Citation
Cotton and some of its diseases and insects

Material Information

Title:
Cotton and some of its diseases and insects
Series Title:
Division of Agricultural Extension bulletin 15
Creator:
Jenkins, E. W. (Edward Walker)
Affiliation:
University of Florida -- Division of Agricultural Extension
Place of Publication:
Gainesville, Fla.
Publisher:
Division of Agricultural Extension, University of Florida
Publication Date:
Language:
English
Physical Description:
19 p. : ill. ; 23 cm.

Subjects

Subjects / Keywords:
Agriculture ( LCSH )
Farm life ( LCSH )
Farming ( LCSH )
University of Florida. ( LCSH )
Agriculture -- Florida ( LCSH )
Farm life -- Florida ( LCSH )
Cotton -- Diseases and pests -- Florida
Cotton ( jstor )
Plants ( jstor )
Bolls ( jstor )
Spatial Coverage:
North America -- United States of America -- Florida

Notes

Funding:
Florida Historical Agriculture and Rural Life

Record Information

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:
AMT5597 ( NOTIS )
47285048 ( OCLC )
002569295 ( ALEPH )

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February, 1919


COOPERATIVE EXTENSION WORK IN
AGRICULTURE AND HOME ECONOMICS
UNIVERSITY OF FLORIDA DIVISION OF AGRICULTURAL
EXTENSION AND UNITED STATES DEPARTMENT
OF AGRICULTURE COOPERATING
P. H. ROLFS, Director



COTTON
AND SOME OF ITS
DISEASES AND INSECTS
By E. W. JENKINS
Before the advent of the boll weevil into the State Florida
was divided into two cotton-growing sections. The western and
northwestern portion of the State was the section in which short
staple was grown. In the northern and north-central portion of
the State, as far south as Marion County, Sea Island or long staple
was the leading variety.
Since the appearance of the weevil, however, conditions with
respect to cotton growing have undergone a very material change.


Fig. 1.-The Two-Row Cultivator is Becoming Popular in Florida


Bulletin 15


il qi~







Florida Cooperative Extension


In the short staple section very little cotton is now planted,
other crops being found more profitable. The Sea Island section
has been extended as far south as Manatee County on the west
coast and as far south as Dade County on the east coast. This
has been brought about by the Sea Island cotton growers looking
for territory not infested with the boll weevil. There are some
soils in the southern counties which produce excellent cotton, and
the probability is that until these counties are invaded by the
boll weevil considerable acreage will be planted in cotton. Short
cotton is now being planted on many farms where formerly only
Sea Island grew.
SEA ISLAND COTTON
Sea Island cotton usually produces a large stalk well limbed
out. The leaves are deep lobed. The boils are small, usually
containing only three locks to the boll, and are late maturing. A
long slender boll denotes a good staple while a short, round boll de-
notes a poorer staple. Many farmers prefer the short round boll
because it is easier to gather, not knowing that they are produc-
ing an inferior grade of cotton. The staple of Sea Island cotton
varies in length, usually from one and a quarter to two inches in
length. Some planters in South Carolina grow varieties which
produce a staple two to two and a half inches in length. These
varieties are less productive than those with a medium staple and
experience has shown that it is not profitable to attempt to grow
the extra long staple varieties on the interior.
The percentage of lint to the seed varies. It usually runs
around 25 per cent, occasionally running as high as 32 per cent.
SHORT STAPLE COTTON
Short cotton produces a plant varying from a large stalk
with limbs from the bottom to the top of the stalk, to that of the
cluster type having very few limbs. The bolls are larger than
those of Sea Island, usually about the size of a hen's egg. They
are almost round and have a much thicker and harder boll or bur
than the Sea Island, and are not so easily punctured by a weevil.
The percentage of lint of short staple cotton varies greatly,
usually running from 33 to 42 per cent lint, due to the fact, that
there are so many different varieties.
SOIL
Cotton is a deep rooting plant and will do well on a sandy
or clay loam soil, provided it has a compact or clay subsoil and







Florida Cooperative Extension


In the short staple section very little cotton is now planted,
other crops being found more profitable. The Sea Island section
has been extended as far south as Manatee County on the west
coast and as far south as Dade County on the east coast. This
has been brought about by the Sea Island cotton growers looking
for territory not infested with the boll weevil. There are some
soils in the southern counties which produce excellent cotton, and
the probability is that until these counties are invaded by the
boll weevil considerable acreage will be planted in cotton. Short
cotton is now being planted on many farms where formerly only
Sea Island grew.
SEA ISLAND COTTON
Sea Island cotton usually produces a large stalk well limbed
out. The leaves are deep lobed. The boils are small, usually
containing only three locks to the boll, and are late maturing. A
long slender boll denotes a good staple while a short, round boll de-
notes a poorer staple. Many farmers prefer the short round boll
because it is easier to gather, not knowing that they are produc-
ing an inferior grade of cotton. The staple of Sea Island cotton
varies in length, usually from one and a quarter to two inches in
length. Some planters in South Carolina grow varieties which
produce a staple two to two and a half inches in length. These
varieties are less productive than those with a medium staple and
experience has shown that it is not profitable to attempt to grow
the extra long staple varieties on the interior.
The percentage of lint to the seed varies. It usually runs
around 25 per cent, occasionally running as high as 32 per cent.
SHORT STAPLE COTTON
Short cotton produces a plant varying from a large stalk
with limbs from the bottom to the top of the stalk, to that of the
cluster type having very few limbs. The bolls are larger than
those of Sea Island, usually about the size of a hen's egg. They
are almost round and have a much thicker and harder boll or bur
than the Sea Island, and are not so easily punctured by a weevil.
The percentage of lint of short staple cotton varies greatly,
usually running from 33 to 42 per cent lint, due to the fact, that
there are so many different varieties.
SOIL
Cotton is a deep rooting plant and will do well on a sandy
or clay loam soil, provided it has a compact or clay subsoil and







Florida Cooperative Extension


In the short staple section very little cotton is now planted,
other crops being found more profitable. The Sea Island section
has been extended as far south as Manatee County on the west
coast and as far south as Dade County on the east coast. This
has been brought about by the Sea Island cotton growers looking
for territory not infested with the boll weevil. There are some
soils in the southern counties which produce excellent cotton, and
the probability is that until these counties are invaded by the
boll weevil considerable acreage will be planted in cotton. Short
cotton is now being planted on many farms where formerly only
Sea Island grew.
SEA ISLAND COTTON
Sea Island cotton usually produces a large stalk well limbed
out. The leaves are deep lobed. The boils are small, usually
containing only three locks to the boll, and are late maturing. A
long slender boll denotes a good staple while a short, round boll de-
notes a poorer staple. Many farmers prefer the short round boll
because it is easier to gather, not knowing that they are produc-
ing an inferior grade of cotton. The staple of Sea Island cotton
varies in length, usually from one and a quarter to two inches in
length. Some planters in South Carolina grow varieties which
produce a staple two to two and a half inches in length. These
varieties are less productive than those with a medium staple and
experience has shown that it is not profitable to attempt to grow
the extra long staple varieties on the interior.
The percentage of lint to the seed varies. It usually runs
around 25 per cent, occasionally running as high as 32 per cent.
SHORT STAPLE COTTON
Short cotton produces a plant varying from a large stalk
with limbs from the bottom to the top of the stalk, to that of the
cluster type having very few limbs. The bolls are larger than
those of Sea Island, usually about the size of a hen's egg. They
are almost round and have a much thicker and harder boll or bur
than the Sea Island, and are not so easily punctured by a weevil.
The percentage of lint of short staple cotton varies greatly,
usually running from 33 to 42 per cent lint, due to the fact, that
there are so many different varieties.
SOIL
Cotton is a deep rooting plant and will do well on a sandy
or clay loam soil, provided it has a compact or clay subsoil and








Bulletin 15, Cotton


is well supplied with humus. However, when there is an excess
of humus as with muck soils, a large leafy stalk will be pro-
duced and usually a low yield of lint and seed. Cotton requires
a great amount of sunlight and when too much growth of stalk
and leaf is made the plant will shade itself and bolls forming at
the bottom of the plant will fail to mature and open. Cotton soils,
however, are usually deficient in humus, but this may besupplied
from barnyard manure or by growing legumes and plowing them
into the soil. Cotton should not be planted on the same land for
two years in succession, but should be planted in rotation with
leguminous or soil-improving crops. Cotton requires a well-
drained soil and should not be planted on wet land or land sub-
ject to overflow. Sea Island cotton will thrive in an atmosphere
which contains more moisture than is suited to short staple.

VARIETIES
Among the different varieties of Sea Island are Hinson,
Seabrook,,Rivers, and Sosnowski. The varieties of short cotton
are numerous. Prof. J. E. Turlington gives the following as the
result of variety test work on the Florida Agricultural Experi-
ment Station. This list contains some of the leading varieties
of short staple and one variety of Sea Island (Sosnowski).
"After writing to several of .the southern Experiment Stations and
reliable seedsmen for recommendations as to varieties that would probably
make good in Florida under boll weevil conditions, ten varieties were selected
from these recommendations. The plantings were made in 4' 4" rows and
the hills were put two feet apart in the drill. There were three rows per
plot, making 3/50 of an acre per plot. The results in the following table
are for averages 'of three plots in 1917 and four plots in. 1918, for each
variety.
TABLE SHOWING AVERAGE YIELD OF SEED COTTON PER ACRE, ANDI PERCENTAGE
OF THE CROP PICKED FIRST PICKING IN 1917 AND 1918
1917 1918

Variety


Cleveland Big Boll................... 463 30 95 46
Mexican Big Boll...................... 400 56 110 51
HartsIville No. 9....................... 478 42 88 42
Hartsville No. 11...................... 500 25 62 34
Cook'.3 Improved ....................... 726 48 153 54
Webber's No. 49...................... 532 43 116 45
Trice ....................... ............ 615 72 126 51
Lone Star .................... ......... ... 691 51 83 36
'Dirango ..... ..... ......... ......... 75 56 52 59
Sosnowski .................................. 336 35 25 .11







Florida Cooperative Extension


"During 1917, in addition to the ten varieties run in the regular test,
sixteen varieties were grown in single rows. Only one of these, the Ocala,
showed up favorably with the leading ones of the ten varieties in the regular
test. It yielded 600 pounds.
"It should be stated'that the soil used during the two years was prac-
tically of the same productiveness, and the 1918 crop had the advantage of
two stalks per hill instead of one, which has been shown by the Georgia
Experiment Station to yield more than one stalk to the hill.
"The decreased yield'of 1918 seems to be entirely due to the boll weeviL
The boll weevil did very little damage in 1917."

PREPARATION OF SOIL

When included in a system of crop rotation, cotton should
be planted on land which has been planted the year before in
corn, with either velvet beans, peas, or some other leguminous
plant. The beans or pea-vines, together with the corn stalk,
should be plowed under as early as possible.. This should be done
with a plow that will turn the soil and cover any vegetation which
may be on the land. Immediately after this plowing the soil
should be thoroly pulverized by the use of some suitable harrow.
There are two methods of planting cotton in general use:
one level and the other the ridge method. The modification of
the ridge method will be found best on the majority of the cot-
ton soils in Florida. Just before planting this land should have
a second plowing, and this should be done by the use of a two-
horse cultivator which will bed a row by going over it only once;
and if a two-row cultivator is used two beds may be made at the
time. The beds should be made low, and if very high a section
harrow should be dragged over them to knock them down. The
rows should be four to six feet apart, depending on the fertility
of the soil. Have the rows closer on thin soil and wider on the
fertile land. Cotton is a plant which requires a great deal of
sunlight, and the rows should be far enough apart for the limbs
not to meet between them. There should be distance enough
in the drill for the plants not to be crowded.

PLANTING

No exact date for planting can be given. The time to plant
either Sea Island or short cotton is when all danger of frost is
past and the ground has warmed up enough for the cotton to
come up and grow rapidly.
A one-horse planter does satisfactory work and is well
adapted for use on the average farm.







Florida Cooperative Extension


"During 1917, in addition to the ten varieties run in the regular test,
sixteen varieties were grown in single rows. Only one of these, the Ocala,
showed up favorably with the leading ones of the ten varieties in the regular
test. It yielded 600 pounds.
"It should be stated'that the soil used during the two years was prac-
tically of the same productiveness, and the 1918 crop had the advantage of
two stalks per hill instead of one, which has been shown by the Georgia
Experiment Station to yield more than one stalk to the hill.
"The decreased yield'of 1918 seems to be entirely due to the boll weeviL
The boll weevil did very little damage in 1917."

PREPARATION OF SOIL

When included in a system of crop rotation, cotton should
be planted on land which has been planted the year before in
corn, with either velvet beans, peas, or some other leguminous
plant. The beans or pea-vines, together with the corn stalk,
should be plowed under as early as possible.. This should be done
with a plow that will turn the soil and cover any vegetation which
may be on the land. Immediately after this plowing the soil
should be thoroly pulverized by the use of some suitable harrow.
There are two methods of planting cotton in general use:
one level and the other the ridge method. The modification of
the ridge method will be found best on the majority of the cot-
ton soils in Florida. Just before planting this land should have
a second plowing, and this should be done by the use of a two-
horse cultivator which will bed a row by going over it only once;
and if a two-row cultivator is used two beds may be made at the
time. The beds should be made low, and if very high a section
harrow should be dragged over them to knock them down. The
rows should be four to six feet apart, depending on the fertility
of the soil. Have the rows closer on thin soil and wider on the
fertile land. Cotton is a plant which requires a great deal of
sunlight, and the rows should be far enough apart for the limbs
not to meet between them. There should be distance enough
in the drill for the plants not to be crowded.

PLANTING

No exact date for planting can be given. The time to plant
either Sea Island or short cotton is when all danger of frost is
past and the ground has warmed up enough for the cotton to
come up and grow rapidly.
A one-horse planter does satisfactory work and is well
adapted for use on the average farm.







Bulletin 15, Cotton


Cotton seed should be planted about two inches deep, and
if there is a fair amount of moisture in the soil at the time of
planting, the seeds will sprout readily. If planted too deep it will
be slow to germinate, and this has a tendency to stunt the
growth of the cotton.
FERTILIZERS

Cotton responds readily to proper fertilization.
It must be remembered that in order to obtain the best
results from the use of commercial fertilizers the soil must be


















Fig. 2.-Combination Planter and Fertilizer Distributor

put in first-class physical condition by deep plowing and the addi-
tion of vegetable matter. Stable manure and compost, when used
in connection with acid phosphate, make one of the most effective
and lasting fertilizers. When commercial fertilizer alone is used
a complete fertilizer gives the best results. It is impossible to
give a formula which would be suitable for cotton on all types of
soil. The following formula is suggested for average cotton
soils and may be modified as conditions vary: phosphoric acid 6
to 8 percent, nitrogen 3 percent, and potash 3 percent, applying
from 200 to 600 pounds per acre. When large quantities are
used most cotton farmers prefer to divide the amount into two
applications. However, since the appearance of the boll weevil a
single application is made at the time of planting or before, either







Florida Cooperative Extension


putting down the fertilizer and bedding on it just before plant-
ing, or applying it when planting. If applied when planting a
combination planter is used, which distributes the seed and ferti-
lizer at one operation. (Fig. 2.)

CULTIVATION

Cultivation should begin early. Possibly some of the worst
enemies of cotton are weeds and grass, and everything possible
should be done to keep them down at little expense. The first


Fig. 3.-Adjustable Weeder used for Light Cultivation when
the Plants are Small

cultivation should be made when the plants are from eight to
ten days old, and should be done with a weeder (fig. 3), provided
the land is smooth and clear of stumps. If used in time the
weeder is an effective means of cultivating the first time. By
running at right angles with the rows it is possible to kill the
grass and weeds and at the same time thin out some of the cotton
and save much hoeing.
As soon as the young plants have from three to four leaves
they should be thinned with a hoe, one or two stalks to the hill,
from 12 to 30 inches apart, depending on the fertility of the soil.
Cotton should be cultivated frequently and shallow. If deep








Bulletin 15, Cotton 7

cultivation is given at all it should be done while the plants are
small, otherwise the feeding roots will be torn ff and the plants
badly injured. Many farmers have' a practice,'of giving their
cotton three cultivations, while others cultivate sixtimnes or more.
Possibly the best method is to cultivatelevery ten days, preferably
after each rain, continuing the cultivation thru July.,:,
On land where they can be used it is very economical to use
improved implements in the cultivation' of cotton. The two-row
cultivator is being used by a great many farmers. (Fig. 1.)

COST OF PICKING
Possibly the most expensive work with cotton is harvesting.
Several attempts have been made to put out machines for pick-
ing cotton, but so far none have been satisfactory, The only
practical, way kno\ln to harvest cotton seems to be to pick it out
by hand.
Sea Island cotton having a smaller boll and not opening up
as well as short staple, requires more labor.to gather it. The
prices paid by most farmers fr picking the past season have
been from two to two and a half cents per pound for Sea Island,
and from one to one and a quarter cents for short cotton. An
average hand should pick 200 pounds of short or 100 long staple
cotton per day.
YIELD

The average yield of Sea Island cotton, under normal con-
ditions, is about 350 pounds of seed: cotton per acre. It is dif-
ficult to say what an average yield of 'short staple cotton would
be. As much as 3,000 pounds of seed cotton per acre have been
produced. Possibly 600 pounds per. acre is nearer an average.
These yields are based on normal conditions where there are no
boll weevils, On good land and by the proper methods of culti-
vation, the yield of each variety may be greatly increased.

GINNING
Sea Island cotton is ginned'on roller gins. If ginned on the
ordinary short staple saw gin, the staple is injured. It is usually
packed by steam presses into bales' Weighing about 400 pounds
each. The bales are covered with heavy burlap and sewed
with strong cord. The prices 'charged for ginning vary from








Bulletin 15, Cotton 7

cultivation is given at all it should be done while the plants are
small, otherwise the feeding roots will be torn ff and the plants
badly injured. Many farmers have' a practice,'of giving their
cotton three cultivations, while others cultivate sixtimnes or more.
Possibly the best method is to cultivatelevery ten days, preferably
after each rain, continuing the cultivation thru July.,:,
On land where they can be used it is very economical to use
improved implements in the cultivation' of cotton. The two-row
cultivator is being used by a great many farmers. (Fig. 1.)

COST OF PICKING
Possibly the most expensive work with cotton is harvesting.
Several attempts have been made to put out machines for pick-
ing cotton, but so far none have been satisfactory, The only
practical, way kno\ln to harvest cotton seems to be to pick it out
by hand.
Sea Island cotton having a smaller boll and not opening up
as well as short staple, requires more labor.to gather it. The
prices paid by most farmers fr picking the past season have
been from two to two and a half cents per pound for Sea Island,
and from one to one and a quarter cents for short cotton. An
average hand should pick 200 pounds of short or 100 long staple
cotton per day.
YIELD

The average yield of Sea Island cotton, under normal con-
ditions, is about 350 pounds of seed: cotton per acre. It is dif-
ficult to say what an average yield of 'short staple cotton would
be. As much as 3,000 pounds of seed cotton per acre have been
produced. Possibly 600 pounds per. acre is nearer an average.
These yields are based on normal conditions where there are no
boll weevils, On good land and by the proper methods of culti-
vation, the yield of each variety may be greatly increased.

GINNING
Sea Island cotton is ginned'on roller gins. If ginned on the
ordinary short staple saw gin, the staple is injured. It is usually
packed by steam presses into bales' Weighing about 400 pounds
each. The bales are covered with heavy burlap and sewed
with strong cord. The prices 'charged for ginning vary from








Bulletin 15, Cotton 7

cultivation is given at all it should be done while the plants are
small, otherwise the feeding roots will be torn ff and the plants
badly injured. Many farmers have' a practice,'of giving their
cotton three cultivations, while others cultivate sixtimnes or more.
Possibly the best method is to cultivatelevery ten days, preferably
after each rain, continuing the cultivation thru July.,:,
On land where they can be used it is very economical to use
improved implements in the cultivation' of cotton. The two-row
cultivator is being used by a great many farmers. (Fig. 1.)

COST OF PICKING
Possibly the most expensive work with cotton is harvesting.
Several attempts have been made to put out machines for pick-
ing cotton, but so far none have been satisfactory, The only
practical, way kno\ln to harvest cotton seems to be to pick it out
by hand.
Sea Island cotton having a smaller boll and not opening up
as well as short staple, requires more labor.to gather it. The
prices paid by most farmers fr picking the past season have
been from two to two and a half cents per pound for Sea Island,
and from one to one and a quarter cents for short cotton. An
average hand should pick 200 pounds of short or 100 long staple
cotton per day.
YIELD

The average yield of Sea Island cotton, under normal con-
ditions, is about 350 pounds of seed: cotton per acre. It is dif-
ficult to say what an average yield of 'short staple cotton would
be. As much as 3,000 pounds of seed cotton per acre have been
produced. Possibly 600 pounds per. acre is nearer an average.
These yields are based on normal conditions where there are no
boll weevils, On good land and by the proper methods of culti-
vation, the yield of each variety may be greatly increased.

GINNING
Sea Island cotton is ginned'on roller gins. If ginned on the
ordinary short staple saw gin, the staple is injured. It is usually
packed by steam presses into bales' Weighing about 400 pounds
each. The bales are covered with heavy burlap and sewed
with strong cord. The prices 'charged for ginning vary from








Florida Cooperative Extension


season to season, depending very largely on the price paid
for labor. Ginners at present are charging from 21/4 to 21/
cents per pound of lint.
Upland cotton is ginned on saw gins, which work much
faster than the roller gins. The lint is pressed into bales with
a steam press and covered with burlap, but instead of being
held together with cord they are fastened by steel ties. The price
for ginning seems to be the same as for Sea Island.



























Fig. 4.-Weevils Feeding on Boll. Slightly magnified.
(From Bul. No. 51, Bur. Ent., U. S. Dept. Agric.)

THE COTTON BOLL WEEVIL
The boll weevil entered the United States about the year
1892, and has traveled eastward at an average rate of fifty miles
each year until it has spread over the greater portion of the
cotton belt.
The mature weevil is a gray or reddish brown insect about a
quarter of an inch long. The mouth parts are very small and







Bulletin is,; CottoiA


at the extreme tip of the long snout. This enables the weevil to
bore deeply into the squares and bolls. The development is so
rapid that fully five generations may reach maturity in a season.
The eggs are very small and are laid in a'hole which the
female eats in the square or boll. After placing the egg at the
bottom of the hole the opening to it is sealed airtight by the
mother weevil so that the egg will not dry up and fail to hatch.
Each female may lay more than a hundred eggs, and some lay
even more than two hundred. Only a few days are required for
these eggs to hatch. ,
S When hatching, the little larva or grub finds' itself sur-
rounded by the tender parts of the bud, or boll. and proceeds to
-feed and grow. When the larva has become- about half-grown
the injury to the square is so severe thatthe little leaflike parts
surrounding the bud spread outward and the square turns yel-
low.. In about ten days from the time the egg is laid the square
falls to the ground and the larva continues to feed within it until
fully grown. This requires only about ten to fifteen days. Dry hot
weather may kill the larva within the fallen squares, especially
if the sun cafn get to them.
S Within the shelter of the walls of the fallen square, or boll,
the larva changes to a pupa. In about three days more' it be-
conies a full-grown weevil., The weevil cuts a hole thru the
surrounding walls, and thru this makes its escape to the outside
world. From the time the eegg is laid until the weevil- comes
forth its life is passed in tlie interior of the square or boll ;This
fact makes it impossible to apply any poison so as to destroy the
insect in its early stages. .
The weevils which reach maturity in the late fall are the
ones which are most likely to live thru the winter. 'Onily from
one to ten weevils live thru the winter out of every hundred
.which attempt to do so. At the Iapproach of winter the weevils
find shelter in the old cotton bolls on the stalks, or under any
rubbish in or around the field. The few that survive the winter
leave their placesof shelter gradually during the spring,.;as a
rule between the last of March and the first of July and are ready
to attack the cotton as soon as the first squares are formed in
the spring.
CONTROL MEASURES
The most important steps in control of the weevil are: First,
hastening maturing, which can be done by planting early vari-








Florida Cooperative Extension


Fig. 5.-Injury by Boll Weevil to Squares. a, bloom checked by attack
of larva; b, square opened, showing grown larva; c, square showing pupa;
d, dwarfed boll opened, showing one larva and two pupae; e, weevil
escaping from square; f, emergence hole of adult in square. (From Bul.
No. 114, Bur. Ent., U. S. Dept. Agric.)








Bulletin 15, Cotton


Fig. 6.-Injury by Boll Weevil to Bolls. a, three larvae in boll; b, emergence
hole in dry, unopened boll; c, two larvae in boll; d, weevils puncturing
boll; e, opened boll, with two locks injured by weevil; f, large bolls severely
punctured. (From Bul. 114, Bur. Ent., U. S. Dept. Agric.)







12 Florida Cooperative Extension

eties, early planting and frequent and thoro cultivation, and by
a liberal use of fertilizer., Second, by picking and destroying the
weevils and punctured squares from the cotton. Third, by de-
stroying the green parts of the plants or by plowing under the
cotton stalks in the early fall. ,This deprives the weevils of their
only food and stops their :increase, and reduces the number of
hiding places in which they spend the winter.
Experience has sh6wn that the amount of rainfall during
the months of Junej July ahd August will determine more-than
any other one factor, the 'amount of injury which the boll weevil
:will do t0 cotton. Dr. Hinds, Entomologist, Alabama Experi-
ment Station, :,recmmends 'that where the average rainfall is
less than sixteen inches during the three months mentioned cot-
'ton may be grown at a' profit, but where the rainfall during this
time is greater than sixteen inches other crops suited 'to the
locality can be more profitably grown than cotton.

THE BOLL WEEVIL IN FLORIDA
:.Madison County had its first heavy infestation of the boll
weevil in 1917. This was the first real experience that the Sea
island grower had with the weevil. 'Tliis being the case, the
results in that county were watched with a gieat deal of interest.
After the crop had been gathered a survey .ofa number of farms
was made, which showed the average yield of seed cotton-to be
less than 100 pounds per acre
SDuring the season of 1917 the weevils traveled east infest-
ing the counties up to and including Nassau, Duval and blay;
and on the squth Alachua and Putnam counties were heavily in-
fested. The results have been that the yields in these counties
ini1918 were about the same as in Madison in 1917. Some at-
tempt has been made in the weevil infested territory to substitute
short cotton for Sea Island. The yield has been some better from
the short than from the Sea Island, still it has not been satis-
factory.
In portions of West Florida and southeastern Alabama
where the boll weevils have made cotton growing unprofitable
the farmers have turned their attention to hog raising, with the
results that farming has been much more profitable and a
marked improvement made.
It is very evident that the farmers in the boll weevil infested
territory of Florida are fast turning away from cotton and








Bulletin 15, Cotton


growing such marketable crops as peanuts, sugarcane, and sweet
potatoes, and raising live stock.

OTHER IMPORTANT PESTS OF COTTON

While the boll weevil is the most destructive insect of cot-
ton, there are other pests which cause the cotton growers of
this State a great deal of loss. These are the Cotton Stainer,


Fig. 7.-Sea Island Cotton Grown in Avocado Grove-a dangerous
proposition

Boll Worm, Root Knot, and Red Spider, and are discussed in this
bulletin by Prof. J. R. Watson, Entomologist at the Experiment
Station.

COTTON STAINER
Dysdercus suturellus Herrich-Sch.
This dark bug gets its name from its habit of feeding in
cotton bolls, the lint of which it stains red. The cotton stainer
is markedly gregarious; scattering specimens are seldom seen.
In some years large numbers invade the fields and then for
several years they will be almost entirely absent.








Bulletin 15, Cotton


growing such marketable crops as peanuts, sugarcane, and sweet
potatoes, and raising live stock.

OTHER IMPORTANT PESTS OF COTTON

While the boll weevil is the most destructive insect of cot-
ton, there are other pests which cause the cotton growers of
this State a great deal of loss. These are the Cotton Stainer,


Fig. 7.-Sea Island Cotton Grown in Avocado Grove-a dangerous
proposition

Boll Worm, Root Knot, and Red Spider, and are discussed in this
bulletin by Prof. J. R. Watson, Entomologist at the Experiment
Station.

COTTON STAINER
Dysdercus suturellus Herrich-Sch.
This dark bug gets its name from its habit of feeding in
cotton bolls, the lint of which it stains red. The cotton stainer
is markedly gregarious; scattering specimens are seldom seen.
In some years large numbers invade the fields and then for
several years they will be almost entirely absent.







Florida Cooperative Extension


: .The mature bug is a little less; than a. halfAnch long and is
about 3/16 of an inch wide. Its shape is between -oblong, aik
oval. The head and most of the thorax and the base of the legs
are red. The wings- 'ared dark brown edged: with yellow. When
the wings are crossed over the back in the manner characteristic
of the true bugs, these yellow edges f6rm two father conspicuous
lines which drbg' diagonally onithe back. "...
This bug also attacks citrus fruits and avocados, aid for,
this reason the growing of cotton in citrus communities is dan-
gerous, Altho the bugs are rather sporadic in their appearance,
being abundant some years and scarce others, the practice in-
volves too great a risk.
On truck crops and citrus trees these bugs can be collected
economically, but on cotton it would probably ie too cosj. The
same would be true of spraying, even if we had a spray,.which
would kill the adults and not hurt the plants,-. But wi have no
such spray. If chickens, or better, tulkeys can.be -tc t, to
range over the fields they will keep the. gs'^ thefild is
not too large.

.. .,: BOLL WYORM^ ,
A large caterpillar' frequently bores inif the 'bqijlao:l,tt
utterly ruining them. The lint is, entirely destroyed, amihe
boll usually fails to open. The egg from which this r~ ar
hatches is laid on the cottonplant b:y a grayl shmtbiwihlcsflies
about at night akid on cloudy. days. Wh'n h terpilr nhas
consumed one boll,,it.will cravl out and attack nol;-~ .f is
especially destructive while the bolls are small.
This is the same insect which bores into ears of corn, and
is called the "corn ear worm". It prefers corn to cotton, and
advantage may be taken of this to reduce the damage to -the cot
ton. 'One may plant a double ,row of corn across his cotton field
every hundred feet or so, and in the space between the two rows
of corn, plant cow peas at the time of the last cultivation. This
will. furnish shade for the moths to 'lide in during the day and
tend further to gather the moths into the corn and away from
the cotton.. .... ..
The corn should be planted late so that it will just be begin*
ning to silk out when.the first bolls are forming in the' cotton
Sweet corn is more attractive to the moth than is field corn and
one should avoid the use of Cuban corn. On the other hand corn







Bulletin 16, Cotton


planted so early that it will mature before the Cotton begins to
form bolls will be a disadvantage. 'Avoid planting early corn
near a cotton field for this reason. Worms in early corn will have
matured in the corn and the next generation will thus be ready
for the cotton. Likewise avoid planting cotton on land which has
grown a crop of tomatoes during the winter or' early spring, as
this worm is also an important tomato pest.
A great deal can be done in reducing ravages of this worm
if infested bolls are picked and destroyed. Boys can be used
for this purpose, and can cover many acres in a day.

ROOT KNOT
In nearly all sandy .soils of Florida which have been in
cultivation for a number of years, there is found a small, round
worm belonging to a class known as .Nematodes. This bores
into the. roots of a .great many plants including cotton. .It
poisons the roots and causes them to produce large swellings or
galls which give the roots the appearance of a knotted rope;
hence the name "root knot"., ,An infested plant will turn yellow,
fail to grow and finally die.
There is no practical cure for a plant after it has become
infested with these root worms. Care must'be taken not to plant
cotton on ground which is heavily infested with root knot. It
is best to plant cotton on land which during the preceding season
or two bore crops which do not harbor root knot. Among those
plants which are immune or resistant. are: corn, velvet beans,
oats, rye, and the Iron and Brabham varieties of cow peas. Pea-
nuts and sweet potatoes are ordinarily not heavily infested with
root knot. On the other hand, most truck crops are infested.

RED SPIDER
A small, round spider mite frequently infests cotton, causing
the leaves to turn 'yellow and finally fall. If the plants are
examined carefully, the mites will appear as bright red dots on
the under side of the leaves. The eggs are also red. The cast
off skins are conspicuous on infested leaves and are whitish in
color. The spiders are small, altho.easily seen by the naked eye.
These develop particularly during dry weather; hence do not
trouble cotton in Florida during the months from July to Sep-
tember, as they do in the states farther north. They do their
,greatest damage during the spring anrd early summer, from







Bulletin 16, Cotton


planted so early that it will mature before the Cotton begins to
form bolls will be a disadvantage. 'Avoid planting early corn
near a cotton field for this reason. Worms in early corn will have
matured in the corn and the next generation will thus be ready
for the cotton. Likewise avoid planting cotton on land which has
grown a crop of tomatoes during the winter or' early spring, as
this worm is also an important tomato pest.
A great deal can be done in reducing ravages of this worm
if infested bolls are picked and destroyed. Boys can be used
for this purpose, and can cover many acres in a day.

ROOT KNOT
In nearly all sandy .soils of Florida which have been in
cultivation for a number of years, there is found a small, round
worm belonging to a class known as .Nematodes. This bores
into the. roots of a .great many plants including cotton. .It
poisons the roots and causes them to produce large swellings or
galls which give the roots the appearance of a knotted rope;
hence the name "root knot"., ,An infested plant will turn yellow,
fail to grow and finally die.
There is no practical cure for a plant after it has become
infested with these root worms. Care must'be taken not to plant
cotton on ground which is heavily infested with root knot. It
is best to plant cotton on land which during the preceding season
or two bore crops which do not harbor root knot. Among those
plants which are immune or resistant. are: corn, velvet beans,
oats, rye, and the Iron and Brabham varieties of cow peas. Pea-
nuts and sweet potatoes are ordinarily not heavily infested with
root knot. On the other hand, most truck crops are infested.

RED SPIDER
A small, round spider mite frequently infests cotton, causing
the leaves to turn 'yellow and finally fall. If the plants are
examined carefully, the mites will appear as bright red dots on
the under side of the leaves. The eggs are also red. The cast
off skins are conspicuous on infested leaves and are whitish in
color. The spiders are small, altho.easily seen by the naked eye.
These develop particularly during dry weather; hence do not
trouble cotton in Florida during the months from July to Sep-
tember, as they do in the states farther north. They do their
,greatest damage during the spring anrd early summer, from







Florida Cooperative Extension


April to June, when the weather is liable to be dry. They spread
to the cotton from other plants, such as strawberries, violets,
peas, and rose bushes. These plants should not be allowed to
grow in the vicinity of a cotton field. If the cotton becomes in-
fested, it may be sprayed with lime-sulphur, using about one
part of liquid lime-sulphur to 70 parts of water. This may be
applied with a knapsack sprayer, unless the grower can obtain
a power sprayer from some citrus grower or trucker. Another
good remedy is to dust the plants with flowers of sulphur in the
early morning when they are wet with dew.

IMPORTANT DISEASES OF COTrO(N

Cotton anthracnose is the most important cotton disease the
Florida farmer has to deal with. Another important disease,
but one that is somewhat new, is the Angular Leaf Spot. Both
of these diseases are treated here by Prof. H. E. Stevens, Plant
Pathologist of the Experiment Station.

COTTON ANTHRACNOSE

Cotton anthracnose is a fungus disease widely distributed
thruout the cotton fields of the South, where it often causes a loss
of from 5 to 60 percent of the cotton bolls. It frequently injures
seedling plants and may be largely responsible for an imperfect
stand or an entire loss of the stand. This disease causes a loss
to Florida cotton growers each year that can be obviated if
proper precautions are taken.
The causal fungus attacks seedlings, the stems of older
plants, and the bolls. Probably the greatest injury results from
attacks on the bolls, commonly referred to as boll rot. On the
bolls, the first indications of the trouble are small, round, dull
reddish-colored spots. One spot may gradually enlarge until it
covers from one-fourth to one-half the boll. Several spots may
come together forming irregular, diseased areas involving the
entire boll. In moist weather these spots or diseased areas are
soon covered with a pinkish coat, the spore masses of the fungus.
In dry weather this pink covering may fail to appear and the
spots are then gray or black. When the fungus enters the boll
it soon spreads thru the lint and seed, and if a diseased boll is
cut open the interior will be found discolored and rotten. Very
young bolls when attacked may be killed or become distorted by







Florida Cooperative Extension


April to June, when the weather is liable to be dry. They spread
to the cotton from other plants, such as strawberries, violets,
peas, and rose bushes. These plants should not be allowed to
grow in the vicinity of a cotton field. If the cotton becomes in-
fested, it may be sprayed with lime-sulphur, using about one
part of liquid lime-sulphur to 70 parts of water. This may be
applied with a knapsack sprayer, unless the grower can obtain
a power sprayer from some citrus grower or trucker. Another
good remedy is to dust the plants with flowers of sulphur in the
early morning when they are wet with dew.

IMPORTANT DISEASES OF COTrO(N

Cotton anthracnose is the most important cotton disease the
Florida farmer has to deal with. Another important disease,
but one that is somewhat new, is the Angular Leaf Spot. Both
of these diseases are treated here by Prof. H. E. Stevens, Plant
Pathologist of the Experiment Station.

COTTON ANTHRACNOSE

Cotton anthracnose is a fungus disease widely distributed
thruout the cotton fields of the South, where it often causes a loss
of from 5 to 60 percent of the cotton bolls. It frequently injures
seedling plants and may be largely responsible for an imperfect
stand or an entire loss of the stand. This disease causes a loss
to Florida cotton growers each year that can be obviated if
proper precautions are taken.
The causal fungus attacks seedlings, the stems of older
plants, and the bolls. Probably the greatest injury results from
attacks on the bolls, commonly referred to as boll rot. On the
bolls, the first indications of the trouble are small, round, dull
reddish-colored spots. One spot may gradually enlarge until it
covers from one-fourth to one-half the boll. Several spots may
come together forming irregular, diseased areas involving the
entire boll. In moist weather these spots or diseased areas are
soon covered with a pinkish coat, the spore masses of the fungus.
In dry weather this pink covering may fail to appear and the
spots are then gray or black. When the fungus enters the boll
it soon spreads thru the lint and seed, and if a diseased boll is
cut open the interior will be found discolored and rotten. Very
young bolls when attacked may be killed or become distorted by







Bulletin 15, Cotton


reason of the fungus penetrating one side while the other con-
tinues to make normal growth, thus producing imperfect and
worthless bolls. The young bolls seem to be most susceptible to
attack and are easily invaded by the fungus if moist, warm
weather prevails.
CONTROL
Disease-free seed is the most important factor in keeping
anthracnose in check. 'When seed are to be bought the buyer
should know whether they are diseased. A dependable source of
seed free from anthracnose is the grower's own field. Seed, selected
from cotton plants that show no indications of anthracnose will
produce cotton plants free from the disease. Such seed may
be obtained from fields showing the disease to some extent if
care is used to pick cotton from healthy plants only and as
far removed as possible from those showing the disease. This
selected cotton should be kept separate from all other to avoid any
chance for contamination. It should be ginned separately after
the gin has been cleaned and disinfected. A quantity of seed
sufficient for next year's crop may be easily gathered in this way.
It is good practice for the cotton grower to set aside a certain
portion of land each year for seed production, especially in
localities where the disease is prevalent and desirable seed are
hard to get.
Old seed that have been properly cared for and kept dry
afford a reliable source of disease-free seed. In this case seed
from diseased plants can be planted if the time element is not
important. Such seed should be kept three years to make sure
they can be safely used, as the fungus will not survive that period
even within the seed. In certain localities where anthracnose
has been destructive growers and seed dealers keep all cotton
seed for three years before planting and the results have been
highly satisfactory in preventing losses from anthracnose, By
this method seed from the commercial gins might be made safe.
The anthracnose fungus may live a year or perhaps a little
longer on the dead stalks in the field. Hence, a rotation of
crops is necessary to free an infected field from the disease.
Cotton should not be planted in the same field.where the disease
was bad the previous year. If the infected fields are planted
to some other crop for one year it is usually possible to grow







Florida, Coperatift'e' Exitension


cotton in that field the'folloWing year' Healthy; eed planted on
disease-'infected landiwill yield diseased cotton. --
Dedp, fall plowing: in coniidetion with 'crop rotation has
giver excellent results, especially Whenl'a ciitter is first run'over
the stalks and the land is carefully plowed to cover completely all
rubbish.
ANGULAR LEAF SPOT

SAngular leaf spot i 'a bacterial diseasee of' cotton that is
well known in certain sections of' the cotton belt As yet this
disease does not seem to'be Widespread in Florida. However, a
few cases were observed 'by the writer last seasohl It is one of
the cotton troubles the grower' should 'guard-against, formunder
our FFlorida conditions it is' liable to prove'a dangerous' pest if it
becomes generally distributed thtu the cotton' growing sections.

.:., ; /.AP :. i '' PPEARANCE '

S The disease forms, characteristic angular, spots on the leaves
and blackened, areas on the. stems and branches. The bolls are
also attacked and maybe seriously injured in the earlier stages of
their developnpent.,,. ,
The first appearance of the spotting, on leaves is:indicated by
small grayish specks on the under surface. These specks soon
enlarge and become water-soaked i4 appearance, and, the affected
tissue eventually turns brown, and shriyels, Often the. dead
tissue falls, away, causing holes or ragged edges, of the leaves.
When the disease is first noted only a few: spots may be present,
but as the.season advances other,spots appear, untilthe leaf is so
badly affected that it is shed. Affected plants often shed sixty
percent of their leaves early in the, season.
Attacks on the boll are first indicated by mere.gray specks
similar to those on the leaves. .These spots rapidly enlarge, be-
come water-soaked :and eventually turn brown or reddish.brown
and the affected area becomes sunken. Spots on the bolls are
more circular in outline. Young, rapidly growing bolls are more
subject to ,attack, and if affected when quite young the entire
contents usually rot. In attacks on older bolls the injury may be
confined to a single Jock.
SThe disease develops and spreads rapidly under moist con-







Florida, Coperatift'e' Exitension


cotton in that field the'folloWing year' Healthy; eed planted on
disease-'infected landiwill yield diseased cotton. --
Dedp, fall plowing: in coniidetion with 'crop rotation has
giver excellent results, especially Whenl'a ciitter is first run'over
the stalks and the land is carefully plowed to cover completely all
rubbish.
ANGULAR LEAF SPOT

SAngular leaf spot i 'a bacterial diseasee of' cotton that is
well known in certain sections of' the cotton belt As yet this
disease does not seem to'be Widespread in Florida. However, a
few cases were observed 'by the writer last seasohl It is one of
the cotton troubles the grower' should 'guard-against, formunder
our FFlorida conditions it is' liable to prove'a dangerous' pest if it
becomes generally distributed thtu the cotton' growing sections.

.:., ; /.AP :. i '' PPEARANCE '

S The disease forms, characteristic angular, spots on the leaves
and blackened, areas on the. stems and branches. The bolls are
also attacked and maybe seriously injured in the earlier stages of
their developnpent.,,. ,
The first appearance of the spotting, on leaves is:indicated by
small grayish specks on the under surface. These specks soon
enlarge and become water-soaked i4 appearance, and, the affected
tissue eventually turns brown, and shriyels, Often the. dead
tissue falls, away, causing holes or ragged edges, of the leaves.
When the disease is first noted only a few: spots may be present,
but as the.season advances other,spots appear, untilthe leaf is so
badly affected that it is shed. Affected plants often shed sixty
percent of their leaves early in the, season.
Attacks on the boll are first indicated by mere.gray specks
similar to those on the leaves. .These spots rapidly enlarge, be-
come water-soaked :and eventually turn brown or reddish.brown
and the affected area becomes sunken. Spots on the bolls are
more circular in outline. Young, rapidly growing bolls are more
subject to ,attack, and if affected when quite young the entire
contents usually rot. In attacks on older bolls the injury may be
confined to a single Jock.
SThe disease develops and spreads rapidly under moist con-







Bulletin 15, Cotton 19

editions and during periods of rain it may be spread from a few
scattering centers, practically thru the entire field. It is carried
in the seed and it is generally introduced into fields by the use of
infected seed.
CONTROL

In the matter of control, prevention is the advisable policy
to follow. Only seed that are known to be free from the disease
should be planted.
Where the disease does appear in the field and only a few
plants are involved these should be immediately removed and
destroyed. It will be advisable to closely inspect the cotton fields
for this disease, especially when the plants are in the seedling
stage. Where the plants are well advanced and the disease is
generally spread thru the field very little can be done in the way
of remedial measures.