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






Group Title: Bulletin - University of Florida. Agricultural Experiment Station - no. 381
Title: A preliminary report on iron deficiency of tung in Florida
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00027263/00001
 Material Information
Title: A preliminary report on iron deficiency of tung in Florida
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 20 p. : ill. ; 23 cm.
Language: English
Creator: Dickey, R. D ( Ralph Davis ), 1904-
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1942
 Subjects
Subject: Tung tree -- Diseases and pests -- Florida   ( lcsh )
Iron deficiency diseases -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Bibliography: p. 20.
Statement of Responsibility: by R.D. Dickey.
General Note: Cover title.
Funding: Bulletin (University of Florida. Agricultural Experiment Station) ;
 Record Information
Bibliographic ID: UF00027263
Volume ID: VID00001
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: aleph - 000925184
oclc - 18230932
notis - AEN5830

Table of Contents
    Copyright
        Copyright
    Front Cover
        Page 1
    Summary
        Page 2
    Introduction
        Page 3
    Symptoms
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
    Experiments
        Page 11
        1949 treatments
            Page 11
            Foliage treatments
                Page 11
            Soil treatments
                Page 12
                Page 13
        1941 treatments
            Page 14
            Foliage treatments
                Page 14
            Soil treatments
                Page 15
                Page 16
    Soil reaction
        Page 17
    Discussion
        Page 18
        Page 19
    Literature cited
        Page 20
Full Text





HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida






Bulletin 381


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


A PRELIMINARY REPORT ON

IRON DEFICIENCY OF TUNG

IN FLORIDA

By R. D. DICKEY


Fig. 1.-A mature tung leaf showing chlorosis-
a characteristic foliage symptom of iron deficiency
of tung.

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


December, 1942
















SUMMARY
A physiological disorder of tung in Florida distinct in appear-
ance from bronzing (zinc deficiency) and frenching (manganese
deficiency) is described. This disorder is termed "iron defici-
ency."
Thus far, iron deficiency of tung in Florida has been observed
in only three orchards. It is not general over the orchards in
which it was found but is confined to small groups of trees in
localized areas in these orchards.
Data are presented which indicate that control can be effected
by foliage applications of a 1 percent iron sulfate solution. Re-
sults from soil applications are less conclusive; however, it is
indicated that in some cases control can be effected by this
method of treatment. Tentative methods for spray and soil
treatments are outlined. It is suggested that treatment be con-
fined to those trees which evidence symptoms until such time
as results from experimental tests show the desirability of treat-
ing the entire orchard.
Soil reaction data presented indicate that the disorder is asso-
ciated with both acid and alkaline soil reactions.


Wift of Iuhiug (066








A PRELIMINARY REPORT ON

IRON DEFICIENCY OF TUNG

IN FLORIDA

By R. D. DICKEY
Assistant Horticulturist
CONTENTS
Page Page
Sum m ary .. ............ ...................... .............. 2 1941 Treatm ents ........................................ 14
Symptoms ....... -............... .....-......... ..... 4 Foliage treatments ............................ 14
Experim ents ..................................................... 11 Soil treatm ents ................................... 15
1940 Treatments ....................................... 11 Soil reaction .................................. ........ ... 17
Foliage treatm ents ........................... 11 Discussion ............................................. ... 18
Soil treatments .................................. 12 Literature cited .......................................- 20

INTRODUCTION
A physiological disorder of tung (Aleurites fordi Hemsl.) in
Florida, distinct in appearance from bronzing (zinc deficiency)
and frenching (manganese deficiency), previously described (7,
8)1, was observed during the summer of 1939 on a few trees
in an orchard near LaCrosse in Alachua County, and symptoms
recurred in 1940 (3). A second planting near LaCrosse in which
several trees evidenced acute symptoms was found in 1940 (3).
Several trees, similarly affected, were noted in a third planting
near Gainesville in Alachua County in 1941. This trouble is not
general over the orchards in which it has been found. It is con-
fined to groups of trees in localized areas.
Apparently this disorder is of recent appearance in Florida
because, from time to time, surveys have been made of the com-
mercial tung orchards, yet it was not seen until 1939. Reuther
and Dickey (8) report a similar situation in regard to the ap-
pearance of frenching of tung in Florida. They observed certain
isolated instances of frenching in 1933 and subsequent years,
but it was comparatively rare until the spring of 1936, when a
decided increase was noted.
Iron deficiency has not been previously reported from the
other states in which tung is grown commercially. However,
Finch, Albert and Kinnison (4) working in Arizona on the com-
monly observed physiological chlorosiss," gave a list of 31 plants,
including the tung tree, that responded to treatment with C. P.

Acknowledgments: The author expresses his thanks to R. A. Carrigan
and C. E. Bell for determining the pH of the soils and to J. R. Henderson
for classifying the soils.
SItalic figures in parentheses refer to "Literature Cited" in the back
of this bulletin.






Florida Agricultural Experiment Station


iron salts. Treatments were applied as foliage dips "and in some
cases the dry chemical was placed in holes bored in the tree
trunk or in the soil at the base of the trunk." Ferrous sulfate
and ferric chloride were the chemicals used.
The essential nature of iron for the growth of green plants
was pointed out by Gris (5, 6) in 1843 and 1844, and since that
time many others have substantiated his findings. No attempt
will be made to review the extensive literature on this subject,
since it has been adequately done in many other publications.
Literature on iron deficiency of many plants in the United
States and other countries attests the importance of nutritional
troubles due to this cause. In comparison with micro-element
deficiencies in Florida such as zinc, copper, magnesium and
manganese, iron deficiency is relatively of much less importance.
Nevertheless, the work of Camp and Fudge (2), Dickey and
Blackmon (3), and Bryan (1) shows that nutritional troubles
due to this cause are of economic importance in Florida.
The primary purpose of this bulletin is to identify and de-
scribe the physiological trouble designated as iron deficiency to
differentiate it from frenching and bronzing, previously de-
scribed, and point out that it responds to iron treatment.

SYMPTOMS
The characteristic foliage symptoms of iron deficiency in tung
are chlorosis, a pink to reddish coloration of some of the young
leaves due to an excessive development of anthocyanin pigments,
malformation and dwarfing, brown staining, necrotic spots and
premature abscission of some of the leaves. Twig symptoms
are dead buds and shoots on affected trees. Fruit symptoms
are a light yellowish green color as contrasted with the normal
green, brown staining, premature abscission of some of the fruit
with poor fill of those which remain until apparent maturity.
Chlorosis is the most distinctive and characteristic symptom
of iron deficiency of tung. On severely affected trees it ap-
pears on young foliage developing in the spring. The expanding
leaves are golden yellow with the veins appearing as fine green
lines. Often the terminal leaves of a shoot may be suffused with
a pink to reddish blush due to an excessive development of antho-
cyanin pigments but, as the leaves mature, the reddish coloration
disappears. On mature leaves the veins are green while the
tissue between the veins is bright yellow. Small as well as large
veins are green, which gives the appearance of a green network






Iron Deficiency of Tung in Florida


on a bright yellow background (Figs. 1-4). In acute stages
the tissue between the veins may become light yellow to almost
white and certain leaves may be almost devoid of chlorophyll
(Figs. 1, 4, 5 and 6). The relative amounts of chlorotic and
green tissue in leaves may vary, depending upon the time of
year, position of leaves on the shoot and severity of the deficiency.


Fig. 2.-Tung leaves showing foliage symptoms of iron deficiency.
Upper left, normal leaf; others show chlorosis, necrosis, malformation and
ragged edges.

Malformation and dwarfing are foliage symptoms which de-
velop in conjunction with chlorosis. Early in the growing season
affected leaves may develop to normal size. However, many of
these leaves will have ragged margins and the leaf surface will
be rugose in appearance. As the season advances young leaves
at shoot terminals may be greatly dwarfed and their surfaces
much distorted and roughened and their margins very ragged.
The roughened appearance is produced by the collapse of the
tissue at numerous pin-point spots over the surface followed by
growth of the intervening tissue. Leaves so affected are often
brittle, considerably thickened and cupped with the margins


~





Florida Agricultural Experiment Station


turned either up or down, also dead areas of varying size are
usually present and are more common on the margins.
Later in the season many leaves on acutely affected trees be-
come pale yellowish green and show brown to reddish-brown
markings; however, leaves evidencing the characteristic chloro-
sis also develop the brown markings. These areas distributed
at random over the leaf surfaces have a gum-soaked appearance,
are indefinite in extent and outline and are present on both upper
and lower surfaces of the leaves.
In more advanced stages reddish brown necrotic spots are
developed. These spots are scattered over the leaf surface, may
be few or many in number, irregular in extent and outline, and


Fig. 3.-Branch from tung tree showing acute symptoms of iron deficiency
-defoliation and bud and twig necrosis. (Photographed 9/14/41.)


~fiP






Iron Deficiency of Tung in Florida


in severe cases much of the leaf area may be affected (Fig. 2).
Leaves thus affected show ragged margins and irregular breaks
due to brittleness of the dead tissue and are frequently smaller
than healthy leaves (Figs. 2, 7 and 8). Foliage developed dur-
ing the earlier part of the season may be comparatively free of
necrotic spots but as the season advances, particularly in acute


Fig. 4.-Shoots from trees showing typical foliage symptoms of: Left,
iron deficiency; middle, zinc deficiency (bronzing); and right, manganese
deficiency (frenching).


Fig. 5.-Treated and untreated tung leaves. The three leaves on the
right were dipped in a 2 percent iron sulfate solution when their appearance
was similar to the one on the left, which was untreated. Treated 7/18/40,
photographed 8/28/40.


~' -~

'.8 )r
t~P"






Florida Agricultural Experiment Station


Fig. 6.-Typical treated and chlorotic tung shoots. Left, check or un-
treated shoot; right, shoot dipped in 2 percent iron sulfate solution on
7/18/40, at which time its appearance was similar to that of the untreated
shoot. Photographed 8/28/40.


Fig. 7.-Typical shoots from treated and untreated trees. Left, from
tree which received 1/ pound of iron sulfate to the soil on 7/12/40 and
14a pound on 5/15/41; right, from check (untreated) tree. Photographed
7/31/41.


~i~"f~






Iron Deficiency of Tung in Florida


cases, necrotic spots become more prevalent on both new and old
foliage and on certain shoots the leaves may die soon after they
emerge from the bud.
Premature leaf fall may occur on some severely affected trees.
In severe cases foliage area is much reduced and some twigs
may be com-
pletely defoliated
(Fig. 3). Twigs
have been ob-
served from
which all leaves
have fallen by 1
late July.
Dying of ter-
minal buds and u
twigs occurs in -
varying degree
on severely af- d
fected trees (Fig.
3). All terminal
buds were dead
on one such tree,
a second tree had
only two live
buds, whereas
there were no
dead buds on an-
other tree evi-
dencing acute
symptoms. This
condition usually
is coincident with
severe defoliation
of the shoots and Fig. 8.-Shoot from tung tree sprayed with 1
may be followed percent iron sulfate solution on 5/19/41. New foli-
age produced since spray was applied is chlorotic.
by death of the Photographed 6/26/41.
branch extend-
ing, in some cases, back into the four and five year old wood.
Obviously, the potential yield of a tree is reduced in direct pro-
portion to the number of terminal buds killed.
A light green color as contrasted with the normal green is the
first symptom to develop on the fruit and usually is apparent by





Florida Agricultural Experiment Station


mid-summer. Later, brown stained areas, similar in appearance
to those on the foliage, are evident on certain of the fruit,
usually on that portion exposed to the sun. Premature fruit fall
occurs and such fruits are not filled. Furthermore, many of
those that remain on the tree to apparent maturity do not fill
properly. Fruit symptoms are not present on all trees evidenc-
ing iron deficiency; however, certain severely affected trees have
developed the symptoms described.
Each deficiency, whether of iron, zinc (bronzing), or man-
ganese (frenching), exhibits definite and specific symptoms, and
when recognized, these serve as a means of diagnosis under field
conditions. Chlorosis is the most characteristic symptom of
both iron and manganese deficiency and may be readily distin-
guished from bronzing or zinc deficiency which has malforma-
tion and dwarfing of terminal leaves and bronze color of the
foliage as its most characteristic symptoms. Furthermore, iron
deficiency and frenching symptoms appear as the trees start
growth in the spring, while symptoms of bronzing are rarely
apparent much before early summer and usually it is late sum-
mer before symptoms become acute. The principal difference
between the chlorosis of iron deficiency and that of frenching
is in the relative amounts of chlorotic and green tissue and in-
tensity of color of the affected foliage (Fig. 4). Characteris-
tically, with iron deficiency only the veins of the leaves remain
green, giving the appearance of a green network on a bright
yellow background, whereas frenching differs in that relatively
more of the tissue surrounding the main veins remains green
and the cholorotic tissue is a dull yellow or yellowish green in
contrast to .the bright yellow of iron deficiency. These differ-
ences are illustrated in Figures 1, 2 and 4.
The three disorders are characterized by the formation of
necrotic areas. Frenching exhibits dark-brown spots in accord-
ance with the cholortic areas and individual spots are small.
Bronzed leaves show relatively large dead areas scattered at
random over the leaf surface, while leaves showing iron defici-
ency have reddish brown spots, very variable in size and num-
ber and scattered at random over the leaf surface. The necrotic
spots of zinc deficiency are associated with malformation and
dwarfing of the terminal leaves and a bronze color of the foliage,
particularly on the under surface of the leaf, so characteristic
of this disorder, while the necrotic spots of iron deficiency are






Iron Deficiency of Tung in Florida


associated with the characteristic chlorosis and brown staining
of the foliage (Figs. 2 and 4).

EXPERIMENTS
The experimental work herein reported was conducted in 1940
and 1941 in three tung orchards, two near LaCrosse and one near
Gainesville, Alachua County, Florida. One of the orchards in
the LaCrosse area was planted in 1930, the other in 1931; the
orchard near Gainesville was planted in 1924. Two of the plant-
ings are now in commercial production but the third has been
abandoned for several years. Poorly drained soil is one of the
principal reasons for the failure of this last; however, several
trees in one area show iron deficiency symptoms. The soils on
which the affected trees are located in the three orchards are:
Planting 1, gradation form between a typical Leon fine sand and
Scranton loamy fine sand with some typical Leon fine sand;
Planting 2, Jamison loamy fine sand; Planting 3, Leon fine sand.
Treatments consisted of both foliage and soil applications of
several of the micro-elements alone and in various combinations.

1940 TREATMENTS
Foliage Treatments.-Initial response to iron was obtained on
four severely affected tung trees in two plantings near LaCrosse
in Alachua County (Figs. 5, 6). On July 12 severely chlorotic
shoots were selected, tagged and dipped in 2 percent solutions
of several compounds to all of which hydrated lime and calcium
caseinate had been added. These compounds were applied singly
and in various combinations. Similar untreated shoots were
selected, tagged and used as controls. Results of these treat-
ments are summarized in Table 1.
Response was obtained only when iron sulfate was present in
the solution. When copper sulfate was added the effect of the
iron was nullified on five affected shoots thus treated. There
was no indication of additional response when manganese and
zinc, in addition to iron, were added to the solution or of detri-
mental effects due to their use.
When first observed, 26 days after treatment, several of the
shoots dipped in certain of the solutions containing iron had
completely recovered. This indicated a rapid response to foliage
treatments and undoubtedly this could have been noticed several
days earlier.






Iron Deficiency of Tung in Florida


associated with the characteristic chlorosis and brown staining
of the foliage (Figs. 2 and 4).

EXPERIMENTS
The experimental work herein reported was conducted in 1940
and 1941 in three tung orchards, two near LaCrosse and one near
Gainesville, Alachua County, Florida. One of the orchards in
the LaCrosse area was planted in 1930, the other in 1931; the
orchard near Gainesville was planted in 1924. Two of the plant-
ings are now in commercial production but the third has been
abandoned for several years. Poorly drained soil is one of the
principal reasons for the failure of this last; however, several
trees in one area show iron deficiency symptoms. The soils on
which the affected trees are located in the three orchards are:
Planting 1, gradation form between a typical Leon fine sand and
Scranton loamy fine sand with some typical Leon fine sand;
Planting 2, Jamison loamy fine sand; Planting 3, Leon fine sand.
Treatments consisted of both foliage and soil applications of
several of the micro-elements alone and in various combinations.

1940 TREATMENTS
Foliage Treatments.-Initial response to iron was obtained on
four severely affected tung trees in two plantings near LaCrosse
in Alachua County (Figs. 5, 6). On July 12 severely chlorotic
shoots were selected, tagged and dipped in 2 percent solutions
of several compounds to all of which hydrated lime and calcium
caseinate had been added. These compounds were applied singly
and in various combinations. Similar untreated shoots were
selected, tagged and used as controls. Results of these treat-
ments are summarized in Table 1.
Response was obtained only when iron sulfate was present in
the solution. When copper sulfate was added the effect of the
iron was nullified on five affected shoots thus treated. There
was no indication of additional response when manganese and
zinc, in addition to iron, were added to the solution or of detri-
mental effects due to their use.
When first observed, 26 days after treatment, several of the
shoots dipped in certain of the solutions containing iron had
completely recovered. This indicated a rapid response to foliage
treatments and undoubtedly this could have been noticed several
days earlier.






Iron Deficiency of Tung in Florida


associated with the characteristic chlorosis and brown staining
of the foliage (Figs. 2 and 4).

EXPERIMENTS
The experimental work herein reported was conducted in 1940
and 1941 in three tung orchards, two near LaCrosse and one near
Gainesville, Alachua County, Florida. One of the orchards in
the LaCrosse area was planted in 1930, the other in 1931; the
orchard near Gainesville was planted in 1924. Two of the plant-
ings are now in commercial production but the third has been
abandoned for several years. Poorly drained soil is one of the
principal reasons for the failure of this last; however, several
trees in one area show iron deficiency symptoms. The soils on
which the affected trees are located in the three orchards are:
Planting 1, gradation form between a typical Leon fine sand and
Scranton loamy fine sand with some typical Leon fine sand;
Planting 2, Jamison loamy fine sand; Planting 3, Leon fine sand.
Treatments consisted of both foliage and soil applications of
several of the micro-elements alone and in various combinations.

1940 TREATMENTS
Foliage Treatments.-Initial response to iron was obtained on
four severely affected tung trees in two plantings near LaCrosse
in Alachua County (Figs. 5, 6). On July 12 severely chlorotic
shoots were selected, tagged and dipped in 2 percent solutions
of several compounds to all of which hydrated lime and calcium
caseinate had been added. These compounds were applied singly
and in various combinations. Similar untreated shoots were
selected, tagged and used as controls. Results of these treat-
ments are summarized in Table 1.
Response was obtained only when iron sulfate was present in
the solution. When copper sulfate was added the effect of the
iron was nullified on five affected shoots thus treated. There
was no indication of additional response when manganese and
zinc, in addition to iron, were added to the solution or of detri-
mental effects due to their use.
When first observed, 26 days after treatment, several of the
shoots dipped in certain of the solutions containing iron had
completely recovered. This indicated a rapid response to foliage
treatments and undoubtedly this could have been noticed several
days earlier.






12 Florida Agricultural Experiment Station

TABLE 1.-RESULTS OF 1940 FOLIAGE TREATMENTS OF AFFECTED SHOOTS
ON FOUR TUNG TREES. TREATED 7-12-40, FINAL INSPECTION 8-28-40.
Number of Restoration of
Treated Shoots Treatments Green Color
4 2% (CP) manganese sulfate none
7 2% (CP) zinc sulfate none
13 2% (CP) copper sulfate none
10 2% borax none
15 2% (CP) iron sulfate 8-complete recovery
5-90-95% recovery
1-85% recovery
1-75% recovery

12 2% (CP) manganese sulfate none
plus 2% (CP) zinc sulfate
3 2% borax none
plus 2% (CP) zinc sulfate
6 2% (CP) iron sulfate plus 3-complete recovery
2% (CP) manganese sulfate 1-95% recovery
plus 2% (CP) zinc sulfate 2-85% recovery
5 2% (CP) iron sulfate plus
2% (CP) manganese sulfate none
plus 2% (CP) zinc sulfate
plus 2% (CP) copper sulfate
25 check (no treatment) none


In general, younger leaves of a shoot tended to respond more
rapidly and more completely to iron treatments, provided severe
necrosis has not begun. This was more apparent later in the
season when there was a much greater difference in age between
the terminal and basal leaves of a shoot. Leaves that had be-
come curled, cupped, roughened or otherwise deformed did not
become normal in shape following treatment; however, they
usually assumed a normal green coloration similar to leaves that
showed no malformation. In some instances the leaf did not
become uniformly green, as some areas were darker green than
the surrounding tissue (Fig. 5).
Soil Treatments.-Soil treatments were made in conjunction
with the foliage dips in Planting 1 on July 12. At the time of
treatment the trees were examined and a record was made of
the relative severity of the disorder. Observations were re-
peated from time to time during the 1940 and 1941 seasons.
For convenience in presenting results these records were con-










Tree
No.


TABLE 2.-RESULTS OF 1940 AND 1941 SOIL TREATMENTS TO TUNG TREES IN PLANTINGS 1 AND 2*.

11940 1941


Treatments (July 12) Record of Iron Deficiency I Treatments Record of Iron Deficiency
7-12-40 8-28-40 1 10-8-40 I (May 10 and July 31) 5-10-41 6-25-41 9-11-41 110-10-41


Planting 1
1 % lb. copper sulfate ..... 100 100 100 V lb. iron sulfate ........ 100 100 100 100
2 1 2 lbs. magnesium sulfate 100 75 50 check ................................ 100 75 50 50
3 2 lbs. manganese sulfate( 75 50 50 2 lbs. iron sulfate ........ 100 75 100 100
4 i / lb. borax ..................... 100 25 25 check .................... ..I 75 35 25 25
5 1 lb. iron sulfate .............. 100 25 10 lb. iron sulfate** .... 5 0 0 0
6 I 3 lbs. iron sulfate ............ 100 50 50 Sprayed Tree 6-See Table 3
7 /4 lb. each of manganese,
magnesium and iron sul-
fates and %/ lb. borax 50 25 5 Not treated ...... 15 5 5 5
8 check ---.......................... 50 35 15 Sprayed Tree 8-See Table 3
9 check ........ .. ............ 100 100 100 check ................................ 75 100 75 75
10 check ............................... 100 75 100 1 lb. iron sulfate .......-. 100 100 50 50
11 check .................................. 25 15 25 | lb. iron sulfate ........ 50 0 0 0
12 check -.. ..... ...... 0 25 0 check .............................. 75 25 15 5
14 check -............. .... 75 50 35 check ................. ... ..........( 75 75 25 25
Planting 2
15 check -................ .......... 100 1 100 75 check ................ ......... 75 65 25 25
16 check -..................... 75 50 50 1 b. iron sulfate** ...... 65 25 0 0
* See Table 4 for location of planting and soil type.
** Application made on May 10 only.






Florida Agricultural Experiment Station


verted into numerical values for each tree and indicated condi-
tions as follows: 100-deficiency very severe with all growth
affected; 75 and 50-intermediate; 25-slight; 0-exhibiting no
symptoms.
Several of the micro-elements alone and in combination were
broadcast under the spread of the branches. The materials ap-
plied and a summary of the results are given in Table 2.
An examination of the data shows that Trees 5, 6 and 7 which
received iron sulfate showed definite improvement when ex-
amined August 28 and October 8 (Fig. 7). Trees 5 and 6 were
adjacent to Tree 9, which was untreated. Trees 2, 3, 4 and 8
showed some improvement in condition (Tables 2 and 3). Upon
resumption of growth the following spring, all again exhibited
symptoms. From this and subsequent observations it was evi-
dent that symptoms are most acute during the early part of the
year and that certain trees tend to recover later in the season,
whether they are treated or not.
These results, in conjunction with the foliage treatments
previously mentioned, were considered adequate evidence that
this disorder is due to iron deficiency. Consequently, the 1941
treatments consisted of foliage and soil applications of iron sul-
fate only.
1941 TREATMENTS
Foliage Treatments.-In the spring and summer of 1941 foli-
age treatments were made by spraying the entire tree, or in
some instances one-half of the tree with the remainder serving
as a check. The spray used was a 1.0 percent solution of C. P.
iron sulfate to which had been added hydrated lime and calcium
caseinate. This mixture was prepared by dissolving 3 ounces
of C. P. iron sulfate in 21/2 gallons of water. The iron sulfate
was dissolved by sprinkling the material directly into a container
of water while stirring vigorously with a paddle. One and one-
half ounces of finely ground hydrated lime and 1 ounce of cal-
cium caseinate were mixed in another container and then made
into a smooth paste by the addition of a small quantity of water.
This mixture was slowly poured into the container to which the
iron sulfate had previously been added while the solution was
stirred vigorously. The iron-lime spray thus resulting was ap-
plied with a bucket pump. Any type of spraying equipment
producing a good mist would have been satisfactory; however,
it was necessary to strain the spray solution through a material






Florida Agricultural Experiment Station


verted into numerical values for each tree and indicated condi-
tions as follows: 100-deficiency very severe with all growth
affected; 75 and 50-intermediate; 25-slight; 0-exhibiting no
symptoms.
Several of the micro-elements alone and in combination were
broadcast under the spread of the branches. The materials ap-
plied and a summary of the results are given in Table 2.
An examination of the data shows that Trees 5, 6 and 7 which
received iron sulfate showed definite improvement when ex-
amined August 28 and October 8 (Fig. 7). Trees 5 and 6 were
adjacent to Tree 9, which was untreated. Trees 2, 3, 4 and 8
showed some improvement in condition (Tables 2 and 3). Upon
resumption of growth the following spring, all again exhibited
symptoms. From this and subsequent observations it was evi-
dent that symptoms are most acute during the early part of the
year and that certain trees tend to recover later in the season,
whether they are treated or not.
These results, in conjunction with the foliage treatments
previously mentioned, were considered adequate evidence that
this disorder is due to iron deficiency. Consequently, the 1941
treatments consisted of foliage and soil applications of iron sul-
fate only.
1941 TREATMENTS
Foliage Treatments.-In the spring and summer of 1941 foli-
age treatments were made by spraying the entire tree, or in
some instances one-half of the tree with the remainder serving
as a check. The spray used was a 1.0 percent solution of C. P.
iron sulfate to which had been added hydrated lime and calcium
caseinate. This mixture was prepared by dissolving 3 ounces
of C. P. iron sulfate in 21/2 gallons of water. The iron sulfate
was dissolved by sprinkling the material directly into a container
of water while stirring vigorously with a paddle. One and one-
half ounces of finely ground hydrated lime and 1 ounce of cal-
cium caseinate were mixed in another container and then made
into a smooth paste by the addition of a small quantity of water.
This mixture was slowly poured into the container to which the
iron sulfate had previously been added while the solution was
stirred vigorously. The iron-lime spray thus resulting was ap-
plied with a bucket pump. Any type of spraying equipment
producing a good mist would have been satisfactory; however,
it was necessary to strain the spray solution through a material






Iron Deficiency of Tung in Florida


such as cheesecloth or a wire screen to prevent clogging of the
spray nozzle.
Halves of four severely chlorotic trees in Planting 1 were
sprayed with the iron-lime spray on May 15 and the other halves
served as checks. The same parts of two of the four trees were
again sprayed on July 31, and at the same time one-half of
another tree in the same orchard, but somewhat removed from
the area in which the treated trees were located, was sprayed.
Five comparable trees were used as checks.
The results as given in Table 3 indicate that excellent control
was obtained by foliage applications. In most instances two
sprays during the growing season were apparently necessary to
effect control, since only the foliage covered by the spray re-
sponded and that which developed later was chlorotic (Figs. 8
and 9).


















Fig. 9.-Typical shoots from treated and untreated tung trees. Left,
from tree sprayed with 1 percent iron sulfate solution on 5/19/41 and
resprayed on 7/31/41; right, from check (untreated) tree. Photographed
9/14/41.
Soil Treatments.-In addition to Trees 5, 6 and 7 previously
treated with iron sulfate to the soil in Planting 1, three other
trees, Trees 1, 3 and 10, evidencing severe symptoms were given
1/2, 1 and 2 pounds respectively of a commercial grade of iron
sulfate and 1 tree in Planting 2 received 1 pound on May 10
(Table 2). Improvement in condition of the three newly treated
trees in Planting 1 was not apparent by mid-summer, so they






Florida Agricultural Experiment Station


were retreated on July 31. Following the second treatment Tree
10 showed definite improvement in condition by September 11.
However, Trees 1 and 3 showed no improvement throughout the
season.
Results from soil treatments with iron sulfate under condi-
tions of this experiment are not wholly conclusive, since some
trees have, as yet, failed to respond satisfactorily and the foliage
of others which were untreated "greened-up" considerably or
entirely. Nevertheless, certain trees evidencing acute symptoms
showed definite response to soil treatments in 1940 and evidenced
little if any symptoms in 1941 (Trees 5 and 7, Table 2), whereas
check trees and others immediately adjacent which had received
no iron sulfate in 1940 showed acute symptoms in the early
spring of 1941 (Trees 1, 2, 3, 4, 9 and 10, Table 2).
Previous to treatment in 1940 Tree 6 (Tables 2 and 3) had
been severely injured near the ground and the trunk had been
girdled except for a strip of bark about two inches wide. It
showed some improvement in condition following treatment in
1940 but the new foliage was quite chlorotic in the spring of
1941. It was thought that this injury may have had some effect
upon its response to the soil application, so it was sprayed with
iron-lime spray on May 12, and by June 25 it was rated at
approximately 95 percent (Table 3).
Results by late summer from 1942 foliage and soil treatments
with iron sulfate were similar to those obtained in 1940 and
1941.
Iron deficiency of tung in Florida has, as yet, been observed
in a limited number of orchards and is not general over these
plantings. It is confined to small groups of trees in localized
areas in the orchards. It is suggested that treatments be con-
fined to those trees which evidence symptoms until such time
as results from experimental tests show the desirability of treat-
ing the entire orchard. It is further suggested that soil applica-
tions be made in April or May at the rate of 1/4 to 2 pounds
of iron sulfate per tree, depending upon tree size. If satisfac-
tory response has not been obtained by mid-summer the affected
trees should be retreated with the same amount given in the
first application. In cases where the desired response is not
obtained from soil treatments it will be necessary to effect con-
trol by spraying the tree with a 1 percent iron-lime spray. In
most instances two sprays during the growing season will be
necessary to effect control, the first in April or May and the






Iron Deficiency of Tung in Florida


TABLE 3.-RESULTS OF 1941 SPRAY APPLICATIONS OF IRON SULFATE TO
TUNG TREES IN PLANTING 1.
Date of
Tree Treat- Treatments Record of Iron Deficiency**
No.* ment 5-10-41 6-25-41 7-31-41|9-11-41110-10-41

5-15-41
6 and sprayed 100 5 5 5
7-31-41
5-15-41
8 and sprayed 1 50 5 5 5
7-31-41
2 5-15-41 % tree sprayed 100 5 5 5
% tree check 100 75 50 50
4 5-15-41 tree sprayed 75 5 5 5
'/ tree check 75 35 25 25
13 7-31-41 % tree sprayed 50 5 5
% tree check 50 50 35
9 un-
treated check 75 100 75 75
12 un-
treated check 75 25 15 5

See Table 4 for location of planting and soil type.
** Refers to foliage covered by spray, new leaves chlorotic.

second in June or July (Figs. 8 and 9). Spray applications alone
will produce excellent control but tung growers generally do not
have proper equipment and soil applications are a much more
practical method of control. A commercial grade of iron sulfate
may be used for both spray and soil applications.

SOIL REACTION
Much has been published indicating that physiological dis-
orders of the plants known to respond to iron treatments are
most often associated with slightly acid to alkaline soils, such
as overlimed or calcareous soils and soils with an extremely
high manganese content. However, iron deficiency is not neces-
sarily confined to soils in the neutral to alkaline range of re-
action, since it has been observed on citrus, azaleas and gar-
denias in Florida on soils which are slightly to highly acid in
reaction.
Soil samples were taken in the three orchards from the areas
where the trees evidenced symptoms of the disorder. The data
obtained are presented in Table 4. Soil Samples 5 and 6 were






Florida Agricultural Experiment Station


TABLE 4.-SOIL REACTION OF AREAS IN THREE TUNG ORCHARDS IN WHICH
IRON DEFICIENCY SYMPTOMS OCCURRED.
Plant- I Sam- Soil Soil Re-
ing Location of Soil Type pie Layer action
No. Planting _I No. (inches) or pH
1 Near LaCrosse, Gradation form between 1 0-6 4.47
Alachua County typical Leon fine sand 2 6-18 4.13
and Scranton loamy 3 0-6 4.51
fine sand with some 4 6-18 4.20
typical Leon fine sand. 5 0-6 4.81
6 6-18 5.00
2 Near LaCrosse, Jamison loamy fine sand 7 0-6 4.88
Alachua County 8 6-18 4.98
9 0-6 5.13
10 6-18 5.00
3 Near Gainesville, Leon fine sand 11 0-6 8.40
Alachua County 12 6-18 8.84
13 0-6 7.89
14 6-18 7.94


taken from a location between the trees, while the remainder
of the samples were taken from a location under the spread of
the branches.
The soil reaction data presented show that this disorder is
associated with an acid soil reaction in Plantings 1 and 2 and
with an alkaline soil reaction in Planting 3. Normally, a soil
of the series found in Planting 3 is quite acid in reaction. In
this case the alkaline reaction was produced by the incorporation
of wood ashes in a small area of soil in which the affected trees
are growing.
DISCUSSION

Using visual symptoms as a method of diagnosis, iron defici-
ency has, as yet, been observed in only three tung orchards in
Florida. Based on this method of measurement the percentage
of affected trees in these plantings is very small. The possi-
bility should not be overlooked, however, that in these and other
orchards there may be trees affected by the deficiency which
evidence no visual symptoms. There are numerous reports in
the literature of other plants responding to applications of vari-
ous of the micro-elements, such as iron, when no symptoms could
be detected. Winsor (9) reports that in soil supplement tests
conducted on Leon fine sand, under controlled conditions, the
yield of collards was increased over 50 percent by the use of
iron sulfate at the rate of 100 pounds per acre. No symptoms






Iron Deficiency of Tung in Florida


of iron deficiency were visible but a decided increase in growth
was obtained when iron sulfate was applied.
According to Camp and Fudge (2) iron deficiency of citrus
in Florida occurs most often on alkaline soils and under these
conditions is much more persistent and acute; however, it does
occur on acid sandy soils but is considerably less common, the
symptoms are much less pronounced and may clear up without
treatment. They state that occasional response to soil applica-
tions of iron in affected groves under acid soil conditions has
been reported.
Iron chlorosis of gardenia (Gardenia jasminoides Ellis) is
seen occasionally in Florida on plants growing in acid soils.
From these samples it is apparent that iron deficiencies,
though less prevalent and acute than on alkaline soils, are found
on acid soils in Florida.
It should be noted that foliage applications of iron for the
purpose of controlling iron deficiencies have not been equally
successful with all plants. Citrus in Florida does not respond
satisfactorily to foliage applications of iron (2). On the other
hand, pineapple yellows, chlorosis of grapes, and iron deficiency
of tung and many other plants have been successfully controlled
in this manner.
An examination revealed that many of the fruits on severely
affected tung trees developed to normal size and fell at the usual
time for that tree but nevertheless had failed to fill. This prob-
ably was due to the reduction in foliage caused by the severe
premature leaf fall on acutely affected trees and the lessened
effectiveness of the leaves that remain.
The soils upon which several of the affected trees are located
in Planting 1 is a gradation form between a typical Scranton
loamy fine sand and Leon fine sand with Leon fine sand in
two locations. In these areas of the orchard, during rainy
periods, the water table was two to three feet from the surface
and therefore these locations were relatively poorly drained. In
the cultivation practice a ditch was opened down the middle of
each land, which somewhat improved drainage. Soils in the
remainder of the orchard were closely related to the area where
the trees evidence the disorder. The soils of Planting 2 were
predominantly well drained sandy soils of the Norfolk series;
however, there was a narrow strip bordering the edge of a lake
which graded off into a Jamison loamy fine sand and it was upon
this soil type that a few trees evidencing symptoms of iron defici-






Florida Agricultural Experiment Station


ency were located. The remainder of the trees in the orchard
showed no visible symptoms. Planting 3 was on typical Leon
fine sand similar to Planting 1, except that drainage was some-
what poorer, as there were no ditches between the rows. Here
again the disorder was present on soils in which drainage was
relatively poor.
It is of interest that several plants growing in and near the
areas in Plantings 1 and 2, where tung showed iron deficiency
symptoms, also evidenced a chlorosis. Those showing chlorosis
were blackberry (Rubus sp.), water oak (Quercus nigra L.),
French mulberry (Callicarpa americana L.), Mexican tea (Am-
brina ambrosioides (L.) Spach.) and maiden cane (Panicuni
hemitomon Schult.). Chlorotic shoots of blackberry and water
oak, when dipped in a 1 percent solution of C. P. iron sulfate,
recovered, indicating that the chlorosis of these plants was due
to an iron deficiency.

LITERATURE CITED

1. BRYAN, O. C. Yellowing of centipede grass and its control. Fla. Agr.
Exp. Sta. Press Bul. 450. 1933.
2. CAMP, A. F., and B. R. FUDGE. Some symptoms of citrus malnutrition
in Florida. Fla. Agr. Exp. Sta. Bul. 335. 1939.
3. DICKEY, R. D., and G. H. BLACKMON. Propagation, planting and fer-
tilizing tests with tung oil trees. Fla. Agr. Exp. Sta. Ann. Rept.
1941: 80.
4. FINCH, A. H., D. W. ALBERT and A. F. KINNISON. A chlorotic condi-
tion of plants in Arizona related to iron deficiency. Proc. Amer.
Soc. Hort. Sci. 30: 431-434. 1933.
5. GRIs, E. Nouvelles experiences sur 1'action des composes ferrugineux
soluble, appliques a la vegetation, et specialement au traitment de
la chlorose et de la debilite des plants. Compt. Rend. Acad. Sci.
(Paris) 17: 679. 1843.
6. GRIS, E. Nouvelles experiences sur l'action des composes ferrugineux
soluble, appliques a la vegetation, et specialement au traitment de
la chlorose et de la debilite des plants. Compt. Rend. Acad. Sci.
(Paris) 19: 1118-1119. 1844.
7. MOWRY, HAROLD, and A. F. CAMP. A preliminary report on zinc sul-
fate as a corrective for bronzing of tung trees. Fla. Agr. Exp. Sta.
Bul. 273. 1934.
8. REUTHER, WALTER, and R. D. DICKEY. A preliminary report on french-
ing of tung trees. Fla. Agr. Exp. Sta. Bul. 318. 1937.
9. WINSOR, H. W. Mineral content of vegetable crops with special refer-
ence to iron. Fla. Agr. Exp. Sta. Ann. Rept. 1937: 69.




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