• TABLE OF CONTENTS
HIDE
 Front Cover
 Front Matter
 Introduction
 Symptoms
 Experiments
 Soil reaction
 Discussion
 Summary
 Literature cited














Group Title: Bulletin - University of Florida. Agricultural Experiment Station ; no. 344
Title: A preliminary report on little-leaf of the peach in Florida
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00015122/00001
 Material Information
Title: A preliminary report on little-leaf of the peach in Florida a zinc deficiency
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 19 p. : ill. ; 23 cm.
Language: English
Creator: Dickey, R. D ( Ralph Davis ), 1904-
Blackmon, G. H ( Gulie Hargrove ), 1886-
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1940
 Subjects
Subject: Peach -- Diseases and pests -- Florida   ( lcsh )
Zinc deficiency diseases in plants -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Bibliography: p. 18-19.
Statement of Responsibility: by R.D. Dickey and G.H. Blackmon.
General Note: Cover title.
Funding: Bulletin (University of Florida. Agricultural Experiment Station)
 Record Information
Bibliographic ID: UF00015122
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 000924575
oclc - 18229658
notis - AEN5202

Table of Contents
    Front Cover
        Page 1
    Front Matter
        Page 2
    Introduction
        Page 3
    Symptoms
        Page 4
        Page 5
        Page 6
    Experiments
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
    Soil reaction
        Page 14
    Discussion
        Page 15
        Page 16
        Page 17
    Summary
        Page 18
    Literature cited
        Page 18
        Page 19
Full Text



Bulletin 344


March, 1940


UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATION
GAINESVILLE, FLORIDA
WILMON NEWELL, Director



A PRELIMINARY REPORT

ON LITTLE-LEAF OF THE PEACH

IN FLORIDA-

A ZINC DEFICIENCY

By R. D. DICKEY and G. H. BLACKMON


I T j.r7 m q
Fig. 1.-Typical shoots from treated and untreated peach trees (Jewel). Left, from
check (untreated) tree; right, from tree which received 1 pound zinc sulfate to the soil.
Treated 3-28-39, photograph taken 9-12-39.


Single copies free to Florida residents upon request to
AGRICULTURAL EXPERIMENT STATION
GAINESVILLE, FLORIDA









EXECUTIVE STAFF
John J. Tigert, M.A., LL.D., President of
the University"
Wilmon Newell, D.Sc., Director3
Harold Mowry, M.S.A., Asst. Dir., Research
V. V. Bowman, M.S.A., Asst. to the Director
J. Francis Cooper, M.S.A., E-Aitor3
Jefferson Thomas, Assistant Editor3
Clyde Beale, A.B.J., Assistant Editor3
Ida Keeling Cresap, Librarian
Ruby Newhall, Administrative Manager8
K. H. Graham, Business Manager3
Rachel McQuarrie, Accountant8


MAIN STATION, GAINESVILLE
AGRONOMY
W. E. Stokes, M.S., Agronomist'
W. A. Leukel, Ph.D., Agronomist3
G. E. Ritchey, M.S., Associate2
Fred H. Hull, Ph.D., Associate
W. A. Carver, Ph.D., Associate
John P. Camp, M.S., Assistant
Roy E. Blaser, M.S., Assistant

ANIMAL HUSBANDRY-
A. L. Shealy, D.V.M., Animal Husbandman' s
R. B. Beeker, Ph.D., Dairy Husbandman3
L. M. Thurston, Ph.D., Dairy Technologist3
W. M. Neal, Ph.D., Asso. in An. Nutrition
D. A. Sanders, D.V.M., Veterinarian
M. W. Emmel, D.V.M., Veterinarian3
N. R. Mehrhof, M.Agr., Poultry Husbandman3
W. G. Kirk, Ph.D., Asso. An. Husbandman3
R. M. Crown, B.S.A., Asst. in An. Husb.3
P. T. Dix Arnold, M.S.A., Assistant Dairy
Husbandman3
L L. Rusoff, M.S., Asst. in An. Nutritions

CHEMISTRY AND SOILS
R. V. Allison, Ph.D., Chemist' 3
Gaylord M. Volk, M.S., Chemist
F. B. Smith, Ph.D., Microbiologist8
C. E. Bell, Ph.D., Associate Chemist
H. W. Winsor, B.S.A., Assistant Chemist
J. Russell Henderson, M.S.A., Associate3
L. H. Rogers, M.S., Asso. Biochemist
Richard A. Carrigan, B.S., Asst. Chemist

ECONOMICS, AGRICULTURAL
C. V. Noble, Ph.D., Agricultural Economisti 3
Bruce McKinley, A.B., B.S.A., Associate
Zach Savage, M.S.A., Associate
A. H. Spurlock, M.S.A., Assistant

ECONOMICS, HOME
Ouida Davis Abbott, Ph.D., Specialist'
Ruth Overstreet, R.N., Assistant
R. B. French, Ph.D., Associate Chemist

ENTOMOLOGY
J. R. Watson, A.M., Entomologist'
A. N. Tissot, Ph.D., Associate
H. E. Bratley, M.S.A., Assistant

HORTICULTURE
G. H. Blackmon, M.S.A., Horticulturist'
F. S. Lagasse, Ph.D., Horticulturist2
Harold M. Sell, Ph.D., Asso. Hort.2
A. L. Stahl, Ph.D., Associate
F. S. Jamison, Ph.D., Truck Horticulturists
R. J. Wilmot, M.S.A., Specialist, Fumigation
Research
R. D. Dickey, M.S.A., Assistant Horticulturist
J. Carlton Cain, B.S.A., Asst. Horticulturist
Victor F. Nettles, M.S.A., Asst. Hort.
PLANT PATHOLOGY
W. B. Tisdale, Ph.D., Plant Pathologist1
George F. Weber, Ph.D., Plant Pathologists
L. O. Gratz, Ph.D., Plant Pathologist
Erdman West, M.S., Mycologist
Lillian E. Arnold, M.S., Assistant Botanist


BOARD OF CONTROL'
H. P. Adair, Chairman, Jacksonville
W. M. Palmer, Ocala
Chas. P. Helfenstein, live Oak
R. H. Gore, Fort Lauderdale
N. B. Jordan, Quincy
J. T. Diamond, Secretary, Tallahassee

BRANCH STATIONS
NORTH FLORIDA STATION, QUINCY
J. D. Warner. M.S., Agronomist Acting in
Charge
R. R. Kincaid, Ph.D., Asso. Plant Pathologist
Elliott Whitehurst, B.S.A., Asst. An. Husb.
Jesse Reeves, Farm Superintendent
CITRUS STATION, LAKE ALFRED
A. F. Camp, Ph.D., Horticulturist in Charge
John H. Jefferies, Superintendent
Michael Peech, Ph.D., Soils Chemist
L. H. Greathouse, Ph.D., Chemist
B. R. Fudge, Ph.D., Associate Chemist
W. L. Thompson, B.S., Asso. Entomologist
W. W. Lawless, B.S., Asst. Horticulturist
R. K. Voorhees, M.S., Asst. Plant Path.
EVERGLADES STATION, BELLE GLADE
J. R. Neller, Ph.D., Biochemist in Charge
J. W. Wilson, Sc.D., Entomologist
F. D. Stevens, B.S., Sugarcane Agronomist
Thomas Bregger, Ph.D., Sugarcane
Physiologist
Frederick Boyd, Ph.D., Asst. Agronomist
G. R. Townsend, Ph.D., Plant Pathologist
R. W. Kidder, B.S., Asst. An. Husbandman
W. T. Forsee, Ph.D., Asso. Chemist
B. S. Clayton, B.S.C.E., Drainage Engineer2
SUB-TROPICAL STATION, HOMESTEAD
W. M. Fifield, M.S., Horticulturist Acting in
Charge
S. J. Lynch, B.S.A., Asst. Horticulturist
Geo. D. Ruehle, Ph.D., Asso. Plant Pathologist
W. CENTRAL FLA. STA., BROOKSVILLE
W. F. Ward, M.S., Asst. An. Husbandman
in Charge2

FIELD STATIONS
Leesburg
M. N. Walker, Ph.D., Plant Pathologist in
Charge
K. W. Loucks, M.S., Asst. Plant Pathologist
Plant City
A. N. Brooks, Ph.D., Plant Pathologist
Cocoa
A. S. Rhoads, Ph.D., Plant Pathologist
Hastings
A. H. Eddins, Ph.D., Plant Pathologist
Monticello
Samuel O. Hill, B.S., Asst. Entomologist2
Bradenton
Jos. R. Beckenbach, Ph.D., Truck Horticul-
turist in Charge
David G. Kelbert, Asst. Plant Pathologist
Sanford
R. W. Ruprecht, Ph.D., Chemist in Charge,
Celery Investigations
W. B. Shippy, Ph.D., Asso. Plant Pathologist
Lakeland
E. S. Ellison, Meteorologist2
B. H. Moore, A.B., Asst. Meteorologist2
1Head of Department.
'In cooperation with U.S.D.A.
'Cooperative, other divisions, U. of F.







A PRELIMINARY REPORT ON LITTLE-LEAF OF THE
PEACH IN FLORIDA A ZINC DEFICIENCY
By R. D. DICKEY and G. H. BLACKMON
CONTENTS
PAGE .PAGE
SYMPTOMS ...................... ................... ..... 4 Zinc-Lim e Spray ................................. 11
EXPERIMENTS .......... .... .............................. 7 Manganese-Lime Spray ...................... .... 13
Soil Treatments ......................................... 9 Zinc-Manganese-Lime Spray ................ 13
Zinc Sulfate ............................................ 9 SOIL REACTION ........................ ........... 14
M anganese Sulfate ..... ........................... 9 DISCUSSION ..................................... ............... 15
M agnesium Sulfate ................................. 10 SUMMARY ........................................... ............ 18
Folisge Treatments ................................ 11 LITERATURE CITED ...................-........................ 18
INTRODUCTION
Within the past few years commercial peach growing in Flor-
ida has, on a small scale, experienced a revival. The success
thus far obtained by a few growers in all probability will en-
courage others to make additional plantings. While examining
two of these peach orchards during their first growing year,
it was noted that the foliage of some of the trees was chlorotic
(mottled). During the second year the amount and severity
of the disorder observed the previous season had greatly in-
creased and by the end of the second year approximately 60 per-
cent of the trees evidenced symptoms in some degree. The
noticeable increase led to the experimental work herein reported
which has shown it to be the physiological disorder known as
"little-leaf" of peach.
Little-leaf of peach has been observed in many locations
throughout Florida in seedlings about homes as well as in or-
chard trees and has but recently been identified and reported
by the writers in the 1939 Annual Report of the Florida Agri-
cultural Experiment Station.
Literature dealing with little-leaf of peach and other related
physiological disorders is quite extensive and will not be re-
viewed in its entirety. Chandler, Hoagland and Hibbard (6, 7
and 8)1 have shown the effectiveness of zinc in correcting related
physiological disorders of deciduous fruits, nuts, grapes and
various other woody plants. Independently, other workers have
discovered that zinc applied through the soil and in other ways
would cure a serious nutritional disease of several other plants.
In a recent paper, Chandler (5) has reviewed the extensive
literature on this subject and suggests that, since the disease

Acknowledgments.-The authors wish to express their thanks to R. J.
Wilmot for assistance in conducting the tests; to J. R. Henderson for classi-
fying the soils; to C. E. Bell for determining the TH of the soils, and to
R. P. Thornton, who permitted the use of his orchard and willingly co-
operated in conducting the experiment.
1Italic figures in parentheses refer to "Literature Cited" in the back
of this bulletin.






Florida Agricultural Experiment Station


which is called little-leaf of stone fruit trees and grapevines
and some other trees, rosette of pecans and apples, mottle-leaf
(frenching) of citrus, and yellows on walnuts is cured by the
application of zinc, it be called "zinc deficiency".
The work of Mowry (11), Mowry and Camp (12), Camp (3),
Barnette and Warner (1), Barnette et al (2), Townsend (16)
and others leaves no doubt of the tremendous importance of
zinc in Florida agriculture.

SYMPTOMS
The characteristic foliage symptoms of zinc deficiency in
peaches are: Chlorosis; crinkling of the leaves; little-leaf; a red
to purple coloration of some of the leaves due to an excessive
development of anthocyanin pigments in chlorotic areas and
premature abscission of some of the leaves. Twig symptoms
most commonly associated with zinc deficiency in Florida are
rosette and death of twigs on affected trees.
Chlorosis (mottling) is the foliage symptom most character-
istic and is a condition in which lighter green to pale yellow
areas appear between the main and secondary veins (Figs. 1,
2 and 3). The pattern is evident over the entire surface of
the leaf and is developed in conjunction with the growth of
the leaf. At first these areas are pale green in color but, as
the leaf reaches maturity, the color changes to pale yellow.
The relative amounts of chlorotic and green tissue in leaves
vary from small light yellow blotches between the midrib and
larger lateral veins in mild stages of zinc deficiency to that
where only the tissue immediately surrounding the midrib re-
mains green with the remainder of the leaf becoming pale yellow
in acute stages. Some of the unfolding leaves are light yellow
in color over their entire surface but, as growth continues, the
characteristic pattern of chlorosis is developed (Fig. 2).
Another very characteristic symptom, "crinkled leaves", is
especially noticeable on foliage at twig terminals. It is evi-
denced by a crinkling or rolling which gives to the surface of
the leaf a wavy appearance. The entire surface of the leaf is
crinkled but this is more pronounced along the margins and
midrib (Figs. 2 and 3).
In acute stages affected trees show tufts or rosettes of leaves
that are greatly attenuated in size. It is this symptom which
has led to the name "little-leaf". These leaves also evidence
chlorosis and crinkling (Fig. 4). Associated with little-leaf is







A Preliminary Report on Little-Leaf of the Peach


N.
N





r


Fig. 2.-Peach leaves (Jewel) showing typical steps in the development of chlorosis
and crinkling. From left to right: leaves 1 to 5 from untreated tree; 6, normal leaf
from tree treated with 1 pound of zinc sulfate to the soil.


Fig. 3.-Shoots from peach trees (Jewel) showing zinc deficiency treated with: left,
2 pounds magnesium sulfate to soil; center, % pound manganese sulfate to soil; right, 2
pounds zinc sulfate to soil. Treated 3-28-39, photograph taken 9-12-39.







6 Florida Agricultural Experiment Station

a condition described as "rosette" which is a shortening of the
internodes of shoot or branch and results in the crowding of
the foliage into a rosette (Fig. 4). Rosette is always associated
with little-leaf but often there may be a definite reduction in
twig growth without the true little-leaf condition being evi-
denced; this happens in many cases where chlorosis and crink-
ling are evident.








































Fig. 4.-Young peach tree (Jewel) showing acute symptoms of zinc deficiency (little-
leaf, rosette and twig necrosis). This tree sprayed with a zinc-lime spray on 3-29-39.
Photograph taken at time of treatment. Cf. Fig. 5.







A Preliminary Report on Little-Leaf of the Peach


On some leaves anthocyanin pigments form in the chlorotic
areas between the midrib and main lateral veins and appear
as red to purple blotches indefinite in extent and outline. This
is somewhat more noticeable on the under surface of affected
leaves.
Necrotic symptoms observed are dying of the yellowed tips
of badly chlorotic leaves (Fig. 1), premature leaf fall, particu-
larly in acute stages, and the failure of twigs to "put out" growth
in the spring and their subsequent dying back in varying degree
(Figs. 4 and 7).
Characteristically, affected trees show symptoms plainly on
the new growth. This is followed by shoots that may have
normal foliage in the early stages but, as the season progresses,
the later leaves on this growth develop symptoms. Shoots so
affected show little-leaf symptoms when growth begins in the
spring. Trees that appear normal early in the year may show
chlorosis (mottling) in late summer, with the little-leaf phase
of symptoms showing the next spring. Badly affected trees
may start into growth much later in the season than healthy
trees. Also there may be trees which show symptoms and later
become healthy.
EXPERIMENTS
The experimental work herein reported was conducted in 1939
in a peach orchard of the Jewel variety located near Blanton,
Florida, in Pasco County. The planting is on Norfolk fine sand
underlain with a clay subsoil. It consists of -20 acres, 52 rows
of 27 trees each which have been used as interplants with citrus
trees. This orchard was beginning its third year when treat-
ments were applied.
Treatments consisted of both soil and spray applications of
zinc sulfate and manganese sulfate, alone and in combination,
and of soil applications of magnesium sulfate both alone and in
combination with zinc and manganese sulfate. The treatments
applied and results obtained are given in Table 1.
At the time of treatment in March these trees were examined
and a record was made of their condition as to health and vigor,
number of trees evidencing symptoms and the relative severity
of the disorder. This was repeated in September to determine
the effect of the various treatments. For convenience in pre-
senting results these records were converted into numerical
values for each tree and averaged to give a comparative value
for the plot.








Florida Agricultural Experiment Station


TABLE 1.-RESULTS OF SOIL AND FOLIAGE APPLICATIONS OF ZINC SULFATE,
MAGNESIUM SULFATE AND MANGANESE SULFATE TO PEACHES; SOIL AND
FOLIAGE APPLICATIONS MADE 3-28-39 AND 3-29-39 RESPECTIVELY.


Plots
i At Time o]

U

Treatments ( .
E4 i N
.d ]
Z a


/2 lb. zinc sul-
fate to soiP .... 103
2 lbs. zinc sul-
fate to soil .... 103
z/ lb. manganese
sulfate to soil' 102
2 lbs. manganese
sulfate to soil 103
Ib. zinc sulfate
and % lb. man-
ganese sulfate
to soil ............. 105
5 lbs. zinc sul-
fate to soil ...... 27
5 lbs. manganese
sulfate to soil 25
2 lbs. magnesium
sulfate to soil3 10
2 lbs. magnesium
sulfate and 2
lbs. zinc sul-
fate to soil ...... 8
2 lbs. magnesium
sulfate and 2
lbs. manganese
sulfate to soil 9
2 lbs. magnesium
sulfate, 2 lbs.
zinc sulfate and
2 lbs. mangan-
ese sulfate to
soil ................... 10
Zinc-lime spray 175
Manganese-lime
spray .............. 164
Zinc-manganese
lime spray ...... 97
Check, no treat-
ment ................ 284


32

33

33

28



30

36

39

25



44



42




43
27

31

32

31 1


68



56



58




70
71

70

65

64


Record
f Treatment




E4 E-4 *
Zc; Cw 0r tc r.
ZMM Cm) NQ


On 9-12-39

W o



0 a



86 13 90

85 7 96


'Commercial 89% zinc sulfate used in all treatments.
2Commercial 80% manganese sulfate used in all treatments.
5Commercial 90-92% magnesium sulfate used in all treatments.


Zinc deficiency was indicated by percentages as follows: 25
indicated slight zinc deficiency and 100 very severe zinc defi-







A Preliminary Report on Little-Leaf of the Peach


ciency with all of the growth affected and little-leaf and rosette
symptoms evident, while 50 and 75 indicated intermediate con-
ditions with zero indicating no zinc deficiency. The values for
the individual trees were then added and the sum divided by
the number of trees in a plot to arrive at the relative amount
of zinc deficiency evidenced by the trees in a plot. Condition
of the trees as to health and growth were recorded as poor,
fair, good and excellent and these values were transposed into
25, 50, 75 and 100, respectively, and the average value for the
plot calculated. In interpreting these figures it can be seen
that a tree with zinc deficiency of 100 would be very severely
affected, while a tree with a condition value of 100 would be in
excellent condition.
SOIL TREATMENTS
Zinc Sulfate.-Zinc sulfate (89%) was applied broadcast
under the spread of the tree branches at the rates of 1/2, 2 and
5 pounds per tree, and in combination with manganese sulfate
at the rate of 1/2 pound of each per tree. Results of these treat-
ments are summarized in Table 1.
The results indicate that 1/2 pound zinc sulfate was as effective
as larger amounts in the control of this disorder. Though the
response has been very marked, zinc deficiency has not been
completely eliminated by one application of the amounts used;
however, for all practical purposes the amounts applied effected
excellent commercial control (Figs. 1, 3, 7 and 8). There was
no indication of additional response when both zinc and man-
ganese sulfate were applied or of detrimental effects due to the
use of the manganese.
There was some indication that the 5-pound application of
zinc sulfate produced slight foliage injury evidenced by partial
defoliation and slight fruit drop; however, in about two weeks
these trees showed no evidence of this injury.
Manganese Sulfate.-Manganese sulfate (80%) at the rates
of 1/2, 2 and 5 pounds per tree was applied broadcast under the
branches, and in combination with zinc sulfate at the rate of
1/2 pound of each per tree. No response was observed to any
of the amounts when manganese sulfate was used alone (Table
1 and Fig. 3). Only when used in combination with zinc sul-
fate was response evident. Injury similar to that described
for zinc sulfate was produced by the 5-pound application of
manganese sulfate.







Florida Agricultural Experiment Station


Magnesium Sulfate.-Magnesium sulfate (90-92%), 2 pounds
per tree, was applied and also in combination with zinc and
manganese sulfate at the rate of 2 pounds of each per tree.
No beneficial or detrimental effects were obtained with mag-
nesium alone or in combination except the improvement noted
in tree condition where zinc sulfate was included in the applica-
tion (Table 1 and Fig. 3).


*~ir ffl~--
r~


Fig. 5.-Same tree shown in Fig. 4, but photograph taken 9-12-39. Sprayed with a
zinc-lime spray which effected complete control of zinc deficiency and reduced defoliation
by peach rust.







A Preliminary Report on Little-Leaf of the Peach


FOLIAGE TREATMENTS
Zinc-Lime Spray.-The spray was prepared by screening 5
pounds of zinc sulfate into 100 gallons of water while the spray
tank was being filled. Two and one-half pounds of finely ground
hydrated lime and one pound of calcium caseinate were mixed
in approximately 2 gallons of water, and this mixture was slowly
poured into the spray tank to which the zinc sulfate previously
had been added. It is essential that the agitator be kept going
during the entire procedure and until the tank has been sprayed
out. When spraying operations have been completed for the
day the sprayer should be thoroughly cleaned immediately to
avoid corrosion of metal parts of the machine.
The data given in Table 1 show that foliage applications of
zinc sulfate effected as satisfactory control of the zinc deficiency
as did soil applications (Figs. 4 and 5). In order to effect con-
trol it was necessary that the foliage be covered with the spray,
as only those portions of the tree responded which had been
sprayed.
It is desirable to spray peaches for the control of the plum
curculio, and for this purpose lead arsenate is used. Lead
arsenate can be combined satisfactorily with zinc-lime-spray,
and therefore no additional spray operations will be necessary
in the use of zinc in foliage applications for the control of zinc
deficiency. Furthermore, Roberts and Pierce (15), Poole (13)
and others have shown that zinc sulfate when added to the spray
mixture materially reduces the possibility of injury to peach
trees by lead arsenate. Also, zinc-lime and lead arsenate can
be combined with any of the sulfur sprays used on peaches for
disease control.
Roberts and Pierce (14) reported upon the fungicidal value
of zinc-lime spray and demonstrated its effectiveness in the con-
trol of bacterial spot of the peach. In their report they noted
that the spray frequently seemed to produce greener and more
vigorous leaves. In a later paper (15) they confirmed their
previous findings and report that zinc-lime spray "can be de-
pended upon to control at least moderate outbreaks of scab",
and "results in the control of brown rot are not conclusive but
indicate that zinc-lime will check and probably control the dis-
ease". Dunegan (9), Kadow and Anderson (10) and others
have reported upon the fungicidal value of zinc-lime spray. In
Florida one of the serious foliage diseases of the peach is rust,
which is often responsible for early partial defoliation of the







Florida Agricultural Experiment Station


tree. It was observed that the rows sprayed with zinc-lime
showed much less defoliation from rust than the unsprayed rows
(Figs. 5, 6 and 8) and had a greater amount of healthy foliage.


Fig. 6.-Young peach tree (Jewel) showing zinc deficiency symptoms. Photograph taken
9-12-39. This tree was untreated and serves as a check for trees shown in Figures 5 and S.







A Preliminary Report on Little-Leaf of the Peach


The desirability of using zinc-lime spray for the control of
zinc deficiency is evident, since it apparently also effects partial
control of a serious foliage disease (rust) and likewise reduces
materially the possibilities of injury by lead arsenate when used
for curculio control.
Manganese-Lime Spray.-This spray was prepared in the same
manner as the zinc-lime spray except manganese sulfate was
used instead of
zinc sulfate. No
response was ob-
tained nor were
detrimental ef-
fects observed
from manganese-
lime spray (Ta- p
ble 1).
Zinc Mangan-
ese -Lime Spray. .
-The method of
preparation was
similar to that
given for zinc-
lime spray with b'
the variation that
3 pounds of zinc
sulfate, 3 pounds
of manganese sul-
fate and 3 pounds
of finely ground .:
hydrated lime
were used. -
The data given : -
in Table 1 show
that this ig. 7.-Young peach tree (Jewel) showing acute symptoms
that this spray of zinc deficiency. This tree treated with 2 pounds of zinc
was as effective sulfate to the soil on 3-28-39. Photograph taken at time of
treatment. Cf. Fig. 8.
as zinc-lime spray
in the control of the zinc deficiency. There was no indication
of additional response when both zinc and manganese were
combined in the spray and there were no detrimental or inhibit-
ing effects manifested due to the use of manganese sulfate.







Florida Agricultural Experiment Station


SOIL REACTION


Considerable literature has been published indicating that
physiological disorders of the several plants known to respond
to zinc treatment are often associated with slightly acid to alka-
line soils such as overlimed or calcareous soils. However, zinc


S'" *
*1..l


4Jird



'Jk
"3;--


za~


Fig. 8.-Same tree as shown in Fig. 7, but photograph taken 9-12-39. Treatment with
2 pounds of zinc sulfate to the soil effected complete control of zinc deficiency but did not
reduce defoliation by peach rust.


~a~rp#r~r








A Preliminary Report on Little-Leaf of the Peach


deficiency is not necessarily confined to soils in the neutral to
alkaline range of reaction since it has been observed on citrus
(frenching), tung trees (bronzing) and pecans (rosette) in Flor-
ida growing on soils which are slightly to highly acid in re-
action.
Soil samples were taken in three orchards in the vicinity
of Blanton, in Pasco County, and at Gainesville, in Alachua
County. In these orchards zinc deficiency symptoms were pres-
ent throughout the plantings. The data obtained are presented
in Table 2. Soil samples 1 through 4 were taken from loca-
tions between the trees in the orchard in which the experiment
was conducted.

TABLE 2.-SOIL REACTION OF FOUR PEACH PLANTINGS LOCATED ON
NORFOLK FINE SAND.


Location
Sample of
Number Planting

1 Near Blanton,
2 Pasco Co.
3
4


5 Near Blanton,
6 Pasco Co.
7
8


9 Near Blanton,
10 Pasco Co.
11
12


13 Gainesville,
14 Alachua Co.
15
16


Planting
Number

1




2




3




4


Age of Soil
Planting Layer
(Years) (Inches)

3 0-6
7-24
0-6
7-24


2 0-6
7-24
0-6
7-24.


3 0-6
7-24
0-6
7-24


3 0-6
7-24
0-6
7-24


The soil reaction data presented show that, in the four or-
chards under consideration, this disorder is associated with an
acid soil reaction.
DISCUSSION

The primary purpose of this bulletin is to identify and de-
scribe zinc deficiency of the peach as it exists in Florida and
point out that satisfactory commercial control usually can be


Soil
Reaction
or pH

5.95
5.85
5.67
5.75


5.63
5.89
5.98
5.89


5.55
5.63
5.47
5.63


5.37
5.47
5.81
5.98






16 Florida Agricultural Experiment Station

effected by either soil or foliage applications of zinc sulfate,
although under certain conditions soil applications may be in-
effective.
Information relative to possible differences in varietal sus-
ceptibility of peaches to zinc deficiency in Florida is, as yet,
limited. In addition to Jewel, zinc deficiency has been observed
on Waldo, Angel and Luttichau varieties and on numerous peach
seedlings in various locations in the state.
In a small orchard on the University grounds, trees of the
Excelsior variety of plums adjacent to affected peaches, as yet,
show no symptoms, but Red June, McRea and Terrell have de-
veloped mild symptoms of chlorosis which resemble those previ-
cusly described for peaches. Since no treatments have been
made, this condition has not yet been identified with certainty
as a zinc deficiency.
It is of interest that zinc deficiency symptoms (frenching)
were noted on orange trees with which the peaches were inter-
planted in the three orchards under observation in Pasco County.
Previously it has been pointed out that zinc deficiency of plants
apparently is not necessarily confined to soils in the neutral to
alkaline range of reaction for it has been observed on citrus,
tung and pecans in Florida growing on soils which are slightly
to highly acid in reaction. Also, it has been shown by a number
of workers that manganese deficiency of several plants in Flor-
ida may occur under comparable soil conditions. Camp and
Reuther (4) report that manganese deficiency symptoms are
commonly associated with zinc deficiency on citrus in Florida
and, for complete response, it will be necessary to treat affected
trees with both manganese and zinc.
Manganese applications were included in the experiment
herein reported. The data presented in Table 1 show that no
beneficial effects were obtained from any of the manganese
treatments.
Magnesium deficiency, resulting in chlorosis as one of the
primary symptoms, occurs on citrus in Florida and is particu-
larly prevalent on the light sands commonly used for planting
citrus. To determine whether the observed disorder of peaches
was in any way connected with a deficiency of magnesium, mag-
nesium treatments were included in the experiment. The results
given in Table 1 show that no beneficial effects were obtained
from these applications.







A Preliminary Report on Little-Leaf of the Peach


Chandler, Hoagland and Hibbard (7 and 8) observed injury
to deciduous and citrus trees in California when large quanti-
ties of zinc sulfate were applied during the growing season.
Also, during seasons when rainfall was light they had injury
from soil applications made to deciduous trees while the leaves
were off, but, in general, the injury was not nearly so severe
as that produced by applications during the growing season.
In the experiment here reported injury was noted from 5-pound
applications of both zinc and manganese sulfate; however, the
damage was slight and could not be detected two weeks after
applications had been made. Furthermore, excellent control of
the zinc deficiency was obtained with each of the 1/2 and 2-pound
applications of zinc sulfate and no injurious effects were evident.
The eventual decline and death of trees as reported in Cali-
fornia by Chandler, Hoagland and Hibbard (6) has, as yet, not
been identified with certainty on peaches in Florida. However,
it is thought that, if severe cases of zinc deficiency were allowed
to continue indefinitely without the use of control measures,
this phase of the symptoms would result. It may be possible
that some of the injury heretofore assigned to nematodes may
have been due, in part, to this disorder.
No attempt will be made to review the work of others who
have contributed to the knowledge of the essential role of zinc
in the nutrition of the higher plants, and to its use under field
conditions as a corrective for the related nutritional disorders
of several plants, as this has been ably done in other publica-
tions. Several theories have been proposed as to the cause of
little-leaf and related disorders and to the role that zinc plays
in the correction of such disorders. Chandler (5) in a recent
paper has carefully reviewed these and points out that the
volume of evidence indicates that little-leaf and related dis-
orders under field conditions are the result of the plant's in-
ability to obtain sufficient zinc to supply its needs (that zinc
functions as a plant nutrient) which, in turn, is influenced by
the soil reaction, soil type and soil flora, among other things.
Most of the experimental work in Florida supports the theory
that disorders corrected by zinc treatment are caused by an
actual deficiency of zinc in the basic nutrition of the plant.
The data presented here lend further support to this premise.







Florida Agricultural Experiment Station


SUMMARY
A deficiency of the peach in Florida which has been called
"little-leaf" was corrected with zinc sulfate applied either ti
the soil or as a foliage spray. The symptoms of the disorder
have been described and illustrated.
The experimental plots occupied 20 acres in a commercial
orchard near Blanton in Pasco County on Norfolk fine sand!
soil. Zinc sulfate applied to the soil in different amounts war
compared with manganese and magnesium sulfate separately
and in combination. Foliage applications also of zinc sulfat(
and manganese were made separately and in combination.
In a comparison of the effects of the treatments in correcting
the deficiency, there was a very significant growth response ir
the trees where zinc sulfate was applied, either to the soil or
as a foliage spray. No response was obtained with manganese
sulfate and magnesium sulfate, either alone or in combination
but where zinc sulfate was added in any of the treatments, the
deficiency was corrected.
Zinc deficiency in peaches occurs over a wide area in the
state, as it has been observed in orchard trees and seedlings
about homes in many locations. Indications are that a satis-
factory control usually can be obtained with zinc sulfate applied
either to the soil or as a foliage spray, although under certain
conditions soil applications may be ineffective.

LITERATURE CITED
1. BARNETTE, R. M., and J. D. WARNER. A response of "chlorotic" corn
plants to the application of zinc sulfate to the soil. Soil Sci. 39:
145-159. 1935.
2. BARNETTE, R. M., J. P. CAMP, J. D. WARNER and 0. E. GALL. The use
of zinc sulfate under corn and other field crops. Univ. of Fla.
Agr. Exp. Sta. Bul. 292. 1936.
3. CAMP, A. F. Studies on the effect of zinc and other unusual mineral
supplements on the growth of horticultural crops. Univ. of Fla.
Agr. Exp. Sta. Ann. Rept.: 67-69. 1934.
4. CAMP, A. F., and WALTER REUTHER. Studies on the effect of zinc and
other unusual mineral supplements on the growth of horticultural
crops. Univ. of Fla. Agr. Exp. Sta. Ann. Rept.: 132-135. 1937.
5. CHANDLER, W. H. Zinc as a nutrient for plants. Bot. Gaz. 98: 625-
646. 1937.







Florida Agricultural Experiment Station


SUMMARY
A deficiency of the peach in Florida which has been called
"little-leaf" was corrected with zinc sulfate applied either ti
the soil or as a foliage spray. The symptoms of the disorder
have been described and illustrated.
The experimental plots occupied 20 acres in a commercial
orchard near Blanton in Pasco County on Norfolk fine sand!
soil. Zinc sulfate applied to the soil in different amounts war
compared with manganese and magnesium sulfate separately
and in combination. Foliage applications also of zinc sulfat(
and manganese were made separately and in combination.
In a comparison of the effects of the treatments in correcting
the deficiency, there was a very significant growth response ir
the trees where zinc sulfate was applied, either to the soil or
as a foliage spray. No response was obtained with manganese
sulfate and magnesium sulfate, either alone or in combination
but where zinc sulfate was added in any of the treatments, the
deficiency was corrected.
Zinc deficiency in peaches occurs over a wide area in the
state, as it has been observed in orchard trees and seedlings
about homes in many locations. Indications are that a satis-
factory control usually can be obtained with zinc sulfate applied
either to the soil or as a foliage spray, although under certain
conditions soil applications may be ineffective.

LITERATURE CITED
1. BARNETTE, R. M., and J. D. WARNER. A response of "chlorotic" corn
plants to the application of zinc sulfate to the soil. Soil Sci. 39:
145-159. 1935.
2. BARNETTE, R. M., J. P. CAMP, J. D. WARNER and 0. E. GALL. The use
of zinc sulfate under corn and other field crops. Univ. of Fla.
Agr. Exp. Sta. Bul. 292. 1936.
3. CAMP, A. F. Studies on the effect of zinc and other unusual mineral
supplements on the growth of horticultural crops. Univ. of Fla.
Agr. Exp. Sta. Ann. Rept.: 67-69. 1934.
4. CAMP, A. F., and WALTER REUTHER. Studies on the effect of zinc and
other unusual mineral supplements on the growth of horticultural
crops. Univ. of Fla. Agr. Exp. Sta. Ann. Rept.: 132-135. 1937.
5. CHANDLER, W. H. Zinc as a nutrient for plants. Bot. Gaz. 98: 625-
646. 1937.








A Preliminary Report on Little-Leaf of the Peach 19

6. CHANDLER, W. H., D. R. HOAGLAND and P. L. HIBBARD. Little-leaf or
rosette of fruit trees. Proc. Amer. Soc. Hort. Sci. 28: 556-560. 1931.

7. CHANDLER, W. H., D. R. HOAGLAND and P. L. HIBBARD. Little-leaf or
rosette of fruit trees, II: Effect of zinc and other treatments. Proc.
Amer. Soc. Hort. Sci. 29: 255-263. 1932.

8. CHANDLER, W. H., D. R. HOAGLAND and P. L. HIBBARD. Little-leaf or
rosette of fruit trees, III. Proc. Amer. Soc. Hort. Sci. 30: 70-86.
1933.

9. DUNEGAN, JOHN C. The bacterial spot disease of the peach and other
stone fruits. U. S. D. A. Tech. Bul. 273. 1932.

10. KADOW, K. J., and H. W. ANDERSON. Further studies on zinc sulfate
in peach sprays, with limited tests in apple sprays. Univ. of Ill.
Agr, Exp. Sta. Bul. 424. 1936.

11. MOWRY, HAROLD. Propagation, planting and fertilizing tests with
tung-oil trees. Univ. of Fla. Agr. Exp. Sta. Ann. Rept.: 91-95. 1933.
12. MOWRY, HAROLD, and A. F. CAMP. A preliminary report on zinc sulfate
as a corrective for bronzing of tung trees. Univ. of Fla. Agr. Exp.
Sta. Bul. 273. 1934.

13. POOLE, R. F. Arsenical injury on the peach. N. C. Agr. Exp. Sta.
Tech. Bul. 49. 1935.

14. ROBERTS, JOHN W., and LESLIE PIERCE. A promising spray for the con-
trol of peach bacterial spot. (Abst.) Phytopath. 19: 106-107. 1929.

15. ROBERTS, JOHN W., and LESLIE PIERCE. Zinc-lime: a fungicide for the
peach. Phytopath. 22: 415-427. 1932.
16. TOWNSEND, G. R. Zinc sulfate sprays for vegetable crops. Univ. of
Fla. Agr. Exp. Sta. Press Bul. 488. 1936.




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