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STUDIES (N THE CONTROL OF CHERRY LEAF SPOT,

ONGOINCES KIWI-IS HIGGINS

3!
Colin Inna Rom

kTHESIS

admitted to the Waste School of [101113311
Stats 00110;. of 531'!th and Applied
Scienc- in pol-1.131 fulfilmont of tho
requirements for tho dcgru of

magma OF SCIENCE

DOWt of Botany
1939

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ICKNOWLEDGIENTS

The writer is indebted to Mr. Donald Cation {or
invaluable advice and assistance in conducting this
etudy, to Dr. E. J. Miller for the chemical analyses
and to Dre. 8. A. Rooney and J. H. Unncie for a critical

reading of the manuscript.

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b V .

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4Fa‘VJ-J'U J

TABLE OF CONTENTS

Introduction
Historical Review

The Problem
Experimental Procedure
Summary

Conclusions

Literature Cited

Tables

Figures

Page

37
38
69
74
76
84

105

INTRODUCTION’

Cherry leaf’spot caused by the fungus-Qggggglggg_hig!§1ig'
Higgins is the most serious and destructive-disease of cherries in
Iichiaan. The effects of this disease are the main limiting factors
in cherry production. Epiphytotics of this disease in the last eleven
years has occurred in Iichigan in 1928 (2:5). 1929 (14), 1935 (20).
1951 (22. so) and me (81).

The most striking and apparent effect of the disease is preaature
defoliation of the trees. Loss of leases. occurring before harvest.
say cause an uneven and delayed ripening of the fruit. Repeated
attacks of leaf spot any seriously loser the quality and production of
the.erep for several years. Trees that have prematurely lost their to»
lia‘e durins-a.single season may be winter killed during the folio-ins
dormant period. Trees that have been.defoliated several years in
succession seldos survive a severe sister.

After effects of leaf spot infection.aay bees-e evident in years
following defoliation. Delayed blossoming periods eith.feser and

’Contrary to the usual practice it became desirable to have
certain portions of the inforaation obtained in the course

of the research published in short papers prior to the cea-

pletion of the thesis as folloss:

cation. D. and c. I. Robertson. Basicop ae.a cherry
'Fra’e Michigan Agricultural Experiment
Station Quarterly Bulletin 20: 199-210. 1938.

Robertson. 6. I. and D. Cation. Basicop as a cherry
spray in 1938. Hichigan Agricultural In»

periment Station Quarterly Bulletin 21:
29l-295. 1939.

-2-

smaller blossoms have been noted. Reductions in fruit size and number
of cherries may occur as sell as delayed and uneven ripening of the
fruit.

Grosth of old and new wood may be reduced. Fewer fruit spurs may
be formed. Hardening of the vood is also a resultant of leaf spot in-
fection folloving severe defoliations of the previous year. Gallovay
(45) states that the active vood of defoliated nursery stock hardens
Mn such a.manaer that the buds can not be inserted or that imperfect
unions with the stock result causing the buds to die. Buds or grafts
that gros are checked by premature defoliation to such an extent that
it is questionable ehether the trees seer fully recover.

The frequency with which this disease occurs and the seriousness
of the residual effects makes it apparent that satisfactory control
methods for the leaf spot disease are necessary for the successful
culture of cherries in nichigan.

Satisfactory control of cherry leaf spot may be gained by erad-
ication of overvwintered leaves and the proper use of protestant
fungicides. Investigators have recognised that the amount of primary
infection is limited by early spring destruction of the old leaves
since Higgins (54) proved the megns by vhich the fungus over-sinters.
Arthur (5) described an ascogenous form on plum leaves similar to
Eggggglggg,higgalig Higgins and apparently realised the significance of
the old lease in the 11:. history when he advised their destruction.
Hansel (10) in 1891 described a similar perfect stage but. as vith
Arthur. the genetical connection sith the amperfect stage was not proved.
Keitt (58) found that early clean cultivation in the spring greatly re-

inforced the spray schedule in Wisconsin. He also found (62) that

-3-

eradicative sprays applied to the leaves in the fall prevented or
aaterially reduced the amount of primary infection in experimental
Plat 3.

Main reliance for control of the disease in commercial cherry
production is placed upon the use of protestant fungicides supplemented
by destruction of the old leaves by early spring cultivation when the
latter does not interfere vith recommended horticultural practices.
Thus. investigations conducted to devise measures of control for this
disease have dealt largely vith sprays. Since the production of the
fruit on a large scale began, much.experimental sork had been conducted
on the types of spray materials. the methods and timeliness of appli-

cation.

HISTORICAL REVIEW

e: a result of observations and. in 1886, Arthur (5) suggested
the use of sodium hyposulphite or potassium sulphide as spray materials
for the control of plum leaf spot.’ The follosing year Arthur (6) con-
ducted experiments using six:applications of potassium sulphide solu-.
tion. The foliage of the treated trees mas retained longer and appeared
more vigorous than that of the untreated trees.

The first attempt to control leaf spot of cherries. according to
Fairchild (40), mas inaugurated by Galloway in 1889. In 1890 he (42)
made trials of ammoniacal copper’carbonate and bordeaux mixture using
six:applications at 12 day intervals beginning about May 1. Obser-
vations indicated that the two materials sere equally efficient and
that each treated plat was superior to the unsprayed control. Experi-
seats (45) conducted in 1891,.1892 and 1893 on Black Tartariam,
Governor Wood and Early Purple varieties demonstrated that trees sprayed
mith bordeaux mixture 6-4-22 made an increased grosth over untreated
trees, a.fact he could not explain as entirely due to the efficiency of
the spray as a fungicide and insecticide. No difference sas noted he—
tseen early or late sprayed stock nor see there any perceptible dif-
ference betveen plats receiving 7 and 5 sprays.

Thaxter (99) in 1889 reports the application of bordeaux.mixture
6-6-22 on tso Lombard plum trees leasing a third as a control tree.

1222221221 W 151685-08 (55). since aha-m to be a
distant fungus from the causal organism of cherry leaf

spot Coccggzces hiemglis Higgins. (54).

.5.

Three sprays were applied and the treated trees held their foliage
until Octobeerhile the control tree was defoliated in August. 0h-
servations (100) on a cherry and plum orchard to which an application
of hordsaux mixture had been made, showed that the treated trees held
their foliage free from leaf spot while the untreated trees were de-
foliated early in the season. an instance is also cited in which
seseral plum trees received the same treatment and retained their
foliage.

lairchild (3?. 38. 43. 44) in 1891 used an asmoniacal solution
of copper carbonate in comparison with bordsaux.mixture 6-4-22 as spray
materials for cherry leaf spot control. lassard and Iahalsb nursery
stock was used, one half of each.receiving 8 sprays while the other half
received only 3 sprays. Infections were too slight and appeared too
late in the season to indicate the comparative efficiencies of the two
fungicides. although the treated tress had fewer infections than.the
untreated. In 1892 (39) he again tested the some materials on lasaard
stock:and on Iindsor and Yellow Spanish nursery varieties budded on
IIhaleb-stock. Trees receiving 3 applications had superior foliage to
the untreated trees and bordeaux:mixture 2-2-15 was slightly superior
to the ammoniacal solution. Treatments with the latter produced foliage
injury. Stellar results were obtained on all.varieties.

Due to the injury caused by the ammoniacal solutim of copper
carbonate. Fairchild (39) tested only bordeauxzsdxture the following
year. and. since little evidence of the disease was noted. there were
no indications as to the fungicidal effectiveness of the spray aaterial.
In 1894 he (40) reported that bordeaux mixture might be considered a
specific for the control of cherry leaf spot of nursery stock. Tests

indicated that the best results were obtained when the first spray was

-6-

applied directly after the foliage was fully formed and repeated at
two week intervals until six applications were made.

Green (49) stated in 1391 that trees sprayed with bordsaux mixture
4-4-50 held their foliage until late in the season while unsprsyed
trees were defoliated early in August. Although the number of applica-
tions necessary was not determined. it was pointed out that one helped
‘a great deal' and that probably 2 or 3 would be sufficient.

Fuel (70) in 1891 conducted a one-spray and three-spray pro-
gram with an anoniacal copper carbonate solution on nursery stock of
the Grictte Du lord variety. Distinct differences were noted. there
being many more leaves on the three-spray plat than on the trees re-
ceiving one spray and the control trees lost much more foliage than either
treated plat. Bearing Groa Gobet trees were given three applications
of bordeaux mixture 6-4-22 and two sprays of c-sniaoal solution of cop-
per carbonate. Excellent control was obtained on the treated trees
while the controls had considerable defoliation during the latter part
of August. Similar results were noted on trees of the Gelatin variety.
No infected leaves were found on Duchesse D'Ingoulems trees that re-
ceived two sprays of bordeaux mixture 6-d-22. The control tree was
partially defoliatsd early in the season. Additional treatments were
.de with a-soniacel copper carbonate solution but the disease was so
slight that even the untreated controls were uninfected.

In 1892 PM!» (11) applied 10 sprays of moniacal copper car-
baxate solution to a Russian variety budded on Ilahaleb seedlings and
obtained fully 50 percent more lease and better growth on the treated
than on the untreated stack. Seven applications of bordeaux mixture

12-8-50 were applied to seedling Russian cherries and on Russian

-7-

varieties budded on Iahaleb stock. The treated trees had fewer in-
fected leaves and superior growth to the control trees in each case.
King‘s Iorallc. Griotte du Nord and Sklanks varieties of budded
cherries received 5 applications of bordeaux mixture 12-8-50. and mid-
season observations showed almost 50 percent more leases per treated
tree than on the untreated tress.

Pam-e1 (12) estimated in 1893 that three-fourths of the leaves
remained on four cherry trees of the Gros Gobet variety given four
sprays of bordsaux mixture 8-4-45 as compared with the unsprayed cen-
tro1.which was almost completely defoliated.

Pemmel and Carver (73) tested five-spray programs of bordeaux
mixture 6-4-22 and ammoniacal solution of copper carbonate in 1894.
Superior growth and approximately 80 percent more leases resulted on
the bordsaux:mixture treated trees as compared with the untreated. Re-
cults were sheilar but less pronounced with smmpniscal copper carbonate
solution and. in addition. there was a slight amount of foliage injury
and infections per leaf were more numerous.

reach (10) conducted experiments in 1895 on Ilontmorcncy, Reine
Hortense and larly Richmond varieties using a three-spray program of
can celeste soap mixture and of bordeaux.mixturc. Although it was
noted that the can celests soapimixture produced serious injury to the
foliage. little information was gained in regard to leaf spot control
because even the untreated control trees had excellent foliage at the
and of the season. Continuation of these experiments was made in
1896 (11) in an effort to determine the timeliness and the number of
applications of bordeaux.mixture necessary to control the disease.

Disease incidence was slight even on the control trees. and results of

-8-

the tests were of little value although no spray injury to the foliage
wasrfound.

Beach, Lowe, and Stewart (12) stated in.1899 that the disease
could be controlled satisfactorily by the proper applications of
bordeaux:mixture but that these treatments could not be applied at the
opportune times because the spray residue seriously interfered with the
market value of the fruit. Consequently no positive recommendation was
given but a.pre-blcom.and petal-fall application of bordeaux:mixture
was suggested with the possible addition of a third spray.

Taft (95) in 1894 recommended bordeaux mixture 4-3-32 for a pre-
hloom and petal-fall application and a summer spray 10-14 days later.
as a.supplementary spray the latter was to be repeated if signs of brown
rot appeared. Tb eliminate spray residue, ammoniacal copper carbonate
solution was advised for the fourth regular spray. The following year
he (96) advised a pro-bloom spray of copper sulphate solution 1-25, a
petal-fall and a.summer spray 10-14 days later of bordeaux mixture
d-3-40. The latter was to be repeated if symptoms of brown rot appeared.
The fourth regular summer spray, lO-l‘ days later, consisted of an ap-
plication of weak copper sulphate solution 1-250 or 1-500. If leaf
spot infections continued to occur. the fourth spray was to be repeated
at suitable intervals. The 1898 spraying calendar for Bichigan (97)
recommended a.dormant spray of copper sulphate solution 1-15 or 1-25 or
bordeaux mixture t-t-do. and the same spray 2 to 3 weeks later and re-
peated as often as the occasion demanded.

Stewart, Rolfe. and Hall (89) in 1900 reported the disease to be
of little concern to hearing trees or nursery stock, although Iaaaard

cherry seedlingswerse frequently attacked.

-9-

Rolf (82) in 1907 advised sprays of bordeaux mixture 5-5-50 as
soon as the leaves came out, followed by a second spray two weeks later.
Under conditions of severe leaf spot it was thought a third and fourth
application might be necessary although they should be applied only in
extreme cases because the residue might seriously injure the market
value of the fruit.

Hsin (53), experimenting with bordeaux mixture in 1908, found
that little benefit was derived from a pro-blossom spray although leaf
spot became severe when the last application, equivalent to the four-
weeks spray, was omitted. Trees sprayed with bordeaux mixture after
the leaves were almost fully developed showed very few yellow leaves
the latter part of the season while the unsprayed control trees were
one-half defoliatcd in mid-season. The recommendation as a result of
these experiments was a three-spray program, a petal-fall and two
additional sprays applied at 14 to 18 day intervals.

Due to the encouraging results obtained with self-boiled lime-
sulphur on peach and apple foliage in 1908 (85), Scott tested self-
boiled lime-sulphur 10-10-50 and 6-6-50 and lime sulphur 1-40 in
comparison with bordeaux mixture 2-4-50 on cherries the following
year (86). varieties Montmorency, Dyehouse, Early Richmond, Wragg, and
0stheimer received three sprays, the first beginning one month after
bloom. The self-boiled lime-sulphur 10-10-20 and lime sulphur 1-40
sprayed trees were almost equally perfect in foliage. The self-boiled
lime-sulphur 6-6-50 was nearly as efficient as the 10-10-50 concentra-
tion but was considered slightly too weak for the best results. The plat
treated with bordeaux mixture exhibited no injury and the disease was al-

most entirely prevented while the controls were completely defoliated.

lilacs and Stone (10:5) in 1909 recommended applications of bordeaux
mixture 3-3-50 at pro-blocs, at shuck-fall, a third spray two weeks
after chuck-fall, and a fourth spray two weeks later.

In 1910 Norton and Norman (69) advised applications of bordeaux
mixture 3-6-50 as soon as the leases were out and a second spray two
weeks later.

Rulsey, Giddings, and Dacy (83) recommended in 1911 the use of
self-boiled lime-sulphur or bordeaux mixture 3-3-50 or 3-5-50 when the
leases are expanding and a second spray 3 or 4 weeks later.

Clinton and Britten (24) used a.three-spray program.of home-made
1hme sulphur 1-60 in 1912 and obtained no evidence of injury to the
foliage but obtained no infermation in regard to the fungicidal value
of thelmixture since there was very little leaf spot infection.

The use of bordeaux mixture 5-5-50 or liquid lime sulphur 1-50
was advised in 191‘ by Y. 8. Stewart (91) for nursery stock when the
first year buds were 8 to 10 inches in height and repeated at two week
interwals throughout the summer until 5 to 7 applications had been
wade. Superior sticking qualities and less burning of the foliage was
obtained by the addition of IQ pounds of iron sulphate to each 50 gal-
lons of the lime sulphur solution.

Cook (25) stated in 1915 that cherry leaf spot can be controlled
by after-harvest applications of self-boiled lime sulphur. In the
sale circular Headlee, Blake, and Cook recommended the.application of
self-boiled lime sulphur with 3 pounds of lead.arsenate at petal-fall
and when the fruit is the six! of a swell pea. In after-harvest ap-

plication of self-boiled lime-sulphur was also advised.

- 11 -

V. 8. Stewart (92) made a comparative trial of liquid lime sulphur
2-100 and commercial bordeaux;sixture 10-10-100 on Tartarian nursery
stock. The sprayed stock was far superior to the unsprayed control
trees and slightly superior growth was obtained on trees treated with
line sulphur as compared with those sprayed with bordeaux:mixture. The
following year, first year Tartarian stock treated with a six-spray
program of line sulphur 2-100 showed a.marked increase in diameter in
addition to a slight increase in height over the unsprayed control tress.

Brooks and Fisher (15), in an attempt to control brown rot
figlgggtigigrcinergg;(Bon.) Ior. in 1916, obtained no foliage injury on
Royal Ann or Black Republican varieties of sweet cherries with either'
bordeaux mixture 2-4-50 with 2 pounds of resin-fishoil soap, liquid lime
sulphur 1-50 or self-boiled line-sulphur 8-8-50 with 2 pounds of resin-
fisboil soap.

In 1914 Cooper (27) recommended bordeauxrwdxture 2-3-50 or self-
boiled lime-sulphur 8-8-50 for a pro-bloom, a.shuck-fall and a third
spray two weeks after shuck-fall.

Fisher (41) noted, as a result of the application of fungicides
tn 1915, 1916, and 191?, that sweet cherries were considerably reduced
in sise. Bordeaux:mixture 2-4-50 and self-boiled line-sulphur 8-8-50
caused production of’valueless fruit due to shrivelling. This condition
was not as pronounced with liquid lime sulphur 2-100. Portions of certain
trees received two applications of bordesux mixture, the first as soon
as the cherries began to color which was followed by the second spray
two weeks later. It was found that the reduction of size of ripe sweet
cherries was proportional to the amount of alkaline material in the

spray. This condition was thought to be caused by excessive tran-~

-12..

spiration due to the destruction of the waxy bloom of the fruit.

V. 8. Stewart (93) in 1916 compared sulphur-arsenate of lead dust
90-10 with liquid lime sulphur 1-50 on Tartarian nursery stock using a
seven-spray program. Due to heavy seasonal rainfall, it was difficult
to protect the new growth thoroughly. The latter part of August the
average loss of leases in the unsprayed plat was 37 pe roent, the
dusted plat 8 percent and in the sprayed plat 15 percent. The location
of the sprayed plat partially accounted for the relative increased
efficiency of the dust over the spray. V. 3. Stewart (94) reported the
one experiments again in 1911 with slightly different percentages in
the amount of defoliation. lpproximately 68 percent of the.leaves were
lost from the untreated controls in 1916 while sulphur-arsenate of lead
90-10 dusted trees lost only 16 percent.

Roberts and Pierce (79) in 1919 tested the value of numerous com-
mercial and home-made copper and sulphur materials in Michigan. Three
applications were made, the petal-fall, the three-weeks, and the after-
barvest 89?”. Trees treated with self-boiled lime-sulphur showed
almost no leaf spot control while bordesux mixture 3-4-50 and liquid
lime sulphur Zi-IOO gave excellent control. Three applications of
liquid lime sulphur were not sufficient to control severe attacks of
leaf spot but a program of petal-fall, two-week, four-week, and after-
harvest sprays gave excellent control of the disease. Leaf spot was
met satisfactorily controlled with applications of dust although there
was less defoliation on the dusted plats than on the control trees.
Burdens mixture produced severe inJury on sweet cherries and the English
Iorelle and Wrmgg varieties of sour cherry and it was also fotmd nec-

essary to reduce the concentration of liquid lime sulphur to 1-50.

-13-

Dates (8) tested bordeaux mixture 4-4-50 with soap spreader.
liquid lime sulphur 1-45, and Atomic Sulphur 6-50. Six sprays were
applied in such a manner as to give an indication of the separate
value of each spray. Results indicated that the first and last two
applications were of no value for the control of leaf spot. Trees re—
ceiving the three intervening sprays of hordeaux mixture had excellent
control. Atomic Sulphur controlled the disease comparatively well.
Plats sprayed with liquid lime sulphur had such severe burning of the
foliage and defoliation that no data could be taken upon the fungicidal
efficiency of the material. Foliage sprayed with bordeaux mixture was
the best appearing and was retained the longest in the experimental
plats. Unsprayed controls were severely defoliated. Tests were con-
ducted in 1917 but no information was obtained since there was a com-
plete absence of infection. Bares recs-ends. from data collected in
these experiments, applications of bordeaux mixture 4-4-50 with spreader
beginning about Kay 1 and repeated at 3 to 4 week intervals until dry
mar weather is permanently established. He considers that later ap-
plications. might be necessary if rainy periods developed throughout the
simmer.

Keitt (58) tested self-boiled lime-sulphur 8-8-50. Atomic Sulphur
5-50, hrius Sulphur 3-50 and various concentrations of bordeaux mixture
and lime sulphur. Four sprays were applied, a late pro-bloom. petal-
tan. two weeks, and an after-harvest application. Results of two
years' experiments (1917-1918) indicated that bordeaux mixture and lime-
sulphur gate satisfactory control vhile the other spray materials failed
to control the disease adequately. Comparative results obtained with

bordeaux mixtures 4.4.50, 3.3-50, and 2-2-50 were almost equal. Como

-14-

paratively good commercial control was obtained.with the formula 1.1-50
one year but it is considered took weak for general recommendations.
Lime sulphur 1.30. 1-40, and 1-50 satisfactorily controlled the disease
and produced no injury to the foliage. Arsenate of lead 3/4.5o or 1-50
was used in.all sprays and it was found that where lime sulphur was used
wdthout the insecticide the spray was less effective in the control of
leaf spot. When'the pro-bloom spray was omitted, the control was as
good as the four-spray program. Omission of the after-harvest spray
gave results almost as satisfactory as where it was applied. Resultant
recommendations advised applications of hordeaux mixture 3-3-50 or

line sulphur 1-40 or 1930 at petal-fall, two weeks later and also an
after-harvest spray if considered necessary.

I. 0. Stewart (90) based New York recommendations for cherry
sprays in 1919 on Keitt's work (58} in Iisoonsin, advising two or three
sprays of bordeaux mixture 3-3-50 or lime sulphur 1-40 applied as
petal-fall, twodweeks. and after-harvest applications.

In 1920 Coons (26), basing recommendations upon the work of
Roberts and Pierce (79), advised.applications of bordesux mixture 4-4.50
or liquid lime sulphur lfi-SO at petal-fall, about three weeks later.
and directly after the fruit was harvested.

Button (30) in 1918 and 1920 tested comparatively dilute lime
sulphur and dusting sulphur on nontmorenoy and English Morello cherries.
The dust did not control the disease. Dilute lime sulphur adequately
controlled leaf spot on English Morellos until late in September. In-
fections were so slight on the Montmorency control trees that no

information was obtained in regard to disease control on this variety.

- 15 -

Anderson (1) found in 1920 that either liquid lime sulphur 1-40
or bordeaux mixture applied at petal-fall and two weeks later would
adequately control the disease. addition of lead arsenate seemed to
increase the fungicidal walue of the spray,and iron sulphate li-SO de-
creased the asount of injury to the foliage.

In 1920 Sanders and DeLong'(84) applied petal-fall. two-weeks.
and after-harvest sprays of bordeaux mixture 3-3-50 with 1 pound of
lead arsenate, hydrated lime-sulphur-arsenate of lead dust 50-45-5,
lime sulphur 1-40. and sulphur-arsenate of lead dust 90-10. The trees
treated with hordeaux mixture showed between 30 and 40 percent de-
foliation on September 19, the hydrated lime-sulphur-arsenate of lead
dusted plat 35-45 percent defoliation, the lime sulphur sprayed plat
25 percent of the leases infected and a slight defoliation. The sulphur-
arsenate of lead dusted trees showed 25 percent of the leaves infected
and no defoliation. The results indicated that the sulphur-arsenate
of lead dust was superior to the other treatments due to the relatively
high efficiency in control of leaf spot, curculio and slug.

Barre (7) found in 1922 that leaf spot was controlled.wery well
by bordeauxzmixture 25-6-50 applied as petal-fell, three-weeks, and
after-harvest applications on all.warieties of sour cherries included
in the tests except the Iragg and English Iorello cherry.

Button and Johnston (31) in 1920 tested comparatively liquid
line sulphur 2i-100, bordeanx mixture 4-6-50, sulphur-dust, and de-
hydrated copper sulphate (15 percent dehydrated). Tests in 1921 in-
cluded liquid lime sulphur 3-100, bordeaux:mizture 4-7-50. sulphur-
liae-arsenate of lead dust 80-10-10 and dehydrated copper sulphate

(20 percent dehydrated) with 10 percent talc. Petal-fall, two-weeks,

- 15 -

four-weeks, and after-harvest sprays were applied on the Hontmorencys
and, in.additicn, a pro-harvest spray was applied on the English
lorsllos both years. Four-weeks and after-harvest sprays were omitted
on the Hontmorencys both years since there was little leaf spot. Leaf
spot.was not severe on the unsprayed control trees in 1920. The disease
was newer serious on the Montmorencys and even the dusted plats showed
no defoliation at the end of the season, although the sulphur dusted
plats had less infection than the copper dusted plate. Slight infection
was found early in the season in the liquid lime sulphur sprayed plat.
Bordeaux.mixture caused severe foliage injury on the English Morellos
and slight injury on the Iontmorencys. Bordeaux mixture, on the English
norellos ranked highest in fungicidal efficiency, liquid line sulphur
second, and.the two dusts slightly loser than lime sulphur, Results in
1921.were less conclusive. leaf spot control being almost perfect with
every material. No spray injury to the foliage was noted in 1921
although dwarfing of the English Morello cherries was noted in plate
sprayed with bordeaux mixture.

In experiments designed to determine the number of applications
necessary after the harvest of the fruit, Moore (68) concluded in 1925
that three sprays of liquid lime sulphur 2i-100, beginning directly
after harvest in addition to the regular petal-fall and second spray at
the ties the fruit.is well formed, would give good commercial control.

Button and Wells (33) found that bordeaua mixture 8-14-100.
5.14.100, and 5-10 -100 (lunp lime) produced satisfactory control in
experiments conducted in 1922, 1923, and 1924, respectively. It was
found, however, in certain instances that severe foliage injury and con-

siderahle dwarfing of the fruit occurred. Liquid lime sulphur 2i-100

- 17 -

or 3-100 gave as satisfactory control as bordeaux:mixture although,
generally. the control was not as complete on English lorellos. Lime
sulphur caused.a small amount of foliage injury and only a slight re-
duction in fruit size. Pyrox:lB-100 caused severe foliage injury and
defoliation but the fungicidal effectiveness of the material was not
tested adequately. Colloidal sulphur 10-100 and copper or sulphur
dusts caused no apparent foliage injury and very slight dwarfing of
the fruit but did not control the disease satisfactorily.

Ksitt and Jenes (60) found in 1923 that the pro-blossom spray
light be emitted from the schedule since cherry 1...: spot makes little
progress during the cool period of early spring and develops rapidly
in the early part of the summer, reaching maximal development during
wanasr'tesperatures.

Keitt (59), speaking before the Ohio State Horticultural Society
in 1925, stated.that various concentrations of liquid lime sulphur,
self-boiled lime-sulphur, dry lime sulphur. wettable sulphur, and barium
tatrasulphide.were tested over a period of years for the control of
cherry leaf spot. Results indicated that bordaaux:mixture 5-5-50 gase
the most satisfactory control although it occasdonally caused injury.
Liquid lime sulphur applied as*a three-spray program adequately con-
trolled.the disease although it was not sufficient in abnormally wet
seasons. Pro-blossom sprays were found to be of value in certain years.
The after-harvest application, although generally recommended, was of
no value under certain seasonal conditions.

Brooks and Fisher (16) conducted experiments for the control of
brown rot on Napoleon, Black.Republican, and Lambert varieties of sweet
cherries. Bordeaux:mixture 2-4-50 with 2 pounds of roein-fishoil soap,

8-8-50 self-boiled lime-sulphur with 2 pounds of rosin-fishoil soap and

- 1a -

liquid lime sulphur 1-50 were tested. A three-spray program of these
materials produced no spray injury in 1915. Similar results were ob-
tained the following year with a.four-spray program but the cherries
from the self-boiled lime-sulphur sprayed plat were smaller than average.
Ldme sulphur caused foliage injury in 1917 and cherries from the bor-
dsauxzand self-boiled lime—sulphur sprayed plate were smaller than
cherries from the untreated controls. The following year similar
treatments produced foliage injury on the plat treated with lime sulphur,
and the cherries from the plat sprayed.with bordeaux mixture were some-
what smaller than those from the unsprayed trees. In 1919 liquid lime
sulphur 1-50 with casein spreader. neutral bordeauxzmixture 4-50 with
rosin-fishoil soap, and sulphur arsenate of lead dust 85-15 were ap-
plied twice on Napoleons. The control trees and the dusted plats pro-
duced better appearing cherries although the dust was not as effective
in the control of the disease as the sprays. Severe defoliation and
yellowing was noted on hordeaux;mixture sprayed plats three months after
the final applications.

Toothaker (101) states in 1921 that a petal-fall application of
bordeanx mixture followed by liquid lime sulphur and lead arsenate
after harvest failed to control the disease.

Is a result of field observations in 1921. 1922, and 1923 on the
effects of various spray materials on the size of fruit, Button and
tells (3?) conducted transpiration studies on the English Morello
cherry. The water loss per unit area of leaf surface was found to be
the least with unsprayed shoots, slightly more with shoots sprayed with
liquid lime sulphur and significantly more with shoots sprayed with

bordsaux mixture. The rate of water loss per unit area of leaf surface

-19-

during a 24 hour wilting period maintained the same relationship in re-
gard to the effects of the two spray materials. Observations and exp
perimental evidence indicated that leaves sprayed with bordeaux mixture
had a greater power to withdraw water from the green cherries than did
unspraysd leaves during the wilting period. Resistance of the foliage
to frost injury was apparently decreased by the use of bordeaux mixture
while foliage sprayed with.1iquid lime sulphur,or unsprayed, was more
hardy and not as affected by low temperatures.

Experiments conducted in 1925 by ucClintock (67) indicated that
cherry leaf spot was controlled satisfactorily by thorough applications
of bordeaux:mixture 2-4-50. No injury or fruit dwarfing was produced.
The time and number of sprays was not stated.

It was found in New Jersey (4) that five spray applications are
necessary when the disease is severe. Dry mix sulphur-lhme 8-4-50 is
used in the petal-fall and chuck-fall sprays. Commercial m. sulphur
Zi-loo is used in the after-harvest application, in a spray two weeks
later and also in the final application three weeks following the fourth
'PrIJ.

Gloyer (46) observed lesions on the fruit and pedioels of English
Iorellos, as noted by Button (30), and abundant dwarfing at the fruit.
The injuries occurred in orchards sprayed with lime-sulphur to which
arsenate of lead had been added. Experimental plate were arranged in
1925 in such a.manner as to indicate the injuriousness of lime sulphur,
lead arsenats, and the two materials applied in combination. It was
evident that lead arsenate was the primary cause of the lesions upon the
pedicels and fruit and also responsible for a.certain amount of fruit

dwarfing. Similar injury was noted on trees sprayed.commsroially with

- 20 -

dry lime sulphur, proprietary bordsaux.mixture, wettable sulphur, and
sulphur dust when each was applied in combination with lead arsenate.
Wettable sulphur and sulphur dust, each with arsenate of lead, caused
the least injury. The efficiency of the various materials for the con-
trol of leaf spot was not determined.

In 1926 Call (17) obtained almost perfect control with a three-
spray program of summer strength lime sulphur and bordeaux mixture
5-4-50 while unsprayed branches were severely infected. Although no
comparisons of fruit size were made with fruit from unsprayed trees.
it was found that Early Richmond and Montmorency fruit sprayed with
bordeaux:mixture 5-4-50 was larger than lime sulphur treated fruit,
while the reverse was true of English Morello sprayed fruit._

Iiggans and Hoppert (102) in 1928 recommended a shuck-fall and a
second spray three weeks later using either liquid lime sulphur li-lOO
or dry lime sulphur 4-100. Recommendations includsden_after-harvest
spray of liquid lime sulphur lé-100 or bordeaux.mixture 4-4-50 if in-
fections continue to occur.

Due to the excellent control growers obtained with bordeaux
mixture in a severe leaf spot year, Hewitt (56) recommended in 1928
that bordeaux mixture be applied at chuck-fall and 10-12 days later.
Liquid lime sulphur was advised 10-12 days following the second spray,
with the addition of a bordeaux mixture application after harvest, if
the season was wet.

Crosby, Mills, and Blauvelt (28) in 1929 recommended liquid lime
sulphur 2é-100. dry-mix sulphur-lime 25-100. or a sulphur dust applied
at petal-fall. and shuck-fall. followed by two applications timed
primarily for the control of the cherry fruit fly. If leaf spot in-

fections continusdto occur at harvest, an after-harvest application

-21..

was advised.

Wilson and Keitt (105) found wide variation from year to year.
and from orchard to orchard in regard to the influence of spray
materials upon fruit size. Increased weights of Montmorency cherries
sprayed with liquid lime sulphur over fruit of the same variety sprayed
with bordeauxrmixture were as follows: 1924. 15 percent; 1925, 13 per-
cent; 1926, 9 percent; 1927. 16 percent; and. in 1928 the average of
four different orchards was 8 percent. Increased weights of fruit
sprayed with liquid lime sulphur over cherries sprayed with bordeaux
mixture in the four orchards were: Early Richmond. 1 percent, 4 per-
cent. 6 percent. and 8 percent; and on Montmorency. 2 percent, 6 per-
cent. 11 percent and 13 percent. The increase in weights appeared to
be correlated with increased weights of the fleshy portion of the
cherry since there was small variation in the size of the pits.

In 1931 Talbert and Swartwout (98) obtained better control of
leaf spot with bordeaux mixture 3-4-50 than with either Dritomic Sul-
phur 3-50 or liquid lime sulphur 15-100. During years in which light
infection occurred. no significant difference in control was noted be-
tween liquid lime sulphur and bordeaux mixture. although the latter
consistently produced smaller fruit during the years in.which the ex-
periments'were conducted.

is a result of five years' experiments. Young (106) stated in 1929
that bordeaux mixture as weak as 1-3-50 caused severe foliage inJury
and that sulphur dusts were ineffective. Liquid lime sulphur zi-IOO
controlled the disease satisfactorily when the first spray was applied
at petal fall. Results also indicated that mild wettable sulphur

sprays were more effective than sulphur dusts.

-22..

Philip (74) in 1930 stated leaf spot is not considered a serious
factor in cherry production in California except in certain sections
near the coast. No spray schedule has been developed completely.

In 1930 Elmer (36) stated that bordeaux.mixture 4-4-50 and liquid
lime sulphur gave equally good control but that the former dwarfed the
fruit and caused foliage injury. Recommendations include petal-fall,
two-weeks, and after-harvest applications. A four-weeks spray is ad-
vised in seasons especially favorable for the development of the disease.

Bliss (13) applied 12 sprays on first year English Morello trees
between May 25 and August 14 in 1930. Trace sprayed with bordeaux mix-
ture 4-4-50, with 1 pound of Kayso, averaged considerably better growth
than unsprayed trees. Bordeaux mixture with Kayso was considered the
best treatment. Kopper's Thylox dust and Niagara‘Vitidust were as ef-
fective as bordeaux mixture without Kayso. Unsatisfactory materials in-
cluded liquid lime sulphur 2-100 with Kayso, dusting sulphur, Kopper's
Perrox and Nickel dusts, Thylox, Ferrox and Nickel pastes 5-50, and Ni-
agara dry mix and soluble sulphurs 4-50.

Smith (88) in 1930 found bordeaux mixture 6-10-100 superior to
either Ferrox flotation 12-100 or Gray flotation sulphur 12-100 applied
as four-spray programs. Thylox flotation sulphur was compared with
liquid lime sulphur, and both satisfactorily controlled the disease until
mid-season, when a certain amount of defoliation occurred.

Gould (48). following Roberts and Pierce (79), in 1932 recommended
applications of liquid lime sulphur lé-SO or bordeaux mixture 3-4-50 at
petal-fall, three weeks later, and directly after harvest. Powdered
lead arsenate 1-50 or paste 2-50 was advised for insect control.

In 1932 Sherbakoff (87) compared various numbers of applications

- 23 -

of bordeaux:mixturs 2-4-50 with summer strengths of liquid lime sul-
phur and flotation sulphur. Pour sprays of bordeaux.mixture, be-
ginning lay l. and repeated every four weeks, gave as satisfactory
control as seven sprays of the same material. and better results than
seven sprays of liquid lime sulphur. Flotation sulphur was less
satisfactory than liquid lime sulphur.

Headles. Martin, and Farley (52) in 1932 recommended sprays of
flew Jersey Dry Mix 25-100 or equivalent at shuck-fall, and 10 days
later. liquid lime sulphur 2-100 when the fruit begins to color, im-
mediately after the fruit is picked. and 2 to 3 weeks later.

is a result of five years' experiments, Goes (47) found in 1934
that four sprays were advisable in the average year, and that the petal-
fall spray was the most important. Very slight differences were ob-
tained when liquid lime sulphur Zk-loo was used in comparison with dry
lime sulphur, or when Oxybordeaux.or bordeaux:mixturee.were used in the
after-harvest application.

In.l934 Andres (3) obtained adequate control of cherry leaf spot
with a three-spray program. i pro-harvest spray of liquid lhme sulphur
zl-Ioo was followed by an after-harvest spray and an additional ap-
plication four weeks later. each of bordeaux;mixture 4-6-50. Bordeaux
mixture gave superior control to either liquid lime sulphur or
flotation sulphur in experiments conducted in.l93l. Flotation pastes
5-50 gave inadequate control. The concentration of flotation sulphur
was increased to vfi-so the following year. and, although the foliage
of trees sprayed with this material had the best appearance, foliage
sprayed.with bordeaux mixture had atmuoh lower percentage of infected

leaves. In 1934 malachite green 1-5000 with fishoil emulsion, and the

- 24 -

addition of Dutox in the shuck-fall and two-weeks spray gave control
equal to that obtained by the use of bordeaux mixture 4-6-50 in the
after-harvest spray, preceded by liquid lime sulphur zi-IOO.

louse and Elise (66) during a four year period tested thirty
different spray and dust combinations of Early Richmond, English
lorello and lontmorency nursery stock. They reported in 1935 that
bordeeux:mixture 4-6-50 with spreaders was considered the best
materiel. although it tended to retard growth of the tree. The bor-
deaux:nixture effectively prevented defoliation caused by leaf spot.
thus resulting in enough growth to offset the tendency to dwarf the
tree. The efficiency of bordeaumeixture was increased when spreaders
were added to the spray. Dust treatments, in general, were not as
effective as the sprays, although they apparently did not retard the
growth of the trees. Kolodust was not effective in wet seasons. Col-
loidal sulphur. paste, and wettable sulphur were not satisfactory.
Sprays applied every 10 to l5 days. beginning when the growth was from
8 to 12 inches in length --- depending upon the weather conditions...“
were found to be most effective.

Young (10?) stated in 19:55 that leaf spot cannot be controlled
by wettable sulphurs in Ohio. Thoroughly applied liquid lies sulphur
1-50 or its equivalent in the dry form effectively controlled the
disease. Although it was found difficult to determine which of the
two sprays caused the least injury. bordeaux:mixture is gradually being
substituted. due to the dwarfing of the foliage caused by effects of
the lime sulphur solution. He further suggested that weaker solutions
applied thoroughly and more frequently will probably give adequate con-

trol and less injury.

-25-

Button and Parish (35) in 1933, testing a series of bordeaux
‘sixtures of copper-lime ratio lzli with either high-calcium or
dolomitic lime on Hontmorencys, found. in a season of deficient rain-
fall. that the amount of teminal growth decreased as the spray material
concentration was increased. They regard this condition due to seasonal
variations in availahle rainfall. The percent of defoliation in a
season of deficient rainfall was found in direct proportion to the
strength of bordeaux mixture with either lime. The plate sprayed with
bordeaux mixture 8-18-100 with either lime retained more leases than
any plat in the respective series of treatments with the exception of
the 2-3-100 high-calcium lime bordeaux mixture. They considered: this
condition to be due to drought condition. accentuated by bordeaux
mixture. rather than copper injury. Very little defoliation occurred
in a season of adequate rainfall. and no consistent differences between
berdeaux mixtures with different lime were noted. Series of bordeaux
sinures with the copper-dolomitic lime ratio lzfi caused less foliage
injury than similar treatments with high-calcium lime. They concluded
that the dolomitic lime in bordeaux mixture is superior to or at least
equal to the high-calcium lime.

Tests, conducted during a four year period. reported by Keitt,
Blodgett, and mi. (61) in 1936 indicated bordeaux mixture to be the
most effective spray on replicated Montmcrency plats. Very slight dif-
ference was found in the size of fruit from plats treated continuously
with bordesux mixture and lime sulphur solution. Innual alternation of
bordeaux mixture and liquid lime sulphur sprays produced much larger
fruit in the plat sprayed with lime sulphur than in the corresponding

plat treated with bordeaux mixture. Control trees. or plate sprayed

~26-

with liquid lime sulphur that were defoliated Just prior to harvest,
produced the largest fruit. Cherries from trees defoliated shortly
before harvest had a.smaller sugar content than fruit from bordeaux:
mixture sprayed trees which retained their foliage. In certain in-
stances bordeaux mixture apparently caused fruit dwarfing. Thq con-
sidered, however, that the increased fruitfulness following the proper
use of bordeaux:mixture sufficiently counter-balanced the advantage of
liquid lime sulphur, in regard to the fruit size on lontmorency trees.
Rasmussen (75) in 1937 applied two series of bordeaux mixture
with high-calcium lime and dolomitic lime to nontmorencys that had re-
ceived identical treatments for three successive years. Trees sprayed
with high-calcium lime lost two to three times the number of leaves
per spur that were lost by trees receiving similar treatments with
high-magnesium lime bordeaux:mixtures. There was no evidence of a con-
sistent correlation between leaf fall and the bordeaux mixture con-
centration, regardless of the type of lime used. The growth of the
tree decreased as the concentration of the spray material increased.
The stronger concentrations of bordesux mixture produced less increase
of trunk circumference, and it was found that slightly more growth
occurred in plate treated with high-magnesium lhme bordeaux mixtures,
than in those sprayed with high-calcium lime bordeaux:mixtures. High-
magnesium lime bordeeux left more copper residue on the foliage than
corresponding concentrations of bordeaux:mixture with high-calcium lime.
Although the trees were not large enough to produce a commercial crop,
the higher yields of fruit occurred on the plate sprayed with magnesium-
lime bordeaux mixture. The largest fruit.was borne on the plate sprayed

with the lowest concentrations of bordeaux mixture, this relation being

' - 27 -

similar with either lime. Stronger concentrations of bordeaux mixture
with high calcium lime showed a tendency to produce smaller fruit than
equal concentrations of magnesium lime-bordeaux mixture. The percent
of total solids of the fruit was correlated with the concentration of ‘
bordeaux mixture, i.e. the higher the spray concentration, the higher
the percent of total solids. Fruit on the plat sprayed with high mag—
nesium lime-bordeaux was slightly higher in the percent of total solids
than that from plats sprayed with equal concentrations of high calcium
lime-bordeaux'mixture.

In 1937 Keitt, Blodgett, Wilson, and Magic (63), reporting the
results of 18 years experiments on the control of cherry leaf spot,
stated that no material tested was found equal or superior to bordeaux
mixture. Bordeaux mixture 3-4-50 applied at petal-fall, two weeks
later, and after harvest, is considered the best recommendation for
general use. Liquid lime sulphur 1-40 with the same timing and an
additional application two weeks after the second spray is also recom-
mended although it is not considered equal to the bordeaux mixture
spray program. Addition of various spreaders and stickers did not
increase the effectiveness of either bordeaux mixture or liquid lime
sulphur. There were no results that indicated that bordeaux mixture
caused commercially significant reduction in the size of the fruit.

The two standard spray materials for the control of cherry leaf
spot, bordeaux mixture and liquid lime sulphur, are considered un-
satisfactory in certain cherry producing areas. Injury has resulted
from the use of bordeaux mixture, and liquid lime sulphur had failed to
control the disease adequately. Thus, attention has been attracted to
various proprietary insoluble copper compounds recently placed upon the

market as substitutes for bordeaux mixture. It has been found that

- 28 l

certain of these commercial materials will satisfactorily control the
disease and produce less injury than bordeaux:mixture.

lid-season experiments conducted by Cation (20) in 1934 indicated
that Cuprocide (red oxide of copper) equalled bordeaux:mixture in.
fungicidal effectiveness. Although the cause was not definitely de-
termined, foliage injury was noted on certain trees sprayed with this
compound. The following year various concentrations of Cuprocide and
Cupro K'(copper oxychloride) were compared with liquid lime sulphur
zé-lOO and bordeaux:mixture at 4-6—100 and 6-8-100. Just prior to
harvest, infections were well established when the only spray of the
season was applied. Cupro K 4-100 or 6-100 with or without lead are
senate z-lOO treatments appeared the best at the end of the season.
Effects of Cuprocide treatments varied in regard to leaf spot control
and amount of foliage injury and appeared to be correlated with the
concentration of the material. Bordeaux:mixture produced a moderate
amcunt of injury but controlled almost perfectly. Trees sprayed with
liquid lime sulphur had Very poor control of the disease and were
further defoliated than any other sprayed trees. The best plats were
those that received sprays of Cuprocide 1,100 with spreader and nicotine,
Cupro K 6-100 with lead arsenate 2-100, cupro K 4-100,and Cupro K 6-100.
Continuations of these tests were conducted in 1936. Liquid lime sul-
phur zé-lOO, bordeaux:mixture 4-6-100 and 6-8-100, Cupro K 4-100,
20 (copper seclite) 5-100, Cuprocide l-lOO and Oxyhordeaux 6-100 were
the materials used. Three pro-harvest sprays, beginning at petal-fall,
and repeated at 10 day intervals, were applied. Trees sprayed with
liquid lime sulphur were heavily infected, but showed only a light
amount of defoliation due to leaf spot. Plats receiving sprays of

Oxybordeaux and 20 had a light amount of infection and defoliation.

-29-

Trees treated with Cuprocide and bordeaux mixture 6-8-100 showed no
infection but had a moderate amount of defoliation caused by injury.
Neither bordeaux mixture 4-6-100 or Cupro K sprayed plats showed in-
fection, but the former had a heemy defoliation due to injury, while
the latter had a light amount of injury. Cupro K, from the bases of
leaf spot control and spray injury, was considered the best material
tasted. Evaluations of single sprays applied after infection were
well established, placing Cupro K 5-100 considerably above Oxybordeaux
8-100, Cuprocide li-lOO, 20 5-100, lime sulphur {ii-100, and bordeaux
mixture 6-8-100.

In 1937 additional experiments were conducted by Cation (20) f
and has-memes (77) with Cupro K 3-100, Cuprocide l-100, Oxybordesux
6-100, 30 3-100, liquid lime sulphur 2i-100, and bordeaux mixture
6-8-100. Three pro-harvest sprays were applied. 80. leaf spot in-
fection occurred on foliage sprayed with Cuprocide or bordeaux mixture,
although the latter showed severe defoliation duets spray injury.
Curpocide treated trees also had a light defoliation due to injury to
the foliage. Leaf spot infection and resultant defoliation was
severe in plats treated with Oxybcrdeaux, 20, and liquid lime sulphur.
Capra K sprayed trees showed the least amount of defoliation, although
a null amount of injury was noted, and a light infection of leaf spot
occurred, the latter part of the season.

To determine the effect of spray materials on the fruit and
tree, Rasmussen (77) in 1937 applied liquid lime sulphur Eli-100 and
certain concentrations of high-calciun and high-magnesium line bor-
dsau mixtures to plate of uontmorencys which had received previously
identical treatments for three consecutive years. In addition, 30 4-100,

Cupro K 4-100, Cuprocide 1-100, Oxybordeaux 8-100, and a combination of

- 30 -

bordeaux mixture 3-4-100 and Kopper's dry flotation sulphur 2§-100
were tested. Arsenate of lead 2-100 was included in all pre-harvest
sprays. Three pro-harvest and one after-harvest sprays were applied.
no leaf spot lesions were noted in any of the plats. Severe size re-
duction of fruit occurred on trees treated with 4-6-100 and 6-8-100
bordeaux:mixture. The percentage of solids was smaller and the pits
were larger in fruit from trees sprayed with liquid lime sulphur. The
difference in sins of pits was not considered significant. A greater
increase in trunk circumference, superior retention of foliage, in-
creased shoot growth, and a larger total yield of cherries occurred in
plate sprayed with liquid lime sulphur than in plats treated with high-
calcium bordeaux mixture. The 6-8-100 bordeaux.mixture was more in-
jurious than lower bordeauxzconcentrations. Bordeaux mixture with

4 pounds of copper sulphate showed no consistent correlation between the
effect of the spray upon the fruit and tree and different amounts of
lime. Cuprocide caused excessive foliage injury. Other proprietary
copper compounds were less toxic than bordeaux:mixture, and were as
efficient as liquid lime sulphur in regard to leaf spot control and
the amount of spray injury. Cupro K sprayed plats showed more de-
foliation than plats treated with either 30 or-Oxybordeauxt Cupro K
sprayed foliage had much greater amounts of copper residue than either
30 or Oxybordeaux.

It was found in Ohio (108) that the insoluble copper compounds
are generally less effective than bordeaux:mixture in controlling leaf
spot and somewhat less injurious to the foliage and fruit. Cupro K,
Basicop (basic copper sulphate), and Coposil (copper ammonium silicate),

were tested at the company recommendations. The proprietary materials

- 31 -

tested in 1937 controlled the disease better than any other material
and caused very little injury. Liquid lime sulphur li-lOO, dry lime
sulphur 6-100, or proprietary copper compounds are recommended for

the shuck-fall application, 2 to 3 weeks spray, and a third spray when
the fruits begin to color. in after-harvest spray of lime sulphur
li-lOO, or dry lime sulphur 6-100 is also advised; none of the insoluble
proprietary copper compounds are recommended for the fourth spray.

To determine the efficiency of various proprietary copper com-
pounds, Cation (19, 21) and Rasmussen (76, 21) conducted experiments
using a four-spray program on the Montmorency variety of sour cherry in
1937. Basicop-lime 3-8-100, bordeaux mixture 3-4-100, Bordow 6-100,
Coposil 3-100, Grasselli copper oxychloride li-lOO, and Cupro K 3-100
satisfactorily controlled the disease and did not cause significant
amounts of foliage injury. 20 3-100, Oxybordeaux 6-100, Basicop-lime
lé-l-lOO, and Copper Hydro '40' 3-100, although superior to liquid lime
sulphur 2§-100 treatments, did not give satisfactory control of leaf
spot. No appreciable dwarfing of the fruit was caused by any of the
proprietary copper compounds.

Kadow and Anderson (57, 2) tested various proprietary copper
compounds on Montmorency, Early Richmond, and Dyehouse varieties of
sour cherries, using a four-spray program. They found that Bordeaux
'34'-sinc sulphate-lime 1L-i-Q-ioo, Cupro K 2-100, and liquid lime
sulphur 2-100 adequately controlled leaf spot and did not cause
significant amounts of foliage injury. Copper Hydro '40', Coposil,
Basicop, Cuprocide 54, and a Niagara copper compound satisfactorily con-

trolled the disease but caused considerable spray injury to the foliage.

Sprays applied by Hamilton (50) in 1938 on Montmorencys consisted

-32-

of petal-fall, shuckbfall, and after-harvest applications. These
sprays were supplemented by two cherry fruit fly sprays, approximately
a month before harvest. The sulphur compounds were generally in-
effective in control of leaf spot. The most effective sulphur spray
was Kopper's flotation paste 10-100 used with Orthcx (oil sticker).
Flotation sulphur 10-100. liquid lime sulphur with goulac and lime,
liquid lime sulphur l-lOO with Catalytic Sulphur 4-100, Magnetic
Sulphur 6-100 with soybean flour é-loo, ancholofog 6-100, did not give
satisfactory control. Results indicated that the sulphur materials

are more effective-if leaf spot is not allowed to become established.
Although foliage injury occurred, perfect control was obtained in

plate sprayed with both calcium and magnesium lime bordeaux mixtures
at 5-4fi-1oo and.6-9-100. Trees, sprayedwith magnesium lime bordeaux
mixture, retained their foliage slightly longer than those sprayed
sith calcium lime bordeaux, although not enough to be considered of
commercial significance. Delayed maturation and an approximate 25 per-
cent reduction in size of the fruit occurred on fruit sprayed with bor-
deaux mixture. Bordeaux mixture 6-9-100 produced smaller fruit than
the 3-4§-100 concentration. Both strengths of magnesium lime bordeaux
mixture caused smaller fruit than the calcium lime bordeaux.mixtures.
It was found that the fruit size was almost normal when Orthsx was added
to the 3-4i-100 bordeaux:mixture. Omission of one or more applications
of bordeaux:mixture caused no significant difference in fruit size or
time of fruit maturation. He stated that copper injury, which may
occur within three weeks after an application of bordeaux mixture, was

largely prevented in the pro-harvest period by repeated applications of

- 33...

the spray. Sprays of lime applied as foliage injury first appeared,
prevented the yellowing and defoliation. He also stated that lower
concentrations of bordeaux mixture, within certain limits, produce more
foliage injury, due to greater ionization of the copper --- there being
less ionisation in higher concentrations. Although bordeaux mixture is
not advised as a pro-harvest spray except in severe epidemics of leaf
spot, recommendations include bordeaux:mixture 3-6-100 with one pint of
Orthax, rather than higher concentrations.

Hamilton (50) also found in 1938 that the proprietary copper com-
pounds used with lime and Orthex.controlled leaf spot better than the
sulphurs, caused little foliage injury, and showed no evidence of fruit
dwarfing. Cupro K 3-100 and Coposil 3-100, each with 3 pounds of lime
and one pint of Orthex, were the two best insoluble copper sprays tested.
addition of Orthcx to the materials reduced the amount of defoliation
50 percent and also the amount of infection. He stated that increased
effectiveness of a spray with Orthex was not wholly due to better
adhesion but, in part, to superior spreading of the.material. The
addition of one pound of lime for each pound of 20-25 percent copper
was found essential. As the amount of lime used with Coposil was in-
creased, the copper deposited per unit of leaf area decreased. If
applied on an equal copper basis, Micronised.Copper showed greater
adhesion but also caused more foliage injury than the other copper com-
pounds. Cuprocide-lime 1-1-100 with one pint of Orthex gave better
leaf spot control but produced more foliage injury than the other
materials tested.

Daines (29) in 1939 tested liquid lime sulphur, liquid lime sul-

phur in combination with aluminum sulphate and lime, wettable sulphur,

-34-

wettable sulphur with Orthex, bordeaux mixture 1-3-50 and 2-3-50 with
magnesium and calcium limes, bordeaux:mixture with metallic zinc,
home-made and commercial copper phosphate with and without bentonite,
Coposil with and without Orthex, ZO, Cupro K. Oxybordeaux, Basicop,
Copper-Hydro 40, '34' with sinc sulphate, Cuprocide 54, and aluminum
sulphate with lime. The proprietary copper compounds were used with
and without lime. The copper materials more effectively controlled
leaf spot than the sulphur materials. Bordeaux mixture at all con-
centrations caused injury to the cherries. Certain insoluble copper
compounds caused injury when used without lime. The fungicidal.
efficiency of the copper sprays was generally correlated with the ad-'
hesive properities of the material. Aluminum sulphate with lime and
liquid lime sulphur was more effective than liquid lime sulphur used
alone. lettable sulphurs with Orthex:gave superior control to wettable
sulphur alone. He further stated that the lack of injury in certain
cases was probably due to poor adhesion.

Keitt and Clayton (64) found in 1939 that bordeaux:mixture in
any concentration gave control superior to other materials tested.
However, the trees sprayed with bordeaux;mixture also bore the smallest
fruit. The plat sprayed with basicop-lime 3-8-100, of the plats treated
with proprietary copper compounds, had the least defoliation. Coposil-
lime 2-4-100 with 0rthex.1-400 was superior to Cupro K 3-6-100.
. Liquid lime sulphur 1-40 was superior to Coposil. The unsprayed con-
trol trees bore the largest fruit, and no significant difference was
found in fruit size between any of the insoluble proprietary copper
compounds.

Rasmussen (78), in comparative four-spray program tests on Mont-

- 35 -

morencys, found in 1938 that Basicop-lime 3-8-100, Bordow 6-100,
Grasselli Compound A lé-100 with one pint Orthex, and bordeaux mix-
tures 3-4-100 and 6-8-100 gave excellent control. Tennessee 26-lime
3-3-100, bordeaux:mixture 2-3-100, Coposil-lime 3-3-100, and Bordeaux
34-lime Zi-3-100 gave good control; Cupro K-lime 3-3-100 and liquid
lime sulphur 2£-100 gave only fair control. All the proprietary
copper compounds caused slight amounts of injury to the foliage, and
Grasselli Compound A produced severe injury. Bordeaux.mixtures 3-4-100
and 6-8-100 caused moderate amounts of foliage injury.

Hamilton (51) reported in 1939 that liquid lime sulphur reduced
’the fruit set of English Morellos and also caused severe foliage in-
iuryo Tests indicated flotation sulphur paste 8-100, with one pint of
Orthsxa to be the most effective of the sulphur combinations used.
FlotoxLS-lOO, with one pint of Orthex, gave superior leaf spot control
to liquid lime sulphur. In a season of light rainfall, copper com-
pounds applied on equivalent copper bases, with or without 0rthex:or
spreader-sticker, produced excellent leaf spot control. Cupro K was
the safest copper material when used alone. He found after-harvest
applications of lime checked injury on sweet cherries. Grasselli Copper
Compound I. with lime gave comparatively satisfactory results, but its
effectiveness was not definitely determined. Basicop, Copsil, Cup-
rocide, and '26' controlled leaf spot almost as effectively as Cupro K,
but caused some foliage injury. The best bordeaux combination was
3-6-100 with one pint of Orthex, but it caused tooxauch foliage injury
and dwarfed the fruit too severely to be recommended unless applied very
lightly. Results indicated that bordeaux:mixture applications, alter-

nated with 10-100 lime, may be a desirable schedule. Bordeaux:mixture,

-36-

alternated with Cupro K, also appeared promising --- especially under
severe leaf spot conditions. Recommendations include Orthex in the
regular copper sprays and lime in the after-harvest spray to check in-
jury, especially if recent pre-harvest sprays omitted lime. An after-
harvest spray of lime is advised if no leaf spot is present. Cuprocide
applied just before harvest leaves no residue, and the lime application

applied after harvest effectively checks the foliage injury.

~ 3?

THE PROBLEM

The purpose of this study was to determine the value of Basicop’
and certain other compounds as spray materials for cherries in Mich-
igan. Experiments were planned to study the fungicidal effectiveness
of the materials on the pathogens causing cherry leaf spot (Coccggyces
higgglis Higgins) and also to determine their physiological effects

upon the cherry fruit and foliage.

'Basicop is a proprietary copper compound manufactured by the
Sherwin-Williams Company, Cleveland, Ohio. It is a powdered form of
basic copper sulphate. the formula of which may be considered as
ensue e 20u(0H)2. The pure commercial product contains:appromeately
53.8 percent metallic copper; The average of the market output of
Basicop, however, contains 50 to 52 percent metallic copper, this may
be the result of a slight lack of balance in the proportion of basic
and acid copper molecules or perhaps some little water of crystal-
lisation or combined moisture.

EXPERIMENTAL PROCEDURE

Roach Orchards, Hart, Michigan, 193?

Materials and methods

Fifteen year old vigorously growing trees of the Hontmorency
variety of sour cherry were selected for experimental purposes at the
Roach Orchards, Hart, Michigan. The block of approximately 192 trees,
32 trees long and 6 wide, was divided into 16 plats of 12 trees each
and arranged 3 trees wide by 4 trees long. This block was fairly uni-
form in sise and vigor of trees, and all trees had received similar
cultural and spray treatments in previous years. It was originally
planned to have the plats consist of 12 trees but occasional dead or
dying trees -- due to winter-injury and Armillaria root rot (Armillgia
ggllgg) -- and a few young, non-bearing trees were scattered through-
out the orchard. Data were, therefore, taken on all representative
vigorous, mature trees in each plat.

The spray materials tested-were: two proprietary copper compounds,
Basicop and Cupro K, two concentrations of bordeaux mixture, several
sulphur sprays, and liquid lime sulphur. Dolomitic lime was used in the
combinations requiring lime because certain experimental results (35,
15) have indicated that magnesium lime is superior to high calcium lime
in bordeaux mixture. Lead arsenate was used in the two-weeks and four.
weeks applications with all materials at the concentration of 3 and 2

pounds, respectively, to one hundred gallons of water. The materials

-39..

and concentrations tested are presented in Table l.

The recommended four-spray program of Michigan which consists of
three pre-harvest and one after-harvest sprays was adopted in the exe
periment. As shown in the rainfall and spray chart (Figure l), the
petal-fall spray was applied May 30-31, the two-weeks spray on June 15-
16, the fourbwesks application on June 26-27, and the after-harvest
application on August 7-8. In order to determine the effect of a three-
spray program on the control of leaf spot and the amount of spray
injury, the plate treated with Basicopolime 3-8-100, Cupro K 3-100,
Gupro K 5-100, bordeaux mixture 3-4-100, and bordeaux mixture 6-8-100
were divided into two portions of approximately six trees each for the
after-harvest sprays. One-half of each plat was given the regular
after-harvest spray while the other half received no application. In
addition, three unsprayed control trees were maintained throughout the
season. ‘

lash spray was carefully and thoroughly applied from the ground
with a single nozzle gun and each tree was completely sprayed before
beginning another. Between 5 and 8 gallons of spray per tree were ap»
plied and, as a result of this overspraying, a certain amount of drip
occurred. A pressure of 400 to 450 pounds was maintained in all sprays.

Two days were necessary to complete the entire series of applications.

Epidemiglogical conditions

The Roach Orchard in 1936 received four pro-harvest sprays of
liquid lime sulphur 3-100. Cation (20) reported that a great deal of
leaf spot infection occurred in this orchard during the late August and

early September rains and that the trees were almost wholly defoliated

- 4o -

by leaf spot on October 9. These late infections of 1936 resulted in
an abundance of ascosporic inoculum in the spring of 1937 as evidenced
by examinations of the old leaves. Microscopical examination and forced
ascospore discharge in the laboratory from apothecia collected on leaves
during the first week of Ray revealed that the ascospores were mature
and ready to be discharged upon the occurrence of favorable moisture
and temperature relations. V

The growing season of 1937 was especially favorable for the de-
velopment of cherry leaf spot in epiphytotic form. Rains occurred about
every ten days (Figure 1) throughout the season. After the latter part
of June, yellowing of the leaves and resultant defoliation appeared ap-
proximately ten days after each rain in which infections occurred on
trees not properly protected. A light primary infection may have
occurred on May 16, although the foliage was not far advanced. Observa-
tions indicated that the first serious ascosporic infections did not
occur until the rain of May 21 (Figure 1). Additional primary infection
occurred May 28 and possibly some secondary, since sparsely scattered
mature acervuli were noted may 29. The first significant secondary in-
fection occurred June 5 and was followed by abundant infections during
the frequent rainy periods throughout the remainder of the season. De-
foliations due to leaf spot were first noted June 26 and continued to

occur at frequent intervals until the latter part of September.

Results

Conditions during 1937 were particularily advantageous for the
evaluation of fungicides due to the severity and frequency of leaf spot

attacks and, also, due to the opportunities offered to observe the

physiological effects of the spray materials on the fruit and foliage.

The earliest determination of comparative infection was made
June 23 (Table 2). The infected leaves showed from.one to five lesions
per leaf, and no attempt was made to differentiate between leaves
lightly or heavily infected. Examination of these data show that, re-
gardless of the spray materials used, infections were well established
on all plats. Foliage sprayed with copper materials showed a tendency
towards less infection than foliage treated with the sulphur compounds.
The percentages of infection do not necessarily indicate the amount of
defoliation due to leaf spot that occurred on the plate later in the
season. The copper sprays almost completely checked defoliation due to
leaf spot and also checked further infection while the disease was never
satisfactorily controlled by the sulphur sprays.

Data presented in Table 3, almost a month prior to harvest, show
that leaf spot had caused almost no defoliation in the majority of the
plate sprayed with copper materials. There was a slight loss of foliage
in plate treated with Basicop-lime 3-1-100, Basicop-lime lé-4-100,
and Cupro K 3-100 but not sufficient to be considered commercially
significant. Very poor control was evident in plats pprayed with the
sulphur compounds. Dry lime sulphur 10-100 and liquid lime sulphur
25-100 gave superior disease control to the other sulphur materials
tested, although not equal to any of the copper compounds. The remainder
of the sulphur sprayed plats showed almost no control and were com-
parable to the unsprayed check trees.

Comparative determinations of the amount of spray injury to the
foliage in the different plats were made June 30 (Table 3). Plate

sprayed with the sulphur materials showed no evidence of yellowing,

-42..

burning or defoliation due to spray injury. Foliage sprayed with dry
lime sulphur and 325 mesh sulphur 2-4-100, dry lime sulphur 4-100, and
Ilectric sulphur 4-100 appeared to be slightly larger than that of the
plat sprayed with liquid lime sulphur 2§-100. This effect was soon
lost, however, due to the tremendous defoliation caused by leaf spot.
Spray injury was not evident in plate treated with bordeaux mixture
3-4-100 or 6-8-100, Basicop-lime 3-8-100, or Basicop-lime li-4-100.
Light defoliation due to spray injury was noted in plate treated with
Basicop-lime 3-1-100, Basicop lé-lOO, Cupro K 6-100, and Cupro K 3-100.

lid-season observations also indicated, as shown in Table 3, that
the foliage of trees sprayed with Basicop-lime 3-8-100, bordeaux mixture
3-4-100, and bordeaux mixture 6-8-100 was excellent in appearance, the
leases being broad, flat and deep green in color, showing no evidence
of chlorosis. However, trees sprayed with any of the remaining copper
treatments had a few yellow leaves scattered throughout the foliage.
The greater percentage of the leaves of unsprayed control trees and of
trees sprayed with the sulphur compounds was distinctly yellow in color
and showed very little evidence of disease control.

Copper materials gave superior disease control to the sulphur
materials throughout the season. We defoliation caused by leaf spot
occurred on the plate treated with Basicop-lime 3-8-100, Basicbp 3-100,
Basicep lfi-lOO, Cupro K 6-100, bordeaux mixture 6-8-100, or bordeaux
mixture 3-4-100. Traces of defoliation caused by the disease were noted
on plate grayed with Cupro K 3-100 and Basicop-lime 3-1-100 while the
weaker concentrations of Basicop and Basicop-lime, lé-lOO and li-d-lOO

respectively, showed light defoliaticns.

Observations throughout the season served to emphasize the
general ineffectiveness of the sulphur compounds as compared to the
high relative efficiency of the copper compounds in controlling leaf
spot. Losses of foliage continued to occur shortly after each rain in
the sulphur sprayed plats and, by the harvest period, the majority of
the trees were almost completely defoliated. Consequently, the sulphur
treatments were abandoned in the after-harvest applications, and
Basicop-lime 2-3-100 substituted. This spray preserved the small amount
of foliage left and also protected the secondary leaves that were be-
ginning to appear.

Several light waves of yellowing and defoliation due to spray in-
jury occurred in the majority of the plate treated with the copper
materials. Defoliation on the plate treated with bordeaux mixture did
not occur until a month following the after-harvest applications while
the injury on the plate sprayed with the proprietary copper combinations
occurred at periodic intervals after June 39. The copper sprayed plats
presented, quite generally, an excellent appearance after the injured
leaves were dropped, although when they were on the trees the plate
showed an unnatural yellow color. It was found that many light de-
foliations, due either to leaf spot or spray injury, might be over-
looked unless observations were made upon the condition of each plat
every two or three days.

One main criterion for evaluating the fungicides in relation to
efficiency in controlling the disease and also in relation to the in-
jurious effects to the foliage, is the percent of defoliation in each
plat at the end of the season. The data on the final comparative de-

foliation are presented in Table 4.

Both leaf spot and spray injury were responsible for the de-
foliation that occurred in plats sprayed with Basicop li-lOO and
Basicop-lime 1§-4-100. The determining factor of defoliation in the
remainder of the copper sprayed plate was spray injury. As shown in
these data, it is apparent that the addition of lime to Basicop prevents
much of the spray injury to the foliage. Basicop and lime 3-8-100 gave
results superior to Basicop 3-100 without lime. The addition of one
pound of lime to 3 pounds of Basicop was insufficient to correct spray
injury. Three pounds of Basicop satisfactorily controlled the disease
regardless of the addition of one or 8 pounds of lime. Any benefit
obtained from the addition of 4 pounds of lime to Basicop li-lOO was
not determined since leaf spot was largely the causal agent of defol-
iation. It seemed apparent, however, that the addition of lime
slightly decreased the toxicity of low concentrations of Basicop.
Rasmussen (78) obtained similar results with Cupro K. Cupro K at
concentrations of 3-100 or 6-100 adequately controlled the disease but
caused considerable spray injury to the foliage. Dry lime sulphur 10-
100 and liquid lime sulphur Zfi-lOO gave very poor control of the disease.
The defoliation of the remainder of the sulphur treated plate was so
complete that records were not taken. The percent of defoliation of
plats sprayed with dry lime sulphur 4-100, dry lime sulphur with 325
mesh dusting sulphur 2-4-100, Electric sulphur 4-100, liquid lime
sulphur 1—100, and liquid lime sulphur with Electric sulphur 1-4-100
was arbitrarily estimated at 98 percent. Much of the defoliation on
the sulphur sprayed plats was due apparently to poor adhesion of the
materials during rainy periods. This condition was particularly evident

in the six-week interval between the four-week and after-harvest ap-

plications.

-45-

It will be noted from comparisons between early infections
(Table 2) and defoliations at the end of the season (Table 4), that
the percent of defoliation recorded for the sulphur sprayed plats
and the unsprayed control trees on September 25 corresponds to the per-
cent of leaf spot infection determined on June 23. However, apparent
similarities between the percentages of defoliation and leaf spot in-
fection on the copper sprayed plate can not be correlated since the
defoliation was caused by spray injury in the majority of the plate, and
not by leaf spot.

Plats sprayed with Basicop and lime at 3-8-100, bordeaux mixture
3-4-100, and bordeaux mixture 6-8-100 applied as three-spray programs,
had more defoliation than when given four-spray programs (Table 4).
Leaf spot and spray injury were responsible for the loss of foliage in
the plat receiving sprays of Basicop 3-8-100. Defoliation in the plate
treated with bordeaux mixture was caused only by spray injury. Three
applications of Cupro K 3-100 or 6-100 resulted in less defoliation
than four sprays of either concentration. The defoliation in each of

these instances was caused by spray injury.

8 ec s a re-b o s ra u im an u 9

Growers using the liquid lime sulphur spray schedule have offered
the observation that an additional spray applied in the pro-bloom
period has given better control of leaf spot than the regular four spray
schedule which begins with a petal-fall application. Experimental
evidence is controversial on the value of a pre-bloom spray (53, 58, 60,
80).

An experiment was undertaken to determine the effect of 5 sprays

of liquid lime sulphur (including a pre-bloom application) compared with

-46.-

a four-spray schedule (no pro-bloom application) of the same material.
In arranging the plats in duplicate, it happened that the trees in two
of the adjacent plats receiving the different spray treatments had re-
ceived copper sprays the previous year while the other two comparative
plats had received liquid lime sulphur sprays. The copper sprays con-
trolled leaf spot excellently the year previous while the liquid lime
sulphur sprays gave poor control. Consequently, there was a tre-
mendous difference in the amount of ascosporic inoculum beneath the
trees according to the treatment of the previous year. EXamination of
over-wintered leaves showed (Table 5) that apothecia were scarce under
trees that had excellent control. Mature apothecia were abundant in
the section of the orchard where control was poor in 1936.

Comparative determinations of leaf spot infection were made on
June 23. Reference to the data presented in Table 5 shows that the
plat, number 16, receiving the pre-bloom spray had only 2.65 percent of
the leaves infected while the plat immediately adjacent, number 17,
which received the first spray at petal-fall, had 61 percent of the
leaves infected. Fifty-eight percent of the leaves were infected in
plat 42 which also received the first spray at petal-fall.

Although no numerical determinations of the amount of infection
were made on plats l and 2, it is significant that correspondingly less
infection was found in plats 1 and 2 than in plats 16 and 17. The dif-
ference may be explained by the lack of initial inoculum in the former
plats, due to effective spray treatments the previous year. Keitt has
obtained similar results with the elimination of initial inoculum by
early spring cultivation (58) and the use of eradicative sprays (62).

The results in one instance of the experiment show that the inocu-

- 47 -

lum.immediately beneath each tree was the determining factor in the
resulting amount of infection and that the amount of lateral dissem-
ination of inoculum which may have occurred was insignificant. The
trees of plate 1 and 2, under which there were few apothecia, were
separated in one direction by only a single row from trees that were
liberally infected with leaf spot and under which there wan an abundance
of initial inoculum. A block of severely infected trees which also had
an abundance of ascosporic inoculum was separated by a narrow roadway
from another end of the experimental plate. In spite of the proximity
of abundant inoculum, the trees of plats 1 and 2 maintained significantly
little infection until the six-week interval between the four-week spray
and the after-harvest application.

Uhtil shortly before the harvest period, the plate that received
the pro-bloom sprays showed less infection and defoliation than the
corresponding adjacent plate that received the first spray at petal-
fall. Thus, plat l was superior to plat 2 in the low inoculum area, and
plat 16 appeared definitely superior to plat l? in the high inoculum
area. However, the differences became less apparent later in the season
and very little difference could be noted in the comparative amounts
of control between the pre-bloom and petal-fall spray schedules in ad-
jacent plate. This condition was not especially marked in the high in-
oculum area since plat 1 retained more foliage than plat 2. Observations
indicated that the effectiveness of pre-hloom applications of liquid
lime sulphur in seasons of abundant rainfall is lost during the late
summer and early fall and, also, in the sixeweek interval between the
four-week spray and the after-harvest application.

The percentages of defoliation taken September 25-26 (Table 5)

-48..

show that plats receiving the pre-hlossom spray had slightly superior
control to the adjacent plats that received the regular four-spray
program of liquid lime sulphur. The amount of initial inoculum present
governed, to a certain extent, the amount of defoliation that occurred
by the end of the season. Plats in which there was a scarcity of
primary inoculum retained distinctly more foliage than plate in which
apothecia were abundant.

Comparisons of the defoliation and infection data (Table 5)
show that the percentages of infection do not indicate the amount of
final defoliation. This is due, in part, to the loss of protective
action of the spray materials during rainy periods. It is also ap-
parent from the data presented in Table 5 and Figure 1 that the
applications of the four-spray programs were not well timed in regard
to the rains to produce the highest degree of control with liquid lime

sulphur.

R s o u lo 3 t t s z '. .

Hany investigators recognize that spray materials may affect
cherry fruit size. To determine the effect of the‘various sprays on
the size of the fruit, 25 cherries were similarily selected and picked
from each quarter of the tops of 6 representative trees in each plat.
One-hundred cherries were selected from each tree, making a total of
600 cherries used in the fruit size determination of a plat. The com-
parative fruit size determinations are presented in Table 6.

Plats that had considerable defoliation just prior to harvest
bore the largest sized fruit. Keitt, et a1. (63) found that defoliation
before harvest sometimes resulted in such an increase in size. Many

investigators (15, 17, 29, 32, 33, 41, 45, so, 61, 63, 54, 75, 77, 105)

-49..

have noted definite dwarfing of the fruit on trees sprayed with certain
fungicides. This reduction in fruit size was readily detected by
casual observation in the plat sprayed with bordeaux:mixture 6-8-100.
Fruit from.the plat treated with bordeaux mixture 3-4-100 was small

but the reduction in size was not as pronounced as with the stronger
concentration. Although,in one instance as much lime was used as in
bordeaux mixture 6-6-100, fruit of trees sprayed with Basicop or
Basicop and lime compared favorably in size with that from trees sprayed
with either liquid lime sulphur or other copper compounds. Cherries
from trees sprayed with either Basicop, Basicop-lime, or Cupro K were
wuperior in size to that from the plats sprayed with bordeaux:mixture

6-8-100 or bordeaux misture 3-4-100.

Residual copper 9n fgliage.

The amount of copper residue on the foliage was determined for
each plat at the end of the season. A disk, one centimeter square,
was punched near the mid-rib from the center of each leaf. Analyses
were based upon 100 disks from each plat. As is shown in the data pre-
sented in Table 7, plate receiving four sprays retained a greater
amount of residual copper in each instance than plats given three
sprays of the same material and concentration. Foliage treated with
four sprays of bordeaux mixture 6-8-100 retained distinctly more capper
than leaves receiving any other treatment. The data indicate that
bordeaux mixture 6-8-100 or 3-4-100 used either in a four-spray or
three-spray program has superior adhesive qualities to most of the con-
centrations of Basicop tested. Similar results have been reported by
Wilson (104) and McCallan and Wilccxon (65). The data.also indicate

that the addition of lime to Basicop did not materially affect the

-50..

weather resisting qualities of the fungicide. The amounts of copper
deposit show that Cupro K (20 to 25 percent metallic copper) adheres to
the foliage better than Basicop when the two materials are applied at
equal copper content concentrations. McCallan and Wilcoxon (65) have
also pointed this out. Since no direct correlation can be drawn between
the amount of residual capper and the amount of defoliation due to spray
injury, it appears that the chemical character of the residual copper

complex may be the determining factor in the amount of defoliation.

Field Orchard, Shelby, Michigan, 1937
Materials anQJQethods

A.block of 54 Hontmorency trees approximately twenty years old
was used in an experiment at the Field Orchard, Shelby, Michigan. The
trees were large and closely planted with the majority of the foliage
in the tops. Three plats of 18 trees each received three pre-harvest
and one after-harvest sprays. The petal-fall spray was applied June 1,
the two-week application June 16, the four-week and after-harvest
sprays on June 28 and August 13, respectively. The spray materials
used were Basicop-lime 3-19100, Cupro K 6-100, and liquid lime sulphur
2i-100. Lead arsenate was added in the two—week and four~week ap-
licstione at the rate of 2 and 3 pounds, respectively, to 100 gallons
of'Iater.

Results

The orchard was clean cultivated during the early part of the

spring, and, as a consequence, infections became relatively heavy only

- 51 -

throughout the latter part of the season. Defoliation due to leaf
spot began to occur August 12 on the trees sprayed with liquid lime
sulphur. No loss of foliage caused by the disease was found during the
season in the plats treated with the copper materials.

Several light defoliations caused by spray injury occurred in the
plats sprayed with Basicop-lime and Cupro K, the first leaf fall occur-
ring July 13. Despite these defoliations, the two plats presented a
much better appearance at the end of the season than did the plat sprayed
with liquid lime sulphur. The actual percentage of defoliation was not
determined.

Twenty-five cherries were picked from.each quarter of the tops
of 12 to 15 representative trees in a.plat to determine the effect of
the sprays on the size of the fruit. is shown in Table 8, no appreci-
able difference in the size of the fruit from the three plats could be

determined.

McClary Orchard, Empire, Michigan, 1937

Materials and methods

Three plate of approximately 60 trees of the variety Montmorency
were selected at the McClary Orchard, Empire, Michigan. Basicop and
lime 2-19100, bordeaux:mixture 4-5-100. and Cupro K 4-100 were the
materials used. The petal-fall spray was applied June 4, the two-week
and four-week sprays on June 18 and 30, respectively. Lead arsenate
3.100 was added to the materials in the second and third sprays. The
plat sprayed with bordeaux mixture 4-5-100 did not receive a four-

week spray. A11 plate were dusted with sulphur to prevent brown rot

infections following the severe windstorm of July 25.

Results

Initial inoculum was almost absent since bordeaux mixture had
given excellent control the previous year. Leaf spot infection was so
slight that records of the comparative control value of the different
spray mixtures were not obtained.

Although the experimental plate were not under continuous ob-
servation, a light defoliation due to spray injury was noted August 8.
As shown in Table 9, the plat sprayed with Cupro K showed conspicuously
more injury than did the plate treated with Basicop-lime or bordeaux
mixture. This injury was observed two weeks after the windstorm. If
the defoliations were considered as a result of soluble copper entering
wind-bruised leaves, the lack of injury on the plat sprayed with \
Basicop might be attributed to a more sheltered position. This condition
was not true, however, for the plat treated with bordeaux mixture.
Further, the remainder of the 90 acre cherry orchard was sprayed with
Basicop-lime 3-6-100 and showed little injury. Only slight defoliation
was apparent frem casual observation on any of the plats, even as late
as October 13. The percentages of defoliation were not obtained.

To determine the effect of the sprays on the size of fruit, 100
cherries were selected at random from 24 filled lugs. Each lug that
was sampled was taken from a representative tree of each treatment. The
weights of 2,400 cherries were determined for each sprayed plat. Only
sileugs were sampled from the control tree. The results presented in

Table 10 are significant in that no dwarfing due to bordeaux mixture

-53..

could be ascertained. This is at variance with the results obtained
at the Roach Orchard previously noted in this paper and with results
published by other investigators where three pre-harvest sprays were
applied. Keitt's, et al., results (63) indicate the dwarfing effect
of bordeaux mixture to be slight, but his records were taken from
trees receiving two pre-harvest sprays. As the third bordeaux spray
was emitted at the ucClary Orchard and as no fruit dwarfing could be
detected, the results naturally suggest that the third spray is re-
sponsible for the dwarfing effect on fruit sprayed with bordeaux:mixe
ture. Similar results have been reported by several Michigan cherry
growers who consistently use only two pre-harvest sprays of bordeaux
mixture and who stated they found no reduction of fruit size re.
sulting from that procedure. Cherries from the unsprayed control tree
were much larger than fruit from any of the sprayed plats. Fruit
sprayed with Cupro K was the smallest and there was little difference
in the size of fruit treated with either bordeaux mixture or Basicop

3nd lime.

Smith Orchard, Omens, Michigan, 1937

Materials and methods

 

Three plate of Montmorency trees, ranging in size from 39 to
84 trees, were selected at the Smith Orchard, Omens, Michigan. The
petal-fall spray was applied June 3, the twooweek spray June 18, and
the four-week application on June 30. Basicop and lime li-l-lOO,
Cupro K 3-100, and liquid lime sulphur 2i-100 were the materials tested.

Lead arsenate 3~100 was added to the two-week and fouroweek sprays.

-54..

Results

No leaf spot infection was noted even on the unsprayed control
tree since the season was abnormally dry at Onena. The plat treated
with liquid lime sulphur appeared to be superior to the trees sprayed
with either Basicop—lime or Cupro K. However, the differences between
the appearance of the treatments was so slight that no defoliation per-
centages were determined.

Cherry sise determinations of fruit from 18 to 20 representative
trees in each plat were taken. Approximately 100 cherries were picked
at random from each tree. The cherries from the trees sprayed with
copper were nellrthsn those from trees sprayed with lime sulphur, as

shown in Table 11.

Roach Orchard, Hart, Michigan, 1938

Materials and methods

Approximately 280 nine year old Montmorency trees were chosen
for experimental pruposes at the Roach Orchard, Hart, Michigan. The
block was arranged 32 trees long by 9 wide. Each of the 33 plats con-
sisted of 6 to 12 trees. The trees were planted in sandy loam but
were not exceedingly vigorous due to defoliations the previous two
years.

As shown in Table 12, the materials used were: certain concen-
trations of Basicop, Basicop-borax, Basicop~iron sulphate~lime,

Basicop-lime, Basicop-magnesium hydroxide, Basicop-zinc sulphate-lime,

-55..

bordeaux mixture, copper arsenate,’ copper arsenate-lime, Cupro K,
Fungibordo (a proprietary dry bordeaux mixture manufactured by the
Sherwin-Williams Company, Cleveland, Ohio), and liquid lime sulphur.
In addition, one plat received applications of only lead arsenate.
Unless otherwise indicated, highncalcium lime was used in all combina-
tions requiring lime. Lead arsenate 2-100 was added to all materials
in the two-week and four-week applications with the exceptions of the
plats sprayed with copper arsenate or copper arsenate-lime.

The standard spray program for cherries in Michigan was used for
most of the experimental plats. The petal-fall sprays were applied on
May 10 and 22. Due to a delay in shipment of certain materials, all
the plats did not receive the early sprays on the same dates (Table 12).
The two-week sprays were applied may 27, 28, 30, and June 6, while the
four-week applications were made June 16, 17, and 20. After~harvest
sprays were applied August 6 and 7. In an effort to determine the
dwarfing effect of the four-week spray of bordeaux mixture, certain
plats treated with bordeaux received only two pre-harvest and one after-
harvest spray. One plat sprayed with Basicop-lime 3-6-100 also re-
ceived only the petal-fall, two-week, and after-harvest spray. Three
unsprayed control trees were included in the experiment.

Hethods of spray application were comparable to those of the 1937
experiments at the Roach Orchards. The trees were thoroughly sprayed
until drip appeared. Each tree received an average of 5 gallons of spray
material per application. Each spray was applied with a pressure of

375 to 400 pounds.

'Copper arsenate is a definite chemical compound containing 40 per—
cent copper and 40 percent arsenic pentoxide. In the course of
manufacture the copper and arsenic pentoxide contents are reduced
to 39 percent each.

- 55 -

Epidemiological conditigns

Three pre-harvest sprays of liquid lime sulphur failed to control
leaf spot in the Roach Orchards in 1937, and almost complete defoliation
had occurred by the harvest period (July 22 - August 5). Selection of
the trees for experimental purposes in 1938 was made in anticipation of
the presence of abundant leaf spot inoculum. It was found, however,
that most of the overwintering leaves were destroyed by early spring
cultivation and sheet erosion of the soil. Consequently, the control of
leaf spot did not become a serious problem in most of the experimental
plats, although conditions were very favorable for severe attacks of
leaf spot in the vicinity.

Mature ascospores of Cogpgmyces higmalis Higgins were not found
until May 18, although the period of fullsbloom was exceptionally
early (May 2-9). The first scattered leaf spot lesions appeared on the
untreated control trees and in other Oceans County orchards on May 31.
Examination of a limited number of apothecia on June 2 indicated that
many ascospores were not discharged. The appearance of acervuli
approximately 10 days after the rain of May 20 (Figure 2) strongly in-
dicated that the first primary infections occurred on that date.
Further observations showed that additional primary infections occurred
during the rains of May 25 and 27.

The appearance of numerous lesions and resulting yellowing and
defoliation on June 12 in neighboring orchards indicated that secondary
infections began to occur with the rains of June 1 and 2.

An abnormal amount of rainfall throughout the latter part of May.
and the month of June, combined with comparatively warm temperatures
(Figure 2), furnished ideal conditions for epidemic development of the

disease in orchards inadequately protected. As observed in many of the

-57-

orchards in Oceans County, successive defoliations occurred at ap-
proximately ten day intervals during rainy period throughout the re-
mainder of the season.

Although the first infections of the season were noted on the
untreated control trees, no defoliation due to leaf spot occurred until
the time of harvest (July 22). Defoliation was complete on control
trees the latter part of August. The fact that these untreated trees
were lightly infected during the pro-harvest period indicates that this
orchard had a much less acute leaf spot control problem than many

orchards in the immediate vicinity.

Results

Although conditions for evaluating the fungicidal effectiveness
of the spray materials were not optimum in the experimental orchards,
excellent opportunities were afforded to determine the injuriousness of
the spray treatments. As stated above, the trees were in a weakened
condition due to defoliations of the previous seasons and it is generally
recognized that trees with a lowered vitality are much more susceptible
to spray injury than those that are vigorous and strongly growing.

so comparative determination of leaf spot infection.wes made
during the season because there was very little infection on foliage
sprayed with copper materials and very few lesions on foliage of the
unsprayed control trees until late in the season.

The first yellowing and defoliation due to leaf spot in the ex»
perimental block occurred on two of the three unsprayed control trees on
July 2. Severe leaf spot defoliation and yellowing in the plat sprayed

with liquid lime sulphur did not occur until August 5-6, although the

- 58 -

foliage showed many scattered lesions throughout the latter part of the
pre-harvest period. Defoliation was complete the latter part of August.

Continuous observation throughout the season revealed that the
amount of leaf spot on the trees sprayed with copper materials was not
significant. Leaf spot infections caused only slight defoliation on
unprotected new growth during the latter part of August and the period
between the four—week spray and the after-harvest application. Such
defoliations were particularly evident on the plate sprayed with
Basicop-zinc sulphate-lime at 2-3/4-4~ICO and l§-£-&~lOO, as shown in
Table 15.

Spray injury to the foliage was first noted June 5 on trees
sprayed with liquid lime sulphur 2%-lOO. The injury was evidenced by
a marked dwarfing and crinkling of the leaves. No further increase in
the amount of injury in this plat was observed during the remainder of
the season.

The first plate sprayed with copper materials to show foliage in-
jury were the two sprayed with Basicop-lime 3-8-100 and Cupro K 3—100.
The injury, as manifested by yellowing and losses of foliage, occurred
June 9. Slight waves of yellowing and defoliation continued to occur
at frequent intervals throughout the season on the plat sprayed with
Cupro K 3-100. However, very little additional injury was observed on
the plat sprayed with Basicop-lime 3-8-100. The cause of the first
appearance of injury in these two plate was not determined. Evidence
of injury in these plats first is at variance with the results of the
1937 experiments in which spray injury first appeared in plate sprayed
with Basicop with or without small amounts of lime.

Severe yellowing of the foliage and resultant defoliation due to

- 59 -

injury, occurred June 10 on plate sprayed with Basicop-borax 2-2-100 and
2-5-100. Defoliations, almost wholly caused by spray injury, continued
to occur throughout the season until the loss of foliage was complete

by the latter part of August.

Slight amounts of foliage injury became evident July 11 on plate
sprayed with Basicop-lime at concentrations of 2-6-100, 2-4-100, and
2-2-100. Severe defoliation due to injury occurred in plats treated
with Basicop lfi-lOO, Basicop-magnesium hydroxide 2-2-100 and 2-4-100,
copper arsenate 3—100, copper arsenate-lime 3-3-100, and copper arsenate-
lime 4-4-lOO.

Foliage of the plats sprayed with Basicop-iron sulphate-lime
2-2-2~lOO and 2-2-4-100 was excellent in appearance until after cherry
harvest. Although Anderson (1) and Stewart (91) stated that the addition
of iron sulphate to cherry sprays decreased the "burning“ of the leaves,
severe defoliation due to spray injury occurred on both plats about
August 6. However, very little additional injury occurred during the
remainder of the season. Keitt, et al. (63) found that the efficiency
of bordeaux mixture was not increased by the addition of iron sulphate.

The plate sprayed with Basicop-zinc sulphate-lime 2~£~4-100,
2—1-15-100, lé-fi-S-IOO, and l§~&-&-IOO showed no indication of spray in-
jury throughout the entire season. Although a slight amount of leaf
spot defoliation occurred in certain of these plate, as previously
noted, they maintained the best appearance of the plate that were sprayed
with proprietary copper compounds. Similar results have been obtained
with Bordeaux 34 (basic copper sulphate) with zinc sulphate and lime
by Kadow and Anderson (2, 57).

No significant foliage injury appeared in the plate sprayed with

Basicop-lime 396-100. The use of either dolomitic or high—calcium

- so -

limes at this concentration appeared to make little difference in the
appearance of the plate.

The plat that received two sprays of bordeaux mixture 6-8-100
and two sprays of Basicop-lime 3-8-100 consistently maintained the
best appearance of the plate in the experimental block. No defoliation
due to leaf spot or spray injury occurred in the plat during the entire
season.

EVidence of foliage injury in the plate sprayed with bordeaux
mixture first appeared on July 29. The plats that received two pre-
harveet sprays of bordeaux mixture 3-4-100, 4~5-100, and 6-8-100 had
light amounts of yellowing and defoliation while plats receiving three
pro-harvest sprays of corresponding concentrations had only a few
scattered yellow leaves in the tree and very little defoliation.
Further injury occurred on all plats during the last of August and the
month of September, regardless of the pre-harvest spray schedule.
Fellowing the after-harvest applications on all plats sprayed with
bordeaux, no difference could be noted in the amount of spray injury
between plats receiving three or four sprays of each concentration.
However, the largest amount of injury was noted in the plate sprayed
with bordeaux mixture 6~8-IOO, while very little difference was evident
between the amount of injury in the plate sprayed with bordeaux mixture
364-100 or 4-5-100.

The plat given two applications of lead arsenate 2-100 began to
show very severe yellowing and defoliation due to spray injury on July 11.
Losses of foliage continued to occur until defoliation was complete on
August 8. Examination of the injured leaves showed the injury to be

indistinguishable in appearance from that found in many of the plats

- 51 -

sprayed with copper materials. This condition naturally suggests that
some of the injury obtained in orchards sprayed commercially with

copper compounds and which has hitherto been termed “copper injury“

may have been caused, in part, by lead arsenate. Careful examination

of the fruit and pedicels in this plat showed no indication of the

injury which has been noted and described by Button (30) and Gloyer (46).

Final comparative evaluations of the spray treatments taken
October 8 show, as presented in Table 13, that no foliage injury occurred
in the experimental plats sprayed with Basicop-zinc sulphate~lime
2-1-4-100, 2-l-lk-100, li-l-S—lOO, lfiwé-i-IOO, or in the plat sprayed
with two applications of bordeaux mixture 6-8-100 and two sprays of
Basicop-lime Sat-100. Treatments of Basicop without lime at li-lOO,
Basicop-magnesium hydroxide 2-2-100 or 2-4-100, Basicopnborax 2—2-100
or 2.5-100, Basicop-lime 2—2-100 or 2-4-100, copper arsenate 3-100,
capper arsenate-lime 3-3-100 or 4-4-100, Cupro K 3—lOO, Enngibordct4alOO,
end-certain concentrations of bordeaux mixture were found to be un-
satisfactory due to the moderate to heavy amounts of resulting spray in-
jury to the foliage. Treatments causing only light amounts of spray
injury, as Basicop-lime 2—6»lOO, 3-6-100, 3-8-100, and Basicopo
magnesium lime 3-6-100 were satisfactory since the amount of injury
was not considered commercially significant.

Although opportunities for determining the effectiveness of the
materials against leaf spot were limited, observations again indicated
the different concentrations of bordeaux mixture to be the most efficient
of the fungicides tested. Under conditions of light leaf spot inn
fection occurring in this experiment, no difference could be noted in

the degree of disease control obtained with bordeaux mixture at con-

centrations of 6-8-100, 4-5-100, or 3-4-100. Also, the three-spray
and four-spray programs of each concentration appeared to give equal
control of leaf spot.

Treatments of Basicop-iron sulphate-lime at 2-2-2-100 and
2-2—4-100, Basicop-lime 2-2-100, 2-4-100, 2-6-100, 3-6-100, and 3-8-100,
Basicop-magnesium lime 3—6-100, Basicop-zinc sulphate-lime 2-2-4-100,
2-l-lfi-lOO, and li-l-S-lOO, Cupro K 3-100, and Fungibordo 4-100
satisfactorily controlled leaf spot throughout the season.

Although much superior to liquid lime sulphur zé-lOO, Basicop
li-lOO, Basicop-magnesium hydroxide 2-2-100 and 2-4-100, and Basicop~
zinc sulphate-lime li-é-é-lOO did not adequately control leaf spot, The
value of the use of four-spray programs of these materials at the given
concentrations remains questionable, especially during seasons of abun-
dent rainfall and in orchards with an abundance of leaf spot inoculum.
It was also determined that two~pre~harvest sprays and one after—
harvest application of Basicop-lime 3-6-100 were not sufficient to con~
trol the disease satisfactorily.

Very severe early foliage injury occurring in plate sprayed with
Basicop-borax 2-2-100 and 2-5-100, copper arsenate 3-100, and copper
arsenate-lime 3-3-100 and 4-4-100 concentrations prevented satisfactory

evaluations of the combinations in regard to leaf spot control.

gglgtions of fungicides to the siggZQf fruit

To determine the effect of the various sprays on the size of fruit,
50 cherries were similarily selected and picked from each quarter of the
tops of all representative trees in each plat. Two hundred cherries
were thus correspondingly chosen from each tree and the number carefully

checked three times to prevent error. The weight of the cherries per

- 53 -

tree was then determined to the nearest gram. The data on comparative
fruit size determinations are presented in Table 14.

Reduction of fruit size caused by spray materials was not marked
in 1938. Abnormal amounts of rainfall throughout the season tended to
prevent dwarfing of the fruit.

The largest fruit in the experimental block was borne in plats
sprayed with Basicopumagnesium hydroxide 2-2-100, Basicop-magnesium
hydroxide 2-4-100, and lead arsenate 2-100. Following the observations
of Keitt, et al. (63), the increased size of fruit in these plate may
have been due, in part, to severe defoliations just prior to harvest.
However, severe defoliations early in the summer appeared to have no
special effect upon fruit size in plats sprayed with Capper arsenate-
lime 3-3-100 and 4-4-100, Copper arsenate 3-100, and Basicop-borax
at 2~2-lOO and 2-5-100.

Combinations of Basicop~zinc sulphate-lime at 2-2—4-100, 1%-
é-i-lOO, 2-1-15-100, or li—é-3-lOO and Basicop-iron sulphate'lime at
2-2-2-100 or 2-2-4-100 showed no tendency to depress the fruit size.

No significant difference was found in the size of fruit from trees
sprayed with Basicop-lime 2-2—100, Basicop-lime 2-4-100, liquid lime
sulphur zfi-lOO, or Cupro K 3~lOO.

Trees given three sprays of Basicop-lime 3-6-100, in one in-
stance, produced fruit slightly larger than cherries from trees receiv-
ing only two pro-harvest sprays of the same material and concentration.
However, one plat in a different location in the orchard that also
received three pre-harvest sprays of Basicop~lime 3o6~100, produced
fruit much smaller than the plat which received two pro-harvest sprays.

Fruit of trees sprayed with Basicop lfi-lOO, Basicop-lime 3-8-100,

- 64 _

Fungibordo 4-100, Basicop-lime 2—6-100, and Basicop-magnesium lime

3-6-100 was comparatively smaller than fruit of trees sprayed with
liquid lime sulphur zk-lOO.

Trees given three pre-harvest sprays of bordeaux mixture 3-4-100,
4-5-100, and 6-8-100 produced fruit smaller than trees given two pre-
harvest sprays of corresponding concentrations. Fruit Sprayed twice
with bordeaux mixture 4-5-100 was 50 grams heavier per 100 cherries on
an average than fruit receiving three pro-harvest applications of the
same concentration. The difference in the size of fruit was less
marked in plate given two-spray and three-spray programs of bordeaux
mixture 6-8-100. No significant difference in fruit size occurred in
plate receiving two and three sprays of bordeaux mixture 3-4-100 before
harvest.

Theesize of cherries in the plats sprayed twice with bordeaux
mixture 6-8leO and once with Basicop 3~8elOO before harvest was the
smallest in the experimental block. Hewever, the fruit size was only
slightly smaller than that of the plat given three pre~harvest sprays
of bordeaux mixture 6-8-100 or of one plat that received three pre-

harvest applications of Basicop-lime 3-6—100.

R a n ear efo a 937 t
and s ze of fruit in 3938

Plats sprayed with various sulphur materials in 1937 had severe
early defoliations, while such defoliations were very slight in plats
sprayed with copper compounds. All trees, regardless of spray treat-

ment of the previous year received four pro-harvest sprays of Cupro K

3'100 in 19380

— 65 -

To determine the effect of early defoliation in 1937 upon the
total yield and size of fruit in 1938, all cherries picked from each
tree were weighed to the nearest one-quarter of a pound and randomized
selections of 100 cherries per tree were weighed to the nearest gram.

No data were taken upon the total yield of fruit per tree in
1937. Fortyonine trees that were defoliated early by leaf spot in 1937 '
produced an average of 49.7 pounds of fruit per tree the following
year, as shown in Table 15. Forty-four trees, in which little early
defoliation occurred the previous year, yielded an average of 55.9
pounds of cherries per tree. The figures presented do not truly
represent the residual effect of leaf spot defoliation upon the sub—
sequent yield of fruit as indicated by Button and Wells (33). Many
of the trees that received sulphur sprays in 1937 were larger trees
than those sprayed with copper materials and, consequently, bore more
fruit. This condition naturally tended to obscure any effect of de-
foliation of the previous season toward reducing the total size of the
crop. However, uneven ripening and exceptionally small fruit could be
noted at the time of harvest by casual observation on trees that had
poor control of the disease the previous year.

Determinations of the average weight in 1937 of 100 cherries
from 30 copper sprayed trees showed the fruit to be slightly smaller
than fruit from a corresponding number of trees sprayed with sulphur
materials.

Comparative fruit size determinations in 1938 were based upon
two plats, each including 30 trees used in the collection of similar
data the previous year. (Table 15). One hundred cherries were cor-

respondingly selected from each of 44 trees that had very poor control

.66.-

cf the disease with sulphur sprays the previous year and from each of

49 trees that had good control of the disease with copper materials.
Data presented in Table 15 show that cherries picked in 1938 from

trees that had severe early defoliation due to leaf spot the previous
season were considerably smaller than cherries from trees that had
slight losses of foliage prior to harvest in 1937. Button and Wells (33)
have also reported smaller fruit from trees defoliated by leaf spot the

previous year.

Residual copper on foliagg

The amount of copper residue on the foliage was determined for
each plat at the end of the season. A disk, one centimeter square,
was punched near the mid-rib from the center of each leaf. Ten disks
were taken from four sides of each representative tree in a plat.
Analyses were based upon the total number of disks from each plat.

As shown in Table 16, foliage sprayed with certain concen-
trations of bordeaux mixture, the bordeaux mixture and Basicop-lime
combination, copper arsenate-lime, copper arsenate, and Basicop-iron
sulphate-lime retained distinctly more copper than foliage receiving
other treatments. Leaves receiving three sprays of bordeaux mixture
retained less copper per unit area than leaves receiving four sprays
of corresponding concentrations. Analyses showed that three sprays of
bordeaux:mixture 3-4-100 left almost as much copper deposit as four
sprays of Basicop-magnesium lime 3-6-100.

Foliage sprayed with Basicop-lime 3-6-100, 3-8-100 and 2-4-100,
or Basicop-borax 2-2-100 and 2-5-100 showed no appreciable difference
in the amount of copper deposit, although not equal to the amount left

on leaves receiving three sprays of bordeaux mixture 3-4-100.

-67..

Almost as much copper deposit was found on foliage sprayed with
Basicop-zinc sulphate-lime lfi-é-3—100, 2-l-lé-lOO, 2-2-4-100, lé-fini-lOO
and Basicop-lime 2-2—100 as on foliage sprayed with Basicop-lime 3-8-100.
Hewever, the data indicate that the weathering qualities of the Basicop-
iron sulphate-lime treatments were superior to Basicop—zinc sulphate-
lime sprays.

Foliage sprayed with Basicop-magnesium hydroxide 2-2-100 and
2-4-100, three applications of Basicop-lime 3-6-100, Basicop li-lOG,
Basicop-lime 2-6-100, and Cuprc K 3-100 retained less capper deposit

than foliage receiving any of the other spray treatments.

ngervations pn commercially sprayed orchards

The Harden orchard, located at South Haven, Michigan, was treated
with a four-spray program of Basicop-lime used at a concentration of
2i-5-100 which is slightly below the recommended concentration of
3-8-100 or 3—6-100. Very good control of the disease was obtained and
no foliage injury was noted throughout the season.

The Booker orchard at Hart, Michigan received a three-spray
program of Basicop-lime at 3-8-100. No injury resulting from the sprays
was observed during the season. Control of leaf spot in this orchard
was excellent until after the harvest period. No afteroharvest ap-
lication was made which accounts for the appearance of leaf spot that
became evident the latter part of August.

The Jonassen orchard at Hears, Michigan, was heavily infected
with cherry leaf spot during the early part of the season. The first
leaf spot lesions were noted in this orchard on May 31. A severe wave
of yellowing and defoliation of the leaves appeared on June 12 and was

followed shortly by another on June 20. Unfortunate timing of sprays

- 68 -

in relation to rains and an abnormal amount of rain resulted in a loss
of protective action of the two sprays previously applied. Although
another proprietary copper spray material had been used in the first
two sprays, a change to Basicop-lime at 3—8-100 applied at 10 day inter-
vals effectively checked the progress of the disease and gave no evi-
dence of foliage injury. Bordeaux mixture 6-8-100 was used in the late
after-harvest spray.

The Ellendale Farm orchard at Acme, Michigan, received a four-
spray program of Basicop 3-8-100. The part of the orchard receiving
sprays with proper timeliness showed no evidence of spray injury and
had adequate control of leaf spot at the end of the season. In one
section of the orchard a delay of approximately 20 days in the appli-
cation of the third spray resulted in defoliation due to leaf spot.
Immediately after the third spray was finally applied the progress of

the disease was satisfactorily checked.

-69..

SUMMARY

Certain spray materials at selected concentrations were tested
in Michigan in 1937 and 1938 to determine their relative fungicidal
efficiency for the control of cherry leaf spot, Coccomyces hiemalip
Higgins. Determinations of the injurious effects of the fungicides
upon the foliage and fruit of cherry trees were also conducted.

The main portion of the experiment was conducted at Hart,
Michigan, and supplementary studies were made at Empire, Omens, and
Shelby, Michigan. The growing season of 1937 was especially favorable
for the development of cherry leaf spot in Michigan. Although in-
fections were well established in all plats, it became apparent early
in the season that copper sprays were more effective in checking the
disease than sulphur sprays. This condition was readily observed
throughout the entire season. Unsprayed control trees and plate sprayed
with dry lime sulphur 4-lOO-or lO-lOO, Electric sulphur 4-100. liquid
lime sulphur l~100 or 25-100, and liquid lime sulphur with Electric
sulphur 1—4-100 were completely defoliated due to leaf spot. Plats
sprayed with Basicop lé-loo and Basicop lfi-4-100 were the only plats
sprayed with copper materials that showed a significant amount of de-
foliation caused by the disease. Basicop~lime 3-8-100 and 3-1—100,
Basicop 3-100, Cupro K 3-100 and 6-100, and bordeaux mixture 3-4-100
and 6-8-100 satisfactorily controlled the disease throughout the season.

Evidence of spray injury to the foliage in 1937 was not noted in

plate sprayed with the sulphur materials. Varying amounts of injury

- 19 -

occurred on trees sprayed with copper materials. It was readily
determined that the use of Basicop without lime was unsatisfactory
(i.e. Basicop lé-lOO and 3-100) due to severe foliage injury, and that
the addition of lime decreased the amount of defoliation. No appreci-
able amount of Spray injury occurred in the plat sprayed with Basicop-
lime 3-8-100, while Basicop 3-100 with only one pound of lime caused
severe injury. Cupro K at concentrations of 3-100 or 6-100 also caused
considerable spray injury to the foliage. Losses of leaves occurred
late in the season in the plats sprayed with bordeaux mixture 3-4-100
and 6-8-100.

In 1937 the data on early leaf spot infections in the plats
sprayed with sulphur and the unsprayed control trees were found to
correspond to the amount of defoliation at the end of the season. How-
ever, the amount of early infection in the plate sprayed with copper
material was found to indicate in no way the amount of resultant de-
foliation late in the season, thus showing that the copper materials
may impede the progress of the disease after it has once become well
established, as has been previously reported by Cation (20).

Plats which received three sprays of Basicop-lime 3-8-100, bor-
deaux mixture 3-4-100 and 6-8-100 in 1937 had more defoliation than
when given four sprays, while plats receiving three applications of
Cupro K 3-100 and 6-100 resulted in less defoliation than four sprays.

The data in one instance of the experiment in 1937 show that the
ascosporic inoculum immediately beneath each tree was the determining
factor in the resulting amount of infection, while the amount of

lateral dissemination of inoculum which may have occurred was insig-

nificant.

The application of a pro-bloom spray of liquid lime sulphur was
shown to be of definite value in the control of the disease in 1937.
However, observations indicated that the effectiveness of pre-bloom
applications of liquid lime sulphur in seasons of abundant rainfall is
lost during the late summer, early fall, and in the six-week period
prior to the application of the after-harvest spray.

It was determined in 1937 that plats losing considerable foliage
just prior to harvest bore the largest cherries. This condition was
especially marked in plats in which exceedingly poor control was ob-
tained with the use of sulphur sprays. Definite dwarfing of the fruit
occurred on trees sprayed with bordeaux mixture 6-8-100. Reduction of
the size of fruit was not as pronounced on trees sprayed with bordeaux
mixture 3-4-100. Cherries from trees sprayed with Basicop lé-lOO and
3-100, Basicop-lime 3-1-100, 3-8-100, and l§~4p100, and Cupro K 3-100
and 6-100 compared favorably in size to fruit from trees sprayed with
liquid lime sulphur Zé-lOO and were superior in size to cherries from
plats sprayed with either bordeaux:mixture 3-4—100 or find-100. No
dwarfing of the fruit from trees given two pre-harvest sprays of
bordeaux mixture 6-8-100 at Empire, Michigan, was noted.

Plats that received four sprays of copper materials in 1937 re-
tained a greater amount of residual copper in each instance than plats
given three sprays of the same material and concentration. The data
show that bordeaux.mixture 6-8~100 or 3-4-100 used either in a four-
spray or three-spray program had superior adhesive qualities to most
of the concentrations of Basicop or Basicop and lime. The data also
show that Cupro K had adhesive qualities superior to Basicop when the

two materials were applied at equal copper content concentrations. The

-72..

addition of lime to Basicop did not significantly affect the weather
resisting qualities of the fungicide in 1937.

Experiments in 1938 were conducted at Hart, Michigan. The leaf
spot disease was not as severe in the experimental blocks as in the
immediate vicinity as indicated by the unsprayed control trees. is in
193?, liquid lime sulphur did not adequately control the disease. Bor-
deaux mixture 3—4-100, 4-5-100, and 6-8~lOO completely controlled the
disease whether three or four sprays were applied. The minimum con-
centration of Basicop necessary to control leaf spot satisfactorily
appeared to be 2 pounds in 100 gallons of spray. Plats sprayed with
Basicop-iron sulphate-lime 2-2-2-100 and 2-2-4-100, Basicop-lime
2-2-100, 2b4-100, 2—6-100, 3—6~100, and 3-8-100, Basicop-magnesium
lime 3-6-100, Basicop-zinc sulphate-lime lé-l-S-lOO, 2-2—4—100 and
2-lelé-100, Cupro K 3-100, and Fungibordo 4-100 had adequate control of
the disease throughout the season. Basicop lfi-lOO, Basicop-zinc sulphate-
lime lé—i-fi-IOO did not satisfactorily control leaf spot.

Conditions were favorable for evaluating the comparative in-
juriousness of spray treatments in 1938. Foliage injury was so severe
in plats sprayed with Basicop-bore: 2-2-100 and 2-5—100,copper arsenate
3-100, and copper arsenate-lime 3—3-100 and 4-4—100 that satisfactory
evaluations of the materials in regard to disease control were prevented.
Small amounts of lime in addition to zinc sulphate completely checked
foliage injury when used with Basicop. No spray injury occurred in
plats treated with Basicopuzinc sulphate-lime lé—i-é-lOO, l£~l~3~100,
Qwaquloa, 2-l-li-IOO, or in the plat sprayed with two applications of
bordeaux mixture 6-8-100 and two sprays of Basicop-lime 3-8-190. Basi-

cop lfi-lOO, Basicop-lime 2-2-100 and 2~4~lOO, Basicop-iron sulphate-lime

-73..

2-2~2-100 and 2-2—4—100, Basicop-magnesium hydroxide 2-2-100 and
2-4-100, Cupro K 3-100, Fungibordo 4-100 and certain concentrations of
bordeaux mixture caused moderate to heavy amounts of foliage injury.
Sprays of Basicop-lime 2-6-100, 3-6-100, 3-8-100, and Basicop-magnesium
lime 3-6-100 caused only insignificant amounts of foliage injury.

Spray injury caused complete defoliation in the plat given two pre-
harvest sprays of lead arsenate 2-100.

Spray materials did not cause marked dwarfing of the fruit in
1938 since abnormal amounts of rainfall throughout the season tended to
prevent reduction of fruit size.

The residual effect of cherry leaf spot defoliation upon the size
of fruit was determined. In 1938 trees that had severe early defoliation
the previous season produced conspicuously smaller, unevenly ripened
fruit than trees that had little loss of foliage in 1937 prior to the
harvest period.

Analyses of the residual copper on cherry foliage at the end of
the season again showed that bordeaux mixture has weather resisting
qualities superior to Basicop or Basicop with lime. Foliage that re-
ceived four sprays of copper materials retained more copper per unit
area than leaves that were given three sprays of the material at the
same concentration. The addition of iron sulphate to Basicop and lime
increased the adhesiveness of copper material. Borax, magnesium hy-
droxide, or zinc sulphate applied in combination with Basicop or Bas-
icop and lime did not appear to affect significantly the amount of
copper residue on the foliage at the end of the season. Copper arsenate
or copper arsenate with lime retained more copper per unit area than

the different Basicop combinations.

1.

2.

3.

4.

5.

6.

8.

9.

- 74 -

CONCLUSIONS

Copper sprays are more effective in controlling the disease than
sulphur sprays.

Copper materials are more efficient than sulphur materials in
checking the progress of the disease after infection has once
become well established.

A four-spray program of Basicop-lime 3—8-100 gives a good control
of cherry leaf spot in years of normal rainfall and causes little
appreciable spray injury. Basicop-lime 3~6-lOO appears to give
equally satisfactory results.

Two pounds of Basicop in 100 gallons of spray appears to be

the minimum concentration necessary to control the disease
satisfactorily.

Basicop-zinc sulphate-lime 2-1-1fi-lOO appears to be a prom~
ising spray combination.

Cupro K without lime controls the disease satisfactorily but
causes serious foliage injury.

Bordeaux mixture gives excellent control of the disease but
frequently causes severe spray injury.

Pre-bloom applications of liquid lime sulphur 2§~lOO may be of
definite value in certain years for the control of cherry leaf
spot.

Pour sprays of dry lime sulphur 4-100 or lO~lOO, Electric sul~
phur 4-100, liquid lime sulphur l-lOO or 2g-1oo, or liquid lime

sulphur with Electric sulphur 4-100 fail to control the disease

10.

11.

12.

13.

14.

15.

16.

17.

18.

19.

-75..

in certain years.

The amount of ascosporic inoculum immediately beneath each tree
may be the determining factor in the resultant amount of early
infections. In certain years the amount of lateral dissemination
of primary inoculum is not significant.

Basicop used without sufficient lime causes severe foliage
injury.

Basicog applied in combination with borax or magnesium hydrox-
ide increases the amount of foliage injury.

Capper arsenate or copper arsenate and lime may cause severe
foliage injury. '

Lead arsenate 2—100 is capable of causing severe foliage injury
when used alone.

Three pre~harvest sprays of bordeaux mixture cause definite
dwarfing of the fruit in certain years.

Basicop, Basicop-lime, and Basicop-zinc sulphate-lime cause no
appreciable dwarfing of the fruit when compared to fruit
sprayed with liquid lime sulphur ZQ-lOO.

Trees that lose considerable foliage just prior to harvest may
bear the largest fruit.

Bordeaux mixture has adhesive qualities superior to Basicop,
Basicop-lime, Basicop-iron sulphate-lime, or Basicop~zinc
sulphate-lime.

The addition of iron sulphate to Basicop and lime increases the
adhesiveness of the copper material but may cause serious
foliage injury.

Early severe defoliation may cause the production of small

unevenly ripened fruit the following year.

1.

2.

3.

4.

5.

6.

8.

10.

11.

12.

-76..

LITERATURE CITED

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TABLES

- 35 -

Table 1

Concentrations of materials used to make 100 gallons
of spray in experiment at Roach Orchard, Hart, Michigan, 1937.

 

 

Concentration
figtgrial in .poundg
Basicop 3-100
Basicop léolOO
Basicopelime 3-8-100
Basicop-lime 3-l~100
Basicop~lime lfi-4—100
Bordeaux mixture 6~8~lOO
Bordeaux mixture 3~4-100
Cupro K' 6-100
Cupro K 3-100
Dry lime sulphur lO-lOO
Dry lime sulphur - 325-mesh sulphur 2—4nlOO
Dry lime sulphur 4-100
Electric sulphur** 4-100
Liquid lime sulphur 1-103
Liquid lime sulphur - Electric sulphur 1-4-100
Liquid lime sulphur 29’100

A

‘Copper oxychloride principal ingredient, manufactured
by Rhom &.Hass Co.

*‘A wettable sulphur manufactured by Stauffer Chemical Company.

Table 2

Comparative percentages of infected leaves at
Roach Orchard, Hart, Michigan June 23, 1937.”

 

 

 

Leaves Total Amount
Leaves Non- Leaves of
Treatment infected Infected. Counted' Infection
number nugber number per cent
Basicop-lime 3-8-100 61 204 265 29.9
Bordeaux 6-8-100 105 275 385 38.1
Basicop-lime 3-1-100 114 255 369 44.7
Cuprc K 6-100 99 219 318 45.2
Bordeaux 3-4-100 103 227 330 45.3
Basicop-lime lé-4-lOO 128 251 379 50.9
Basicop 3-100 157 298 455 52.6
Cuprc K 3-100 154 271 425 56.8
Dry Iime-sulphur 2 lbs., 325-mesh
sulphur 4 lbs. - 100 132 232 364 56.8
Liquid lime-sulphur 2§-100 145 249 394 60.9
Dry lime-sulphur 10-100 134 220 354 60.9
Basicop lé-lOO 195 304 499 64.1
Liquid lime-sulphur 1-100 147 199 346 73.8
Dry lime-sulphur 4-100 168 222. 390 75.6
Electric sulphur 4-100 156 200 356 78.0
Liquid lime-sulphur and
Electric sulphur (1.4-100 163 207 370 78.7
Check tree ..- -~- --- 98.0

 

’This table has been previously published in the Michigan
Agricultural Experiment Station Quarterly Bulletin ('22 .

"Counts were made on four representative trees in each plat.

Table 3

Comparative evaluations of plat treatments at
Roach Orchard, Hart, Michigan, June 30 ~ July 1, 1937.

 

 

 

 

laterial and Defoliation ___ Foliage
anggntggtign. Leaf spot Spray injury Appearancg
Basicop-lime 3-8-100 0 0 Excellent
Basicop-lime 3-1-100 Trace Trace Good
Basicop-lime 1Q-4-lOO 1 0 Good
Basicop 3-100 0 1 Good
Basicop léolOO 0 Trace Good
Cupro K.6~lOO 0 Trace ‘Good
Cupro K'3-1OO Trace Trace Good
Bordeaux mixture 6-8-100 O 0 Excellent
Bordeaux:mixture 3-4-100 O 0 Excellent
Dry lime sulphur 325 mesh

sulphur 2-4-100 3 0 Poor
Dry lime sulphur 4-100 3 0 Poor
Dry lime sulphur lO-lOO 1-2 0 Poor
Electric sulphur 4-100 3 0 Poor
Liquid lime sulphur 1-100 2 0 Poor
Liquid lime sulphur

Electric sulphur 1-4-100 3 0 Poor
Liquid lime sulphur 2§-100 192 0 Poor
Control trees 3 0 Poor

 

Legend for Table 3:

0 - No defoliation
Trace - Very slight defoliation
1 - Slight defoliation
2 - Moderate defoliation
3 - Heavy defoliation

-88-

Table 4

Comparative defoliation in experimental plats at
Roach Orchard, Hart, Michigan, September 25, 1937.‘

 

Represen- Amount

 

 

Total tative of
Treatment Leaves Leaves Leaves Trees Defolia-

Migsing Present Counted, §gmpled tion

number number number ggghgg 2;: gen:
Basicop-lime 3-8-100 110 1,662 1,772 5 6.2
Bordeaus 3-4-100 245 1,981 2,226 5 11.0
Bordeaux 6-8-100 293 1,684 1,977 5 14.8
Basieep-lee.3»8-100" 369 1,742 2,111 6 17.4
Bordeaux 3-4-100” 332 1,486 1,818 6 18.2
Cupro K 3-100" 325 1,146 1,471 4 22.0
Bordeaux 6-8-100” 481 1,676 2,157 6 22.2
Cupro K 6~100" 192 620 812 3 23.6
Basicop 3-100 1,169 3,393 4,562 12 25.6
Cupro K 3-100 534 1,301 1,835 5 29.1
Basicop-lime 3-1-100 1,110 2,427 3,537 10 31.3
Cupro K 6-100 407 879 1,286 3 31.6
Basicop lfi-lOO 1,255 2,523 3,778 9 33.2
Basicop~lime lé-4-100 1,433 2,448 3,881 12 36.9
Dry lime-sulphur 10-100 1,889 921 2,810 8 67.2
Liquid lime sulphur
2é-100' 2,816 801 3,617 9 77.8
unsprayed control 370 6 376 ' 1 98.4

 

’See footnote (') at bottom of page 86.

"Received no after-harvest application.

 

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- go -

Table 6

Comparative fruit size determinations at
Roach Orchard, Hart, Michigan, July 26, 1937.“

 

 

 

 

Total Average
Weight Weight
Treatment of 600 of 600
_§herrig§:' Cherries
.EEEQE E£§E§_____
Liquid lime-sulphur (1 gal.) 2,291 381.8
and 4 lbs. Electric sulphur - lOO
Liquid lime-sulphur 1 gal. - 100 2,289 381.5
Basicop 3-100 2,286 381.0
Cupro K 3-100 2,285 380.8
Electric sulphur 4 lbs. - 100 2,283 380.5
Liquid lime-sulphur 2é-100 2,219 369.5
Basicop lé-IOO 2,199 366.5
Basicop-lime 3-8-100 2,177 362.8
Basicop-lime 3-1-100 2,165 360.8
Cupre K 6-100 2,127 354.5
Dry lime-sulphur (2 lbs.) and 2,083 347.1
325-mesh sulphur (4 lbs.) - 100
Basicop-lime- 1§-4-100 2,071 345.1
Bordeaux 3-4-100 2,031 338.5
Bordeaux;6-8-100 1,747 291.1

 

“See footnote (') at bottom of page 86.

"100 cherries were picked from each of six representative

trees in a plat.

Table 7

Ana1ysis of residual copper deposit on leaf samples collected
October 9, 1937, at Roach Orchard, Hart, Michigan.“

 

 

 

 

 

Amount of Amount of

Copper Copper
Treatment per 100 by

Diggg Height

grams per cent
Bordeaux 6-8-100 .00255 .231
Cupre K 6-100 .00099 .11?
Bordeaux 6-8-100 *" .00107 .109
Bordeaux 3-4-100 .00080 .092
cuprc K 6-100 "' .00052 .063
Basicop 3-100 .00050 .062
Bordeaux 3-4-100 "' .00054 .054
Basicop-lime 3-8-100 .OOOSO" .050
cupro K 3-100. .00054 .048
Basicop-lime 3-8-100 "' .00042 .043
Basicop-lime lé-4-100 .00035" .036
Cupro K 3-100 "’ .00034 .034
Basicop 1Q-100 _ .00026 .025
Control tree "" .00027 .018

Basicop-lime 3-1-100 No record

 

'See footnote (’) at bottom of page 86.

"These disks were not counted but the average weight of
100 disks in the remaining samples sas used to figure the
number of disks.

"*Received but three pro-harvest sprays.
*'*'Received one after-harvest spray of Basicop-lime 2-2-100.

- 92 -
Table 8

Comparative fruit size determinations at
Field Orchard, Shelby, Michigan, July 21, 1937.’

 

 

 

 

Average
Weight
Treatment Trees Cherries Total of 100
m Picked vmight Carries.
nugber number s rams
Cuprc K 6-100 15 1,500 6,837.0 459.3
Liquid lime-sulphur 2i-100 12 1,191 5,465.2 455.8

 

'See footnote (') at bottom of page 86.

- 93 _
Table 9

Comparative spray injury determinations at
the IcClary Orchard, Empire, Michigan, August 8, 1937'

 

 

 

 

Spurs Spurs

Showing Showing

Treatment Spurs Yellow' Yellow

#Counteg VirLeaves Leaves

2 number number per cent
Basicop-lime 2-1-100 200 6 3.0
Cuprc K 49100 460 123 26.0
Bordeaux 4-5-100 619 82 13.0

 

'See footnote (’) at bottom of page 86.

Table 10

Comparative fruit size determinations at
the IcCIary Orchard, Empire, Michigan, July 30, 1937'

 

 

 

Average

weight

Treatment Applies! Cherries Total of 100

tiog§_ Weighed Weight ghgrries
number ngmber rams ams
Bordeauxr4-5.100 2 2,400 9,475.0 394.7
Basicop-lime 2-1-100 3 2,400 9,376.0 390.6
Cuprch 4-100 3 2,400 8,644.0 360.0
Control (unsprayed) 0 600 2,714.0 452.3

 

“See footnote (') at bottom of page 86.

-95..

Table 11

Comparative fruit size determinations at the
Thomas Smith Orchard, Omens, Michigan, July 31, 1937'

 

 

 

Represen- Average

tative Weight

Treatment Trees Cherries Total of 100

Sampled Picked Weight Cherries

number number grams, grams.

Lime-sulphur Iii-100 20 2,000 6,782 339.1
Basicop-lime lé—lolOO 18 2,000 6,213 310.6
Cupro K 3-100 20 2,000 6,199 309.9

 

'See footnote (') at bottom of

page 86.

-96..

Table 12

Spray dates and concentrations of materials used to make
100 gallons of spray in experiment at
Roach Orchard, Hart, Michigan, 1938

 

Spray Applications

 

 

 

Concen- Petal- Two~ Four- After-
Iaterial tration Fall Week Baggy Harvest
Date Date Date Dag;

Basicop 19-100 May 10 May 28 June 16 August 6
Basicop-borax 2.2~100 10 3O 16 7
Basicop-borax 2—5-100 10 30 16 7
Basicop-iron

sulphate-lime 2-2-2-100 10 30 16 6
Basicop-iron

sulphate-lime 2-2-4-100 10 30 16 6
Basicop-lime 3-8-100 10 27 16 6
Basicop—lime 3-6-100 10 27 16 6
Basicop-lime 3-6-100 10 27 6
Basicop-lime

(magnesium 3~6~100 22 June 6 20 7
Basicop-lime 2-6-100 10 May 27 16 6
Basicop-lime 2—4-100 10 28 16 6
Basicop-lime 2-2-100 10 28 16 6
Basicop-magnesium

hydroxide 2-2-100 10 3O 16 7
Basicop-magnesium

hydroxide 2~4~1OO 10 3O 16 7
Basicop-sine

sulphate-lime 2-3/4-4-100 10 28 16 6
Basicop-sine

sulphate-lime 2-1-l§~100 10 28 16 6
Basicop-sine

sulphate-lime lé—fi—3-IOO 10 3O 16 7

Table 12 (continued)

 

Spray Applications

 

 

Concen- Petal- Tso- Four- After-
Material tration Fall Wee; Week Harvest
Date Date Date Date
Basicop-sine
sulphate-lime 11-1-1-100 Hay 10 May 30 June 16 August 7
Bordeaux mixture 6-8-100 10 3O 16 6
Bordeaux mixture 6-8-100» 10 3O 6
Bordeaux mixture 4-5-100 10 30 16 6
_Bordeaux mixture 4-5-100 10 30 6
Bordeaux mixture 3-4-100 10 30 16 6
Bordeaux mixture 3-4—100 10 30 6
Bordeaux mixture 6-8-100
(tso sprays)
and Basicop-lime 3-8-100
(tso sprays) 22 June 6 30 7
Copper arsenate 3-100 22 6 20 7
Copper arsenate-
1ime 3-3-100 22 6 20 7
Copper arsenate~
lime 4-4-100 22 6 20 7
Cupro K 3~1OO 10 May 28 16 6
Bungibordo 4-100 22 June 6 2O 6
Lead arsenate 2-100 6 20

Liquid lime sulphur 2§-100 10 May 28 16 6

 

Table 13

Comparative Evaluations of Spray Treatments in Experimental Block,
Roach Orchard, Hart, Michigan, October 8, 1938.

 

 

21a1_1:eatment .1 Control. Injury
Basicop lfi-lOO Fair Very heavy
Basicop-borax 2-2-100 ~--' Very heavy
Basicop-borax 2-5-100 ”a Very heavy
Basicop-iron sulphate-lime 2-2-2-100 Good Moderate
Basicop-iron sulphate-lime 2-2-4-100 Good Moderate
Basicop-lime 2-2~100 Good Moderate
Basicop-lime 2-4-100 Good Hoderate
Basicop-lime 2-6—100 Good Light
Basicop-lime (Three sprays) 3-6-100 Fair Light
Basicop-lime 3-6-100 Good Light
Basicop-magnesium lime 3-6-100 Good Light
Basicop-lime 3-8-100 Good Light
Basicop-magnesium hydroxide 2-2-100 Fair Very heavy
Basicop-magnesium hydroxide 2-4-100 Fair Very heavy
Basicop-sine sulphate-lime 29i-4-100 Good None
Basicop-zinc sulphateolime 2-l-lé-1OO Good None
Basicop-sine sulphate-lime lfi-é-3-100 Good None
Basicop~ainc sulphate-lime lé-i-é-lOO Fair None
Bordeaux mixture (Three sprays) 6-8-100 Excellent Very heavy
Bordeaux mixture 6-8-100 Excellent Heavy
Bordeaux mixture (Three sprays) 4-5-100 Excellent Heavy
Bordeaux mixture 4-5-100 Excellent Baderate
Bordeaux mixture (Three spra ys) 3-4—100 Excellent Heavy

Table 13 (continued)

 

 

21§1_I:§atment. Control lpjury__
Bordeaux mixture 3-4-100 Excellent Moderate
Bordeaux mixture (two sprays 6-8-100

and Basicop-lime (two sprays) 3-8-100 Excellent None
Copper arsenate 3-100 --~' Very heavy
Copper arsenate-lime 3-3-100 ---’ Very heavy
Copper arsenate-lime 4-4-100 ---' Very heavy
Cupro K 3-100 Good Very heavy
Fungibordo 4—100 Good Moderate
Lead arsenate (Two sprays) 2-100 ---' Very heavy
Liquid lime sulphur 2§—1OO Poor Light

 

'Early severe foliage injury prevented satisfactory evaluation
of the material in regard to leaf spot control.

- 100 -

Table 14

Comparative fruit size determinations at
Roach Orchard, Hart, Michigan July 21-23, 1938

 

Total
Represent- Weight lverage
ative of Weight

 

 

Treatment' trees Cherries of 100
mud ” Sappled Cherries
number grams Agrppp__

Basicop-magnesium hydroxide 2-2-100 5 4273 427.3
Basicop-magnesium hydroxide 2-4~100 6 49995 416.2
Lead Arsenate (Tho sprays) 2-100 7 5768 412.0
Basicop-sine sulphate-lime 2-2-4-100 10 8232 411.6
Basicop-lime 2~4-lOO 10 8042 402.1
Basicop-sine sulphate-lime lfi-L-fi-IOO 6 4816 401.3
Basicop-lime 2-2-100 3 2404 400.6
Liquid lime sulphur 25-100 7 5562 397.2
Basicop-iron sulphate-lime 2-2-2-100 5 3966 396.6
Basicop-zinc sulphate-lime 2-1-1é-100 9 7073 392.9
Bordeaux mixture (TWo sprays) 4-5-100 6 4701 391.7
Cupro K; 3-100 10 7815 390.7
Copper arsenate-lime 303-100 6 4682 390.1
Basicop-zinc sulphate-lime lé-i-3-100 9 6997 388.7
Basicop-lime 3-6-100 5 3849 384.9
Copper arsenate 3-100 6 4618 384.8
Basicop-lime (Two sprays) 3-6-100 5 3810 381.0
Basicop-borax 2—2-100 6 4491 374.2
Basicop-borax' 2-5-100 6 4460 371.6
Basicop li-lOO 6 4429 368.3

- 101 -

Table 14 (continued)

 

 

 

Total
Represent- Weight Average
ative of Weight
Treatment“ trees Cherries of 100
Sampled" Sampled Cherrieg
npgber pgrams gramp_
Basicop-lime 3-8-100 10 7275 363.7
Basicop-iron sulphate-lime 2-2-4-100 3 2171 361.8
Fungibordor 4-100 12 8635 359.7
Basicop-lime 256-100 10 7148 357.4
Copper arsenate-lime 4.4-100 5 3561 356.1
Bordeaux mixture (Two sprays) 6-8-100 12 8412 350.5
Bordeaux mixture (Tue sprays) 3-4-100 8 5563 347.6
Bordeaux mixture 3.4-100 9 6161 342.2
Basicop-magnesium lime 3-6-100 4 2728 341.0
Bordeaux:mixture 4-5-100 5 3410 341.0
Bordeaux mixture 6-8-100 10 6688 334.4
Basicop-lime 3-6-100 4 2670 333.7
Bordeaux mixture (tvo sprays 6—8-100
and Basicop-lime (one spray) 3-8-100 7 4628 330.5

 

'Bach treatment consisted of three pre-harvest sprays unless

otherwise indicated.

"Two hundred cherries were picked from each representative

tree in a plat.

- 102 ~

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- 103 -

Table 16

Analysis of residual copper deposit on leaf samples collected at
Roach Orchard, Hart, Michigan, October 3, 1938.

 

Average
Amount of

Represent- Amount Copper per

Treatment' ative of copper square cen-
trees in whole timeter of
sampled" sample leaf area

 

nggber milligzams milligrams

 

Bordeaux mixture
Bordeaux mixture

Bordeaux mixture
(three sprays)

Bordeaux mixture
(three sprays)

Bordeaux mixture"'
(two Sprays) and
BQ'iOOp-limg
(two sprays)
Copper arsenate-11me...
Cappor arsenate-11mg
COPPer arsenate"*
COPPOY arsenate-limeees

Bordeaux mixture

Basicop-iron
sulphate-lime

Basicop-iron
sulphate-lime

Fungibordo
Basicop-magnesium lime

Bordeaux mixture
(three sprays)

6-8-100

4-5-100

6-8-100

4-5-100

6.8-100
3-8~100
4-4-100
4-4-100

3-100
3.3.100

3—4-100

2n2-4-100

2-2-2-100

4-100

3-6~100

3-4-100

10

6

11

1.94

.630
1.15

.518

.795
.555
.479
.444
.358

.535
.368

.260
.463

.127

.280

 

.0194

.0105
.01045

.01036

.00993
.00925
.00793
.0074

.00595

.00594
.00525

.0052
.00385

.0031?

.00311

- 104 -

Table 16 (continued)

 

average
Amount of
Represent- Amount Copper per
Treatment’ ative of copper square cen-
trees in whole timeter of

sampled" sample leaf area_
milligramgrmilligrams

 

Basicop-lime 3-6-100 6 .163 .00271
Basicop-lime 3-6-100 4 .108 .0027
Basicop-lime 2-4-100 11 .270 .00245
Baeicop-borax"’ 2-2-100 6"" .038 .00223
Basicop-borax... 2-5-100 5 .133 .00221
Basicop-lime 3-8-100 11 .225 .00204
Basicop-zinc

sulphate-lime li-é-S-lOO 8 .163' .00203
Basicop-zinc

sulphate-lime 2-l-lQ-100 8 .155 .00193
Basicop-zinc .

sulphate-lime 2ai~49100 10 .188 .00188
Basicop-zinc

sulphate-lime lé-é-é—lOO 6 .109 .00181
Basicop-lime 2-2»100 6 .105 .00175
Basicop-magnesium

hydroxide "* 2-2-100 6 .090 .00150
Basicop-magnesium

hydroxide "’ 2~4~lOO 6 .090 .00150
Basicop-lime (three sprays) 3~6~1OO 6 .089 .00148
Basicop 1%»100 6 .089 .00148
Basicop-lime 2-6-100 10 .143 .00143
Cupro K . 39100 10 .114 .00114

 

'Unless otherwise indicated, each treatment consisted of four sprays.
nTen disks collected from each representative tree.

'**Samples collected on October 8, 1938.

""Only 17 disks were used in copper determinations.

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