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Title: Florida quarterly bulletin of the Department of Agriculture
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Permanent Link: http://ufdc.ufl.edu/UF00077080/00028
 Material Information
Title: Florida quarterly bulletin of the Department of Agriculture Volume 39. Number 2.
Series Title: Florida quarterly bulletin of the Department of Agriculture.
Uniform Title: Report of the Chemical Division
Physical Description: 9 v. : ill. (some folded) ; 23 cm.
Language: English
Creator: Florida -- Dept. of Agriculture
Publisher: s.n.
Place of Publication: Tallahassee Fla
Publication Date: July 1929
Frequency: quarterly
regular
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Subject: Agriculture -- Periodicals -- Florida   ( lcsh )
Agricultural industries -- Statistics -- Periodicals -- Florida   ( lcsh )
Genre: periodical   ( marcgt )
Periodicals   ( lcsh )
Statistics   ( lcsh )
 Notes
Dates or Sequential Designation: Vol. 31, no. 4 (Oct., 1921)-v. 39, no. 3 (July 1929).
General Note: Title from cover.
General Note: Each no. has also a distinctive title.
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General Note: Issues occasional supplements.
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Volume ID: VID00028
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Table of Contents
    Title Page
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    Plant diseases and pests: Part I
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Full Text





VOEIJT~~riimiTg 19 NI'IXIBLI-1 I


Plant Diseases and Pests

and


Their Treatment


FLORIDA QUARTERLY BULLETIN OF THE
DEPARTMENT OF AGRICULTURE
JULY, 1929





CONTENTS

Part I-Organic Kingdoms: Life Kingdoms Outlined; Classes
of Parasites; Methods of Transmission of Plant Diseases;
Forms of Bacteria; Pathogenic Bacteria; The Struggle
Between the Higher and Lower Orders of Life.
Part II-Florida Truck and Garden Insects.
Part III-Miscellaneous.




NATHAN MAYO
Commissioner of Agriculture



Entered January 31, 1903, at Tallahassee, Florida, as second-
class matter under Act of Congress of June, 1900. "Acceptance
for mailing at special rate of postage provided for in Section
1103, Act of October 3, 1917, authorized September 11, 1918."


VOLUME 39


NUMBER 3










Plant Diseases and Pests

Part One


By T. J. BROOKS
Assistant Commissioner of Agriculture


LIFE KINGDOMS
The two great life kingdoms are the vegetable and the
animal. There is a point where the two orders so nearly
blend that the line of demarkation eludes the scientist.
*Divisions of the Animal Kingdom
Zoology being that branch of biology that treats of ani-
mal life has various schemes of classification adopted by
naturalists. The following classification is standard and
will help us to locate our subject in the general scheme of
biological studies.
1. Mammalogy treats of mammals, a class of vertibrates
whose females have milk-secreting mamae to nourish
their young, embracing all warm-bodied quadrupeds,-
also bats, seals, cetaceans and sirenians.
2. Ornithology, of birds;
3. Herpetology, of reptiles;
4. Ichthyology, of fishes and lower aquatic vertibrates;
5. Ascidiology, of the tunicata-a division of metazoans;
6. Echinology, of the echinodermata-a division variously
ranked;
7. Conchology, of the molusca;
8. ENTOMOLOGY, of the INSECTA;
9. ARACHNOLOGY, of the ARACHNIDA-spiders, scor-
pions, etc.;
10. Crustaceology, of the crustacea-lobsters, crawfish,
shrimp, prawns, barnacles, sow bugs, etc.;
11. HELMINTHOLOGY, of the vermes or worms;









DEPARTMENT OF AGRICULTURE


12. Zoophytology, of the coelentera-invertebrates as coral,
or hydroid, the sea anemones, jelly fish, etc.
13. Paleontalogy, of the fossil remains of plants and ani-
mals.
*Those organisms that destroy, and subjects relating thereto, are
capitalized in the following outline. We are concerned about those that
are useful but for the present discussion we are more concerned about
the destructive creatures of the living world.
There are disorders of plants and animals caused by numerous things
other than parasites. Among the diseases of plants which are not
caused by organisms may be mentioned those caused by injurious sprays,
poisonous gases, malnutrition, dieback due to lack of drainage or too
much ammonia, etc. Injuries from frost, heat, flood, drouth, depreda-
tions by insects and higher animals are not really diseases.

Divisions of the Vegetable Kingdom

Botany being the science of plants is somewhat older
than zoology, but its nomenclature was long the subject of
controversy. The International Botonical Congress of 1905
(which met in Vienna) adopted certain rules which has
done much to bring order out of confusion. The principal
branches of botany are:

1. Morphyology, relating to external form;
2. Histology, relating to structure of tissues;
3. Cytology, relating to the cell;
4. Embryology, deals with the development of the egg-cell.
5. Physiology, with the functions and vital actions of
organs;
6. PHYTOPATHOLOGY, with PLANT DISEASES;
7. Ecology, with environment influences;
8. Phytogeography, with plant distribution;
9. Taxonomy, with the classification of plants.
10. Paleobotany, of fossil plants;
11. ECONOMIC BOTANY,-including
(a) Agriculture
(b) Forestry
(c) Horticulture
(d) Pharmacognosy
(e) Floriculture
and cognate subjects.

Animal life is defined as "Sentient organisms, having
organs of sense; life which feeds on other organisms.











PLANT DISEASES AND PESTS 5


Animal life is usually to be distinguished by their taking
food into a digestive tract or cavity, and by the power of
voluntary motion."

The comparative relationship of the various divisions
may be shown as follows:


Al Kingdom
a2 Sub-kingdom
a3 Class: phyla
a4 Order: group of families
a5 Family: usually comprising two or more genera
a6 Sub-family: one or more genera
a7 Genus: a classafactory group embracing one or
more species
a8 Species: capable of fertile interbreeding
a9 Breed: group within a species
al0 Strain: a line within a breed with dis-
tinct peculiarities.
b3 Phyla:
a4 Protozoa
b4 Purefera
c4 Coelentera
d4 Vermes
e4 Moluska
f4 Echendoermata
g4 Vertebrata
h4 Anthropoda

Vegetable life is defined as "living organisms not pos-
sessed of animal life."

The comparative relationship of the various divisions
may be shown as follows:


B1 Kingdom
a2 Sub-kingdom
a3 Class: phyla
a4 Order: group of families
a5 Family: two or more genera
a6 Sub-family: one or more genera
a7 Genus: one or more species
a8 Species: capable of fertile interbreeding
a9 Breed: a group within a species
alO Variety: a line of breed with distinct
peculiarities.

13 Phyla:
a4 Cryptogamia: flowerless-propagating by spores
a5 Myzophyta-slime molds
c5 Thallophyta: algae, fungi and lichens
d5 Bryophyta: mosses and liveworts
e5 Pterodophyta: ferns and their allies.
f5 Schezophyta-fusion plants, including bacteria
b4 Phanerogamia: flowering-having stamens and pistils
a5 Angiosperms
a6 Dicotyledons
b6 Monoctyledons
b5 Spermatophyta
c5 Gymnosperms








DEPARTMENT OF AGRICULTURE


Divisions on Another Basis
On another basis we may divide animal life as follows:
A. Vivipora: Those which are born and suckle their young
a Man
b All warm-blooded quadrupeds
c Bats, seals, cataceans and sirenians
B. Ovipora: Those that hatch from eggs and do not suckle
a Fish
b Fowls
c Insects
d Reptiles-exceptions
C. Spores: Containing no embryo
a Protozoans
b Bacteria


CLASSES OF PARASITES

The Diseases They Produce and Remedies
Al Animal Parasites: Creatures with digestive tract and
organs, with power of voluntary motion, that live in
or on some other organism
a2 Insects: Six-legged anthropods; 300,000 species have
been named and five times as many unnamed.
a3 Kinds
a4 Chewing
a5 Curculio
b5 Codling moth
c5 Canker worm
d5 Fall web worm
e5 Tent Caterpillar
f5 Pear slug
g5 Larva of moths and butterflies
h5 Beetles and their grubs
i5 Grasshoppers
j5 Crickets
k5 Saw flies and their larva








PLANT DISEASES AND PESTS

Sprays for Chewing Insects
1. Paris Green
2. Arsenate of lead
3. Arsenate of soda
4. Arsenate of lime
5. Scheele's green
6. London purple
7. White arsenate
8. Hellebore
b4 Sucking
a5 San Jose scale
b5 Oyster shell scale
c5 Plant lice
d5 Leaf hoppers
e5 Pear psylla

Sprays for Sucking Insects


Lime sulphur concentrates
Self-boiled lime-sulphur mixture
Fish-oil soap wash
Kerosene emulsion
Crude petroleum emulsion, distilled emulsion
Nicotine solution
Pyrethrum
Caustic potash
Carbolic acid emulsion
Sulphur spray
Resin wash


Fumigants

Effective against all insects when feasible to use them:
1. Hydrocyanic-acid gas
2. Carbon disulphid
3. Sulphur dioxid
The mosquito is both herbiverous and carnivorous, there-
fore omnivorous. That is to say, it eats herbs and sucks
blood, therefore is both a chewing and a sucking insect-








DEPARTMENT OF AGRICULTURE


chewing plants and sucking animals. It is a menace only
to the latter.
B1 Vegetable Parasites: Organisms not possessed of animal
life; 400,000 species have been described.
a2 Fungi: Thallophytic plants destitute of chlorophyl
a3 Obligate parasites, with power to exist under but
one condition
b3 Faculative parasites, having power to accommo-
date themselves to different conditions-aerobic
c3 Obligate saphrophytes, living on dead organic
matter
d3 Faculative saphrophytes living without free oxy-
gen

Diseases They Produce
1. Brown rot of peach
2. Bitter rot of apple
3. Rusts
4. Scabs
5. Moulds
6. Smut
7. Mildew
8. Some "blights"
9. Citrus canker
Citrus canker is caused by the fungus Macrophoma
curvispora.

Sprays for Vegetable Parasites
1. Bordeaux mixture
2. Lime sulphur
3. Sulphur dust
4. Copper sulphate-lime dust
5. Corrosive sublimate
b2 Slime Molds: Not differentiated into cells, a mass
of protoplasm propagating by spores-functioning
as seed in plants.
c2 Cuscuta:







PLANT DISEASES AND PESTS


d2 Bacteria: The unicellular variety which propogates
by fission-splitting of the organism. No univer-
sally accepted and satisfactory classification of bac-
teria has been made.

Methods of Transmission of Plant Diseases

There are half a dozen methods by which plant diseases
are transmitted:

1. By soil inoculation: such as the Irish potato scab, the
Irish potato rhizoctonia, and the same with beans and
onions, tomato fuscopiceous wilt, and lettuce drop.
2. By water infection: as the lemon brown rot of Cali-
fornia.
3. By air infection: as the lemon scab, celery leaf spot,
cucumber downy mildew, tobacco peronoaper, peach brown
rot.
4. By insect transportation: such as pear fire blight,
cucumber wilt-bacterial-potato mosaic, peach brown rot.
5. By seed inoculation:as bean anthracnose, bean bac-
terial blight, sugar cane red rot, watermelon anthracnose,
cucumber angular leaf spot.
6. By dead wood: such as wither tip of citrus fruit,
stem-end rot of citrus fruits.
7. By miscellaneous methods: some diseases are spread
by more than one method.







DEPARTMENT OF AGRICULTURE


Other Divisions of the Subject of Plant Diseases
As to effect of disease on plants:
1. Killing: blights, rusts, wilts, etc.
2. Reducing health conditions
3. Producing malformations
As to parts affected:
1. Roots
2. Stalk
3. Foliage
4. Fruit
As to kind of plants attacked:
1. Forests
2. Fruit groves
3. Field crops
4. Truck crops
5. Ornamental shrubs
6. Vines
Pathology is that branch of medicine which treats of
morbid conditions: their causes, symptoms and character-
istics-including a study of physiology and anatomy.
Therapeutics is that department of medical science that
relates to the treatment of disease and the action of remed-
ial agents on the human organism, both in health and dis-
ease.
A physician is one versed in or practicing the art of
medicine or healing bodily diseases, usually by the admin-
istration of remedies regarded as standard by the profession
-such are in the Pharmacopoeia.

Forms of Bacteria
A bacterium is a schizomycetes, or microscopic fusion
fungus-microbe.
Spherical bacteria-cocci.
Rod-shaped bacteria-bacilli.
Spiral bacteria-spirilla.
Staphylococcus poygenes aureus: the principal agent in
supuration-the process of forming pus.
Pathogenic bacteria: capable of doing harm directly-









PLANT DISEASES AND PESTS


a few score of them. Two general classes: those which are
strictly parasitic and those which live free in nature. A
full list of the species and of the diseases which they pro-
duce would be too comprehensive for present purposes even
were such a list scientifically established.


NAME OF BACTERIA
Bacillus anthracis
Bacillus dipthereae
Bacillus mallei
Bacillus influenza
Bacillus leprae
Bacillus tetani
Bacillus tuberculosis
Bacillus typhi abdominalis
Bacillus bubonic
Streptococcus pyogenes
Streptococcus of erysipelas
Gonococcus
Doplococcus
Spirillum obermeieri
Spirillum choleriae Asiaticae
Lactic acid bacteria (bulgaricum)
Bacteria nitrifyingg)
Bacillus of potato rot (solanace-
arum)


NAME OF DISEASE PRODUCED
Anthrax (malignant postule)
Diptheria
Glanders
Influenza
Leprosy
Tetanus (lockjaw)
Tuberculosis and Scrofula
Typhoid fever
Bubonic plague
Agent in spreading inflammation
Erysipelas
Gonorrhoea
Pneumonia
Relapsing fever
Asiatic cholera
For combating noxious bacteria in
intestines
Lodged in roots where they fixate
nitrogen and leave it in the soil.


A plant pathologist is one versed in diagnosing and treat-
ing plant diseases.
It is an anomaly in the economy of nature that human
life is dependent upon micro-organisms and at the same
time the greatest enemies of the human race are to be
found among these micro-organisms.
Some of the uses of bacteria may be mentioned-
In the arts:
1. Maceration Industries-Such as Linen, Jute, Hemp,
Sponges, Leather.
2. Fermentative Industries-Such as Vinegar, Lactic
acid, Butyric acid, Bacteria in Tobacco Curing.
In Natural Processes:
1.-As Scavengars.
2.-In Food Processes.
3.-In Soil Fertility.
4.-In Silo.
5.-In the Dairy.
The science of microscopic life is modern in origin-in a
practical sense it is less than a hundred years old. All







DEPARTMENT OF AGRICULTURE


parisites are not microscopic, and such as are not received
earlier attention. Insects, fungi, and bacteria constitute
a militant army that is the most formidable enemy of the
human race. Some of these are man's friends, and it be-
hooves him to understand each class, that he may cope with
the problems which they present.
That branch of biology which includes a study of human
life reaches its highest and most complex themes in psychol-
agy and sociology.
Morphology treats of form-the static form of life.
Physiology treats of function-the dynamic phase of life.
For the purpose of our present study we shall have to
confine ourselves to those branches of biology which have
to do with organisms that work an economic injury to the
human race, touching incidentally those which work a
physical inury in our treatment of bacteria.
Therefore, by process of elimination, we come to the
three branches of biological study:
Entomology-the study of insect life, as it relates to
plant pathology and economic botany.
Mycology-the study of fungi, as it relates to plant
pathology and economic botany.
Bacteriology-the study of bacteria, as it relates to
plant pathology, economic botany and human pathology-
pathogenic bacteria.
The limitation of this volume will not permit a treatise
on each of these subjects. Therefore we shall devote space
only to pathogenic bacteria. The reader is concerned prin-
cipally with means and methods of destroying injurious
insects, bacteria and fungi.


PATHOGENIC BACTERIA

Destructive Organisms
(Affecting the Human Body)
Pathogenic, disease-producing bacteria constitute a rela-
tively small number of species of bacteria. The harmless
species are not parasitic and cannot grow in an animal







PLANT DISEASES AND PESTS


organism. There are two general classes of bacteria which
cause disease.
1. The pathogenic class, which live free in nature and
are not strictly speaking parasitic.
2. The true parasitic class, which live in the bodies of
animals.
The most generally accepted theory of how bacteria
cause disease is that they produce in their growth a num-
ber of bi-products of decomposition and that some of these
bi-products are poisonous. It has not been shown that all
pathogenic germs produce their effect that way, but it has
been proven that it is the method in a number of cases.
Recognizing that bacteria may produce poisons, we read-
ily see that it is not always necessary that they should
be parasitic in order to produce trouble.
Ptomaine poison is caused by eating putrified animal
matter, or of alkaloids produced by bacteria. An alkaloid
is any nitrogenous organic base, especially of vegetable
origin, having a powerful toxic effect on the animal economy
-as strychnine or morphine.
It is not always the case that a specific germ produces a
definite disease, nor that each germ disease has its specific
bacterium. For instance, the inflammation of wounds,
formation of pus, or the different types of blood poisoning,
such as septicaemia pyaemia, gangrene, etc., all appear to
be caused by bacteria, and it is impossible to make out any
definite species associated with the different types of these
troubles. There are three forms of so-called pus cocci, and
these are found almost indiscriminately with various types
of inflammatory troubles.
Germs are in the air, in the ground, in the water, on
clothing, on the skin, in the mouth and the alimentary canal.
Commonly they do no harm, but they have the power of
doing injury if they get into wounds or susceptible mem-
branes. Some species are universal inhabitants of the ali-
mentary canal and are ordinarily harmless, but under other
conditions they invade the tissues and give serious trouble.
The following diseases are among those regarded as
caused by distinct specific bacteria: Measles, whooping







DEPARTMENT OF AGRICULTURE


cough, bronchitis, endocarditis, peritonitis, pneumonia,
syphilis.
Most pathogen bacteria can be in some way so treated
as to suffer a diminution or complete loss of their powers
of producing a fatal disease; on the other hand conditions
may cause an increase in the virulence of a pathogenic
germ.
The general course of a germ disease is divided into
three stages: (a) incubation, (b) development, (c) recov-
ery. Disease germs enter the body through the mouth,
nose, skin and secretary ducts.
The germs of smallpox, tuberculosis, scarlet fever, etc.,
are carried to us through the air and breathed into the
cells of the lungs, where they find lodgment and penetrate
the delicate membranes and get into the circulation. It is
then that a battle ensues between the powers of the body
and the microscopic invaders. Only a few of the thousands
of species are able to combat nature's resisting power.
Those that sometimes win out and produce disease we des-
ignate as pathogenic.
In the blood and lymph of man and other animals there
are certain products called alexines, which are poisonous
to germ life. Ordinary micro-organisms are destroyed at
once when brought in contact with these mysteriously gen-
erated poisons.
Apparently the pathogenic bacteria are able to overcome
the alexines of the body by producing in their turn certain
other products which neutralize the work of the alexines.
These pathogenic bacteria are capable of producing bodies
which have been named lysines, whose mission is to neutral-
ize the effect of the alexines. This marks the line of dis-
tinction between the pathogenic and the non-pathogenic
bacteria-the power to produce these mysterious lysines or
the lack of this power.
However, if the lysines do overcome the alexines the
battle is not over. There are minute bits of protoplasm
present in the blood and lymph in large quantities, known
as white corpuscles. They have a power distinct from red
corpuscles. They are active and capable of locomotion







PLANT DISEASES AND PESTS


They are not compelled to follow blood vessels. They are
life-savers. When the flesh is cut they rush direct through
the body and throw themselves into the gaping wound in
order to form a blood clot and stop the waste of blood.
They are martyrs. In the moment of danger they are val-
iant soldiers. They are frequently found to take into their
bodies small objects with which they come in contact.
They absorb irritating bodies which may be in the blood or
tissues and carry them away for excretion-acting as scav-
engers. They collect in great quantities at the point of in-
vasion of bacteria, and their presence is manifest by what
we call inflammation. When these white corpuscles die in
the contest they may accumulate in the form of pus, and
should be discharged, as absorption takes it up as a poison
and it must be eliminated in some other way. If the bac-
teria are stronger than the corpuscles the disease proceeds
unabated.
Remember that the bacterium is a schizomycete or micro-
scopic fission-fungus, and that all minute organisms are not
bacteria. While most germ diseases are caused by bacteria,
there are some whose inciting cause is organisms belonging
to other groups. Some of these are plants and some are
animals. Their life habits are somewhat different from
bacteria, hence the nature of the disease is commonly dif-
ferent.
It is generally conceded that malaria is caused by a
unicellular animal, related to the amoeba. Little is really
known of this pestiferous animal. Its most deadly drug
seems to be quinine, and so is used as a specific for this
intruder. There are other disease-producing microscopic
animals, but we cannot extend the discussion.
There are parasitic plants which fasten themselves in
the skin and produce irritation. Ringworm, thrush, alo-
pecia, and a number of other diseases are caused by plants.
The study of medicine has been mostly empirical-by
experimental observation-and with very little scientific
basis. Most of the advance made in scientific medicine is
the result of the discovery of the germ theory of disease,
and this discovery is due to bacteriology. The science has







DEPARTMENT OF AGRICULTURE


borne its most beneficial fruits in the line of preventative
medicine and hygiene.
In contagious diseases what is needed is a germicide that
is harmless to the human body and that can be introduced
into the circulation. Pasteur said that each contagious dis-
ease is caused by a pathogenic germ or germs which may
be identified. He predicted that a universal germicide
would be discovered, harmless to human beings, and that
thereafter no one need contract disease by infection, and
that contagion would be impossible in the presence of such
a universal germicide.
Inasmuch as a germicide that would destroy plant germs
might not destroy animal organisms, it might not be pos-
sible to have a universal parasitic specific. But if a germi-
cide can be found that is harmless to animal organisms, but
which destroys all vegetable germs, it would mark the
greatest stride in remedial science. The production of such
a germicide is claimed for the invention of William John
Knox of Ann Arbor. It produces scientifically a germicidal
vapor which is respirable. It is a chemical product pro-
duced by a union of ozone and vapor of pinene. Atmo-
sphere is introduced into the machine and dried, coming
in contact with electric volts guaged to rule, when ozonized
and vaporized it is expelled in the form of vapor, the
formula of which is C10 H16 O3-a gaseous pinene ozonide.
The Struggle Between the Higher and Lower Orders of Life
Man is destined to struggle for his existence and the
attainment of his desires. It is by struggle that he ad-
vances. The more complex the civilization the more stren-
uous the struggle. Only the primitive barbarian has no
complex problems to worry him. The absence of difficult
problems indicates a primitive society. The capacity of
the human race to support themselves in great numbers
in a given territory is dependent upon a complex social
compact and efficiency of efforts. The wider the circle of
man's activities the stronger the conflict between mankind
and nature.
The struggle between man and the microscopic organ-







PLANT DISEASES AND PESTS


isms of the living world has become intensified many fold
during the last century. This intensification has been
brought about by the spread of parisites and the diseases
which they produce on the animal and vegetable kingdoms.
This spread has been accentuated by the universal exchange
of commodities and the migration of people from clime to
clime.
But for some friendly help automatically furnished by
certain of the feathered tribe and other consumers of worms
and insects the struggle would have been vastly intensified.
He has not always appreciated these helpers in the struggle
for existence.
It is not much trouble for man to rid the community
of wild game of the larger kinds, that are a menace to him
or his crops and domestic animals, but when it comes to
dealing with the microscopic living world the struggle is
shifted to an entirely different field. Although he has
among these some which contribute to his welfare there is
enough of the injurious kind to render it necessary for
him to be of grave concern.
In the outlines which have proceeded the attempt has
been made to place before the reader a comparative analysis
or classification of living things, so as to make it easy to
see the relationship of living creatures to man's welfare.
Knowing this, it will be easier to protect plants and ani-
mals from the inroads of their enemies. The pursuit of
this task is more interesting as we understand the char-
acteristics and life habits of the underworld which we must
combat.
There are 300,000 species of insects already classified,
and several times as many not classified. A large percent
of these is parasitic-pestiferous as to plants or animals,
or both.
There are 400,000 species of vegetable parasites classi-
fied. A considerable percent of these infest plants or ani-
mals, or both.
The distribution of these enemies of life is so nearly
universal and their operation is so continuous and destruc-
tive that they constitute man's greatest economic and







DEPARTMENT OF AGRICULTURE


physiological menace. Millions of dollars must be spent
annually to combat the enemies of vegetation and other
millions to combat the enemies of animals and of man.
Man has enough to enlist all his fighting energies if he
keeps back the armies of untold millions and billions which
are continually attacking him personally and the sources
of his means of a livelihood. Only by constant vigilance
and the help of science and the art of employing efficiently
the most destructive agencies to the myriads of creatures
which are a menace to the vegetable and animal kingdoms
which minister to the welfare of mankind can the race
survive in the struggle for existence.


INSECTS AND SPRAYS

Mistakes Often Made
1. Treatments are often made for troubles which are
incurable; consequently no results could possibly be ob-
tained from any operation which might be attempted
against them.
2. Treatments are often given where there are no needs
for them. When first starting to control insects many
people get the idea that they must spray even if they do
not know whether a pest is present or not.
3. Expensive methods are often used when cheaper ones
would serve the purpose equally as well. Even when a
cheap method is used, it can be so manipulated that maxi-
mum results may be obtained with a minimum expense.
4. The wrong time is chosen to make the application for
many insects. It is necessary to understand the general
principles of the life history of a pest in order to make
timely treatments for it.
5. The improper selection of the material to use against
an insect is the most common mistake that is made. As
will be clearly shown later, it is not possible to kill sucking
insects by the use of poison.
6. Too often the grower unknowingly purchases an in-
ferior grade of spray material. The grower must insist on







PLANT DISEASES AND PESTS


a good grade of spray material, since he is paying good
money and can rightfully demand the best.
7. The use of a spray outfit not adapted for the par-
ticular operation, and the improper use of a good outfit,
are the causes of much failure. There are accessories for
use with spray outfits that will greatly simplify the oper-
ation.
If some of these common mistakes are guarded against
there is no reason why more satisfactory results cannot be
obtained in the spraying operations against insect pests.
Local experience is really the sure guide for successful
spraying operations.


INSECTICIDES
Materials which are used to destroy insects are called
insecticides. They may be divided into four classes:
1. Poisons-which kill by being eaten and usually con-
tain some form of arsenic; so are often called arsenicals.
2. Contact insecticides-which kill by clogging up the
breathing system by suffocation or by a corrosive action on
the skin.
3. Repellents-which keep the insects from attacking
the plant or animal to which they are applied.
4. Gases-which are used for fumigating.
Poisons
Poisons are the cheapest form of an insecticide. They
are applied to the food of the insects and must be eaten to
be effective. It is evident that poisons are effective only
against biting insects, which go beneath the surface of the
plant for their food. Nearly all of the poisons are made
from arsenic and consequently are termed "arsenicals."
The amount of arsenic varies with the different poisons,
but the standard for each is set by law. Arsenicals are
insoluble in water, and it is necessary constantly to stir
a liquid spray to prevent the poison from settling. In some
of the arsenicals there is a small quantity of what is termed
"water-soluble" arsenic. Such arsenic will readily combine







DEPARTMENT OF AGRICULTURE


with water, and when such a combination takes place heat
is given off. It is in this way that the foliage of plants
is burned when such sprays are applied. The poorer grade
poisons contain more water-soluble arsenic than the better
grades. With those poisons which contain this water-sol-
uble arsenic it is necessary to add lime to prevent or reduce
the burning of the foliage. Most of the arsenicals may be
used either as a dry or dust spray, or as a liquid spray.
White Arsenic
This material should never be used as a spray to put on
plants, since it severely burns all tissue that it come in
contact with. The only place it can be safely used is in
making poisoned baits for grasshoppers and cutworms. It
is the cheapest form of poison that can be purchased.
London Purple
This material is so variable in composition that the re-
sults obtained by its use have been very unsatisfactory.
It should never be sprayed on any plants since it will severe-
ly burn the foliage. It is possible to use this material in
the poisoned bran mashes, but it is seldom recommended.
The use of London purple has been discontinued for many
years in progressive spraying sections of the country.
Paris Green
From the beginning of the spraying practice Paris green
has been the only material that was generally recommended.
However, it has not given entire satisfaction. When used
as a liquid spray it settles very quickly and causes an un-
even application. It does not stick well on the foliage, and
as it contains a considerable amount of water-soluble ar-
senic, it may burn the foliage of the plants to which it is
applied. As a spray material Paris green has practically
gone out of use.
Liquid Spray.-Never more than one-half pound of Paris
green should be used for fifty gallons of water, and when
one is spraying tender plants, such as the peach, only one-
fourth pound should be used. The Paris green should be







PLANT DISEASES AND PESTS


thoroughly mixed into a thin paste and then added to the
water. This insures a better mixing of the powder and
water. To neutralize the action of the water-soluble arsenic
it is necessary to add two pounds of good stone lime to
every fifty gallons of water.
Under some conditions it is advisable to use a combined
spray of a poison with a fungicide. When Paris green is
used in combination with Bordeaux mixture, the same
amount is required for fifty gallons of Bordeaux as for
fifty gallons of water, and it is not necessary to add the
lime.
Dry Spray.-For many crops it is not advisable to use
a liquid spray. Paris green may be applied as a powder,
but it must be dusted with eight or ten times its weight
of flour or air-slaked lime, preferably the latter. As it is
usually best to apply a dry poison when there is some dew
on the plants, and since dew will combine with the water-
soluble arsenic, there is certain to be considerable burning
of the leaves from the use of this spray upon cotton. The
cotton plant is particularly sensitive to burning by Paris
green, and for that reason it is not recommended now for
use on cotton.
Arsenate of Lead
This material is now almost universally used as a poison
spray. It is possible to make this material at home, but
the commercial preparations are to be preferred, as the
contents of the product are guaranteed. This poison is
available to the grower in two forms-paste and powder.
The cost of the powder is somewhat higher than that of the
paste, but the cost of the spray made from either is about
the same. This poison is far superior to Paris green, as
it does not settle so quickly in the spray tank, is much more
adhesive to the foliage, and does not burn the plants; so
there is no need for the addition of lime to the spray. The
action of this poison is somewhat slower than that of Paris
green but certainly as effective.
Liquid Spray.-For a liquid spray either the paste or
powdered form of arsenate of lead may be used; three







DEPARTMENT OF AGRICULTURE


pounds of the paste or two pounds of the powder are re-
quired for fifty gallons of water. Mix the required amount
of paste or powder into a thin paste before adding to the
barrel of water. It is also possible to use this poison with
the Bordeaux mixture, the same proportions being used as
suggested for water.
Dry Spray.-When a dry spray is desired the powdered
arsenate of lead may be used without the addition of any
other material. The powdered arsenate of lead is recom-
mended for use on cotton against all chewing insects.

Zinc Arsenite
This poison is comparatively new, but the results which
have been obtained from it thus far indicate that it may
be superior to any other poison now on the market. The
greatest feature of this poison is that it is very adhesive
to the foliage.
There are two materials which are poisonous to insects
but not to higher animals unless taken in quantities. These
are hellebore and pyrethrum or Persian insect powder.
Hellebore
Hellebore is a white powder made by grinding the roots
of the Hellebore plant. This powder loses its strength rap-
idly and must be fresh to be of any value. It may be used
as a dry or liquid spray. If a dry spray is desired, mix
the hellebore with flour at the rate of one to three pounds,
respectively. For a liquid spray use one ounce of hellebore
to three gallons of water. As the hellebore loses its poison-
ous properties quickly, it may be safely applied to fruits
and vegetables just before harvest.
Pyrethrum
Pyrethrum is a yellowish powder made by grinding the
dry flowers of the plant. The destructive power of this
material is due to an essential oil. It may be used in the
same manner as suggested above for hellebore and in the
same proportions. This material is also valuable as a spray
for fruits and vegetables that are ripening. If one will







PLANT DISEASES AND PESTS


close up rooms that are infested with flies and mosquitoes
and then fill the air with pyrethrum and keep the rooms
closed over night, most of the insects will either be killed
or stupified and drop to the floor.

Poison Bran Mash for Grasshoppers
Probably the best poison for this purpose is called "Kan-
sas Grasshopper Poison." This is made as follows:
Bran ---....-...-----......... .----- 20 pounds
Paris green, or white arsenic..... ------ 1 pound
Syrup--...... ...-------------.. 2 quarts
Lemons .-................------ ---..-- 3
Water.-------------------- 3 gallons
To prepare this mash mix the bran and the poison thor-
oughly in a wash tub while dry. Squeeze the juice of the
lemons into the water and chop the pulp and peel into fine
bits and add to the mixture. Dissolve the syrup in the
water and then wet the bran and poison with the mixture,
stirring so as to dampen the mash thoroughly. The amount
of water here given is sufficient to properly moisten the
bran.
Poisoned Baits for Cutworms
In addition to the Kansas grasshopper poison, which is
successful against cutworms, the following poison mash
gives excellent results:
Wheat or rice bran -.- ...---------.-.. 50 pounds
Arsenic or Paris green..----..... -----. 1 pound
Molasses........-.. ------- ------- 1 quart
Water to moisten.
Mix the poison and the bran together dry. Dilute the
molsses in a gallon or two of water and add it to the poison.
Mix thoroughly and add only enough water to make the
mixture moist but not sloppy.
Poisoned baits of clover are often successful against cut-
worms. For this purpose cut a small quantity of clover
or alfalfa and chop this into rather fine bits. Then spread
it out and spray with Paris green at the rate of one-fourth
pound to twenty gallons of water. After the poison is dry








DEPARTMENT OF AGRICULTURE


on the clover it is ready to be distributed in small bunches
around the base of the plants that are liable to attack by
the cutworms. This poisoned clover should be made late
in the afternoon and distributed just before dark so that
it will be attractive to the worms when they come from
their hiding places at night.
Caution.-These particles of clover or alfalfa which have
been sprayed will retain the poison for some time. If the
worms do not eat this freely it should be collected and
burned and not allowed to dry up and blow around where
stock and poultry may get it.
Ant Poison
The following formula is especially valuable against
those ants which are attracted to sweets. This formula
is best prepared by a druggist:
White Arsenic...... ---- 1/4 gram
Cane sugar- .. ---.... ... .....---- ----- 20 grams
Water.....-.... --..---..-... --.. -- ....- 100 c.c.
The arsenic is dissolved in a portion of the water by
boiling and the sugar in the remaining portion. The two
solutions are then mixed and water is added to make up
for the evaporation. Some color of fruit paste should be
added to warn of the poisonous nature of this solution. For
use this poison may be put in shallow dishes which are
placed in the locations frequented by the ants. The use of
this poison is not advisable where there are small children
in the home.


CONTACT INSECTICIDES
Contact sprays are applied to the insects and only inci-
dentally to the plants. With these the great aim is to apply
the material so carefully that it will certainly come in con-
tact with all the insects, as a mere spraying of the foliage
is of no value whatever.

Lime-Sulphur Wash
The lime-sulphur wash has always been the standard








PLANT DISEASES AND PESTS


remedy for the San Jose scale, and during the last few
years has come into wide use throughout the country. The
lime-sulphur wash is a chemical combination of the lime and
the sulphur. It has also been found to be an efficient
fungicide, and the spring applications just before the buds
start are very effective in killing the winter spores of var-
ious fungous diseases.
The material is used both as a winter spray, when the
trees are dormant, and as a summer spray; but the solu-
tion for the summer is much weaker. Materials of the
proper strength for winter use must never be used on trees
that are in leaf, as it will burn the foliage. The most ef-
fective season to apply the winter strength of lime-sulphur
is the early spring, just before the buds begin to swell. It
may be applied in the fall, however, any time after the
leaves drop.
There are three ways of preparing the winter wash of
lime-sulphur: by diluting the commercial concentrated solu-
tion to the required strength; by making a concentrated
solution at home, and diluting when needed, and by making
a solution which, when finished, is ready for use without
diluting.

Commercial Concentrated Lime-Sulphur
The leading manufacturers and dealers in insecticides
are now selling a concentrated lime-sulphur solution which
is made ready for use by merely diluting to the desired
strength. This is sold at a price that makes the final
product cost 2% to 3 cents per gallon,-nearly as cheap as
it can be made at home and with the saving of time and a
disagreeable job.
Commercial concentrated lime-sulphur is a clear, reddish-
brown liquid. For use, this material is simply diluted with
water. The amount of water to be added is usually indi-
cated on the container, but it is best to test the strength.
This is done with a hydrometer, which will indicate the
specific gravity. These hydrometers, made especially for
testing the lime-sulphur mixture, may be obtained from
Bausch & Lomb Optical Company, Rochester, N. Y., and








DEPARTMENT OF AGRICULTURE


other dealers in laboratory glassware. The dilutions should
be made according to the table given later.
Since the spray is quite clear it shows but little on the
trees. Some prefer to add lime to the material after it is
ready for the spray tank, but the lime should be added
before the final straining. For this purpose either lump
or air-slaked lime may be used, at the rate of six to eight
pounds to fifty gallons of the spray. There is no real ad-
vantage in adding the lime, but it is easier to tell when the
tree has been well coated with the spray.

Home-Made Concentrated Lime-Sulphur
If suitable appliances are at hand it is feasible to make
up concentrated lime-sulphur at home, which can be diluted
for use when needed. It is absolutely necessary to keep
the finished product sealed from the air. It is also essen-
tial that the purity of the materials to be used are guarn-
teed, and it is highly important that only the best grade of
lime should be used. Lime which is less than 90 per cent
pure should be discarded. In most cases it will be found
that the commercial concentrate is safer to use.
The New York Experiment Station has made extensive
experiments on the best methods of making and diluting
lime-sulphur, and the following is quoted:
Geneva Station Formula for Making Lime-Sulphur
Lime, pure --...----------- 36 pounds
Lime, 95 per cent pure...--------- 38 pounds
Lime, 90 per cent pure ----..... --- 40 pounds
Sulphur, high grade, finely divided -. 80 pounds
Water ------ ..~ 50 gallons
In making, slake the lime in about ten gallons of hot
water, adding the lumps slowly so as to avoid too violent
boiling. The sulphur must be well moistened and made into
an even paste without lumps. Then pour the paste grad-
ually into the slaking lime, stirring constantly to prevent
the formation of lumps. When the slaking has finished
add the full amount of water and boil gently for an hour.
If kettles and fire are used, water must be added from time








PLANT DISEASES AND PESTS


to time to make up for the loss due to the evaporation.
It is much better if the cooking can be done with live
steam in a closed vessel, but an open fire will do. When
the boiling is done in this way the mixture will be more
likely to increase the volume and it will not be necessary
to add any water.
Regular Home-Made Lime-Sulphur Solution
Lime (good stone).----------------- 20 pounds
Sulphur ---------..~~.~..~.------.--- ----- 15 pounds
W ater --... ...............--------- -.... 50 gallons
This material when finished is of the proper strength for
use as a winter spray without any further dilution. It
contains much sediment and must always be carefully
strained before use.
Place the stone lime in an open iron kettle and add a
few gallons of hot water; then gradually add sulphur, which
has been made into a paste. Add about twelve gallons of
hot water and boil hard for an hour, stirring constantly.
Dilute with enough water to make fifty gallons.









DEPARTMENT OF AGRICULTURE

Dilutions for Dormant and Summer Spraying with
Lime-Sulphur Mixtures


Reading on
Hydrometer


36-----------------.
35 ----------
34------... --... ...
33---------
32 ...---
31..-- -------------.
30 ---. --...
29----
28--- .
27----.......
26------....-
25--- ........
24 -----------
23---
22--- ... -- -
21 .
20-- --
19---


Amount of Dilution. Number of Gallons of
Water to one gallon of Lime-sulphur Solution

For San Jose For Blister For Summer
Scale of Winter Mite Spraying of
Strength Apples

9 12% 45
8% 12 431/2
81/4 111/2 41%
8 11 40
71/2 10% 373/
71/4 10 36%
63 91/2 341/4
61/2 9 323/4
0 81/2 31
53/ 8 291/2
51/4 71/2 273/4
5 7 26
41/2 612 241/4
41/4 6 2234
3 51/ 211/4
31/2 5 1934
31/4 43/, 18%
3 41/4 17


Kerosene Emulsion
Kerosene emulsion is a very valuable insecticide for the
destruction of sucking insects, such as plant-lice, scale-
insects, etc., and for the destruction of insects hibernating
in rubbish or collected in large masses on tree trunks, etc.
Kerosene emulsion is not a poison, but kills by closing up
the spiracles or breathing pores of the insects. The ingre-
dients of the emulsion are kerosene, soap, and water in the
following proportions:


Laundry soap -----------
Boiling water ------------
Kerosene ----....-...-- .......


1 pound
. 1 gallon
2 gallons


A low grade of kerosene, which is cheap, is as satisfac-
tory as the higher priced illuminating oil and, if desired,









PLANT DISEASES AND PESTS


soft soap may be substituted for the ordinary laundry soap.
The soap forms a coating around each minute particle
of oil, "emulsifying" it and permitting of its then being
dissolved or diluted with water. Both the soap and oil are
active agents in destruction of the insects.
Preparation.-To prepare the emulsion, shave one pound
of laundry soap (or soft soap) into one gallon of soft water
(rain water). Have the water boiling hot. As soon as the
soap is all dissolved remove the solution from the fire and
add the two gallons of kerosene. At once agitate the ma-
terial violently. Continue for at least five minutes. This
is best done by the use of a bucket spray pump; turn the
hose or nozzle back into the bucket or tub so that the ma-
terial is constantly forced vigorously through the pump.
In a few minutes a smooth, creamy emulsion is formed,
without any free oil. This will get thicker as it cools, but
if it is properly made no free oil will separate out. This is
the "stock solution" and will keep indefinitely if sealed
from the air. (Do not try to make the emulsion by stirring
with a paddle, or similar means, for this does not cause
sufficient violent agitation to thoroughly emulsify the
oil.)
Dilution.-For use on trees or shrubs that are dormant,
the stock solution may be diluted with five to seven parts of
water, forming a spray containing 8 to 11 per cent of oil.
On trees or plants that are in leaf, one should dilute the
stock solution with ten to fifteen parts of water, thus mak-
ing a spray containing 4 to 8 per cent of oil. Soft-bodied
insects, such as plant lice, are usually killed with a 5 to 6
per cent solution. The following table shows how to dilute
the stock solution to secure any desired per cent of oil:
For 4 per cent. strength, add 15% gals. water to 1 gal. stock solution.
For 5 per cent strength, add 12 1-3 gals. water to 1 gal. stock solution.
For 7 per cent. strength, add 8/ gals. water to 1 gal. stock solution.
For 10 per cent, strength, add 5% gals. water to 1 gal. stock solution.
For 12 per cent. strength, add 4%1 gals. water to 1 gal. stock solution
For 15 per cent. strength, add 3 V gals. water to 1 gal. stock solution.
For 20 per cent strength add 2 1-3 gals. water to 1 gal. stock solution.

Kerosene emulsion is best applied on bright, sunny days
when the wind is blowing, since a considerable quantity of








DEPARTMENT OF AGRICULTURE


the oil will evaporate quickly, and the danger of injury to
the plants will thereby be reduced.

Commercial Tobacco Extracts
There are now on the market highly concentrated ex-
tracts of tobacco. For use these liquids are diluted with
water according to the concentration of the brand and the
insect which is to be killed. Usually the tobacco sprays
will spread more readily and evenly on the plants if soap
is added to the solution at the rate of one pound to fifty
gallons. It has been found that strong tobacco sprays may
kill the eggs of some plant-lice. The weaker dilutions of
tobacco extracts are especially valuable for destroying soft-
bodied insects, as plant-lice. "Black Leaf 40," "Nico-
Fume," "Sulphate of Nicotine," and "Black Leaf extract,"
are some of the trade names for the tobacco extracts. The
cost of these extracts may seem prohibitive, but when
diluted the spray is not any more expensive than other
materials for the same purpose.
Home-Made Tobacco Extracts
It is possible to make an extract at home from the to-
bacco stems or dust. Place one pound of the stems or dust
in one gallon of water and heat to just the boiling point for
one hour, making up for any loss of water. This solution
should never be allowed to actually boil, as some of the
active principles will be lost in the vapors. Dilute this mix-
ture with two parts of water and add soap at the rate of
one pound to fifty gallons of spray.
Whale Oil Soap
Whale oil or fish oil soap is commonly found for sale in
the hard form, made from caustic soda. The potash soaps
are much to be preferred, as they dissolve more readily in
water. This soap solution is especially valuable for use
against soft-bodied sucking insects, but it is not generally
effective against the more resistant sucking insects. For
plant-lice, dissolve this soap in water at the rate of one
pound to seven gallons. The hard soap must be shaved into








PLANT DISEASES AND PESTS


a small quantity of boiling water and the mixture stirred
for some time. After the soap has been dissolved, cold
water may be added to make the above formula.

Laundry Soap
If whale oil soap is not available, it will be found that a
simple solution of laundry soap is very effective for spray-
ing plant-lice. Any good grade of laundry soap may be
used for this purpose. The formula of one pound to seven
gallons of water has proven very effective against plant-lice.
Laundry soap does not dissolve readily, and it is best to
shave it into a liberal quantity of boiling water and stir
frequently. When the dissolution of the soap is complete,
cold water may be added to make the above formula.

Sulfur
Dry Sulfur or powdered sulfur, sometimes called flowers
of sulfur, is often used as a contact insecticide, especially
against the red spider. The dry sulfur should be thor-
oughly dusted over the foliage in an effort to hit all the
spiders. It is best to apply sulfur when the foliage is moist
with dew. Hydrated lime mixed in equal parts with the
sulfur will make it more adhesive. Sulfur becomes effective
only when the sun vaporizes it; so if applied when the sun
is not shining it will remain inactive until the first bright
day.
Repellents.-A repellent is any material which is applied
to a plant or animal that may be of service in driving away
any insect that might attack it. Dry air-slaked lime is of
service in driving away some pests. It should be dusted
directly on the insects which are feeding upon the plant.
Tobacco dust acts as a repellent to some insects, especially
the root-feeding insects. Napthalene flakes or moth balls
act as a repellent for insects that infest stored products.
Bordeaux mixture, a fungicide, acts as a repellent for many
insects, especially for some forms which feed upon potatoes
and tomatoes. The various fly sprays which are applied
to stock merely act as repellents.








DEPARTMENT OF AGRICULTURE


Protective Tree Washes
1. Dissolve one pound of hard soap in three gallons of
water. Add one-half pint of crude carbolic acid and two
ounces of Paris green. Then add enough lime to make a
thick paste, such as will be easy to apply to the trees.
2. Dissolve sixteen pounds of hard soap in eighty gallons
of boiling water. Then add two quarts of crude carbolic
acid and enough freshly slaked lime to make a thick paste.
3. Slake one bushel of lime in a small quantity of warm
water. Add ten pounds of sulfur, which has been pre-
viously made into paste. Then add one-half gallon of gas-
tar and dilute with water to fifty gallons.
4. Dissolve seventy pounds of quicklime in fifty gallons
of water. Add six pounds of caustic potash and two and
one-half pints of crude carbolic acid.
These washes should be painted on the trunks and lower
limbs of the trees, and the application should be very thor-
ough to be effective. Every small crevice in the bark
should be well coated with the wash. Unless rains occur
immediately after the application is made, two or three ap-
plications will be sufficient during the summer.

Fly Repellents
There are a great many home-made and proprietary ex-
ternal remedies for repelling flies from stock. Many of
them have a value, but many more are of no service whatso-
ever. The most common defect of many of the repellents
is the very short period during which they are effective.
Some repellents are undoubtedly poisonous and should be
used with extreme care. The qualities to be sought in a
satisfactory repellent are absence of toxic or other detri-
mental properties, a decided repellent action on the flies,
and a long period of effectiveness. The following has given
satisfactory results over the country:
No. 1. The Moore formula:
Fish oil ----...........------- .... ---- 100 parts
Oil of tar..................------- 50 parts
Crude carbolic acid. --------- 1 part







PLANT DISEASES AND PESTS


No. 2. The Bishop formula:
Fish oil .......... ~~. ...---------- .. .. 1 gallon
Oil of tar -....-............- ....... -. 2 ounces
Oil of pennyroyal ..................-------- 2 ounces
Kerosene .......------------.--....-----. 1 pint
This mixture is very effective in keeping flies from live
stock when applied lightly with a brush.
No. 3. The Parrott formula:
Fish oil -...........----...---...... 2 quarts
Crude carbolic acid.... ----.- 1 pint
Oil of pennyroyal -. --..-.... --...-..-.... 1 ounce
Oil of tar ---------.......-...----- --- 8 ounces
Kerosene sufficient to make one gallon of the mixture.
The cost of this is given at 80 cents a gallon. It must be
applied with a hand atomizer and not with a brush.
Fumigants
Fumigation is available only for insects that can be
treated in an enclosed space. This method is good for the
treatment of pests which attack stored products and for
greenhouse pests.
Carbon Bisulphide
This material is most extensively used against insects
which attack stored products. Household goods may be
fumigated with this material if the proper precautions are
taken. It is used to some extent for root-feeding insects
by injecting it into the soil. Carbon bisulphide is a clear,
yellow liquid with a very strong and disagreeable odor.
When exposed to the air it evaporates very quickly and the
fumes being heavier than air go to the bottom of the en-
closed space. The fumes are not so effective below temper-
atures of 60 F. and a larger dose is required under such
conditions. Any material to be fumigated should be placed
in as small a space as possible, since it is the confined area
and not the contents that determines the dosage. The
bisuphide should always be put in shallow dishes and
placed on top of the material that is to be fumigated. The
amount of bisulphide necessary for a single application







DEPARTMENT OF AGRICULTURE


varies considerably according to the insect that is to be
killed. One pound to a thousand cubic feet is sufficient
for many insects, but as much as ten pounds is required
for others.
Do not allow any fire or source of fire, as a lighted cigar,
to be near the fumigation or the stored bisulphide. The
fumes from carbon sulphide are highly inflammable and
under certain conditions explosive. Use the same precau-
tion in handling this material that would be used in hand-
ling gasoline. The fumes should not be inhaled as they
cause suffocation which results in dizziness.

Sulfur
The fumes of burning sulphur have long been recognized
as a standard remedy for the fumigation of dwellings. It
is an excellent remedy for bedbugs in empty houses. The
serious objections to the use of sulphur fumes are: they
will bleach fabrics; they will tarnish brass; they will destroy
vegetation, and they will destroy the germinating power of
seeds.
Tobacco
For fumigating greenhouses tobacco fumes are univer-
sally used. This material can be employed where the most
tender plants are grown, and it is especially effective in
controlling plant-lice. Many outdoor plants, as melons,
and low shrubs or trees, may be fumigated with tobacco
fumes by means of specially constructed covers. The meth-
ods of fumigation are to burn tobacco stems, or dust, or to
vaporize some of the liquid extracts, or to burn some of the
punk papers now for sale. This last method is most sat-
isfactory as it is possible to designate the proper amount
of paper to be burned in a given confined space.

Hydrocyanic Acid
This is the most active fumigant known. It is made by
combining water, sulphuric acid, and potassium cyanide.
This gas is a deadly poison to all plant and animal life,
and it should not be used unless the operator has had ex-
perience or unless proper directions are carefully followed.







PLANT DISEASES AND PESTS


STANDARD SPRAYS AND SOLUTIONS USED IN THE
OVERCOMING OF PLANT DISEASES
Bordeaux Mixture is used for the control of fungous
diseases of many vegetables and fruits and as a deterrent
of flea-beetle attack. It can be purchased in convenient
package form from seed dealers or prepared at home from
bluestone (copper sulphate), and fresh stone or lump lime
(quicklime).
Dissolve the bluestone in a wooden or earthenware ves-
sel, using hot water. Dilute with half the water. Do not
use tin or other metal containers, as they would be spoiled
Slake the lime by adding water, a little at a time. When
reduced to a milky fluid, dilute with the rest of the water
and strain through double cheese-cloth or a brass wire
strainer of 18 meshes per inch and pour into it the blue-
stone solution. Stir well and apply at once. This is best
when prepared fresh for each using.
Mercuric chlorid (corrosive sublimate) is used for treat-
ing seed potatoes and cabbage seed for diseases. It may
be purchased at drug stores in the form of tablets. Dis-
solve two large tablets in a quart of water to make a 1 to
1000 solution. For larger quantities use 21/ ounces to 15
gallons of water. Corrosive sublimate is a deadly poison.
It attacks metals and, therefore, must be used only in a
wooden, glass, or earthenware vessel.
Formaldehyde (formalin) is used for treating seed po-
tatoes, seeds, and soil, to prevent diseases. This is a clear
solution of 40 per cent formaldehyde gas in water. It is
very irritating to the eyes and to cuts, but not poisonous.
It does not attack metals. Use teaspoonful to a teacupful
of water, 1 ounce to 2 gallons of water, and 1 pint or pound
to 30 gallons of water (for potatoes and onions). It is not
an insecticide.
Lime is used to control cabbage clubroot. It neutralizes
soil acidity and therefore tends to increase scab on potatoes.
It acts at the same time to a limited extent as a deterrent
against certain insects which may be in or on the soil,







DEPARTMENT OF AGRICULTURE


such as maggots and grubs, and is a good remedy for slugs.
Air-slaked or hydrated lime is the best form to use.

Lime-sulphur is a valuable spray for fruit trees applied
during the dormant season, but not suited for use on vege-
tables. Experiments have shown that potatoes are injured
rather than benefited by it.


Methods Successfully Used in Sterilizing Seed Beds

Steam tile are used to sterilize the soil by placing lines
of 2-inch to 3-inch glazed tile lengthwise in the beds to be
sterilized, 2 to 21/2 feet apart and 15 inches below the sur-
face, and these are left there permanently. They provide
drainage for the beds, may be used for subirrigation, and
are available at any time for sterilizing the soil, the only
labor being the covering of the beds with boards or tar-
paulin and the connecting of the tile with a boiler by means
of a piece of steam hose. It is advisable to spade up the
soil, so that the steam may more readily penetrate it.

Steam pans furnish another method of steaming, by
means of admitting steam under inverted galvanized iron
pans, 6 by 10 feet and 6 inches deep. This has been used
in the sterilization of tobacco seed beds and in greenhouse
beds, and has given very satisfactory results. The use of
steam at pressure of 80 to 100 pounds and treatment for
half an hour to an hour after the soil has reached a tem-
perature of 212F., as indicated by soil thermometers, has
given the best results.

Formaldehyde sterilization is accomplished by drenching
the soil with a 1 to 100 or 1 to 200 solution of standard
formaldehyde (40 per cent), at the rate of 3/ of a gallon
per square foot of area, several days before the soil is to
be used. Formaldehyde, however, does not rid the soil of
nematodes, as steaming does. This method has been used
to excellent advantage in the sterilization of lettuce beds
for the prevention of fungous diseases.








PLANT DISEASES AND PESTS


FUNGICIDES AND INSECTICIDES
Many of these mixtures can be obtained already pre-
pared from reliable dealers, which saves much time and
trouble in mixing them. The following precautions should
be taken into consideration:
1. Care should be taken to keep all substances employed
in spraying where they cannot be gotten at and used by
mistake. All substances should be correctly labeled.
2. Solutions and mixtures containing copper sulphate,
corrosive sublimate and arsenate of lead should be made
in wood, glass or earthen vessels.
3. Arsenical solutions should not be applied to fruits
etc., within two weeks of the time they are to be used as
food.
4. Trees should not be sprayed when they are in blos-
som, as the bees, which are necessary to fertilize the flow-
ers, may be destroyed.
5. Florida growers interested in spraying and other
means of checking insect pests, not fully covered herein,
should write the director of the Florida Experiment Sta-
tion at Gainesville, for further information.

Bordeaux Mixture
4 pounds copper sulphate (blue vitriol).
4 pounds lime unslakedd).
25-50 gallons of water.
Dissolve the copper in hot or cold water, using a wooden
or earthen vessel. Slake the lime in a tub, adding the
water cautiously and only in sufficient amount to insure
thorough slaking. After thorough slaking, more water
can be added and stirred in until it has the consistency
of thick cream. When both are cold, pour the lime into
the diluted copper solution of required strength, straining
it through a fine-mesh sieve or a gunny cloth, and thor-
oughly mix. The standard mixtures are:
(a) 25 gallons (full strength solution, or 4-4-25 for-
mula).








38 DEPARTMENT OF AGRICULTURE

(b) 50 gallons (half strength mixture, or 4-4-50 for-
mula).
It is then ready for use. Considerable trouble has fre-
quently been experienced in preparing the Bordeaux mix-
ture. Care should be taken that the lime is of good quality
and well burned, and has not been air-slaked. Where small
amounts of lime are slaked, it is advisable to use hot water.
The lime should not be allowed to become dry in slaking,
neither should it become entirely submerged in water.
Lime slakes best when supplied with just enough water to
develop a large amount of heat, which renders the process
active. If the amount of lime is insufficient, there is
danger of burning tender foliage. In order to obviate this,
the mixture can be tested with a knife blade or with ferro-
cyanide of potassium (1 oz. to 5 or 6 ozs. of water). If the
amount of lime is insufficient, copper will be deposited on
the knife blade, while a deep brownish-red color will be
imparted to the mixture when ferro-cyanide of potassium
is added. Lime should be added until neither reaction
occurs. A slight excess of lime, however, is desirable.
The Bordeaux mixture is best when first prepared. Stock
solutions of lime and copper can be made and mixed when
required.
2. The following, known as the 6-4-50 formula, is in very
general use:
6 pounds copper sulphate.
4 pounds lime.
50 gallons water.

Bordeaux Mixture for Peach Foliage
The Bordeaux mixture, as ordinarily applied, frequently
injures to some extent the foliage of the peach, etc., caus-
ing a shot-hole effect on the leaves. This injurious effect
has been shown to be largely obviated by the use of the fol-
lowing:
3 pounds copper sulphate.
6 pounds lime.
50 gallons water.







PLANT DISEASES AND PESTS


This is known as the 3-6-50 formula. Some experiment-
ers have also recommended the following for peach foliage:
(a) 2-2-50 formula (Cornell Agr. Exp. Sta. Bull. 180).
(b) 3-9-50 formula.
The latter contains three times as much lime as copper
sulphate.

Bordeaux Resin Mixture

5 pounds resin.
1 pound potash lime.
1 pint fish oil.
5 gallons water.
To make resin solution, place resin and oil in a kettle and
heat until resin is dissolved. Cool slightly and then add
lye slowly and stir. Again place the kettle over the fire,
add the required amount of water and allow the whole to
boil until it will mix with cold water, forming an amber-
colored solution. Take 2 gallons of the resin solution and
add to it 10 gallons of water. Mix this with 40 gallons of
Bordeaux mixture.
Recommended for asparagus rust on account of its ad-
hesive properties. (N. Y. Agr. Exp. Sta. (Geneva) Bull.
188).

Saccharine of Copper

4 pounds copper sulphate.
4 pounds lime.
4 pints molasses.
25 gallons water.
Slake 4 pounds of lime and dilute the same with water.
Dissolve 4 pints of molasses in a gallon of water and mix
with the lime. Stir thoroughly, and let it stand for a few
hours. Dissolve 4 pounds of copper in 10 gallons of water
and pour it into the lime-molasses solution, while stirring
briskly. Allow the mixture to settle. Draw off the clear,
greenish solution for use. Recommended in France as a
substitute for the Bordeaux mixture.







DEPARTMENT OF AGRICULTURE


Ammoniacal Copper Carbonate
5 ounces copper carbonate.
3 pints ammonia (26 Beaume).
50 gallons water.
Dissolve the copper carbonate in ammonia. This may be
kept any length of time in a glass-stoppered bottle and
diluted to the required strength. The solution loses
strength on standing.

Eau Celeste
(Blue Water)
2 pounds copper sulphate.
1 quart ammonia.
50 gallons water.
Dissolve the copper sulphate in 6 or 8 gallons of water;
then add the ammonia and dilute to 50 or 60 gallons of
water.

Copper Carbonate Mixture
1 pound copper carbonate.
40 gallons water.
Mix the copper carbonate with small quantity of water
to make a paste; then dilute with the required amount of
water. For fruit rot of the peach, etc. (Delaware Agr.
Exp. Sta., Bull. XXIX).

Copper Acetate
6 ounces copper acetate (diabasic acetate).
50 gallons water.
First make a paste of the copper acetate by adding water
to it; then dilute to the required strength. Use finely
powdered acetate of copper, not the crystalline form. For
the same purpose, and of the same value, as the preceding
formula.
Copper Sulphate Solution
(Strong Solution)
1 pound copper sulphate.
25 gallons water.
Apply only on trees without foliage.








PLANT DISEASES AND PESTS


Copper Sulphate Solution
(Weak Solution)
2-4 ounces copper sulphate.
50 gallons water.
For trees in foliage.
Potassium Sulphide
3 ounces potassium sulphide.
10 gallons water.
Valuable for gooseberry mildews, etc.
Potassium Permanganate
1 part potassium permanganate.
2 parts soap.
100 Parts water.
Recommended in France for black rot and mildew of the
grape, etc.
Iron Sulphate and Sulphuric Acid
Water (hot), 100 parts.
Iron sulphate, as much as will dissolve.
Sulphuric acid, 1 part.
Prepare solution just before using. Add the acid to the
crystals, and then pour on the water. Valuable for treat-
ment of dormant grape vines affected with anthracnose,
application being made with sponge and brush.

Corrosive Sublimate
(For Potato Scab)
2 ounces corrosive sublimate.
15 gallons water.
Dissolve the corrosive sublimate in 2 gallons of hot
water. Then dilute to 15 gallons, allowing the same to
stand 5 or 6 hours, during which time thoroughly agitate
the solution several times. Place the seed potatoes in a
sack and immerse in the solution for 11/2 hours. Corrosive
sublimate is very poisonous; consequently, care should be
taken in handling it, nor should the treated potatoes be
beaten by stock. The solution should not be made in metal-
lic vessels.








DEPARTMENT OF AGRICULTURE


Formalin
(For Potato Scab)
8 ounces formalin (40% solution).
15 gallons water.
Used for the same purpose as corrosive sublimate, but
not poisonous. Immerse the seed potatoes for two hours.



INSECTICIDES


Paris Green-Dry
1 pound Paris green.
20-50 pounds flour.
Mix thoroughly and apply evenly; preferably when dew
is on the plant.

Paris Green-Wet
1 pound Paris green.
Yz pound quicklime.
200 gallons water.
Slake the lime in part of the water, sprinkling in the
Paris green gradually; then add the rest of the water. For
the peach and other tender-leaved plants, use 300 gallons
of water. Keep well stirred while spraying.

Arsenite of Lime
1 pound of white arsenic.
2 pounds of fresh burned lime.
1 gallon of water.
Boil together for 45 minutes and keep in a tight vessel.
Add 1 quart of this to a barrel (50 gallons) of water, for
use.
This insecticide has been recommended by a number of
experimental stations, but has not yet been sufficiently
tested at the Massachusetts Station to receive an endorse-
ment.







PLANT DISEASES AND PESTS


Arsenate of Lead
4 ounces arsenate of soda (50% strength).
11 ounces acetate of lead.
150 gallons water.
Put the arsenate of soda in 2 quarts of water in a wooden
pail, and the acetate of lead in 4 quarts of water in another
wooden pail. When both are dissolved, mix with the rest
of the water. Warm water in the pails will hasten the
process. For the elm-leaf beetle, use 25 instead of 150
gallons of water.
Whale Oil Soap
2 pounds potash whale oil soap.
1 gallon hot water.
For winter use only.
Kerosene Emulsion
1/3 pound hard soap, shaved fine.
1 gallon water.
2 gallons kerosene.
Dissolve the soap in the water, which should be boiling;
remove from the fire and pour it into the kerosene while
hot. Churn this with a spray pump till it changes to a
creamy, then to a soft butter-like mass. Keep this as a
stock, using 1 part in 9 of water for soft-bodied insects,
such as plant-lice, or stronger in certain cases.

Mechanical Emulsion
A substitute for the last. Made entirely by the pump,
which draws water and kerosene from separate tanks and
mixes them in the desired proportion by a mechanical de-
vice. Several pumps for the purpose are now on the mar-
ket.
Resin-Lime Mixture

5 pounds pulverized resin.
1 pound concentrated lye.
1 pint fish or other animal oil.
5 gallons water.







DEPARTMENT OF AGRICULTURE


Place the oil, resin and 1 gallon of hot water in an iron
kettle and heat till the resin softens, then add the lye and
stir thoroughly. Now add 4 gallons of hot water and boil
till a little will mix with cold water and give a clear amber-
colored liquid; add water to make up 5 gallons. Keep this
as a stock solution. For use, take 1 gallon of stock solu-
tion, 16 gallons water, 3 gallons milk of lime, 1/4 pound Paris
green.
The object of this preparation is to obtain an adhesive
material which will cause the poison to adhere to smooth
leaves. It has been highly recommended by the New York
State (Geneva) Experiment Station.

Lime, Salt and Sulphur

Oregon formula:
50 pounds unslaked lime.
50 pounds flowers of sulphur.
50 pounds common salt.
Slake the lime in enough water to do it thoroughly, add
the sulphur and boil for an hour at least, adding water if
necessary. Then add the salt and boil 15 minutes more.
Add water to make 150 gallons, and spray hot through a
coarse nozzle.
Lime, Salt and Sulphur
Marlatt's formula (from Smith):
30 pounds unslaked lime.
30 pounds sulphur.
15 pounds salt.
60 gallons water.
Boil with stem for 4 hours, and apply hot.

Carbolic Acid Emulsion
1 pound hard soap, shaved fine.
1 gallon water.
1 pint crude carbolic acid.
Dissolve the soap in the water, boiling; add the carbolic








PLANT DISEASES AND PESTS


acid and churn as for kerosene emulsion. Use 1 part of
this with 30 parts of water.
Hellebore
I ounce hellebore.
1/2 gallon water.
Steep the hellebore in a pint of water and gradually add
the rest of the water. Hellebore may also be dusted over
the plants, either pure or mixed with flour or plaster.

Insect Powder; Pyrethrum
Mix with half its bulk of flour and keep in a tight can
for 24 hours; then dust over the plants. Or,
100 grains insect powder.
2 gallons water.
Mix together, and spray.


COMBINED FUNGICIDES AND INSECTICIDES

Bordeaux Mixture and Paris Green
4 ounces Paris green.
50 gallons Bordeaux mixture.
Bordeaux Mixture and Arsenate of Lead
1 gallon arsenate of lead (made by formula No. 20).
50 gallons Bordeaux mixture.
Bordeaux Mixture and Arsenate of Lime
11/2 quarts arsenate of lime (made by formula No. 19).
50 gallons Bordeaux mixture.

Soap Mixture
(Used for White Fly)
1 bar soap (10-cent size).
3 gallons water.
Apply warm, as it thickens on cooling.
Recommended for rose mildew, red spider, plant-lice, etc.
Any common laundry soap, particularly the yellow resin
soaps, dissolved 1 pound of soap to 15 or 20 gallons of water,







46 DEPARTMENT OF AGRICULTURE


is an efficient application for white fly, red spider, plant-
lice, etc. The addition of 1/4 pound of Paris green to each
50 gallons of soap solution adds to its efficiency. There
is probably no better formula for white fly than the above.
Equal parts of soap solution and sulphur wash-made by
dissolving 20 pounds of sulphur with 10 pounds of caustic
soda-is a most excellent general application.

Sulphur Wash
First mix 20 pounds of flowers of sulphur into a paste
with cold water, then add 10 pounds of pulverized caustic
soda (98%). The dissolving lye will boil and liquify the
sulphur. Water must be added from time to time to pre-
vent burning, until a concentrated solution of 20 gallons
is obtained. Two gallons of this is sufficient for 50 gallons
of spray, giving a strength of 2 pounds of sulphur and 1 of
lye to 50 gallons of water. An even stronger application
can be made without danger to the foliage. This mixture
can also be used in combination with other insecticides.
The chemical combination of sulphur and lime, known as
bisulphide of lime, is perhaps a better liquid sulphur solu-
tion than the last as a remedy for mites. It may be very
cheaply prepared by boiling together, for an hour or more,
in a small quantity of water, equal parts of flowers of sul-
phur and stone lime. A convenient quantity is prepared
by taking 5 pounds of sulphur and 5 pounds of lime, and
boiling in 3 or 4 gallons of water until the ingredients com-
bine, forming a brownish liquid. This may be diluted to
make 100 gallons of spray.
Almost any of the insecticides with which the sulphur
application may be made will kill the leaf or rust mites,
but the advantage of the sulphur arises from the fact that
it forms an adhering coating on the leaves, which kills the
young mites coming from the eggs, which are very resistant
to the action of the insecticides and result in the plants
being reinfested unless protected by the sulphur deposit.
For spraying machinery address State Market Bureau,
Jacksonville, Florida.








PLANT DISEASES AND PESTS


Plant Diseases and Pests

Part Two


GENERAL GARDEN INSECTS AND PESTS
By J. R. Watson
Entomologist, University, Gainesville, Florida


There are a number of insects that attack practically all
garden crops and could not well be included under only one
of them. They are treated here.

Heat Treatment for Seeds
A temperature of from 120 to 130 degrees Fahrenheit,
if maintained for a half hour, is fatal to practically all in-
sect life. If a bag of seed can be placed in an oven, with a
dish of water to supply moisture, and kept at a temperature
of 120 to 130 degrees F. for from 20 to 30 minutes, insects
in it will be killed and the germinating power of the seeds
will remain unimpaired.

Mediterranean Fruit Fly (Ceratitis capitata Wied.)
There exists on every continent of the globe a small
fly with striped wings, known as the Mediterranean fruit
fly. This fly deposits her eggs in a great variety of ripen-
ing fruits and vegetables including mangoes, guavas, peach-
es, avacadoes and oranges. Little maggots hatch from these
eggs and burrow thru and thru the fruits utterly ruining
them. This pest has become established in the Hawaiian
Islands, and in the Bermudas just off our coast. In both
places it has ruined the fruit industry with the exception of
growing bananas, pineapples and a few other fruits. It is
stated that the only way in which one can raise an orange
in Hawaii is to tie a paper bag around it while the fruit is
still green.









DEPARTMENT OF AGRICULTURE


Because the larva lives buried inside the fruit it is out
of reach of insecticides. The adult two-winged flies can
be killed by poisoned sweets.
It is hoped that with the present strict quarantine mea-
sures of the Federal government and the State Plant Board,
which should receive the hearty support of the growers,
this insect can be eradicated from the United States.

Plants not troubled by the Mediterranean Fruit Fly:
1. Asparagus 11. Dasheens 20. Peanuts
2. Beets 12. Endive 21. Potatoes, Irish
3. Cabbage 13. Horse Radish 22. Potatoes, Sweet
4. Carrots 14. Lettuce 23. Spinach
5. Cauliflower 15. Mustard 24. Rape
6. Celery 16. New Zealand 25. Rhubarb
7. Collards Spinach 26. Turnips
8. Corn 17. Parsnips 27. Watermelons
9. Cowpeas 18. Onions 28. Pineapples
10. Chufas 19. Parsley 29. Pumpkins
All grasses-Corn, wheat, sorghum, oats, rye, sugar cane.
Cover crops-Cowpeas, velvet beans, beggarweed, crotalaria,
Kudzu.
Morelos Fruit Fly (Anastrepha ludens Loew)
In Mexico and Texas there exists a fly called the
"Morelos Fruit Fly" that belongs to the same family and
works in a similar manner. At present the greatest danger
from this fly is its possible introduction into Florida thru
Gulf ports which have considerable commerce with Mexico.

Scavengers
Many insects breed in injured and rotting oranges. The
most common of these are sap beetles (Nitidulidae) and
pomace flies.
Sap beetles are small, with wings too short to cover the
abdomen. They quickly invade an orange that has split
from any cause but do not, as is often supposed, cause the
splitting.
Pomace flies are small two-winged flies that lay their
eggs in rotting fruit. These hatch into maggots that de-
velop in the rotting fruit. They do not attack sound fruit.
Termites, or white ants, also attack rotting fruit on the
ground.








PLANT DISEASES AND PESTS


Grasshoppers

These insects are particularly annoying on early fall
crops. At that time native vegetation is becoming dry and
unattractive and the grasshoppers, many of which are then
in the late nymphal or the adult stages and consume more
vegetation than the very young, flock to the farmers' crops.
There are many genera and species of grasshoppers.
One of the most common and troublesome is the red-legged
grasshopper. This is one of the smaller kinds but makes
up in numbers what it lacks in size. On flatwoods and
muck lands the lubberly locust is often troublesome. This
is the largest grasshopper in Florida. The young are black
with reddish markings. There are two color-forms of the
adults. Some are of a striking yellow color and others
are almost as black as the larvae. These grasshoppers
have very short wings and are incapable of flight.
Grasshoppers lay their eggs in the ground in waste
places at a depth of 1 or 2 inches. Cultivation will destroy
the eggs when they are laid in cultivated land; consequent-
ly it is in small fields surrounded by waste land that grass-
hoppers are most troublesome. As the amount of land
under cultivation in a neighborhood increases, these insects
become less of a pest.
Control.-Birds, including domestic fowls, especially tur-
keys, are very fond of grasshoppers. The general farmer
should keep a flock of turkeys, for their insecticidal value
if for no other reason. They would, of course, be out of
place on a truck farm or town lot. The lubberly locust is,
however, distasteful to all birds and will not be eaten by
them.
The cheapest and most effective method of dealing with
grasshoppers is by means of poisoned baits, of which the
socalled "Kansas formula" is the best. It has proven very
satisfactory wherever tried. It is
Bran 20 pounds
Paris green or white arsenic (oxide) 1 pound
Water ---- 21/2 gallons
Lemons, oranges, or cantaloupes 3 or 4
Syrup - -- 2 quarts








DEPARTMENT OF AGRICULTURE


The paris green and bran should be thoroly mixed (dry).
Lead arsenate should not be used. It does not work as well.
The lemons should be thoroly grated or chopped very fine,
rind, pulp, and juice, and added to the water. Moisten the
bran with the water until the whole is damp, not sloppy,
so that when sown broadcast over the land it will fall in
small flakes. Last of all add the syrup and thoroly knead
it into the bran. This should be sown in the early morn-
ing, about sunrise or before. Grasshoppers do not eat at
night, and consequently have a good appetite in the early
morning, and the bait should be on hand for their breakfast.
If sown in small flakes over the field there will be no
likelihood of chickens or other domestic animals picking it
up, nor will wild birds be endangered. Ordinarily there will
be no danger to chickens or other fowls eating the dead
grasshoppers as the fowls will not get enough arsenic in
this way to harm them.
Mole Crickets
These are flat, like other crickets. Their front legs are
greatly enlarged and fitted for burrowing (fig. 56). They
live deep in the ground during the
S day-time, coming out at night to
feed. They are very destructive to
vegetation, particularly in gardens
Sand seed beds. They make, just
beneath the surface of the ground,
runways resembling those of moles
but very much smaller.
There are at. least two native
species of mole-crickets that are
somewhat destructive in truck
patches, especially in low ground
where there is considerable vege-
table mold. In addition, the West
Indian mole-cricket or changea"
(fig. 57) is becoming very trouble-
--some in some sections of the State.
FIG. 56.-Native mole-
crioket. Natur1a size. Control.-Sulphur placed in the
(Original.)







PLANT DISEASES AND PESTS


seed drill is said to act as a deterrent. Mole crickets may
be kept out of seed beds by a gauze floor. At the time the
seed bed is made, dig out the earth to the depth of a foot


or so and place in the bottom a
layer of galvanized or copper wire
mosquito netting. It should come
up at the sides and project a couple
of inches above the ground.
Plants set out in the field may
be protected by banding them.
For this purpose melt off the tops
and bottoms of tin cans and place
the cylinder over each plant, sink-
ing it into the earth to some depth.
Instead of the tin cans, tarred
paper may be used.
Mole-crickets may be poisoned
by a mixture of cotton-seed meal,
paris green and syrup. Mix thor-
oughly a pound of paris green with
25 or 30 pounds of cottonseed meal,


x ~


f


F G. 57.-"Changa" or
West Indian Mole-
cricket. Natural size.
(Porto Rico Exp. Sta.)


and then moisten the whole with cheap syrup.
Like other insects which live in the ground, mole-crick-
ets may be poisoned by carbon bisulphide. Sink into the
infested garden several holes to the square yard. These
can be made with a cane, if the soil is a bit moist, and
should go down to a depth of one foot. Pour into each hole
an ounce of the liquid, and quickly cover the hole. Care
must be taken to keep the liquid away from the plants or
they also will be killed; also keep the liquid away from fire
or lights as it is very inflammable.
Another and cheaper liquid which can be used in the
same manner is a solution of sodium cyanide in water, about
an ounce to two gallons of water. Calcium cyanide flakes
or granules can also be used.
If the garden is known to be infested at planting time it
should be treated before it is planted. For this purpose
scatter calcium cyanide in the furrow or treat it with sod-
ium cyanide and ammonium sulphate as advised for root-







DEPARTMENT OF AGRICULTURE


knot. Or the garden may be treated as follows: Plow it
and level it off smooth and compact the surface with a roll-
er or the back of a shovel. If the soil is dry, first wet it.
Leave it over night. The following morning go out with a
solution of cyanide in water. The presence of the mole
crickets will be revealed by their galleries and by little piles
of soil freshly thrown up. Wherever such signs are seen
punch a hole to a depth of a few inches and pour into it a
fluid ounce or two of the sodium cyanide solution or a table-
spoonful of carbon bisulphide. Repeat the operation every
night until no more signs of their presence are seen.
To reduce the number of mole-crickets in badly infested
ground, plow deeply several times in the spring, from
March to June, when they are breeding most actively. Al-
low chickens, and especially turkeys, to follow the plow for
they are very fond of these insects. Pasture hogs on the
field when possible. When mole-crickets are flying dur-
ing March or April (they do not fly much at other seasons)
great numbers can be caught in light traps. Suspend a
lantern in the field and place under it a pan of water on the
surface of which there is a thin layer of kerosene.
A good bait for mole crickets is the poisoned bran bait
mentioned under grasshoppers. Cottonseed meal may be
substituted for the bran or better a mixture of both, 20
pounds of bran and 5 of cottonseed meal. It should be put
out in the evening rather than the morning. It will also
kill cutworms.
A modification of the old "Criddle mixture" for grass-
hoppers has been successfully used. It consists of:
Fresh horse manure -..--- .- .. 20 pounds
Cottonseed meal ....---- 5 pounds
Lead arsenate .- ... 1 pound
Syrup -- 2 quarts
The ingredients must be thoroly mixed.
Either of these baits will remain attractive longer and
hence prove more effective, especially in dry weather, if
buried to the depth of an inch or two in the soil.

Moles
Moles are a nuisance in lawns and gardens because of








PLANT DISEASES AND PESTS


the extensive tunnels they make beneath the surface of the
soil. In making these tunnels they break off the roots of
the plants and cause the soil over the tunnels to dry out.
Contrary to common opinion, they do not feed extensively
on vegetation but are mostly insectivorous in their diet.
They are fond of "white grubs" which are the larvae of
May-beetles or June-bugs. These white grubs are most
abundant on land that has been allowed to grow up in grass
during the summer. The first step in fighting moles is to
get rid of the white grubs. This can be done by raising
some cover crop such as cowpeas, velvet beans or peanuts
on the land to keep down the grass during the summer, and
also by turning pigs in on the land for a few weeks before
the garden is plowed. (See white grubs under potatoes,
page 120, for further suggestions.) Altho, by eating the
white grubs, moles perform a good service to the grower,
like some other troubles, the remedy is often worse than
the disease.
Control.-Moles may be discouraged from burrowing in
the garden by tramping the soil solidly into their runways
or crowding a brick or a stone into it where it enters the
garden from the outside, making sure of course, that the
mole is not in the garden when this is done. The presence of
the mole is best detected in the early morning by the ridges
of fresh dirt or the movement of the soil as he forces his way
thru it. In the latter case the mole can at once be dug out
and either killed or, better, carried off to some pasture or
waste land where his activities will be beneficial rather
than harmful.
Moles make two types of tunnels. One is the feeding
tunnel which is but a few inches below the surface of the
ground. The other is larger and located much deeper, a
foot or more. This is the main highway for the moles in
going from one end of their range to the other. Moles may
be trapped by uncovering this main roadway and placing in
the breach a mole trap, several of which are on the market,
or a handful of calcium cyanide.
The prevalent idea that moles feed largely on the roots







DEPARTMENT OF AGRICULTURE


of plants arises from the fact that their runways are com-
monly used by field mice which do the damage. Stopping
up the runways will discourage the mice as well as the
moles. In the kitchen garden both moles and mice may
often be drowned out by turning the garden hose into the
runway. The mice may be poisoned by putting in the run-
ways some corn that has been soaked in arsenic, paris green
or strychnine.
Salamanders
The so called "salamander" of Florida is a ground squir-
rel much more nearly related to the pocket gopher of the
West than to the true salamander which is a frog-like
animal with a tail. If they invade the garden they may be
poisoned by the bait given above for mice or their burrows
opened and treated with calcium cyanide.

Gophers
Like the "salamander," this animal is misnamed. It is
not related to the true gophers, but is a land turtle. Like
the last, it makes tunnels in the fields but they are much
larger, have only one entrance, and the animals do not
throw up piles of dirt in more or less straight rows as do
the "salamanders." The best way to get rid of these tur-
tles is to put into the holes they make a handful of calcium
cyanide or a wad of cotton which has been soaked in carbon
bisulphide, and at once cover up the entrance to the bur-
row.
Ants
One of the nuisances with which the gardeners and
truckers have to contend is ants. The amount of damage
they will do depends to a large extent on the species. Fol-
lowing are mentioned some of the ways in which they are
annoying in a garden.
They eat off growing plants such as cabbage. Most
species feed to a limited extent only on growing vegetables,
but many species seem to object to the presence of vegeta-
tion about their nests. This is particularly true of the
large yellow agricultural ants which will keep a space many








PLANT DISEASES AND PESTS


feet in diameter about their nests absolutely free from
vegetation. The leaf-cutting ants which are found in the
southern part of the State, cut off and remove to their nests
a large number of leaves. They do not use these directly
for food, but to grow a kind of fungus of which they are
particularly fond. They were the first mushroom grow-
ers. They are particularly annoying to citrus trees in the
tropics where they abound.
One of the most annoying habits of ants is that of car-
rying away seeds from seed beds. They are particularly
fond of lettuce and romaine seed. They use the seeds for
food and will begin to carry them to their nests as soon as
planted and will continue their pernicious activities all thru
the germination period and until the young seedlings have
used up all of the material in the seeds. Ants often cover
up plants by building mounds over them.
Ants are very fond of the honeydew given off by aphids,
some jassids, mealy bugs and other scale insects. For the
sake of this substance many kinds will tend those insects,
sometimes driving away their enemies and more common-
ly carrying those pests from one plant to another. (See
garden aphid under cabbage plant-lice, page 75.)
Ants in the truck patch and garden, especially those that
sting, are somewhat of an annoyance to workers.
Control.-Ants are best destroyed in their nests. For
this purpose carbon bisulphide can be used but sodium
cyanide is cheaper and more efficient. Dissolve the cyan-
ide in water, an ounce to two quarts of water. With a cane
or sharp stick punch a hole to the depth of a foot or more
in the center of the hill and pour into it a few ounces of the
solution. The dosage to be given as well as the depth of
the hole will depend upon the size and depth of the nest.
As soon as the liquid has soaked away, cover up the hole
with dirt and tramp it solid. The gas given off will pene-
trate the galleries of the nest and kill most of the ants and
their young. It is best to do this in the early morning when
most of the ants are "at home." All of the nests within
50 or 60 feet of the seed bed should be treated. As record-









DEPARTMENT OF AGRICULTURE


ed under the head of fumigation, cyanide is one of the most
powerful poisons known, either when inhaled or swallowed.
It should also be kept out of open sores. Some ants will
probably escape the first treatment. These will, however,
lose all interest in the seed bed and will go slowly about,
cleaning the dead ants out of the nest. Their slow and
languid motions are in sharp contrast to their feverish
activity of the previous day. The survivors will probably,
in the course of a few days, start small new nests in the
vicinity. These in turn may be treated.
Root-Knot (Heterodera radicicola)
This is a disease characterized by knot-like swellings on
the roots. Severely infected plants fail to make proper
growth and often turn yellow and die prematurely.
The cause is a minute round-worm or nematode which
bores into the roots to feed. It gives off a poison which
causes the plant to make the swelling. It affects nearly all
garden and truck crops, except corn, to a varying degree.
The worms are not very active during the winter, but dur-
ing the warmer weather from April to October they often
make it impossible to grow a profitable crop of certain
plants on the infested land. Newly-cleared land is usually
free from these worms, but most sandy soils of Florida,
when cleared and cultivated for a number of years, become


infested.
,The following plants commonly
subject to infestation. Those most
come first in the list:


Okra 15.
Tomatoes 16.
Eggplant 17.
Cucumbers 18.
Cantaloupes 19.
Amaranth 20.
(careless weed) 21.
Celery 22.
Tobacco 23.
Peas 24.
Peaches 25.
Figs 26.
Irish Potatoes 27.
Watermelons 28.
Beets 29.


Dasheens
Peppers
Squash
Lettuce
Beans
Rape
Papaya
Carrot
Pineapples
Sunflowers
Bananas
Cotton
Radishes
Sweet Potatoes
Asparagus


grown in Florida are
liable to severe attack

30. Cabbage
31. Cauliflower
32. Collards
33. Soy Beans
34. Mustard
35. Pecans
36. Japanese Persimmon
37. Violets
38. Old World Grapes
39. Sugar Cane
40. Peanuts
41. Catalpa
42. Quince
43. Kudzu







PLANT DISEASES AND PESTS


On land which has been heavily infested it is impossible
to grow profitably the plants at the head of this list. They
may grow well at first but soon become stunted and fail to
bear well.
Control.-The usual way to free infested land is to raise
only non-susceptible crops on it for three years and thus
starve out the worms. Among such immune or partly im-
mune plants, are, most of the true grasses, including crab-
grass and Bermuda, most varieties of corn and wheat, rye,
and some varieties of oats, velvet beans, and beggarweed.
Iron and Brabham cowpeas are usually resistant. Onions,
parsnips, strawberries and turnips are but slightly affected.
While growing any of these crops to free the land of nema-
todes it is important that weeds should not be allowed to
grow there as the nematodes are abundant on many of
them. This is especially true of some species of Amaranth
or "careless weed."
Other General Pests
The following named pests attack a large number of
vegetables and could have been treated appropriately under
this general heading. They are: Fall army worm or grass
worm (see under corn, page 91); red spiders (see under
peas, page 115); garden aphid (see under cabbage, page
75); and cut-worms (see under cabbage, page 67).


BEANS

Bean Leaf-Hopper (Empoasca fabae Harr.)
Several species of jassids severely attack snap beans,
especially those planted early in the fall. Their ravages are
often so severe as to discourage the planting of beans at
that season.
Jassids obtain their food by sucking the juices of plants.
If the insects attack in sufficient numbers the plants will
become stunted in growth, fail to bear well, turn yellow
and finally die.
Several species are concerned in this injury. The most







DEPARTMENT OF AGRICULTURE


abundant is Empoasca fabae or bean leaf-hopper. This is
also called the potato leaf-hopper in the North because it
is there especially injurious to potatoes. It is a light green
insect, 1/8 of an inch long. Under a lens the eyes of the
living insect are white but they quickly turn brown after
death. The bug lives on a variety of plants but is partial
to cowpeas and beans. There are many generations a year.
Control.-These insects can be killed by a strong tobac-
co extract. A successful one is:
Black leaf 40 -- -..---- -- -- .2-5 pint
Bordeaux .. . ..........50 gallons
Kerosene emulsion will also kill them but there is more
danger of burning the delicate plants.
Spraying with an ordinary nozzle is not altogether sat-
isfactory because so many of the bugs escape by flying
away. Much better control can be obtained by covering
the discharge nozzle of the spray with a hood. Full direc-
tions and an illustration of this apparatus can be found in
Bulletin No. 164 of this Station. Good results have also
been obtained with a traction sprayer by nailing burlap
sacks over the top of the platform and to the sides in such
a manner as to hang down and drag on the beans. Hop-
pers flying away from the spray are caught in these sacks
which are always wet with the spray. By the use of these
appliances good crops of beans have been raised during
years when surrounding fields were entirely destroyed. In
some sections a hopperdozer, constructed on the plan of a
vacuum cleaner, has given good results.
It is very important that one raising beans in the fall
should keep a belt several rods wide entirely around the
bean field clear of all herbaceous vegetation. This can be
done by either plowing the strip and giving it frequent
cultivation or cutting the vegetation off and burning it be-
fore the beans come up. This belt around the field in which
there is no vegetation is very effective in checking the
migration of the hoppers from the surrounding vegetation.
On the lower East Coast the bean jassid is more injur-
ious to the winter and early spring crops of beans.








PLANT DISEASES AND PESTS


Three-Cornered Hopper (Stictocephala festina)
In addition to the smaller leaf-hopper, Empoasca fabae,
beans are commonly infested with a much larger one. This
is yellowish-green in color, about a quarter of an inch long
and half as wide. As viewed from above, its outline is
that of a long triangle. This and its habit of feeding on
alfalfa have resulted in its being known in the West as the
"three-cornered alfalfa hopper." It is also a pest of toma-
toes, watermelons, and cowpeas in Florida. We have also
found it common on hickory, oak, goldenrod, and summer
haw (Viburnum). Control measures would be the same as
for the smaller species.

Bean Leaf-Roller (Eudamus proteus)
Another insect which is very troublesome to the early
fall-planted crop is a caterpillar which rolls up the edges
of the leaves after cutting slits in them. From these shelt-
ers the caterpillars range over the leaves which are often
so badly eaten that no pods can be formed.
The caterpillar (fig. 58), which grows to an inch in
length, is a light greenish-yellow, velvety insect. The
brownish-yellow head is attached by a neck which is much
narrower than usual in caterpillars so that there is a mark-
ed constriction between the head and thorax.
In the summer the larva will complete its growth in 14
days, but in October and November, 30 or more days are
required. The larva then forms the pupa on the plants







FIG. 58.-Bean leaf-roller: Larva. Much enlarged.
(Original.)

and in 6 days the bluish butterfly emerges. The insect be-
longs to the group of butterflies known as "skippers,"








DEPARTMENT OF AGRICULTURE


doubtless because of their habit of darting quickly from
plant to plant in search of nectar or a place for an egg.
The eggs are deposited on beans and other legumes, esp-
ecially beggarweed, and hatch in 4 days in summer. This
group of butterflies when at rest, hold their wings at an
angle of about 45 degrees instead of horizontal or perpen-
dicular as do other butterflies. This species may be dis-
tinguished from other skippers by its larger size, 2 inches
across the outstretched wings, and by the prolongations
("tails") of the hind wings.
The insects are scarce in the spring and early summer
so that early beans are not troubled. But by the first of
September the butterflies are abundant and beans become
heavily infested.
Control.-The insect can readily be killed by spraying
with lead arsenate. However, beans are easily injured by
arsenicals so not over 12 ounces of the powdered, or a
pound and a half of the paste, form of lead arsenate should
be used to 50 gallons of water, and to this should be added,
before using, a pound of hydrated lime or the milk obtained
from slacking 2 pounds of quick lime in water. If jassids
are also present, add tobacco to the solution.
It is sometimes desirable (up to the blooming period)
to spray beans with 4-4-50 bordeaux for fungus diseases.
The lead arsenate, and also the nicotine solution, can be
placed in the bordeaux.

Bean-Weevil (Bruchus obtectus)

There are two or three species of weevils that infest
beans. The most common is Bruchus obtectus (fig. 59).
The others are more common on cowpeas and will be treat-
ed under that heading. The ravages of this insect on dried
beans are very conspicuous; in fact, if not checked, it will
entirely destroy seed beans. They also damage snap beans.
The infested pods show wart-like swellings where the fe-
male punctures them to lay eggs in the cavity of the pod.
She gnaws out a narrow slit and then inserts her ovipositor








PLANT DISEASES AND PESTS


in the hole and lays the egg. These "speckled" pods should
not be confused with those having
spots caused by the fungus, Col-
letotrichum. Those spots caused a J
by the fungus are sunken instead
of elevated and attain a much e*.
larger size. The egg hatches in
from 1 to 3 weeks, according to the o
prevailing temperature, into a FIG. 59.-Bean-weevil (Bru-
small, worm-like larva. This re- chus obtectus): a, Adult
beetle, much enlarged; b,
quires from 11 days to 6 weeks to infested bean. (From IT. S.
Bur. of Ent.)
become full grown and then
changes into the pupa. From 5 to 18 days later the adult
emerges. This is an ashyblack beetle about a tenth of an
inch long with hard wing-cases and somewhat flattened
body.
Nothing can be done to protect the beans in the field
from the ravages of this insect. The best method of con-
trol is to plant clean seed in a field that has not recently
produced a crop of cowpeas or beans. Breeding in dried
beans can be prevented by keeping the beans in cold storage
(32 to 34 degrees F.) for two months or more, or they may
be fumigated as recommended for stored seeds.

Lesser Corn Stalk-Borer (Elasmopalpus lignosellus Zell.)

This insect is injurious to corn in the states farther
north; in Florida it does more damage to cowpeas and beans,
altho it is injurious to corn. Next to the bean-jassid it is
the most injurious insect on fall-planted beans. It often
destroys almost the entire stand if control measures are
not adopted. The insect is a bluish-green caterpillar (fig.
60, d) which bores into the stem at the surface of the
ground and tunnels up and down in it, causing the young
plant to wilt and die quickly. If the cowpea-plant gets a
good start before it is attacked it is not easily killed and
may produce some pods, so that the damage is not as notice-
able, but a bean is usually killed outright. The full-grown
caterpillar is about a half-inch long. It is quite smooth;








DEPARTMENT OF AGRICULTURE


i. e., it is not noticeably hairy. There is a large brown
spot on the back of each segment (joint). The head is
brown and hard and the first joint of the thorax is black.
















FIG. 60.-Lesser corn stalk-borer (Elasmopalpus lignosellus):
a, Mole moth; b, wing of female moth; c, moth, showing the
resting position of the wings; d, caterpillar; f, pupa. About
three times natural size. (From U. S. Bur. of Ent.)

The adult is a small, brownish moth with cream-colored
markings (fig. 60, a). It belongs to the same family as
Crambus (see root webworms under corn, page 92) and
rolls its wings about its abdomen in the same manner (fig.
60, c.)
The female lays her eggs on the stem near the surface
of the soil and the caterpillar feeds on the surface of the
roots until about half-grown, when it bores into the stem.
Control.-The caterpillars, working inside of the stems,
are safe from any poison that could be applied to the crop.
The young on the roots are also safe. The only means of
preventing their spread thru a field is to pull up and destroy
all infested plants. Rotation of crops should be practiced.
Beans should not be planted on land that has just grown
beans, peanuts, cowpeas, turnips or corn, as they are all
host plants.
Other Bean Pests

Other insect-pests attacking beans are: Root-knot nema-







PLANT DISEASES AND PESTS


tode (see under general garden pests, page 56); cutworms
(see under cabbage, page 67) ; corn ear-worm (see under
corn, page 85, sometimes mines the pods); cabbage looper
(see under cabbage, page 70), sometimes eats the leaves;
cowpeas pod-weevil (see under cowpeas, page 96); grass-
hoppers (see under general garden pests, page 49) are
troublesome in the fall; pumpkin bug (see under cowpeas,
page 97) and other plant-bugs (see under potatoes, page
119) are among the most troublesome enemies of the bean
grower; garden aphid (see under cabbage, page 75); wire-
worms (see under corn, page 88) ; flea-beetles (see under
beets, page 65); and striped cucumber-beetle (see under
cucumbers, page 104).

LIMA BEANS

Gall Worm (Monoptiloba sp.)

In addition to the pests of other beans, lima beans are
attacked by a caterpillar that bores into the stems. The
plant thus attacked forms a large swelling or gall about the
larva. In this gall the larva lives, feeding on the tissue
until its growth is complete. The adult insect emerges as
a small moth, and lays eggs on the stems of the plant.
These galls are very common on lima beans in Florida.
The attacks of this caterpillar do not usually become se-
vere until summer, hence lima beans planted early usually
produce a fair crop. The only practical means of prevent-
ing this injury seems to be to plant as early as possible
and fertilize and cultivate well.
Bush lima beans are not as much injured as the climb-
ing varieties.

BEETS

Blister-Beetles
These long, slender beetles feed on a variety of truck
plants, including beets, tomatoes and potatoes. In the







DEPARTMENT OF AGRICULTURE


Northern States these insects are known as "old-fashioned
potato bugs" to distinguish them from the more recently
introduced "Colorado potato-beetles." They are known in
parts of Florida as "Yankee bugs," perhaps from the bluish
color of certain species. The adult beetle crushed against
the skin causes a blister, hence the name "blister-beetle."
It is also called "Spanish fly," certain species being the
source of the drug of that name.
Eight species of blister-beetles are more or less trouble-
some to vegetation in Florida. The most common one is
the gray blister-beetle (Epicauta heterodera) which has no
stripes. The striped blister-beetle (E. vittata) (fig. 61) is
frequently seen.
The work of all the species is about the same except
that each shows a preference to different plants. They strip
all the softer parts of the leaves, leaving only
the midribs. The beetles usually feed in col-
onies, sometimes so large that they quickly
strip and ruin a patch or an entire field.
If the colony is small the quickest way to
exterminate it is to collect the beetles in a pan
4 of kerosene. They are quick to take alarm
F G. 61- and the collector must work rapidly. If the
Blister colony is large the plants should be sprayed
Natural with lead arsenate. The larvae feed on the
size.(from
u. s. Bur. eggs of grasshoppers and are beneficial to ag-
of Ent.)
agriculture. For this reason it is better, where-
ever possible, to drive the beetles from the field rather than
to poison them. To do this, use a bundle of twigs with
which to whip the plants and work with the wind, driving
the beetles quite a distance to prevent their quick return.
It may be necessary to repeat this driving frequently.

Beet Leaf-Miner (Pegomyia vicina)
This insect belongs to a large class made up of small
pests which often escape the notice of the trucker because
of the small size of the insect and the wound inflicted, while
the unthrifty condition of the injured plants is laid to a lack








PLANT DISEASES AND PESTS


of fertilizer or water. Collectively they inflict severe
damage.
This maggot-like larva of the two-winged fly frequently
burrows in the tissue of beet leaves. If they become
numerous they will materially check the growth of the
plants.
In its protected position, the grub cannot be reached by
any insecticide, but the grower can check an outbreak by
destroying all infested leaves. This at least should be done
when the beets are gathered, if not before. If the infested
leaves are left in the field the grubs have opportunity to
enter the ground, go into the pupal stage and emerge later
as flies.
Flea-Beetle
This is a small oval beetle (fig. 62) that gets its name




















e
FIG. 62.-Strawberry flea-beetle: a, Adult; b, eggs on
leaf; c, side-view of young larva; e, dorsal view of
larva; f, pupa. Greatly enlarged. (From U. S. Bur.
of Ent.)
from the habit quickly springing several inches when dis-
turbed. Two species are more or less troublesome in Flor-
ida to beets, cabbage, cucumbers, tomatoes and related







DEPARTMENT OF AGRICULTURE


plants. They eat the epidermis on one side of the leaf
and the soft interior cells but leave the veins and other
hard parts.
Bordeaux mixture is usually efficacious in preventing
injury by these insects. The mixture can be made more
efficient by the addition from 8 to 16 ounces of powdered
lead arsenate (or 1 to 2 pounds of the paste) to 50 gallons
of the bordeaux.
One common species of the flea-beetle is usually very
abundant on evening primrose (Oenothera sp.) from which
they often spread to cultivated crops. These weeds should
be destroyed around the edges of truck fields as well as in
the fields.

Striped Morning-Sphinx (Celerio lineata)
The larva of this very common hawk-moth feeds oc-
casionally on beets, although its common host plant in
Florida is purslane. It has the size and general appear-
ance of the tomato worm and belongs to the same family.
Its life history is similar and the control measures are the
same.
Larger Beet Webworm
There are two species of small moths of the genus
Hymenia (or Zinckenia) whose caterpillars attack the beet.
The larger one is the spotted beet webworm (Hymenia
perspectalis). This larva is a small green caterpillar with
purplish dots on its head. The adult moth is a little over
an inch in width across the wings. It is cinnamon-brown
in color with narrow white bands in the middle of the front
wings. The eggs are about 1/50 of an inch in diameter
and are laid on the leaves of the beets and, particularly,
carelessweed (amaranth). The latter is probably its or-
iginal host plant.

Small Beet Webworm (Hymenia fascialis)
This small webworm is much more abundant than
Hymenia perspectalis. During July the moths collect about
the blossoms of catnip and other plants in great numbers.
As with the other species the beet is a minor host plant







PLANT DISEASES AND PESTS


for this insect, whose larvae live chiefly on wild plants.
The moth is smaller than the other species and the white
bands of the wings are larger. Either species can be con-
trolled with lead arsenate.
Cutworms
These greedy pests seem to be especially fond of beets,
the leaves of which they cut off. If this is repeated con-
tinuously the plant is unable to grow. For control see
cabbage.
Other Beet Pests
Other insects which attack beets are: Wireworms (see
under corn, Page 88); white grubs (see under potatoes,
page 120); bean-jassid (see bean leaf-hopper under beans,
page 57); harlequin cabbage-bug (see under cabbage,
page 80); false chinch-bug (see tarnished plant-bug under
celery, page 83); sweet-potato caterpillar (see under sweet
potatoes, page 130); 12-spotted Diabrotica or corn root-
worm (see under corn, page 95); and cabbage looper (see
under cabbage, page 70).

CABBAGE
(Many cabbage insects also attack collards, cauliflower,
brussels sprouts, kohlrabi, and Chinese cabbage.
Cutworms
Cutworms are very fond of any succulent plant, and are
troublesome to most truck and garden crops. Cabbage is
one of the chief sufferers from their attacks. They gnaw
off the young plants just above the ground, making them
worthless.
Cutworms are the almost harmless larvae (fig. 63, a, b)
of any of several species of moths of the Noctuid family.
The moths are night-fliers and are commonly seen about
lights. They are grayish or brownish in color and most
of them have on their fore wings small silvery markings,
dots, dashes, or commas (fig. 63, d, e).
In Florida they do not hibernate but are active and breed
throughout the year, although neither the moths nor the








DEPARTMENT OF AGRICULTURE


caterpillars are active during


FIG. 63.--Cutworm moth (Mamestra
chenopodii): a, b, Larva; c, pupa; d,
moth; e, wing of moth, enlarged.
Natural size. (From U. S. Bur. of


the coldest nights of the
winter. The caterpillars
will remain active at a
lower temperature than
the moths, but the latter
are to be seen about lights
during warm evenings
even in midwinter. The
worms suspend operations
during the coldest nights
only when the tempera-
ture drops below 45 de-
grees.
There are no definite
broods, caterpillars of all
sizes, eggs and moths are
to be seen at one and the
same time.

Control.-The moths
by preference lay their


Ent.) eggs (fig.
in heavy sod land. The larvae feed on
the grasses. Consequently, on land that
has no considerable grass, the cutworms
are most troublesome. As long as the grass
is available there is so much food in pro-
portion to the number of worms that their
feeding is scarcely noticeable. But when
such land is plowed, the normal food sup-
ply of the caterpillars is cut off and they
are concentrated upon the relatively small
amount of vegetation of the farmer's
crop.

When grass land is plowed measures
should be taken to kill the cutworms pres-
ent before the crop is planted. To do
this, prepare' the land ten days or two
weeks before the cabbages are set out.


64) on grasses












b


FIG. 64.-Eggs of
cutworm moth
(Agrotis saucia):
a, Single egg,
greatly enlarged;
b, egg mass on
twig. Natural
size. (From U. S.
Bur. of Ent.)








PLANT DISEASES AND PESTS


During this time many of the cutworms will leave or die
of starvation and the remainder develop a good appetite.
A day or two before the crop is to be set out, cut somd
green and succulent plants such as collards, rape, cowpeas,
etc., and dip them into a strong solution of paris green;
about an ounce to a gallon of water. Scatter this about the
field after sunset, for the hungry cutworms to feed upon
during the night. Instead of the green material the fol-
lowing described poisoned bait may be used:
A. Bran ----.. ------____ 20 pounds
Cottonseed meal -----__ ---- 5 pounds
Paris green -...--...... .----.- ------ ---.. 1 pound
B. Water -..-....---.--.... ....--..... ..- 21/2 gallons

Mix the bran, cottonseed meal and paris green thoroly
while still dry; then wet "A" with "B" until it is decidedly
damp, not sloppy, and of such consistency that it will fall
in fine flakes when sown broadcast over the land. This
should be put out after sunset so that it will be fresh and
attractive when the worms come out to feed in the night.
If the following day is cloudy, the bait will remain attrac-
tive for the second night, otherwise it will need to be re-
newed if the cutworms have not been brought under con-
trol. If properly sown it will fall in such small flakes that
fowls or other birds will not pick it up. In a cabbage field,
better protection will be given to the plants at a smaller ex-
penditure for material if, instead of being sown broadcast,
the bait is placed in small piles about the stalks of the cab-
bage. For protecting other crops it may be scattered along
the rows. Instead of both cottonseed meal and bran, either
may be used alone, in which case 25 pounds is used. Stale
bran or meal, should not be used in making this bait. The
mixture must be made up fresh each day from sweet fresh
material.

In a small garden or in a field where there are but few
cutworms, the easiest, quickest and cheapest method of
dealing with them is to walk thru the patch in the early
morning and look for plants which were cut off during the
preceding night. By scratching the earth away from the







DEPARTMENT OF AGRICULTURE


base of the plant the culprit will usually be found at a depth
of not more than an inch. They may be collected and fed
to chickens.

Cabbage Worms
At least five species of caterpillars feed on cabbages and
related plants in Florida. The most common one during
the cabbage growing season, the winter, is the cabbage
looper.

Cabbage Looper (Autographa brassicae).-This larva
(fig. 65, a) of a Noctuid moth is closely related to cutworms,
which it resembles in general shape. It does not have the
cutworm manner of
feeding but works
on the surface of
cabbage leaves both
day and night. It
c injures the leaves
by eating holes in
-. them and also dam-
/ ages the appearance
of the heads by soil-
ing them with its
Excrement. T h e
Caterpillar is light
green in color and
FIG. 65.-Cabbage looper: a, Larva; b, pupa; grows to a length
c, adult. Natural size. (From U. S. Bur.
of Ent.) of more than an
inch.
The eggs, yellowish-green in color and about a fiftieth
of an inch in diameter, are scattered over the surface of the
leaves. The caterpillar requires about 3 weeks for growth
and spends about 2 weeks in the pupa stage.
The adult moth (fig. 65, c) also looks much like those
of cutworms, and, in the latitude of Gainesville, may be
active all winter.
The Cabbage Plutella (Plutella maculapennis).-The








PLANT DISEASES AND PESTS


cabbage plutella (fig. 66, a), a much smaller caterpillar than
the looper, is common
on cabbages. It is
less than a half-inch
long and is much more .B- *
hairy in appearance /. '
than the looper. : '
When disturbed it
d I--
drops quickly from
the plant, spinning a
silken thread which it e
uses to remount when FIG. 66.-Cabbage plutella: a, Larva; d, e,
pupa; f, moth, h, moth at rest. Two
the danger is over. On and one-half times natural size. (From
U. S. Bur. of Ent.)
the under side of the
leaf, it makes small round holes, rarely extending thru.
Like the looper, this caterpillar is active all winter in the
latitude of Gainesville and south. The cocoon placed on
the leaf is a loosely-woven affair thru which the pupa (fig.
66, e) may be seen plainly.

The adult (fig. 66, f1 is a small moth 5/8 of an inch across
the expanded wings, which are gray with a border of light-
er areas. When the wings are folded in the resting posi-
tion (fig. 66, h) these areas form diamond-shaped patches
along the back. For this reason the moth is also called the
"diamond-back" moth.

The life history occupies from two to three weeks in
summer. It spends about three days in the egg stage, from
one to two weeks in the larval, and from four to eight days
in the pupal stage. Therefore, if one wishes to effect a
thoro clean-up of a heavy infestation of this insect, he
should give the plants a second spraying about ten days
after the first (two weeks in winter.)

Cabbage Butterflies

The caterpillars of these white butterflies are injurious
to late cabbage and collards. They do not seriously trouble







DEPARTMENT OF AGRICULTURE


the main winter-grown crop of cabbage be-
cause they are not active at that season.
Imported Cabbage-Worm (Pontia rapae).
-In the northern and western parts of the
State the most common cabbage butterfly is
the imported cabbage-worm, a pest which
was brought to this country about 1856. It
has since spread over the entire country,
reaching Florida about 1890, but has never
become as abundant as in the Northern 4
States.
The full-grown caterpillar (fig. 67, a) is "Frted c a
about 1% inches long, bright green with a fy; a, arva;
yellowish line down the middle of its back bpupa.s ia-e
and a row f spots of the same color along its (From U. t.
Bur. of Ent.)
sides. Two or three weeks are required for
its growth. It then crawls to some sheltered place and
there transforms into the pupa (fig. 67, b) and 8 or 10





.;--ywi-N--



FIG. 68.-Imported cabbage but- FIG. 69.-Imported cabbage but-
terfly: Female. Natural size. terfly: Male. Natural size.
(From U. S. Bur. of Ent.) (From U. S. Bur. of Ent.)

days later, in warm weather, the butterfly (figs. 68, 69)
emerges. But those which enter the pupa stage in the late
fall remain there all winter, at least in the northern part
of the State. The eggs are white or yellow in color and
are scattered over the surface of the leaf.

Native or Southern Cabbage-worm (Pieris protodice).-
This worm (fig. 72, a) is similar in appearance to the im-
ported worm but has four longitudinal yellow bands. The
butterflies can be distinguished by comparing the illustra-








PLANT DISEASES AND PESTS


tions (fig. 68, 69, 70, 71). The nature of the injury it in-
flicts is identical with that of the species last named.









FIG. 70.-Southern cabbage but-
terfly: Male. Natural size. FIG. 71.-Southern cabbage but-
(From U. S. Bur. of Ent.) terfly: Female. Natural size.
(From U. S. Bur. of Ent.)
Gulf White (Pieris monuste).-This butterfly has a yel-
low caterpillar (fig. 73, a) with four longitudinal stripes of
a purplish hue. It is 1%2 inches long. The butterfly (fig.
73, c) is the largest of the group, measuring nearly 3 inches
across the expanded wings. This is by far the most com-
mon and troublesome caterpillar on cabbage and collards
grown during the late
spring and summer in
the southern part of
the State.
Control.-Any or
all of these caterpil- a
lars are easily con-
trolled by means of
arsenicals. One can
use paris green but
either lead or calcium FIG. 72.-Southern cabbage butterfly: a,
Larva; b, pupa. Natural size. (From
arsenate is preferable. U. S. Bur. of Ent.)
One pound of paris green or 2 pounds of lead or calcium
arsenate powder is put into 50 gallons of water. This
liquid usually does not stick well to cabbage plants on ac-
count of the "bloom," a waxy coating. To make it stick,
add soap when the mixture is made, at the rate of 5 or 6
pounds for 50 gallons of water, according to whether the
water is hard or soft. Any alkaline laundry soap will do.
Flour-paste is also a good substance to make the arsenic
compound stick to cabbage leaves. A paste made by boil-








DEPARTMENT OF AGRICULTURE


ing 2 pounds of flour in 2 gallons of water may be added
to 50 gallons of the arsenical solution.
A spreader recommended by the Illinois Agricultural
Experiment Station is made by dissolving 5 pounds rosin
and 1 pint fish-oil soap in a gallon of water in an iron kettle.
Then add 4 gallons of water and 1 pound of concentrated
lye or potash and boil for a few minutes. When ready to
spray, add to 32 gallons of water 2 gallons of the above so-
lution, 6 gallons of milk obtained by slaking quick lime in
water (strain it so as not to clog the sprayer), and Y2 pound
of paris green or 2 pounds of powdered lead arsenate.
A new "spreader" worked out by the U. S. Department
of Agriculture is a solution of cactus. Thirty pounds of
cactus is chopped fine and allowed to soak over night in 50
gallons of water. This is strained and the arsenic added.
In those parts of the State where some of the wild species
of "prickly pears" or spineless cactus grow, this should
make a cheap "sticker."
Arsenical poisons may be used dry if applied when the
cabbages are wet with dew or rain. It is well to use a filler
of cheap
flour or air-
slacked o r
h y d r ated
lime, mixing
about s i x-
teen parts of
the filler to
one of dry
poison.

;B three com-
pounds, par-
is green is
the least
satisfactory.
a, Its arsenic
content i s
FIG. 73.-Gulf white butterfly: a, larva; b, pupa; c,
adult. Natural size. (From U. S. Bur. of Ent.) variable and








PLANT DISEASES AND PESTS


it may burn tender plants. In some quarters there is a
prejudice against using arsenicals on cabbages on account of
the supposed danger to the consumer. The amount adher-
ing to the cabbage is so minute as not to affect the health of
the consumer in any way. A prominent entomologist has
calculated that in order to be poisoned by eating even un-
washed cabbages which had been sprayed with paris green
one would have to eat a dozen heads at a sitting. Ordin-
arily a rain will wash off so much of the material that it
will not be noticed.
If the presence of the arsenical is likely to hinder the
sale of cabbages, it is recommended that they be not spray-
ed within ten days of the time of harvest. By using zinc
arsenite instead of lead arsenate, one can still further re-
duce the likelihood of danger to the consumer, since zinc
arsenite is less poisonous to man. The common idea that
a cabbage "heads up" by the leaves curling inward is a
mistake. The head is formed entirely by internal growth;
in fact, it is but a big bud and is formed like other buds,
never by the folding up of leaves. Consequently, there is
no danger of the poison being carried into the interior of
the head and held there on the leaves.
Cabbage Plant-Lice
The common aphid on cabbage is the garden aphid or
socalled green peach-aphid (Myzus persicae), altho the
cabbage plant-louse (Brevicoryne brassicae) (fig. 74) and
the turnip louse (Aphis pseudo-brassicae) are also found.
The garden aphid is bright green in color and smooth,


7/




FIG. 74.-Cabbage-aphis: a, Winged fe-
male; b, wingless female. Greatly en-
larged. (From U. S. Bur. of Ent.)


while the others have
a more mealy look,
and the turnip louse is
quite hairy. The
character of the dam-
age, the life history,
and the means of con-
trol are the same for
all three species and
practically the same
for all aphids.








DEPARTMENT OF AGRICULTURE


Aphids suck the juices from the plant on which they
live, stunting its growth, causing the leaves to curl, turn
yellow, and finally, the plant to die. They multiply with
great rapidity, often beginning when only a week old and
producing several young each day. During warm weather,
which means the entire year in Florida, the individuals of
most species bring forth young parthenogenetically, that is,
without mating between the sexes. Indeed, during that
time of the year males are usually not produced at all. Us-
ually the young are born alive and active, the eggs hatch-
ing before they are laid. But with the coming of winter,
in more northern states, males and true females are pro-
duced and eggs are laid which do not hatch until spring.
Most individuals never acquire wings, but from time to
time winged individuals are produced and spread the species
from plant to plant.
Farther north the green peach-aphid spends the winter
in the egg stage on peaches, plums, etc. The first two or
three generations in the spring feed on the tender unfold-
ing buds of those trees. The first generation is pink in
color but their young are green and never become pink.
The second or third generations usually develop wings and
leave the trees for tender vegetables where they live all
summer. This annual migration is common among aphids,
and the last generation returns to the trees in the fall to
lay eggs, enabling the species to get an earlier start in the
spring than would be possible were it necessary to wait for
herbs to grow.
Aphids give off a sweet substance called honeydew of
which ants are very fond. For the sake of this honeydew
ants carefully tend aphids, often protecting them from
their enemies which they drive away. They may carry the
aphids or their eggs from place to place where the "pasture"
is good, carry the eggs into their nests to winter over, or
even build adobe sheds over them for protection from rain
and enemies. For this reason aphids are often called "ants'
cows." Hence it happens that the presence of excited ants
on a plant is often the most evident sign of the presence
of aphids.








PLANT DISEASES AND PESTS


Remedies.-For the control of aphids on cabbage, the
best remedy is to spray the plants with a solution of to-
bacco extract. For directions for making this see melon
aphis under watermelons, page 145. On cabbages a spread-
er of soap and flour-paste should be used as recommended
in the discussion of cabbage worms. If the worms and the
aphids are both present on the cabbages, the tobacco can
be added to the lead arsenate spray, killing both pests at
one time.
Dusting the plants with tobacco dust is of some bene-
fit, and will often keep down the number of aphids and pre-
vent an outbreak, but will not control effectively an out-
break that has gained headway. These outbreaks often
start on plants scattered thru a field and by pulling them
up and destroying them, a general outbreak can be fore-
stalled or at least delayed.
Enemies.-Aphids are a very attractive article of diet
to a large number of enemies which are usually able to hold
them in check. Only the wonderful rate of reproduction
of the aphids enables them to have a surplus with which to
start a destructive outbreak after supplying the "market"
of their enemies.
The smaller birds such as wrens, fly-catchers, and war-
blers destroy great numbers of aphids. A flock of young
chickens, if given the freedom of the garden, will do excel-
lent work in ridding it of aphids.
In a colony of aphids, dead ones may be found which
are so greatly swollen as to be nearly spherical in shape.
These have been killed by the larva of a minute wasp-like
parasite which lives in the interior of the aphid, consuming
its vitals. The parasite pupates in the dead aphid and
when the adult parasite is ready to emerge it bites a hole
in the top of the aphid and crawls out. The egg from which
the parasitic larva hatches is laid inside the aphid which
the female parasite pierces with her ovipositor.
Several kinds of soft-bodied larvae move among the
aphids and destroy them. Some are legless maggots which
impale aphids on their sharp anterior ends and suck the
body fluids. These are the larva of a family of two-wing-








DEPARTMENT OF AGRICULTURE


ed flies, known as syrphus-flies. There are many species.
Another larva is flat, wedge-shaped, with well-developed
legs and a pair of jaws with which it pierces the aphids.
These are aphid-lions. The adults are lace-winged flies
(Chrysopa), bright green insects which measure nearly an
inch across the four gauzy wings and have bright golden
eyes. The eggs are laid in groups and are raised on stalks
a half-inch above the surface of the leaf. This arrange-
ment prevents those first born from using for their food
the unhatched eggs in the group. A similar larva (Heme-
robius) makes a case to cover its body out of the remains
of the victims which it has sucked dry. This case is car-
ried about by the larva, hence it is called a "trash-bug."
The adult is similar to the golden-eyed lace-wing, but is
brown.
Aphids are the choice food of many lady-beetles and
their larvae. The species most common in Florida truck
patches and gardens are the convergent lady-beetle and the
blood red lady-beetle, altho the twice-stabbed lady-beetle, so
common and beneficial in citrus groves, is occasionally
found.
During the rainy season aphids are subject to attack
by fungi, particularly Empusa aphidis. This fungus often
destroys in a few days the aphids from whole fields.
The heavy rains of the Florida summer are directly de-
structive to aphids which are knocked off the plants and
beaten to death on the ground.

Cabbage Root-Maggot (Phorbia fuscipes)
These small, soft-bodied legless maggots (fig. 75, a)
which often do great damage to the roots of cabbage and
related plants in the North are comparatively uncommon
in Florida. The first indications of their presence on the
roots are a check to the growth of the plants which wilt
during the heat of the day and show a bluish, sickly color.
The plants finally turn yellow and wilt down completely.
If these plants are pulled up it is found that the roots have








PLANT DISEASES AND PESTS


been eaten off, and perhaps the main stem mined, by the
maggots which are about Y4 of an inch long when fully
grown.
The adult (fig. 75, c) is a two-winged fly, similar in ap-
pearance to the house- or typhoid-fly but much smaller and
with a proportionally longer abdomen. The female lays her
eggs on the stem of the plant or on the ground near by.
Remedies.-Repellants placed about the roots of the
plants when first set out are of some benefit in discourag-
ing the females from
laying their eggs on
the plants. Perhaps
tobacco dust is about
as practicable as any.
Carbolic acid emul-
sion may be used.
S ( Liberal fertilization
Swill enable the plants
e to outgrow the dam-
age done by a few
~ ~ ^maggots. Repeated
a shallow cultivation
will destroy many of
FIG. 75.-Cabbage root-maggot (Phorbia the eggs laid on the
brassicae): a, Larva; b, pupa; c, female
fly. About four times natural size. (From ground about t h e
U. S. Bur. of Ent.) bases of the plants.
The grower should destroy all heavily-infested plants and
should avoid planting cabbage on land that has just borne
a crop of infested cruciferous plants whether cabbage, cauli-
flower, collards, rape, mustard, or turnips. The maggot
will breed in wild plants of this family and all such found
near the field should be destroyed.
Cabbages in an infested seed bed can be treated with
carbon bisulphide. To do this, make holes with a stick
three or four inches from the infested plant and slanting
obliquely under it. Pour in about a teaspoonful of the car-
bon bisulphide and quickly tramp the soil solid to confine
the fumes.








DEPARTMENT OF AGRICULTURE


In the Northern States it has been found profitable after
setting the plants in the field to protect them from the at-
tacks of this insect by using tarred paper discs. These are
cut open along one radius and fitted closely about the plant.
It is doubtful if the attacks of the insect in Florida fields
are sufficiently common to make this precaution profitable
except in the case of some particularly valuable plants.

Harlequin Cabbage-Bug or Calico-Back
(Murgantia histronica)
This strikingly-colored insect, a native of the Mexican
region, has been slowly working its way eastward and


northward. It is not as
yet abundant in Florida
but may be seen occasion-
ally on late cabbage and is
quite common and destruc-
tive to collards that are
carried thru the summer.
The adult (fig. 76, g) is
black and orange and is
2-5 of an inch long. Both
the adult and young suck
the juices of the plants in-


N,


d e




f '
FIG. 76.-Harlequin cabbage-bug: a,
b, Nymphs; d, e, eggs, greatly en-
larged; f, g, adults. Slightly en-
larged. (From U. S. Bur. of Ent.)


to which they inject a poison. A few bugs are sufficient
to cause a plant to turn yellow and die.
The eggs (fig. 76, c, d, e) are deposited on the under
side of the leaves, usually in two rows. They are keg-shap-
ed, white, with black bands and a small black spot on each
side, increasing the resemblance to a keg with its hoops
and bung-hole. They hatch in 3 or 4 days. The young
are at first yellow, developing the orange markings later.
They are usually present in such number as to make
hand collecting practical, but hand collecting of the young
is less satisfactory because of their small size. Should
these become abundant they can be killed by kerosene emul-
sion. Destroy all infested, dying plants. In the northern
part of the State a crop of late cabbage can be partly pro-







PLANT DISEASES AND PESTS


tected by planting an early
trap crop of mustard, rad-
ishes or turnips. When
this trap crop becomes in-
fested it may be sprayed
with kerosene emulsion or
pulled up and burned.
Cabbage Hair-Worm Or
Cabbage Snake
FIG. 77.-Cabbage hair-worm or cab- (Mermis albicans)
bage snake. (FromU.S.Bur. ofEnt.)
This whitish, thread-
like worm (fig. 77), which sometimes grows to be 2 to 9
inches long, is frequently found in cabbage heads. It is an
internal parasite of grasshoppers and caterpillars and it
gets into the cabbage by crawling out of infested insects.
It is therefore a friend of the grower. In spite of its re-
pulsive looks and the many stories which are told of its
poisonous nature, it is entirely harmless to mankind.

Southern Squash Bug (Anasa armiger)
This insect sometimes attacks cabbage and collards. It
breeds on these plants, as eggs and nymphs are found there.
Control is similar to that of the squash bug, page 123.
Other Cabbage Pests
The following named insects also infest cabbage in Flor-
ida: Blister-beetles (see under beets, page 63) ; flea-beet-
les (see under beets, page 65); tarnished plant-bug (see
under celery, page 83) ; onion thrips (see under onions,
page 112); wireworms (see under corn, page 88); nema-
todes (see root-knot under general garden pests, page 56);
and grasshoppers (see under general garden pests, page
49); serpentine leafminer (see under cowpeas, page 99).


CANTALOUPE

The insect pests of this crop are identical with those of
cucumbers. (See cucumbers, page 101.)







DEPARTMENT OF AGRICULTURE


CARROT
The common insect pests of this crop are: Cutworms
(see under cabbage, page 67) ; garden aphid (see cabbage
plant-lice under cabbage, page 75); black blister-beetle
(Epicauta pennsylvanica) (see blister-beetles under beets,
page 63); celery caterpillars (see under celery, page 84);
and carrot-beetle (Ligyrus gibbosus) (see May-beetles un-
der potatoes, page 120).

CELERY

Celery Leaf-Tyer (Phlyctaenia ferugalis)
During some seasons this insect is extremely injurious
to celery. The eggs are laid on the leaves. The larvae
feed chiefly on the new and tender leaves above the "heart"
of the celery. As the caterpillars get older they descend
the stalks and feed near the bases of the stalks until ready
to pupate. During the later stages of growth the cater-
pillar spins a more or less conspicuous web of silk under
which it feeds, hence the name of webworm. The larva is
a pale yellowish caterpillar and quite hairy. The adult is
a small brownish moth.
Control.-No very satisfactory means of control has yet
been found for this insect, because it feeds more or less in
the interior of the celery where it is protected by the upper
leaves from our spray materials. In order to reach it with
an arsenical it is necessary to use strong pressure. But
the use of arsenical sprays in large enough quantities to
control this insect is objectionable because of the residue
which is left on the plants at harvesting time. Attacks of
the leaf-tyer are most in evidence when celery is fairly well
grown and near the time of harvesting. Some degree of
control has been obtained by the use of poison bran baits
as recommended for cutworms (see under cabbage, page
67), but this also must be carefully placed in the celery by
hand. If simply dropped on top of the celery plants it does
not get down into the heart where the caterpillars are work-
ing.








PLANT DISEASES AND PESTS


Semi-Tropical Army Worm (Prodenia sp.)

This insect, which feeds chiefly on grasses, sometimes
attacks celery in injurious numbers. It is a large cater-
pillar with reddish brown markings. It is closely related
to the sweet potato caterpillar. The same poison baits
which are recommended for that insect will also control
this caterpillar.
Garden Flea-Hopper (Halticus citri)

This is a minute black plant-bug (fig. 78) that attacks
the leaves of cowpeas, beggarweeds, peppers, and a great










d
FIG. 78.-Garden flea-hopper; a, Short-winged female; b, full-winged
female; c, male; d, head of male in outline. Eight times natural size.
(From U. S. Bur. of Ent.)

variety of weeds. The attacked spots turn yellow, giving
the plant a spotted, "peppered" appearance. The insect
may be controlled readily by tobacco extracts.
Tarnished Plant-Bug (Lygus pratensis)
This bug (fig. 79) is very common the country over in
gardens where it frequents blossom heads and other very
young and tender herbage and even the tender shoots of
trees. The succulent stalks of the celery plant afford a
very acceptable feeding place. In addition to stunting the
growth of the plat, due to the insect sucking the sap, brown
spots are produced where the punctures are made. These
greatly reduce the attractiveness of the produce on the
market.
The adult bug is only about 2-5 of an inch long. The








DEPARTMENT OF AGRICULTURE


male is dark reddish-brown and the female light brown


with light yellow
markings. They
breed rapidly. The
young (fig. 79) are
greenish in color.
These bugs are rather
restless and are quick
in their movements.


FIG. 79.-Tarnished plant-bug. Imma-
ture stages. Four times natural size.
(From U. S. Bur. of Ent.)


For this reason they are most easily captured or killed in
the early morning when they are relatively sluggish. A
strong tobacco extract with plenty of soap will kill the
young and most of the adults but kerosene emulsion is bet-
ter.
A number of other bugs, such as False Chinch-bug
(Nysius angustatus), frequently attack celery. The char-
acter of the injury is similar to that of the tarnished plant-
bug and the control measures identical.

Celery Caterpillar (Papilio polyxenes)
This caterpillar sometimes strips the leaves from celery
and, as the caterpillar is rather large, a single one can in-


A





Fig. 80.-Tarnished plant-bug: Adult and
young. About four times natural size.
(From U. S. Bur. of Ent.)


inflict much damage.
It is conspicuously col-
ored in green and
black. It is a close
relative to the com-
mon "orange dog''
(Papilio cresphontes)
and, like that species,
when disturbed, i t
thrusts out a yellow
horn-like process from


the head accompanied by a strong pungent odor. This
seems to protect the insect from birds and possibly other
foes. It grows to a length of 2 inches. The pupa is fast-
ened to a support partly by a silken thread about its mid-
dle. In from 12 to 15 days, in summer, there issues from
it a swallow-tailed butterfly. This is smaller than the adult








PLANT DISEASES AND PESTS


of the orange dog and much darker in color. It is called
the black swallow-tail.
Both the caterpillar and its work are so conspicuous
that hand-picking will usually be the most economical
means of control. As celery is commonly sprayed with
bordeaux for fungus troubles, lead arsenate can be added
(1 pound to 50 gallons of bordeaux) and this, as well as all
other biting insects, be killed.
Other Caterpillars.-Several other caterpillars attack
celery; among them are the celery looper (Autographa
falcifer), an insect closely related to the cabbage looper.
Plant-Lice
At least two species of aphids commonly attack celery
in Florida. One is the common garden aphid or green
peach-aphid (Myzus persicae). The other, Macrosiphum
lactucae is much larger. The control measures are the
same as those given under cabbage, page 77.
Other Celery Pests
Other insects injurious to celery are: Flea-beetle (see
under beets, page 65); cutworms (see under cabbage, page
67); and cabbage root-maggot (see under cabbage, page
78); red spider (see under peas, page 115).


FIELD CORN AND SWEET CORN

Sweet corn it attacked by all the common pests of corn
and there are many of them. Some show a decided prefer-
ence for sweet corn. Only the more important insects at-
tacking corn will be considered here.
Corn Ear-Worm, Or Bud-Worm (Heliothis obsoleta)
This common pest of cotton, corn, tomatoes, beggar-
weed, etc., prefers sweet corn to any other of its host plants.
Early in the season the moth lays her eggs on the young
corn. The early generation of larvae which hatches from
these eggs works in the corn as a "bud-worm." (At least
two other caterpillars that do very similar damage to corn








DEPARTMENT OF AGRICULTURE


are known as "bud-worms.") When mature the caterpil-
lars enter the ground, pupate, and in seven days emerge as
moths which in turn lay their eggs on the silk of the corn
which is by this time beginning to appear. The second
generation of larvae on the corn eats the silk and then en-
ters the ear and feeds upon the developing kernels. Later
generations develop on cotton, beans, beggarweed, etc. The
insect also attacks tomatoes. But whether working in corn
as the "bud-worm" or "ear-worm," in tomatoes as the
"fruit-worm," on cotton as the "bollworm," or fully ex-
posed on beggarweed, it is the same insect. So abundant
is this pest in Florida that it is almost impossible to find
an ear of sweet corn that has not been attacked by at least
one of these caterpillars.
Control.-The work of the first generation in the corn
is usually noticeable when the corn is about knee high. At
this stage it is not difficult to poison the caterpillars by
spraying or dusting some of the arsenic compounds into the
infested buds. The writer has dusted undiluted lead ar-
senate and zinc arsenite powder into the buds without pro-
ducing any harmful effects, but it is safer and more econ-
omical to mix the poison with from 2 to 4 times its bulk of
air-slacked or hydrated lime. The dusting is best done in
the early morning when the plants are wet with dew. The
agitation resulting from brushing against the stalks will
usually be sufficient to cause the dew to run down into the
bud, carrying the poison with it. In a small garden the
poison can be applied by
means of atin can
punched full of holes.
On a large scale the well-
known bag-a n d-p o 1 e
method may be used, but
the most even distribu-
tion will be secured by .
the use of a dusting ma- o
chine. It is important
that this early genera- FIG 81.-Corn ear-worm: Adult. One
and a half times natural size. (Orig-
tion should be destroyed, final )








PLANT DISEASES AND PESTS


if possible. Not only will the injury to the buds be check-
ed, but the number of caterpillars in the following genera-
tion, which works in the ears, will be lessened.
When the silks appear on the young ears of corn they
can be dusted by means of the same apparatus. The cat-
erpillars feed on the exposed silks for only a few days be-
fore entering the ear, where they are safe from insecticides,
so it will be necessary to repeat the dusting every three or
four days. This is too expensive for a crop of field corn,
but on such a high-priced crop as sweet corn it is worth
while.
In a small patch in the garden the worms can often be
removed from the tip of the ear before they have inflicted
material damage. In removing the worms it is not well,
however, to open the ears to such an extent as to expose the
kernels, as other animals such as birds, Carpohilus and oth-
er insects will then attack them. Woodpeckers and blue-
jays are occasionally seen feeding on the worms and the
ears of sweet corn.
Life History.-The eggs are whitish, oval, prominently
ribbed, and about a twentieth of an inch in diameter. They
are scattered over the corn. Those from which the bud-
worm hatches are laid on the leaves; those of the ear-worm
on the silk. They hatch in 3 or 4 days.
The caterpillars vary from a delicate pink to black.
They are marked with rather narrow longitudinal lines.
They require about 17 days for growth in summer, becom-
ing 114 to 2 inches long. The caterpillar then bores a hole
in the side of the ear or stalk and enters the ground to a
depth of 2 to 5 inches where it forms the pupa. Here it re-
mains for a week or two in summer or all winter if it is the
last fall brood.
The pupa lies in an earthen cell. It is about 3v-inch
long. It is at first green in color but soon turns to a light
brown. The moth (fig. 81) which issues from this cocoon
varies in color from a dusky yellow to grayish and expands
from 1Y2 to 2 inches. Unlike most moths it may fly in
broad daylight, but the eggs are usually laid at sunset.








DEPARTMENT OF AGRICULTURE


Carpophilus
If the husk is removed from an ear of corn in the milk
by any cause, such as a woodpecker in his hunt for a corn
earworm, it is at once attacked by these scavenger beetles,
which are also common in decaying fruits. The beetles are
brown and about 1/8 of an inch in length. Their wing-cov-
ers are so short that they do not reach the end of the abdo-
men. The beetles seem unable to penetrate the husk of an
uninjured ear, but very commonly get into the burrows
made by the corn earworm and cause further damage.
They often breed among the kernels which blacken and de-
cay, thus spoiling many ears that would otherwise be us-
able. The larvae are small, whitish, and maggot-like.
Control measures are obviously those which control the corn
ear-worm.
The Corn Lantern-Fly (Peregrinus maydis)
This insect and the bud worm are the worst enemies of
late-planted corn in Florida. In the latter part of August
the lantern-fly becomes extremely abundant and severely
infests practically every stalk of young corn, and quickly
kills it. Stalks that have reached the tasselling stage are
not severely injured.
This lantern-fly is a slender yellowish-green insect about
a sixth of an inch long. Its wings are longer than the body,
and are clear except for some dark-brown markings near
the tip.
They collect in large numbers in the bud and in the axils
of the leaves. These colonies are usually composed of
numerous young of all stages, and a few winged adults.
The most effective and the quickest means of control-
ling this pest is to dust the buds of the corn with nicotine
sulphate-lime dust.
Wireworms, "Drillworms"
These long,slender, hard, wiry "worms" are the larvae
of click-beetles. They feed below the surface of the ground
on the roots and stems of plants into which they often bore.
The infested plant is stunted, turns yellow and may die.








PLANT DISEASES AND PESTS


The larvae are particularly destructive to sprouting seed,
eating the inside.

The adults are called click-beetles from their habit of
throwing themselves into the air with an audible click when
placed on their backs. They are also called 'skip jacks"
and "snap beetles."

There are dozens of species of wireworms in Florida
and at least a half-dozen injure corn. As their habits, life
history, type of soil infested, and control measures differ
for each species, it will be necessary to take up the more
important ones separately.

Spotted Click-Beetle.-The most common wirewor :. in
Florida corn fields is the young of the spotted click- eetle
(Monocrepidius vespertinus) (fig. 82). This is a thick
wire-worm about 1/-inch long and is found in both dry and















FIG. 82.-Spotted click-beetle: Adult; pupa; larva; and egg; greatly
enlarged. (From So. Car. Agr. Exp. Sta.)

wet land but is more destructive in the former. It is also
found on cowpeas.
The eggs are laid in the summer. They hatch in about
9 days according to Dr. A. F. Conradi and H. C. Edgerton
(So. Car. Agr. Exp. Sta. Bul. 179), and the larvae feed un-
til the following spring when they pupate in the ground at








DEPARTMENT OF AGRICULTURE


a depth of from 3 to 5 inches, remaining there about 2
weeks. The earliest adults were taken at Gainesville on
June 7 by Mr. Dozier. They are from 1-5 to 1-3 of an inch
long.
Fall plowing and frequent cultivation of the corn will
destroy many of these insects, particularly if chickens or
other birds follow the plow. They are seldom found at a
greater depth than 4 inches. A few seeds of cotton plant-
ed at the same time as the corn is said to be of benefit.
They prefer the cotton to the corn and while they are feed-
ing on the cotton, the corn has an opportunity to germinate
and get a start.
The nighthawk is an important enemy of the beetles
which fly at dusk, the time when these birds are on the
wing. Nighthawks should be protected by the farmer.

Monocrepidius Lividus.-Associated with the last-nam-
ed species in about the same class of soil is Monocrepidius
lividus. This is perhaps the second most common wireworm
in Florida. Control measures are the same as for the
above named species.

Corn and Cotton Wireworm.-Unlike most wireworms,
this one (Horistonotus uhleri, Horn) works mostly in sandy,
light, dry soils. It differs also from the other species in
its appearance. It is long and white and has a soft skin
instead of the hard, chitinous covering like the others.
Control measures are about the same as those used against
the larva of the spotted click-beetle.

Corn Wireworms (Melanotus sp.).-These are not as
common as the other species. Like most species of wire-
worms they are found mostly in low, poorly-drained land,
especially if it was in grass the previous year. Draining
and liming the land, with deep and thoro cultivation, are
important.
The larvae are about 11/4 inches long, brown in color and
have three small projections on the posterior end. Some







PLANT DISEASES AND PESTS


species require several years for growth. The adults are
brown and from a half to 3/ of an inch in length.
Other wireworms sometimes injurious to corn in Flor-
ida are Lacon curtus and Lacon rectangulus. The control
measures are similar to those for the last-named.


Fall Army Worm, Or Southern Grass Worm
(Laphygma frugiperda)

This well-known pest of grass attacks corn as a second
choice when all of the grass within easy range has been
eaten. Army worms are so named from their habit of as-
sembling in vast numbers and marching in mass formation
to new pastures. These marches come as a result of exces-
sive numbers exhausting the food supply in the place where
they hatched. The word "fall" was prefixed by entomo-
logists in the Northern States and is a misnomer in Florida.
The destructive armies usually form in July and August, but
sometimes as early as April. At other seasons, and dur-
ing the years when no armies are formed, a few of these
caterpillars are found, feeding apart like cutworms.
Control.-These isolated caterpillars may get into the
tips of growing corn and become "bud-worms" where they
may be controlled by the same measures as given for the
corn ear-worms when working as bud worms. (See page
85.) The armies may be repelled with fair success by the
"Kansas bait," (see page 49), or the food-plants may be
sprayed or dusted with lead arsenate, paris green or any
other arsenical. This is applied best while the caterpillars
are working on grass, before entering the cornfield.
The eggs are laid mostly on grasses in masses of fifty
or more and hatch in about ten days. The caterpillars re-
quire about two weeks in which to become full-size, which
is about 11/4 inches long. They are rather slender. Their
color is brown with a narrow yellowish-gray stripe along
the middle of the back and a brownish-black one along the
side. On the head the central line branches, making a con-







DEPARTMENT OF AGRICULTURE


spicuous V-shaped white mark, which helps to identify the
caterpillar. The body is covered with small black promin-
ences from each of which a short, stiff, black hair arises.
The adult is a moth resembling those of cutworms, to which
it is closely related.


Root Webworms (Crambus sp.)

These also are caterpillars that often do severe damage
to young corn in the spring. In April, 1914, they destroyed
many acres about Gainesville and other places. They al-


FIG 83.-Bill-bug (Sphenophorus callosus): a, Larva; d, adult. Greatly
enlarged. (From U. S. Bur. of Ent.)

ways do more damage than they are charged with, much
of their work being attributed to cutworms. There are
several species of these insects, but all of the caterpillars
are reddish, pinkish or brown, with conspicuous dark spots
on their backs. Like cutworms, they feed at night, but
do not cut the plant off. Instead, they strip it of its
leaves, make channels on the surface of the stalk, or mine
the center. They construct a tube of silk just below the








PLANT DISEASES AND PESTS


surface of the ground and hide in this
during the day. This will distinguish
them from cutworms. Furtherimore.
they try to escape when disturbed in-
stead of curling up and "playing pos-
sum" like cut-worms. The adult in-
sects are small, light-colored moths
which are always plentiful in suod land.


When at rest
around t h e i r
bodies instead
of laying them
back more or
less flat like
most moths.
Control. -
Severe injury
by these cater-
pillars is con-
fined to land
which had con-
siderable grass
during the pre-
ceding y e a r.
Such land if
intended for
corn should be
broken as ear-
ly in the fall
as practicable.


they roll their w\ings


I .' 4-' Inju





I. 84.-Injuy
U. i


to corn by Lill-hugs. (From
S. Bur. of Ent.)


Aside from the matter of insect control


this is also the best procedure from the cultural standpoint,
as it conserves the moisture during the dry winter. Some
relief can be obtained by dusting or spraying the young
plants with lead arsenate.
Bill-Bugs (Sphenophorus spp.)

Other insects that injure young corn are species of snout
beetles called "bill-bugs" (fig. 83). They feed on the
young, tender leaves, making parallel rows of holes, after








DEPARTMENT OF AGRICULTURE


the pattern of sap-suckers on trees (fig. 84.) This is done
when the leaf is rolled up in the bud and each row of holes
is produced by a single puncture.
Like the last-named insect, this one is injurious only on
land that grew much grass during the preceding year.
Eggs are laid on grasses in low wet land, where alone bill-
bug injury is ever severe. The young feed chiefly on the
roots of grasses, but one species (S. robustus) may live in
the pith of the corn stalk.
The measures recommended for use against root web-
worms (page 92) are also the ones to be used against bill-
bugs.
Corn-Leaf Blotch-Miner (Agromyza parvicornis)
This larva of a minute black fly makes irregular shaped
blotches in the leaves of corn and some grasses by eating
the tissue from between the lower and the upper epidermis.
Its injuries are most noticeable and serious on young corn.
The egg is laid in the corn leaf and hatches in 3 or 4 days
in summer. The larva feeds from 3 to 12 days in summer.
It breeds during the winter in southern Florida (Jl. Agr.
Research, April 12, 1916).


;-


>16;


FIG. 85.-Southern corn root-worm: a, Adult
beetle, about six times natural size; b, egg;
c, larva; d, anal segment of larva; e, work
at base of corn stalk; f, pupa. (From U. S.
Bur. of Ent.)


Th e insect
cannot be reach-
ed by any insecti-
cide. The only
Course is to pull
up and destroy
bad 1 y infested
' plants, and b y
good care, keep
the others in
such a vigorous-
ly growing condi-
tion as to over-
come the injury.
An excess of corn
should be planted


so that a good


e






i
...,

'j 1








PLANT DISEASES AND PESTS


stand will remain after the requirements of the flies have
been met and the infested plants pulled up.
Southern Corn Root-Worm (Diabrotica 12-punctata)
This insect spends both its larval and adult stages on
corn. The adult (fig. 85, a) feeds on the leaves in which
it makes small holes, but it is more common on the silk of
the young ears which it cuts off. It may attack also the
tassel or the exposed kernels of the ears. The white, grub-
like larvae (fig. 85, c) mine the roots of the corn. The
adult beetles are oblong and about 1/ inch long, red in color,
with 12 black spots on the wing covers. The insects are
more abundant on late corn than on early varieties and ap-
parently are more common in the western part of the State
than on the peninsula.
Corn Weevils (Calandra oryzae and C. granaria)


Sweet, or field cron,
by these small beetles
the kernels. As soon
should be fumigat-
ed with carbon bi-
sulphide, using 2 or
3 pounds to 1000
cubic feet of space
in the bin or crib.
The material is
placed in an open
dish on top of the
corn and allowed to
evaporate. T h e
fumes are heavier
than air and will
sink, and penetrate
the corn. The bin
should be per-
fectly tight before F
the sulphide is in-
troduced, and kept


which is stored, is subject to attack
(fig. 86) which eat the interior of
as weevils are noticed, the corn


~-~7
6


I


'IG. 86.-Calandra granaria: a, Adult; b,
larva; c, pupa; d, Calandra oryzae. About
seven times natural size. (From U. S.
Bur. of Ent.)








DEPARTMENT OF AGRICULTURE


closed afterward for at least 24 hours. All fire and lights,
including lighted pipes, should be kept away for the fumes
are inflammable. A safer fumigant is paradichloribenzene.
It is not inflammable and is not as dangerous to human be-
ings who breathe its fumes. It is a new material on the
market and some difficulty may be met in obtaining it. To
use, dissolve in water 12 ounces for each 100 cubic feet of
space. The liquid is then soaked in a rag which is placed in
the seed box. There is less danger of injuring the germin-
ating ability of the corn by an overdose with this fumigant
than with carbon bisulphide. Even live animals, such as
dogs, cats, and chickens, can be thus fumigated safely in a
box for an hour. Either of these insecticides is more ef-
fective when the temperature is above 60 degrees.

Other Corn Pests
Other insects attacking corn are: Sweet-potato cater-
pillar (see under sweet potatoes, page 130), and serpentine
leaf-miner (see under cowpeas, page 99.) The bean-jassid
(see bean leaf-hopper, page 57), lantern-fly, (see page
88), and the lesser corn stalk-borer (see under beans, page
61) are particularly injurious to very late-planted corn
and, with the bud worm (see page 115) are, the chief cause
of the difficulty of growing a crop of late-fall roasting ears
in central Florida.


COWPEAS

Cowpea Pod-Weevil, Or Cowpea Curculio
(Chalcodermus aeneus)
This black beetle (fig. 87, a), except in color, resembles
the cotton boll weevil and, as it often feeds on young cot-
ton in the early spring, it is frequently mistaken for that
species. It is an exceedingly severe pest on dowpeas.
Early in the season it feeds on the leaves of the plant, but
as soon as the pods begin to set it turns its attention to
them. The females lay their eggs in the developing seeds,








PLANT DISEASES AND PESTS 97

making a puncture thru the pods. They also feed on the
pods, making a feeding puncture similar to the egg punc-
ture. These punctures make unsightly brown spots on
pods and seeds, but the greater injury is done by the grubs
that hatch from the eggs in from 4 to 6 days. This pale
yellow larva (fig. 87, b) eats the seed. It requires a week











' d
FIG. 87.-Cowpea pod-weevil: a, Adult; five times natural
size; b, larva; d, pupa. (From U. S. Bur. of Ent.)

or two to reach full size. It then bores a hole in the side
of the pod and escapes to the ground. The adult is about
1/4 inch long and has deeply-pitted wing-covers.

Control.-Rotation of crops should be practiced. Land
that has grown a crop of heavily-infested cowpeas should
not be planted at once to a late crop of cowpeas. Neither
should such land be planted to beans. When the insects
are feeding on the leaves early in the season, they can be
poisoned with lead arsenate. Use 1 pound of the powder
or 2 pounds of the paste to 50 gallons of water. The de-
struction of the early brood will materially reduce the num-
ber attacking the pods later. On a small garden patch or
on other particularly valuable fields the insects can be col-
lected by hand as recommended for the pumpkin bug.

Pumpkin Bug (Nezara viridula)

This pest attacks nearly all garden plants and especial-
ly legumes, but is particularly at home on cowpeas. The








DEPARTMENT OF AGRICULTURE


adult insects are little more than Y2 inch long and nearly
as broad and are usually light green in color. The young
(fig. 88) are bluish with some reddish markings. They are
quite unlike the adults in appearance. There are several
generations in a year. The adults of the last generation
hibernate but not until late in the fall and are out early in
the spring. These insects do considerable damage to young
plants but the most severe injury is inflicted on the pods.


FIG. 88.-Pumpkin bug (Nezara viridula): Young. Six times
natural size. (From U. S. Bur. of Ent.)

Their numerous feeding punctures make unsightly brown
tough dots. They will also dwarf the pods and if suffic-
iently numerous cause them to drop.

Control.-This is a difficult pest to control. Being a
sucking insect, arsenicals or other stomach poisons are of
no avail. The young can be killed by kerosene emulsion or
a strong soap solution, but the adults are too robust to be
killed by these compounds except at strengths that would
be dangerous to the plants. The only means of combating








PLANT DISEASES AND PESTS


them seems to be hand-collecting. On an ordinary field
crop of cowpeas, it is questionable whether the operation
would pay. It is perhaps best to plant enough for both
bugs and planter and, by good cultural methods, to keep
the vines in such vigorous growing condition that they will
bear peas in spite of the bugs. In a garden, on a particul-
arly valuable patch of cowpeas, or on such valuable crops
as beans, tomatoes, potatoes, etc., hand-picking will pay
well. For this purpose take a pan or other wide-mouthed
dish, pour into it an inch or less of water and on this a film
of kerosene. In the early morning or on a cold rainy day
when the bugs are sluggish, walk along the rows and knock
the bugs into the pan. This is not as slow a process as it
may seem at first. An active boy can collect most of the
bugs from an acre of beans or several acres of potatoes in
an hour.

The smaller but closely related Nezara hilaris does about
the same character of damage, but is comparatively rare
in Florida.

Serpentine Leaf-Miner (Agromyza pusilla)

This is a near relative of the corn-leaf blotch-miner.
(see under corn, page 94.) Like that species, the larva
works in the central tissue of the leaf, but its burrow is
long and narrow, with many bends, hence the name serpen-
tine. It is plentiful in many wild plants, especially such
legumes as beggarweed and coffeeweed, and it is common
in cowpeas. Its life history is similar to that of the corn-
leaf blotch-miner and it may likewise work all winter in
the southern part of the State. The greatest damage is
done to the first two leaves cotyledonss) of very young
seedlings before the true leaves are put out. Both of these
leaf-miners have numerous parasitic enemies which gen-
erally keep them under fair control.








DEPARTMENT OF AGRICULTURE


IVINIg e Cowpea Seed-Weevils

Two species of weevils, the
four-spotted weevil (Pachymerus
4-maculatus) (fig. 89) and the
Chinese weevil (Pachymerus chin-
ensis) (fig. 90), both closely re-
r lated to the bean-weevil (see un-
\ der beans, page 60), do about
Sthe same character of damage to
cowpeas as their relative does to
beans. The bean-weevil also oc-
S casionally attacks cowpeas and
Either or both of the cowpea









FIG. 89.-Pachymerus 4- a
maculatus: a, Adult; b,
c, egg from above and
below; d, head of mature FIG. 90.-Pachymerus chinensis: a, adult;
larva. Greatly enlarged. b, egg; c, larva. About seven times
(From U. S. Bur. of Ent.) natural size. (From U. S. Bur. of Ent.)

weevils often attack beans. They begin their work in the
field but it is in stored peas that they are especially injuri-
ous. These should be fumigated or heated following direc-
tions for stored seeds. If cowpeas are kept in cold storage
at a temperature below 34 degrees for 2 or 3 months, the
eggs, as well as weevils, are destroyed.
Other Cowpea Pests
Other insects attacking cowpeas are: Wireworms (see
page 88); cutworms (see page 67); leaf-footed plant-bugs
(see page 119) ; and lesser corn stalk-borer (see page 61),
and the garden flea-hopper (see under Celery, page 83.)
The harlequin cabbage bug (see page 80) attacks the
pods.




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