratory examination of fungicidal
dusts and sprays. Ann. A'ppl. Biol. 19:263-271. 1932.
80.
Martin, H.
Studies upon the copper fungicides.
II.
Some modifications of Bordeaux mixture designed to
overcome pratical difficulties In its application.
Ann. A p p l • Biol. 20:342-63. 1933.
81.
Martin, H. The incorporation of direct with, protective
insecticides and fungicides.
IV. The evaluation of
the wetting and spreading properties of spray fluids.
Jour. Pomol. and Hort. Sci. 18:34-51. 1940.
82.
MillardeJ;, A- and David, M. E. Resultats de divers
procedes de traitement sur le developperaent du mildiou.
Jour. Agr. Pratique 50:764-70. 1886.
83.
Montgomery, H. B. S. and Moore, M. H. A new method for
precision testing in the laboratory of the toxicity
of lime sulphur and Bordeaux mixtures as protective
fungicides. Rept. E. Mailing Res. Sta. 22:217-22.
1934.
84.
Montgomery, H. B. S. and Moore, M. H. A laboratory
method for testing the toxicity of protective fungi­
cides.
Jour. Pomol. and Hort. Sci. 15:253-266. Ja.
1938.
,-*v
85.
86
.
87.
88
.
Moore, W.
Spreading and adherence of arsenical sprays.
Univ. Minn. Agr. Exp. Sta. Tech. Bull. 2. 1921.
Moore, W. Adherent arsenical preparations.
Chem. 17:465-466. 1925.
Ind. Eng.
Nielsen, L. W. Studies, on the fungicidal properties of
silver.
(Abstract) Phytopath. 30;18. 1940.
Nikitin, A. A. The application of electrodialysis to
the study of copper fungicides.
(Abstract) Phytopath.
28:17. 1938.
89.
Nikitin, A. A.
Studies on the efficiency of colloidal
copper fungicides.
(Abstract) Phytopath. 28:17. 1938*
90.
Nikitin, A. A. Adherence properties of copper fungicides
as determined by chemical analyses and by cataphoresis.
(Abstract) Phytopath. 29:19. 1939.
91.
Nikitin, A. A. The character of supplements and their
effect on the performance of copper fungicides.
Phy­
topath. 30:18. 1940.
92.
Percher, G. Quelques essais sur les soufres et sur les
moulillants. Rev. Vitic., Paris. 89:295-300. 1938.
120
93.
Perraud, J. Rech.erch.es star quelques moyens permettant
d^augmenter l'''adherence des bouillies cupriques.
Compt. Rend. Acad. Sci. 127:876-879. 1898.
94.
Perraud, J. Sur une nouvelle boullle cuprlque, plus specialement destin£e a combattre le black rot.
Compt. Rend. Acad* Sci. 127:978-980. 1898.
95.
Peterson, P. D. The spore-germination method of evalu­
ating fungicides. Phytopath. 31:1108-1116. 1941.
96.
Pierpont, R. L. Rosin residue emulsion as a sticker
for lead arsenate in horticultural sprays. Del. Agr.
Exp. Bull. 221 (Tech. Bull. 25). 1939.
97.
Plakidas, A. G. The mode of action of Bordeaux on
Mycosphaerella fragariae. Phytopath. 28:307-329.
1938.
98.
Reddick, D. and Wallace, E. On a laboratory method of
determining the fungicidal value of a spray mixture
or solution.
Science 31:798. 1910.
99.
Roberts, J. W., Pierce, L. , Smith, M. A. , Dunegan, J. C.,
Green, E. L., and Goldsworthy, M. C. Copper phosphate:
A promising fungicide. Phytopath. 25:32. 1935.
.
100
.
Schmidt, E. W. Eine biologische Methode zum NachWveis
der Regento irkung auf Pflanzenschutzmittel. Zeitschr.
Angew. Chemie 37:981-982. 1924.
•«
101
Schmidt, E. W. TJber die Ausmittelung eines Pflanzenschutzmittels und seine fungizide Bewertung. Zeit­
schr. Angew. Chemie 37:267-270. 1924.
■
102.
Schmidt, E. W.
Zur Bewertung der Fungizidit*at eines
stoffes.
Zeitschr. f. Angew. Chemie 38:67-70. 1925.
103.
Schneiderhan, P. J. Instant bordeaux.
Exp. Sta. Circ. 60:1-8. 1932.
104.
Taubenhaus, J. J. Effect of fungicidal dusts on the
germination of spores of various plant pathogens,
in Fiftieth Ann. Rept. Texas Agr. Exp. Sta. 1937:115.
105.
Taubenhaus, J. J. The effect of aging on the toxicity
of Cuprocide and other fungicidal dusts.
in Fiftieth
Ann. Rept, Texas Agr. Exp. Sta. 1937:116.
106.
Taubenhaus, J. J., Boyd, G. T., and Gelber, E. Fungi­
cidal properties of sulphur and Cuprocide.
in Fortyninth Ann. Rept. Texas Agr. Exp. Sta. 1936:1135-105.
107.
Thatcher, R» W. and Streeter, L. R. The adherence to
foliage of sulfur in fungicidal dusts and sprays.
N. Y. (Geneva) Agr. Exp. Sta. Tech. Bull. 116. 1925.
W. Va. Agr.
121
108.
Upholt, W. M. and Hoskins,
tlie deposit of sprays.
photo graphic apparatus
movement of individual
Econ. Ent. 33:102-107.
109.
Wallace, E., Blodgett, F. M., and Hesler, L. R.
Studies
of the fungicidal value of lime-sulphur preparations*
N. Y. (Cornell) Agr. Exp. Sta. Bull. 290:163-208.
1911.
110
.
W. M. Factors concerned in
VII. Design and use of a
for studj^lng the impact and
drops upon a surface.
Jour.
1940.
Weber, A. L. and McLean, H. C.
The effect of lime and
weathering upon lead arsenate and copper spray mix­
tures.
Proc. Am. Soc. Hort. Sci. 37:391-396. 1939.
.
Studies on the adhesiveness of sulfur
111 • White, R. P.
residues on foliage.
N. Jer. Agr. Exp. Bull. 611.
1936.
112
.
Wilcoxon, F. and McCallan, S. E. A.
The fungicidal
action of sulphur.
I. The alleged role of pentathionic acid.
Phytopath. 20:391-418. 1930.
113.
Wilcoxon, F. and McCallan, S. E. A.
The fungicidal
action of sulphur.
III. Physical factors affecting
the efficiency of dusts.
Contrib.. Boyce Thomp. Inst.
3:509-528. 1931.
114.
Wilcoxon, F. and McCallan, S. E. A. Fungicidal action
of organic thiocyanates, resorcinol derivatives, and
other compounds.
Contrib. Boyce Thomp. Inst. 7:333339. 1935.
115.
Williams, R. C.
Laboratory method for measuring rela­
tive adhesive qualities of fungicidal dusts.
Ind.
Eng. Chem. 1:81-82. 1929.
i
116.
Worthley, H. N. and Frear, D. E. H.
Deposition of lead
arsenate spray mixtures, and its retention on Pyralln
plates, apple leaves, and fruits.
Jour. Econ. Ent.
(In p r e s s ) .
117.
Young, H. C. and Beckenbach, J. R.
Spreader materials
for Insoluble copper sprays.
Phytopath. 26:450-455.
1936.
I
Документ
Категория
Без категории
Просмотров
0
Размер файла
6 691 Кб
Теги
sdewsdweddes
1/--страниц
Пожаловаться на содержимое документа