• TABLE OF CONTENTS
HIDE
 Front Cover
 Table of Contents
 Introduction
 Insects attacking tobacco
 Natural enemies of tobacco...
 Control recommendations
 Phytotoxicity and leaf scorch
 Acknowledgement
 Reference






Group Title: Bulletin - University of Florida Agricultural Experiment Station ; 573
Title: Insect pests of flue-cured tobacco and their control
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00026685/00001
 Material Information
Title: Insect pests of flue-cured tobacco and their control
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 34 p. : ill. ; 23 cm.
Language: English
Creator: Kuitert, Louis Cornelius, 1912-
Tissot, A. N ( Archie Newton ), b. 1897
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1956
 Subjects
Subject: Tobacco -- Diseases and pests -- Florida   ( lcsh )
Tobacco -- Diseases and pests -- Control -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Bibliography: p. 34.
Statement of Responsibility: L.C. Kuitert and A.N. Tissot.
General Note: Cover title.
Funding: This collection includes items related to Florida’s environments, ecosystems, and species. It includes the subcollections of Florida Cooperative Fish and Wildlife Research Unit project documents, the Florida Sea Grant technical series, the Florida Geological Survey series, the Howard T. Odum Center for Wetland technical reports, and other entities devoted to the study and preservation of Florida's natural resources.
 Record Information
Bibliographic ID: UF00026685
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 000926779
oclc - 18279711
notis - AEN7479

Table of Contents
    Front Cover
        Page 1
    Table of Contents
        Page 2
    Introduction
        Page 3
    Insects attacking tobacco
        Page 3
        Page 4
        Page 5
        Page 6
        Budworms
            Page 7
            Page 8
            Page 9
        Green peach aphid
            Page 10
            Page 11
            Page 12
        Cutworms
            Page 13
        Grasshoppers
            Page 14
            Page 15
        Stink bugs
            Page 16
        Wireworms
            Page 17
            Page 18
        Mole crickets
            Page 19
            Page 20
        Tobacco splitworm
            Page 21
        Four-spotted tree cricket
            Page 22
        Suckfly
            Page 22
    Natural enemies of tobacco pests
        Page 23
        Paper wasps
            Page 23
        Red-tail wasps
            Page 24
        Hornworm apanteles
            Page 25
            Page 26
        Predaceous spiders
            Page 27
        Skunks
            Page 27
    Control recommendations
        Page 27
        Control in the plant bed
            Page 28
        Control in newly set plants
            Page 29
            Page 30
        Control on plants developing in the field
            Page 31
    Phytotoxicity and leaf scorch
        Page 31
        Page 32
    Acknowledgement
        Page 33
    Reference
        Page 34
Full Text



Bulletin 573


May 1956


UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATIONS
JOSEPH R. BECKENBACH, Director
GAINESVILLE, FLORIDA






Insect Pests of Flue-Cured Tobacco and

Their Control

L. C. KUITERT and A. N. TISSOT


Fig. 1.-Tobacco hornworm. (Almost 11/2 times natural size.)


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

















CONTENTS
PAGE

INTRODUCTION ........................................ ......... ...... .. .. 3
INSECTS ATTACKING TOBACCO .................. .................... .. .... 3
Hornworms ..................................... .. ................. 3
Budworms ................................. ........ ..... ........-. 7
Green Peach Aphid .................. ...... .. ..... .. ........ .......... 10
Cutworms .......................------........... ...... ......... 13
Grasshoppers ............................... ......... ......... .... .......... 14
Stink Bugs ................................... ...... .......... .......16
Wireworms .............................................. ................. 17
M ole Crickets ................................................................ ...... ...... 19
Tobacco Splitworm .......................................... ............... ........ 21
Four-spotted Tree Cricket .............................. ....... ........... 22
Suckfly .......... ................. ...................... ..... ....... ........... 22
NATURAL ENEMIES OF TOBACCO PESTS .........................---...---------.... 23
Paper W asps ................... ... ..... .............. ........... 23
Red-tail W asps ........ ............. ........ ... .......................... 24
Hornworm Apanteles ................................. .. ........... ........ 25
Predaceous Spiders .......... ............. .............. ... ... ....... ............. 27
Skunks .......... .............. ... .. ..... ....................... 27
CONTROL RECOMMENDATIONS ................................. .... ..... .........- 27
Control in the Plant Bed ........................................-....... 28
Control in Newly Set Plants .................................. ..------...... 29
Control on Plants Developing in the Field ................................. 31
PHYTOTOXICITY AND LEAF SCORCH ................................... ................ 31
ACKNOWLEDGMENTS ..................................... .. --------......... 33
REFERENCES ..................... .... ........................ ....... ..- ........- 34










Insect Pests of Flue-Cured Tobacco and Their Control

L. C. KUITERT and A. N. TISSOT
Entomologist and Head, Entomology Department, Florida
Agricultural Experiment Station

INTRODUCTION
Flue-cured tobacco is one of the important sources of cash in-
come in northern Florida, where more than 20 thousand acres
are devoted to the crop. The 1955 production of nearly 27 million
pounds brought growers a return in excess of 12 million dollars.
Tobacco is an exacting crop and both practical and technical in-
formation are needed to produce it successfully. Like all other
cultivated crops, tobacco is subject to attack by a variety of insect
pests. Florida's mild and humid climate is especially favorable
for insect development, so it is not at all surprising that these
pests present one of the tobacco grower's most troublesome prob-
lems.
The control of tobacco insect pests has undergone revolutionary
changes during the past decade. Before that time growers used
baits and dusts containing Paris green and other arsenicals or
resorted to hand picking to destroy the insect pests. These
methods were laborious and sometimes ineffective and the in-
secticides themselves were likely to injure the plants. The new
synthetic insecticides have changed the picture completely.
Growers now have effective weapons for use against tobacco in-
sects and when these are properly applied the pests can be con-
trolled more satisfactorily than ever before.
This bulletin reviews briefly the life history and habits of the
more common insects that attack flue-cured tobacco. Short de-
scriptions are included to enable growers to identify the pests on
their crops so that proper control measures can be applied. Much
of the information on the insects was obtained from personal ob-
servations and study. The control recommendations are based
almost entirely on experimental work carried on cooperatively by
the Departments of Entomology and Agronomy at the Main Ex-
periment Station in Gainesville.

INSECTS ATTACKING TOBACCO
HORNWORMS
Appearance.-Two species of hornworms are associated with
tobacco, though one of them, the tomato hornworm, is of minor










Insect Pests of Flue-Cured Tobacco and Their Control

L. C. KUITERT and A. N. TISSOT
Entomologist and Head, Entomology Department, Florida
Agricultural Experiment Station

INTRODUCTION
Flue-cured tobacco is one of the important sources of cash in-
come in northern Florida, where more than 20 thousand acres
are devoted to the crop. The 1955 production of nearly 27 million
pounds brought growers a return in excess of 12 million dollars.
Tobacco is an exacting crop and both practical and technical in-
formation are needed to produce it successfully. Like all other
cultivated crops, tobacco is subject to attack by a variety of insect
pests. Florida's mild and humid climate is especially favorable
for insect development, so it is not at all surprising that these
pests present one of the tobacco grower's most troublesome prob-
lems.
The control of tobacco insect pests has undergone revolutionary
changes during the past decade. Before that time growers used
baits and dusts containing Paris green and other arsenicals or
resorted to hand picking to destroy the insect pests. These
methods were laborious and sometimes ineffective and the in-
secticides themselves were likely to injure the plants. The new
synthetic insecticides have changed the picture completely.
Growers now have effective weapons for use against tobacco in-
sects and when these are properly applied the pests can be con-
trolled more satisfactorily than ever before.
This bulletin reviews briefly the life history and habits of the
more common insects that attack flue-cured tobacco. Short de-
scriptions are included to enable growers to identify the pests on
their crops so that proper control measures can be applied. Much
of the information on the insects was obtained from personal ob-
servations and study. The control recommendations are based
almost entirely on experimental work carried on cooperatively by
the Departments of Entomology and Agronomy at the Main Ex-
periment Station in Gainesville.

INSECTS ATTACKING TOBACCO
HORNWORMS
Appearance.-Two species of hornworms are associated with
tobacco, though one of them, the tomato hornworm, is of minor







Florida Agricultural Experiment Stations


importance in the flue-cured area of Florida. The tobacco horn-
worm, Protoparce sexta (Johan.) (Fig. 1), is cylindrical and
more than three inches in length when full grown. The larva or
worm has chewing mouth parts, three pairs of true legs on the
front portion of the body and five pairs of prolegs on the ab-
dominal segments. There is a prominent curved horn, red in
color, at the posterior end of the body. Newly hatched larvae
are almost white and become light green soon after they begin
to eat. The mature larvae usually are green, although some
individuals may be brownish to almost black. There are seven
diagonal black and white stripes on each side of the body of the
older larvae. The mature larva burrows three to seven inches
into the soil and constructs an earthern cell where it then enters
the pupal or resting stage.












Fig. 2.-Tobacco hornworm pupa-resting stage. (Twice natural size.)


Fig. 3.-Adult or moth of the tobacco hornworm. (About natural size.)






Insect Pests of Flue-Cured Tobacco


The pupa (Fig. 2) is about two inches long, is reddish brown
in color and has a slender sheath enclosing the mouth parts which
appears much as the handle of a pitcher.
The adult is a large grayish brown moth (Fig. 3). The moth
has a wing spread of three to five inches. There are six orange
spots on each side of
the abdomen. They
are largest on the
front part of the ab-
domen and become
progressively smaller
toward the tip. The
moth is active at
night and remains
concealed during the
daytime. Occasion-
ally the moth is ob-
served in some pro-
tected place on tobac-
co during the day. A
single female lays
about 300 eggs, al-
though some individ-
uals may lay more
than a thousand. The
eggs are laid at night
and have a green-
ish pearl-like lustre
which changes with
age to almost white.
The eggs (Fig. 4)
are almost spherical
and have a smooth
surface. They are Fig. 4.-Eggs of the tobacco hornworm. (About
about 1/15 to 1/20 twice natural size.)
inch in diameter.
Life History.-The eggs are laid singly, usually on the under
side of the leaf. The eggs hatch in three to six days, de-
pending on the temperature. The newly hatched larva begins
feeding immediately. After feeding for three or four days the
larva sheds its skin or molts and in the process increases greatly
in size. It feeds for several days and again molts. The larva
repeats this procedure until it has undergone 5 molts or increases







Florida Agricultural Experiment Stations


Fig. 5.-Tobacco budworm. (About 11/ times natural size.)


Fig. 6.-Adult or moth of the tobacco budworm. (About 3 times
natural size.)







Insect Pests of Flue-Cured Tobacco


in size. The stage between molts is called an instar. About
25 to 30 days are spent in the larval or caterpillar stage. The
full grown larva then burrows into the soil, pupates and trans-
forms to the adult moth. There is considerable variation in time
spent in the pupal or resting stage; however, two to three weeks
usually are required during the summer. After this interval the
adult moth emerges, feeds on the nectar of various flowers for a
few days, mates and begins to lay eggs.
Damage.-Hornworms rarely cause severe damage in plant
beds because the bed is usually covered with a cloth which ex-
cludes the moths. Eggs have been observed shortly after the
tobacco is set and the newly hatched larvae soon appear. Only
a small amount of tobacco leaf is eaten during the first three or
four larval instars. However, it has been reported that about
three square feet of leaf surface may be eaten during the last
instar. Plants may be almost completely defoliated when three
or four larvae are present at the same time. They do not con-
sume the midrib portion of the leaf.

BUDWORMS
Tobacco frequently is attacked by the tobacco budworm, Helio-
this virescens (F.), and the corn earworm, Heliothis zea (Bod-
die). They are similar in body appearance and the grower does
not need to differentiate between them for control purposes.
The corn earworm seldom becomes a pest until late in the season
when the plants begin to flower and set seed.
Appearance.-The tobacco budworm (Fig. 5) is almost 11/2
inches in length when full grown. It is usually a pale greenish
color but may vary from light green to yellowish or reddish
brown. It is marked with pale longitudinal stripes on the top
and a wide dark stripe on each side. The pupa is reddish
brown and about 3/4 inch in length. The adult is a moth (Fig. 6)
having a wing spread of about 11/4 inches. The forewings are
a greenish color and each bears three dark brown oblique bands.
The moth is active only at night but is frequently observed
resting in the bud or on the lower sides of the leaves during the
day. The eggs are whitish, spherical, and only about 1/50 inch
in diameter (Fig. 7).
Life History.-The adult moth lays eggs singly on the bud or
on the under side of new leaves. During hot weather the eggs
hatch in three to five days. The larva completes its development
in 18 to 31 days and enters the soil to pupate. The pupal or







8 Florida Agricultural Experiment Stations

resting stage requires 12 to 18 days. The adult moth emerges
from the pupa to continue the cycle. There are usually three
generations or broods a year and occasionally a fourth may oc-
cur.


Fig. 7.-Budworm eggs on flower buds. (Almost 3 times natural size.)







Insect Pests of Flue-Cured Tobacco


Damage.-Only the larval stage injures the tobacco plant.
Larval feeding in the bud causes unsightly holes to develop as
the leaves expand. Some leaves become distorted when the
larvae feed on the tips of the developing bud leaves. The newly
hatched larvae feed on the surface of the leaf and seldom eat
entirely through the leaf. This feeding does not cause any ap-


Fig. 8.-Severe budworm injury to tobacco.


- -17~.r.







Florida Agricultural Experiment Stations


preciable damage. The growing larvae soon find their way to
the bud. As the larvae increase in size their appetites increase
immensely and they become very destructive. Older larvae often
feed on mature foliage, consuming large areas of leaf surface
(Fig. 8). Damage by the corn earworm usually occurs late in
the season when the plants are maturing. Most of the larval
feeding occurs in the flowers and seed pods, though they some-
times eat the foliage. The older larvae often bore into the stalks,
and cause them to break.

GREEN PEACH APHID
The green peach aphid, Myzus persicae (Sulz.) (Fig. 9), has
been in Florida a long time. It was reported on various vege-
table crops 60 years ago and it likely infested tobacco in small
numbers from time to time. The aphid was of no economic im-
portance on tobacco until 1946, when it caused severe injury to
shade tobacco in Gadsden and Madison counties. The following
year it caused widespread damage to flue-cured tobacco in Flor-
ida and in that same year it appeared in all tobacco growing
areas from Cuba to Connecticut. It has been more or less
troublesome since then and there still is no explanation why
the insect suddenly became a pest of tobacco.
Appearance.-Aphids are tiny, pear-shaped, soft-bodied, suck-
ing insects often referred to as "lice" by growers. They live in
colonies that may contain thousands of individuals of all sizes
and ages. Most of the aphids are wingless but a few winged
individuals may be found, especially late in the season. The
adult wingless aphids are about 1/8 inch long and pale green in
color. The winged individuals are somewhat smaller and darker.
Life History.-The green peach aphid has been found on some
75 different host plants in Florida. These include most of our
common cultivated crops as well as many weeds and other wild
plants. The mild winters in Florida permit the aphids to re-
main active throughout the year, although development and re-
production are retarded during the cool months. With the com-
ing of warmer weather in spring the aphids become more numer-
ous and active and some make their way to tobacco plant beds.
Unlike most insects, aphids do not lay eggs on tobacco but
give birth to living young. Another perculiarity of their repro-
duction is that all individuals are females and the young are
produced parthenogenetically, that is, without mating. When
conditions are favorable for development they multiply with great
rapidity. An aphid may begin to produce young when less than







Insect Pests of Flue-Cured Tobacco


Fig. 9.-Green peach aphid infestation. (About 2 times natural size.)







Florida Agricultural Experiment Stations


a week old and may give birth to five or six young a day for a
period of two or three weeks. Several generations can develop
during the growth of the tobacco crop and individuals of two
or more generations may be present on the same leaf.
Damage.-Aphids that enter tobacco plant beds begin to re-
produce and multiply there. If infested plants are transplanted
to the field the aphids continue to develop on them and soon
spread to neighboring plants. Other field infestations may start
with winged aphids which go to the tobacco from other host
plants in the area. Aphids suck the sap from tender leaves and
heavy infestations may stunt the plants. They are most in-
jurious during dry weather when they cause a noticeable wilting
and yellowing of the plants. In addition to the direct injury
from their feeding, aphids excrete a sticky liquid called honey-
dew. This collects on the upper surface of the leaves and makes
an excellent medium for the growth of a black fungus called
sooty mold. Tobacco from heavily infested plants and especially
that coated with honeydew and sooty mold is quite worthless.

Fig. 10.-Cutworms and typical injury. (About 1/ natural size).









I a







Insect Pests of Flue-Cured Tobacco


CUTWORMS
Appearance.-Cutworms, as the name suggests, are cater-
pillars which have the habit of cutting off tender plants near the
surface of the ground. Under certain conditions they are present
in sufficient numbers to cause severe damage. Although two or
more species attack tobacco, they are very much alike in ap-
pearance and habits and only the more common form attacking
tobacco will be discussed. The granulate cutworm, Feltia sub-
terranea (F.) (Fig. 10), is brownish in color, cylindrical and
about 1 to 11/ inches in length when full grown. The pupa is
brownish or dull reddish in color and about % inch in length.
The pupal stage is rarely observed. The adult is an incon-
spicuous brownish-gray moth. The fore wings are marked with
dark and white spots. The eggs are very small and are laid in
clusters of 100 or more.
Life History.-The life of these insects is divided into four
stages:- the egg, the destructive caterpillar or larva, the pupa
or resting stage, and the adult. In Florida, the moths are active


Fig. 11.-Tobacco stand much reduced by cutworms which
lupine field on left.


migrated from







Florida Agricultural Experiment Stations


and breed throughout the year, although activity is retarded
during the colder months.
The moth usually lays the eggs on the young plants in the
plant bed or on green vegetation in the field. Each female lays
several hundred eggs. The eggs hatch in two to six days during
summer but may require considerably more time during cool
weather. The larvae begin feeding immediately after hatching.
Most of the feeding is done at night and the larvae are found
coiled up just beneath the soil surface near the plant during the
day. After feeding for several days the caterpillar molts (sheds
its skin) and in the process increases greatly in size. The
larva passes through several different instars (periods between
molts) before finally entering the soil to pupate. About 30 days
are required for the larva to become mature. The larva con-
structs a small earthern cell about two inches below the sur-
face of the soil in which it transforms to the pupa or resting
stage. About 12 to 15 days are spent in the pupal stage during
which the insect transforms into the adult moth. After the
adult emerges from the soil, mating takes place and the female
is ready to lay eggs. There are five or possibly six generations
a year but these overlap and it is impossible to distinguish the
different generations.
Damage.-Cutworms damage tobacco by gnawing off young
plants near the surface of the ground and feeding on leaves that
lie near the ground. Injury is restricted to the plant bed and
newly transplanted plants. Sometimes damage is so severe that
entire fields must be replanted. Cutworms are general feeders
and they attack most vegetable crops as well as tobacco. They
are often most numerous when green cover crops, such as lupines
and oats, are turned under a short time before planting or when
the tobacco is adjacent to such fields (Fig. 11).

GRASSHOPPERS
Two species of grasshoppers frequently cause injury to flue-
cured tobacco. The Southern red-legged grasshopper, Melano-
plus femur-rubrum propinquus Scudder, is commonly a pest
of only young tobacco plants. The large American grasshopper,
Schistocerca americana (Drury), is usually troublesome only on
maturing tobacco. Both species have wings and are good fliers.
They go to the tobacco from surrounding areas. Extensive
damage by grasshoppers is not common in tobacco except dur-
ing seasons when grasshoppers are unusually numerous and the
supply of green herbage is short.







Insect Pests of Flue-Cured Tobacco


Appearance.-The red-legged grasshopper is about 1 inch in
length when full grown. The body is brownish red above and
greenish below. The long slender part of the hind legs is a deep
red color and has numerous black spines. The American or bird
grasshopper (Fig. 12) is one of our larger species. Measured
from head to tip of folded wings, the females are over 21V inches,
while the males are about 2 inches in length. The general body
color is a reddish-brown. A prominent light yellowish line on the
back extends from the head almost to tip of the wings.
Life History.-In general the processes of egg laying, hatch-
ing, and development are similar for both of these injurious
grasshoppers. The insects pass through three distinct forms
during their life: the egg; nymph or growing stage; and adult.
The female grasshopper feeds for several days to several weeks,
then mates and begins to lay eggs. The eggs are laid well be-
low the surface of the soil along fence rows, in idle fields or in
the open areas in lupine and peanut or other fields. The female
works her abdomen into the soil and then deposits the eggs in
the lower portion of the hole. While the eggs are being laid, a
sticky, frothy liquid is added which hardens as it dries. This
either forms a pod or aids in holding the eggs in a compact mass.
The number of eggs in each mass varies from 20 to 100 or more.

Fig. 12.-Immature American grasshoppers and typical feeding injury
on tobacco.







Florida Agricultural Experiment Stations


Each female lays from one to three egg masses. In general, the
bulk of the eggs hatch in April.
After the eggs hatch the young grasshoppers push to the sur-
face of the ground and begin feeding on the nearest vegetation.
Grasshoppers increase in size by molting. The young grass-
hopper grows a new elastic body wall beneath the old one. The
old body wall stretches and finally breaks open along the back
and the insect emerges. The newly molted grasshopper ex-
pands considerably before the body wall hardens. Usually six
such molts occur before the insect reaches the adult stage. The
American grasshopper has two generations a year while the red-
legged species has two and usually a partial third.
Damage.-Grasshoppers damage tobacco mainly by gnawing
and eating the leafy part of the plant. When grasshoppers are
abundant they may eat newly set plants to the ground so that
replanting becomes necessary. Sometimes they feed on the
midrib and cause it to break.

STINK BUGS
A few species of stink bugs are frequently observed on to-
bacco. However, they seldom occur in large numbers and for
this reason are rarely of economic importance. They usually

Fig. 13.-Brown stinkbug, Euschistus sp. (About twice natural size.)







Insect Pests of Flue-Cured Tobacco


migrate from other fields into the tobacco and are troublesome
only on large plants.
Appearance.-The brown stink bug, Euschistus sp. (Fig. 13),
is a rather large insect about 1/2 inch in length by 1/3 inch in
width. It is broadly oval, flattened and has a rough or pitted
surface. It is yellowish brown in color above and somewhat
lighter beneath. The nymphs are almost circular and wing-
less. The eggs are whitish and somewhat barrel-shaped.
Life History.-Stink bugs lay their eggs in neat rows in groups
of 10 to 30, usually on the lower side of the leaf. Each female
produces eggs for three to four weeks and may lay from 75
to more than 100 during her life. The eggs hatch in seven to
10 days during the summer. The young bugs remain in a clus-
ter for about five days. Stink bugs grow or increase in size by
molting. The young stink bug develops an elastic body wall be-
neath the old one. As the immature bug or nymph increases
in size, the old body wall stretches and finally breaks open along
the back and the insect emerges. The newly molted bug in-
creases considerably in size before the body wall hardens.
Usually six such molts, or increases in size, occur before the
insect becomes an adult. The interval between each two molts
is caller an instar. Approximately 50 days are required for the
insect to develop from the egg to the adult stage. There are
several generations a year, and the bugs are present the year
round in Florida.
Damage.-Stink bugs injure tobacco by inserting their beaks
into the plant tissue, especially into the midrib and large veins,
and sucking the sap. Leaves attacked by them often wilt badly
and sometimes turn brown as if scorched by the sun. Some
workers have reported that the wilting is caused by a poison
which the insect injects into the plant.

WIREWORMS
Wireworms (Fig. 14) are the destructive larval or immature
stage of click beetles. Pastures and uncultivated grassy areas
are favorite breeding places. When such infested areas are
planted to tobacco, wireworm injury to newly set plants usually
results. There are probably several species that attack tobacco.
However, their appearance, habits and life history are similar
and discussions will be limited to the tobacco wireworm, Conod-
erus sp.






Florida Agricultural Experiment Stations


Appearance.-The adult wireworm is a click beetle. It is
about 1/3 inch in length and the body is flattened, somewhat
tapered and extremely hard-shelled. This beetle is reddish
brown with some yellow markings on the back. The larva is
slender, cylindrical and about 3/4 inch long when full grown. It is
a shining yellowish brown color, smooth, and almost as tough
as a piece of leather. The pupa is reddish brown and about 1/2
inch in length.
Life History.-The insect passes through four distinct stages:
egg, larva, or immature stage, pupal or resting stage, and
adult. The female beetle lays the eggs in the upper part of the
soil around the base of grass and other plants. The eggs hatch in
several weeks. The tiny larva feeds for several days and de-
velops a new body wall beneath the old one. As feeding con-
tinues the old body wall stretches, breaks and the insect crawls
out (molts). The larva expands considerably in size before the
new body wall hardens. The insect grows and repeats this
process until it has molted five or six times. The larvae require

Fig. 14.-A wireworm feeding on corn. Wireworms attack tobacco in a
similar manner. (About 1% times natural size.)













AMc 7







Insect Pests of Flue-Cured Tobacco


from 10 weeks to a year or more to complete their development.
The full grown larva then makes a chamber in the soil and trans-
forms into the pupa or resting stage. About four to 12 days
are spent in the pupal stage before the adult emerges. There
is one generation a year.
Damage.-Wireworm injury is restricted to newly set plants.
The larger, older, woody plants are not as attractive as young,
tender ones. Damage varies from year to year and there is no
satisfactory way of predicting wireworm outbreaks. They feed
largely on tender roots but at times they bore into the stem
and tunnel through it. When injury is severe it necessitates
replanting to obtain a satisfactory stand. Usually these plants
mature later than the original ones and this is objectionable.
Plants which are not killed are usually stunted and this also con-
tributes to an uneven crop.

MOLE CRICKETS
.Appearance.-Mole crickets are common pests in the tobacco
plant bed and only rarely troublesome in the field. Two species
are involved; however, they may be considered together, since
their habits and appearance are- very similar. The Southern
mole cricket, Scapteriscus acletus R. & H., and the change, S.
vicinus Scudd. (Fig. 15), are the offenders. Mole crickets
are well adapted for burrowing in soil. Adults are about 11/2
inches in length and 3/8 inch in width and brownish in color.
The body is covered with short fine hairs and has a velvety ap-
pearance. The strong, shovel-like front legs serve to dig the
tunnel. The fore wings overlap and are shorter than the abdo-
men. The eggs are 1/ by 1/16 inch in size and are laid in
chambers in the soil. The immature stages are similar to but
smaller than the adult and do not have wings.
Life History.-Mole crickets are active throughout the year
in Florida. Each female lays 20 to 30 eggs in a chamber about
four to seven inches below the surface of the soil. Eggs are
laid from the latter part of March to the latter part of July, with
the peak occurring during May. The eggs hatch in about two
to five weeks. The incubation period decreases as the tempera-
ture increases. First hatch of eggs occurs during the latter
part of April, with the peak hatch occurring during the first
part of June.
The young nymph first feeds on eggs and other weaker
nymphs. As it feeds it develops an elastic body wall beneath






Florida Agricultural Experiment Stations


the old one. After two to three weeks the old body wall
stretches and the insect crawls out and expands considerably
before the new body wall hardens. Six or seven such increases
in size or molts occur before the insect becomes an adult. The
first adults begin to appear in September. Very little develop-
ment takes place after the onset of cold weather and those in-
dividuals which have not reached the adult stage pass the winter
in the immature or nymphal stage.


Fig. 15.-Two species of mole crickets common in seedbeds. (Changa,
left and Southern, right.) (Slightly enlarged.)

Damage.-The favorite habitat of mole crickets is moist loose
soil such as found in plant beds. Injury in the plant bed re-
sults from the burrowing activities just below the surface of
the soil. In the process of making the burrows the mole crickets
cut the roots and uproot the plants. Frequently many plants
are killed through such burrowing activities. In addition, the
loosened soil tends to dry out quickly and this not only injures
or kills the plants above ground but may prevent germination of
seed in the soil. Mole crickets feed largely on decomposing or-
ganic matter, although there are records of their chewing and
severing of both roots and stems of plants.


JL 111.1







Insect Pests of Flue-Cured Tobacco


TOBACCO SPLITWORM
Appearance.-The tobacco splitworm, Gnorimoschema oper-
culella (Zell.), is seldom abundant enough to be considered a
serious pest of flue-cured tobacco in Florida. It is often a serious
pest of potatoes and when found on potatoes is called the potato
tuber worm. The larva is small, being only about % to 1/ inch
when full grown. On hatching from the egg the larva is creamy
white with the head dark brown. The color varies from green-
ish to pink as the larva matures and just before pupation it takes
on a purplish cast. The brown pupa is small, being only 1/5 to
1/4 inch in length. The adult is a small, slender moth having a
wing spread of about % inch. The wings are dark grayish in
color and marked with yellowish streaks. The moth flies at
night and so is seldom observed. The eggs are oval and about
1/50 inch in length. They vary from almost white to yellowish
gray in color.
Life History.-The female moth appears in the spring and de-
posits eggs singly on the leaves. The eggs hatch in about four
to six days, depending on temperature. The larva is very active

Fig. 16.-Tobacco splitworm injury. (About natural size.)







Florida Agricultural Experiment Stations


and feeds as a leaf miner between the upper and lower leaf
surfaces. After feeding for a few days the caterpillar molts
(sheds its skin) and during the process increases greatly in
size. It passes through six larval instars (intervals between
molts) in about 15 to 18 days and then constructs a thin, loosely
woven but tough silken, cocoon in the rubbish and debris at or
near the base of the plant. The larva transforms into the pupa
or resting stage within this cocoon. After about six to nine
days the adult moth emerges. There are five generations a year
and possibly a sixth. The insect passes the winter in either the
pupal or adult stage.
Damage.-The larvae injure the leaves by mining between the
upper and lower surfaces. Usually, only older tobacco leaves are
damaged. Their feeding causes grayish, irregular blotches which
become brownish and very brittle. Much of this injured portion
drops out when the leaf is cured. Mined leaves also may become
distorted and misshapen (Fig. 16).

FOUR-SPOTTED TREE CRICKET
The four-spotted tree cricket, Oecanthus nigricornis quadri-
punctatus Reut., is closely related to the grasshoppers and is
sometimes called a long-horned grasshopper. The adult is
slender bodied and pale greenish-white in color. It is about
1/ inch in length, though the long legs make it appear much
larger. The antennae or feelers are slender and much longer
than the body. The adults migrate to tobacco from adjacent
shrubs and trees when the tobacco is about half grown. Their
habits and life history are similar to those of the grasshoppers,
with the exception of egg-laying. The eggs are laid singly in
the stems of various plants and in the midrib of the tobacco
leaf. For the most part they are active only at night.
Damage.-Both the immature and adult stages eat holes in the
leaf. Tree crickets also damage tobacco through their egg lay-
ing habits. They deposit their eggs in the midrib which weakens
the leaf and may cause it to break during high winds. They
are rarely numerous in fields that are treated regularly with
insecticides to control other pests.

SUCKFLY
The suckfly is a pest of minor importance in the Florida to-
bacco belt. It does not appear in the field until late in the season
and then only in limited number. The suckfly, Cyrtopeltis







Florida Agricultural Experiment Stations


and feeds as a leaf miner between the upper and lower leaf
surfaces. After feeding for a few days the caterpillar molts
(sheds its skin) and during the process increases greatly in
size. It passes through six larval instars (intervals between
molts) in about 15 to 18 days and then constructs a thin, loosely
woven but tough silken, cocoon in the rubbish and debris at or
near the base of the plant. The larva transforms into the pupa
or resting stage within this cocoon. After about six to nine
days the adult moth emerges. There are five generations a year
and possibly a sixth. The insect passes the winter in either the
pupal or adult stage.
Damage.-The larvae injure the leaves by mining between the
upper and lower surfaces. Usually, only older tobacco leaves are
damaged. Their feeding causes grayish, irregular blotches which
become brownish and very brittle. Much of this injured portion
drops out when the leaf is cured. Mined leaves also may become
distorted and misshapen (Fig. 16).

FOUR-SPOTTED TREE CRICKET
The four-spotted tree cricket, Oecanthus nigricornis quadri-
punctatus Reut., is closely related to the grasshoppers and is
sometimes called a long-horned grasshopper. The adult is
slender bodied and pale greenish-white in color. It is about
1/ inch in length, though the long legs make it appear much
larger. The antennae or feelers are slender and much longer
than the body. The adults migrate to tobacco from adjacent
shrubs and trees when the tobacco is about half grown. Their
habits and life history are similar to those of the grasshoppers,
with the exception of egg-laying. The eggs are laid singly in
the stems of various plants and in the midrib of the tobacco
leaf. For the most part they are active only at night.
Damage.-Both the immature and adult stages eat holes in the
leaf. Tree crickets also damage tobacco through their egg lay-
ing habits. They deposit their eggs in the midrib which weakens
the leaf and may cause it to break during high winds. They
are rarely numerous in fields that are treated regularly with
insecticides to control other pests.

SUCKFLY
The suckfly is a pest of minor importance in the Florida to-
bacco belt. It does not appear in the field until late in the season
and then only in limited number. The suckfly, Cyrtopeltis







Insect Pests of Flue-Cured Tobacco


minimus (Uhler), is a small grayish black bug about 1/7 inch
in length and has relatively long legs and antennae (feelers).
The head is black and there is a large round black spot near the
end of each front wing. They sometimes are mistaken for aphids
but are more slender and considerably more active. They are
usually found on the lower surface of the leaf.
Damage.-The suckfly is a sucking insect. It inserts its needle-
like mouth parts into the leaf and feeds on the sap. Heavily
infested leaves turn yellowish and take on a bleached appearance.
Such leaves are reduced in quality. In addition, the insects de-
posit small specks of excrement on the leaf which adds to the
poor appearance of the leaf.

NATURAL ENEMIES OF TOBACCO PESTS
Tobacco growers often are surprised at the rapidity with which
pests multiply in their fields. When one considers the repro-
ductive capacity of the insects, it is amazing that they are not
more destructive. The average female is capable of producing
hundreds of offspring. If even one-tenth of these reached ma-
turity it would be nearly impossible to produce a crop of to-
bacco. Fortunately, the pest insects are held in check by a
combination of factors referred to as natural control. These
include unfavorable weather conditions, diseases and such other
natural enemies as insects, spiders and some larger animals.
Insect predators and parasites are of considerably more im-
portance than is generally realized. Every stage of the pest in-
sects may be attacked by one or more of these natural enemies.
Usually, when serious outbreaks of insects occur it is because
natural control has failed to function normally. Fortunately the
parasites and predators do not appear to be greatly affected by
the insecticides used to control tobacco pests. The resulting
concentration of natural enemies on the few pests that escape
the insecticide reduces them still further and thus greatly ex-
tends the intervals between applications. A few of the more
important natural enemies of tobacco pests are discussed.

PAPER WASPS
Several species of large brown paper wasps, Polistes spp.
(Fig. 17), prey upon hornworms and budworms. Larvae of
various sizes are captured but the wasps seem to prefer those
about an inch long. When a wasp finds a worm it at once begins







Insect Pests of Flue-Cured Tobacco


minimus (Uhler), is a small grayish black bug about 1/7 inch
in length and has relatively long legs and antennae (feelers).
The head is black and there is a large round black spot near the
end of each front wing. They sometimes are mistaken for aphids
but are more slender and considerably more active. They are
usually found on the lower surface of the leaf.
Damage.-The suckfly is a sucking insect. It inserts its needle-
like mouth parts into the leaf and feeds on the sap. Heavily
infested leaves turn yellowish and take on a bleached appearance.
Such leaves are reduced in quality. In addition, the insects de-
posit small specks of excrement on the leaf which adds to the
poor appearance of the leaf.

NATURAL ENEMIES OF TOBACCO PESTS
Tobacco growers often are surprised at the rapidity with which
pests multiply in their fields. When one considers the repro-
ductive capacity of the insects, it is amazing that they are not
more destructive. The average female is capable of producing
hundreds of offspring. If even one-tenth of these reached ma-
turity it would be nearly impossible to produce a crop of to-
bacco. Fortunately, the pest insects are held in check by a
combination of factors referred to as natural control. These
include unfavorable weather conditions, diseases and such other
natural enemies as insects, spiders and some larger animals.
Insect predators and parasites are of considerably more im-
portance than is generally realized. Every stage of the pest in-
sects may be attacked by one or more of these natural enemies.
Usually, when serious outbreaks of insects occur it is because
natural control has failed to function normally. Fortunately the
parasites and predators do not appear to be greatly affected by
the insecticides used to control tobacco pests. The resulting
concentration of natural enemies on the few pests that escape
the insecticide reduces them still further and thus greatly ex-
tends the intervals between applications. A few of the more
important natural enemies of tobacco pests are discussed.

PAPER WASPS
Several species of large brown paper wasps, Polistes spp.
(Fig. 17), prey upon hornworms and budworms. Larvae of
various sizes are captured but the wasps seem to prefer those
about an inch long. When a wasp finds a worm it at once begins






Florida Agricultural Experiment Stations


to bite its prey and tear away the skin. The soft parts of the
worm are rolled into a ball which is carried to the nest and fed
to the wasp larvae. The closely related yellow jackets have
similar food habits but they generally are much less numerous
in tobacco fields.


Fig. 17.-Paper Wasp, Polistes sp. (About 2 times natural size.)

RED-TAIL WASPS
Tobacco budworms are parasitized by a wasp-like insect (Fig.
18) with black wings and a bright red body. Growers often refer
to this insect, Cardiochiles nigriceps (Vier.), as the red-tail
wasp. These insects are seen in tobacco fields throughout the
crop season but usually become most numerous when the plants
begin to bloom. When the female wasp finds a small budworm
she lays an egg inside its body. A small legless larva or grub
develops from the egg and feeds inside the budworm. The
budworm usually enters the ground before it is fully grown and
it never completes its development. The wasp larva leaves the
body of its victim and pupates in the ground. A few weeks
later the adult emerges and begins to lay eggs in other bud-
worms. The parasite has a short life cycle and there are sev-
eral generations a year.





Insect Pests of Flue-Cured Tobacco


/


7 9


Fig. 18.-Red-tailed wasp,


Cardiochiles nigriceps (Vier.). (Nearly twice
natural size.)


HORNWORM APANTELES
Hornworm larvae occasionally are seen with large numbers of
small white cocoons (Fig 19) attached to their bodies. These
cocoons are made by a tiny wasp-like parasite, Apanteles congre-
gatus (Say.). The female parasite lays her eggs in the body
of a small hornworm. The eggs hatch in a few days and the
larvae feed inside the hornworm's body. About 10 days after
hatching the parasite larvae are fully grown. They emerge
through the skin of the host and spin their white cocoons on
its back. About a week later the adults emerge. These parasites
are so tiny that they seldom are noticed except in the pupal


~







Florida Agricultural Experiment Stations


Fig. 19.-Cocoons of a hornworm parasite, Apanteles congregatus (Say.).
(Slightly enlarged.)


Fig. 20.-Green spider, an important predator of small budworms and
hornworms. (About twice natural size.)







Insect Pests of Flue-Cured Tobacco


stage. The hornworms often remain alive after the parasites
have emerged but they never complete their life cycle.

PREDACEOUS SPIDERS
Spiders of various kinds are frequently found on tobacco
plants, where they feed on such insects as they can capture.
One of the most common spiders, Peucetia viridans Hentz (Fig.
20), feeds on tree crickets, suckflies and aphids, as well as small
hornworm and budworm larvae. This spider is rather large with
a greenish body marked with reddish spots and black spines on
its long slender legs.
SKUNKS
Not infrequently small funnel-shaped holes, from an inch to
three or four inches deep, are found in the soil of tobacco fields.
As these holes often are found near the base of plants the
grower may be concerned and believe that something is trying
to dig up the plants. Actually the holes are made by foraging
skunks that dig pupae of hornworms and budworms from the
soil and eat them. The skunks ;re especially active late in the
season and they thus destroy large numbers of overwintering
pupae. This helps to prevent the development of heavy initial
infestations in the spring.

CONTROL RECOMMENDATIONS
Tobacco is subject to attack by insect pests at any time from
the planting of the seedbed to the harvest of the mature leaves.
Some of the pests are troublesome through most of the crop
season, while others are destructive only during certain stages
of plant growth. The growth and management of flue-cured
tobacco makes it easy to divide the crop season into three phases
or stages, namely: (1) plant bed; (2) newly set plants; and (3)
plants developing in the field. For convenience, the various to-
bacco pests are discussed in about the same sequence as they
are likely to be encountered by growers during the development
of their crops.
The insect control recommendations given here are based on
results of experiments conducted during the past five years.
Most of the presently available insecticides, as well as a number
of other materials, were included in these trials. Some were found
to be quite useless, while others gave varying degrees of con-
trol. The materials recommended here were tested repeatedly







Insect Pests of Flue-Cured Tobacco


stage. The hornworms often remain alive after the parasites
have emerged but they never complete their life cycle.

PREDACEOUS SPIDERS
Spiders of various kinds are frequently found on tobacco
plants, where they feed on such insects as they can capture.
One of the most common spiders, Peucetia viridans Hentz (Fig.
20), feeds on tree crickets, suckflies and aphids, as well as small
hornworm and budworm larvae. This spider is rather large with
a greenish body marked with reddish spots and black spines on
its long slender legs.
SKUNKS
Not infrequently small funnel-shaped holes, from an inch to
three or four inches deep, are found in the soil of tobacco fields.
As these holes often are found near the base of plants the
grower may be concerned and believe that something is trying
to dig up the plants. Actually the holes are made by foraging
skunks that dig pupae of hornworms and budworms from the
soil and eat them. The skunks ;re especially active late in the
season and they thus destroy large numbers of overwintering
pupae. This helps to prevent the development of heavy initial
infestations in the spring.

CONTROL RECOMMENDATIONS
Tobacco is subject to attack by insect pests at any time from
the planting of the seedbed to the harvest of the mature leaves.
Some of the pests are troublesome through most of the crop
season, while others are destructive only during certain stages
of plant growth. The growth and management of flue-cured
tobacco makes it easy to divide the crop season into three phases
or stages, namely: (1) plant bed; (2) newly set plants; and (3)
plants developing in the field. For convenience, the various to-
bacco pests are discussed in about the same sequence as they
are likely to be encountered by growers during the development
of their crops.
The insect control recommendations given here are based on
results of experiments conducted during the past five years.
Most of the presently available insecticides, as well as a number
of other materials, were included in these trials. Some were found
to be quite useless, while others gave varying degrees of con-
trol. The materials recommended here were tested repeatedly







Insect Pests of Flue-Cured Tobacco


stage. The hornworms often remain alive after the parasites
have emerged but they never complete their life cycle.

PREDACEOUS SPIDERS
Spiders of various kinds are frequently found on tobacco
plants, where they feed on such insects as they can capture.
One of the most common spiders, Peucetia viridans Hentz (Fig.
20), feeds on tree crickets, suckflies and aphids, as well as small
hornworm and budworm larvae. This spider is rather large with
a greenish body marked with reddish spots and black spines on
its long slender legs.
SKUNKS
Not infrequently small funnel-shaped holes, from an inch to
three or four inches deep, are found in the soil of tobacco fields.
As these holes often are found near the base of plants the
grower may be concerned and believe that something is trying
to dig up the plants. Actually the holes are made by foraging
skunks that dig pupae of hornworms and budworms from the
soil and eat them. The skunks ;re especially active late in the
season and they thus destroy large numbers of overwintering
pupae. This helps to prevent the development of heavy initial
infestations in the spring.

CONTROL RECOMMENDATIONS
Tobacco is subject to attack by insect pests at any time from
the planting of the seedbed to the harvest of the mature leaves.
Some of the pests are troublesome through most of the crop
season, while others are destructive only during certain stages
of plant growth. The growth and management of flue-cured
tobacco makes it easy to divide the crop season into three phases
or stages, namely: (1) plant bed; (2) newly set plants; and (3)
plants developing in the field. For convenience, the various to-
bacco pests are discussed in about the same sequence as they
are likely to be encountered by growers during the development
of their crops.
The insect control recommendations given here are based on
results of experiments conducted during the past five years.
Most of the presently available insecticides, as well as a number
of other materials, were included in these trials. Some were found
to be quite useless, while others gave varying degrees of con-
trol. The materials recommended here were tested repeatedly







Florida Agricultural Experiment Stations


and all have proven their worth in tobacco insect control. They
can be depended upon for consistently satisfactory results if they
are used at the right times and properly applied.
Hand sprayers and dusters were used in most of the trials
but enough tests were made with power equipment to demon-
strate that good control can be obtained with either hand or
power tools. The various insecticides were applied as baits,
dusts or sprays. In some cases both wettable powder and emulsi-
fiable concentrate formulations of a material were used as sprays,
while in other cases only one type was tested.
In general, there is little variation in degree of control ob-
tained with the different formulations or the type of equip-
ment used to apply the insecticide. It is a great deal more im-
portant when and how the insecticides are used. One cannot
over-emphasize the necessity of making insecticide applications
at the proper time. It is equally important that correct amounts
of dusts or sprays be used and that distribution and coverage be
as thorough as possible.

CONTROL IN THE PLANT BED
Tobacco plant beds are made and planted in mid-winter when
insect activity is at a low level. The beds usually are covered
with a protective cloth which helps to exclude pests. It might
be expected that under these conditions insects would not be a
problem in plant beds, but such is not the case. As a matter of
fact, it sometimes is desirable to use an insecticide in a plant
bed even before the seed is planted.
Mole crickets and cutworms occasionally enter the beds from
adjoining areas. Other cutworms may develop in the plant bed
from eggs laid on the young plants by moths that enter through
holes in the cloth or by way of openings at the sides where the
cloth does not fit the frame closely. Aphids are small insects and
an occasional one may enter a plant bed by passing through a
loosely woven cloth cover. However, a well fitted cover in good
condition will help materially to keep them out. Succulent green
vegetation usually is scant in winter, so the tender tobacco
plants are attractive to grasshoppers. The bed is safe from
grasshoppers as long as it is well covered but growers should be
on guard when the cloth is removed to harden the plants prepara-
tory to transplanting.
Examine beds carefully for insects or insect damage as soon
as the plants come up and at frequent intervals afterwards.
Apply insecticides as needed. Aphids, hornworms, budworms







Insect Pests of Flue-Cured Tobacco


and certain cutworms can be controlled by treating the bed with
a dust containing 1 percent parathion and 5 percent TDE. Apply
the insecticide at the rate of 1 pound per 100 square yards of
bed. The same insects can be controlled with a spray contain-
ing one of the combinations shown in Table 1. Dust applica-
tions can be made through the cloth cover as sometimes is done
for blue mold control, though better results will usually follow
if the cloth is removed before treatment. The cloth must always
be removed before spray applications are made.

TABLE 1.-SPRAYS FOR PLANT BED INSECTS.

Insecticide Amount to use per
I 25 gallons of water*
TDE 50% wettable powder ..................... ..... 1/2 pound (2 cupfuls)
or
TDE 25% emulsifiable concentrate ............... %- / pint (1 cupful)
plus one of the following
Parathion 15% wettable powder ...................... I pound (2 cupfuls)
or
Malathion 25% wettable powder .......................... 1 pound (4 cupfuls)
or
TEPP 40% liquid concentrate _........................... 1/ pint (% cupful)

Apply the spray at 3 to 5 gallons per 100 square yards of bed.

Mole crickets, cutworms and grasshoppers may be held in
check by the above treatments but they can be controlled more
effectively with a poison bait. Ready-prepared baits containing
2 percent chlordane are available at many insecticide and seed
stores. As relatively small amounts of bait are needed for seed-
bed treatment, a commercially prepared bait generally is pre-
ferred. However, a satisfactory bait can be made by thoroughly
mixing 2 pounds of 40 or 50 percent chlordane wettable powder
with 50 pounds of corn meal, cottonseed meal or wheat bran.
Moisten the mixture slightly with water before using. Broad-
cast the bait over areas where insects are seen or their damage
noted. Keep the bait off the plants in so far as possible. Use 1
to 1 pound per 100 square yards of bed. To prevent other in-
sects from entering and to provide longer protection, make a
somewhat heavier bait application to a strip around the outside
border of the bed.

CONTROL IN NEWLY SET PLANTS
A good stand of plants of uniform size is always desirable in a
tobacco field. Replants used to replace missing plants seldom







Florida Agricultural Experiment Stations


catch up with the original planting. They often mature late and
this complicates the harvesting process and sometimes produces
leaf of inferior quality. Protecting the newly set plants from
insect pests helps to insure a good stand.
Cutworm damage is especially likely to occur when the land
is prepared only a short time before planting. Cutworms feed
on grasses and weeds and remain in the soil for some time
after the cover is turned under. The most effective way to
insure against cutworm damage is to make a bait application
before the plants are set. The bait used for plant beds is suit-
able for field applications, although any suitable cutworm bait
containing DDT, chlordane or aldrin can be used. Apply the
bait broadcast at the rate of 15 to 20 pounds per acre. If the field
is not treated before planting, cutworms may attack the newly
set plants. In that event, sprinkle the bait along the rows or
apply it lightly around each plant. This method of application
will require 5 to 10 pounds of bait per acre.
Wireworms generally are much less destructive to tobacco in
Florida than in other tobacco growing states. Nevertheless they
sometimes are troublesome and occasionally they seriously de-
plete a stand. If wireworms have injured tobacco in the past or
if they are known to be troublesome in the neighborhood, pre-
ventive measures should be taken. They may be effectively
controlled by adding a suitable insecticide to the transplant
water. Do not use more material than is recommended and
apply as nearly 200 gallons per acre as possible. Wettable pow-
ders of the insecticides generally are preferred, though liquid
concentrates usually give good results when used at comparable
rates. Be sure to keep the mixture well stirred to prevent the
insecticide from settling out. Add the indicated amount of one
of the following insecticides to each 50 gallons of transplant
water:
(a) Aldrin, 25 percent wettable powder--1/ pound (1 cupful).
(b) Chlordane, 40 or 50 percent wettable powder--14 pound (1
cupful).
(c) Heptachlor, 25 percent wettable powder--1/ pound (1 cup-
ful).
(d) Lindane, 25 percent wettable powder--1/ ounce (1 table-
spoonful).
Grasshoppers generally are most troublesome in tobacco fields
soon after the plants are set. If grasshoppers are present in







Insect Pests of Flue-Cured Tobacco


areas bordering the tobacco field, take measures to destroy them
before they attack the tobacco. Generally it will not be necessary
to treat large areas. A barrier strip 20 to 30 feet wide along
each threatened edge of the tobacco field usually will suffice.
Apply one of the following dusts at the rate of 15 to 20 pounds
per acre: (a) aldrin, 21/2 percent; (b) chlordane, 5 percent; (c)
endrin, 1 percent. If sprays are preferred, use either wettable
powder or liquid concentrate of one of the above insecticides.
Follow the manufacturer's directions for mixing the spray.
Aphids are not likely to bother newly set tobacco unless the
plants are taken from infested plant beds. To avoid this possi-
bility, treat the plant bed with 1 percent parathion dust a few
days before the plants are pulled. Apply the dust at the rate of
1 pound per 100 square yards of bed. If aphids are found on
young plants in the field they can be controlled with either 1
percent parathion dust or 5 percent malathion dust applied at 15
to 20 pounds per acre.

CONTROL ON PLANTS DEVELOPING IN THE FIELD
The important pests of growing tobacco are hornworms, bud-
worms and aphids. Others which occasionally cause damage
include grasshoppers, tree crickets, stink bugs and suckflies.
The insect problem varies from year to year and from field to
field. Under some conditions it may be possible to space insecti-
cide applications two or three weeks apart. In other cases when
adult insects are numerous it may be necessary to follow a
treatment with another in a week or 10 days. Careful, frequent
examination of the tobacco is needed to determine when insecti-
cides should be used. The control chart (Table 2) indicates
the kinds and amounts of insecticides to use against the various
pests. After the harvest season begins, do not make insecticide
applications less than five days before a priming and make them
only when necessary to control late infestations.

PHYTOTOXICITY AND LEAF SCORCH
Although tobacco is relatively tolerant of applications of most
insecticides, plant injury sometimes occurs. Considerable care
should be used when applying insecticides to the plant bed.
Never apply these materials when the young plants are moist.
Avoid uneven application in so far as possible and never use
concentrations stronger than those recommended. Control the
amount of insecticide and use it with care to minimize the danger
of plant injury and to insure effective control.







Insect Pests of Flue-Cured Tobacco


areas bordering the tobacco field, take measures to destroy them
before they attack the tobacco. Generally it will not be necessary
to treat large areas. A barrier strip 20 to 30 feet wide along
each threatened edge of the tobacco field usually will suffice.
Apply one of the following dusts at the rate of 15 to 20 pounds
per acre: (a) aldrin, 21/2 percent; (b) chlordane, 5 percent; (c)
endrin, 1 percent. If sprays are preferred, use either wettable
powder or liquid concentrate of one of the above insecticides.
Follow the manufacturer's directions for mixing the spray.
Aphids are not likely to bother newly set tobacco unless the
plants are taken from infested plant beds. To avoid this possi-
bility, treat the plant bed with 1 percent parathion dust a few
days before the plants are pulled. Apply the dust at the rate of
1 pound per 100 square yards of bed. If aphids are found on
young plants in the field they can be controlled with either 1
percent parathion dust or 5 percent malathion dust applied at 15
to 20 pounds per acre.

CONTROL ON PLANTS DEVELOPING IN THE FIELD
The important pests of growing tobacco are hornworms, bud-
worms and aphids. Others which occasionally cause damage
include grasshoppers, tree crickets, stink bugs and suckflies.
The insect problem varies from year to year and from field to
field. Under some conditions it may be possible to space insecti-
cide applications two or three weeks apart. In other cases when
adult insects are numerous it may be necessary to follow a
treatment with another in a week or 10 days. Careful, frequent
examination of the tobacco is needed to determine when insecti-
cides should be used. The control chart (Table 2) indicates
the kinds and amounts of insecticides to use against the various
pests. After the harvest season begins, do not make insecticide
applications less than five days before a priming and make them
only when necessary to control late infestations.

PHYTOTOXICITY AND LEAF SCORCH
Although tobacco is relatively tolerant of applications of most
insecticides, plant injury sometimes occurs. Considerable care
should be used when applying insecticides to the plant bed.
Never apply these materials when the young plants are moist.
Avoid uneven application in so far as possible and never use
concentrations stronger than those recommended. Control the
amount of insecticide and use it with care to minimize the danger
of plant injury and to insure effective control.







TABLE 2.-INSECT CONTROL CHART.
Insect MaterialI Amount Remarks
Aphids (plant Parathion 1% dust 10 to 30 lbs. per acre I Apply as needed. For field applications
lice) or the amount of sprays and dusts used will
Parathion 15C/ wettable 1 lb. 15% or equivalent in vary with the size of the plants and equip-
or 100 gallons of water ment used. Apply as much as will be
Malathion 4 or 5% dust 10 to 30 lbs. per acre needed to give good coverage. Extreme
or caution should be used in handling TEPP
Malathion 25% 4 lbs. 25% in 100 gallons or parathion.
wettable powder of water
or Endrin is effective in keeping down aphids
Malathion 50% emulsifi- 2 pints in 100 gallons but is not effective in cleaning up well
able concentrate of water established infestations.
or
TEPP (40% liquid) Y2 pint 40% or equivalent
in 100 gallons of water |
Budworms and TDE 5% or DDT 5% or 15 to 30 lbs. per acre, de- Make applications when worms appear and
Hornworms Endrin 1 to 11/% dust pending upon size of plants repeat as needed.
or For budworms, direct nozzles into bud of
TDE 50% or DDT 50% 2 to 3 lbs. in enough water plant
wettable powder to cover an acre 10% TDE or DDT dusts will give better
or results against large hornworms than 5.%.
STDE 25% or DDT 25% 3 to 4 pints in enough Larger plants and larger worms require
emulsifiable concentrate water to cover an acre more insecticides than do smaller plants
or and smaller worms. Combination dusts
Endrin emulsifiable 1 to 2 pints in enough containing" 1% parathion and 5% or 10%
concentrate (1.6 lbs. water to cover an acre TDE will control most insects pests of
actual per gallon) tobacco.
Cutworms, Chlordane 1.5% bait 5 pounds per acre for hill Apply before setting plants in the field or
Mole Crickets placement immediately when damage is noticed.
15 to 20 lbs. per acre for
broadcast application _
Grasshoppers Endrin 1 to 11%% dust 15 to 30 lbs. per acre The amount varies with the size of plants.
Sor 1 to 2 pints in enough Parathion gives quick but temporary re-
Endrin emulsifiable water to cover an acre duction of grasshoppers. Endrin and Al-
Sconcentrate (1.6 lbs. drin give better and longer control.
Actual per gallon)
or
I Aldrin 2/2% dust 15 to 20 lbs per acre Aldrin sprays made from emulsifiable con-
centrate or wettable powder formulations
may be used.







Insect Pests of Flue-Cured Tobacco


Plant injury resulting from insecticide applications is rarely
observed in the field. In instances where injury was observed
it was restricted to the dust formulation. In some of these
cases the insecticide was applied at appreciably higher rates than
recommended. The dust treatments were applied early in the
morning while the air was calm and the plants moist with dew.
It is possible that the equipment used failed to function properly
in some instances.
There is a condition called "leaf scorch" which is very similar
to insecticide burn and is often mistaken for it by growers. In a
few instances both conditions were observed at the same time in
the same field. Undoubtedly when this condition appears shortly
after insecticides have been applied the grower is apt to blame
the insecticide. Leaf scorch usually occurs on lush growing
tobacco during hot, dry and windy weather. During such a
period the tobacco tends to wilt badly and certain leaves wrap
around the bud. The lower surfaces of such'leaves are usually
exposed to the sun and certain areas appear to be scalded. This
condition increases in intensity until the plants receive moisture
or cooler weather arrives.

ACKNOWLEDGMENTS
The authors wish to express their appreciation to a number of
persons and concerns who helped in various ways to make this
bulletin possible. Fred A. Clark, of the Agronomy Department,
supervised the planting, cultivating, harvesting and curing in the
pest control experiments. He also secured information on the
grades and market value of the cured leaf. F. A. Robinson. of
the Entomology Department, made many of the photographs
used as illustrations.
Insecticides used in the control tests included some experi-
mental materials not yet commercially available. Samples of
new products were supplied by the following manufacturers and
formulators: American Cyanamid Company; California Spray-
Chemical Corporation; Chemagro Corporation; Commercial Sol-
vents Corporation; Florida Agricultural Supply Company; Geary
Chemical Corporation; Geigy Agricultural Chemicals; Hercules
Powder Company; Julius Hyman and Company, Division Shell
Chemical Corporation; S. B. Penick and Company; Rohm and
Haas Company; and Velsicol Corporation.
The illustrations for Figs. 14 and 15 were taken from Bulletin
534 of the Florida Agricultural Experiment Stations.







Florida Agricultural Experiment Stations


Some of the information on the life history and behavior of the
insects was obtained from the publications listed below.

REFERENCES
1. ALLEN, NORMAN, et al. Tobacco wireworm control by adding an insecti-
cide to the transplanting water. S. C. Agr. Exp. Sta. Bul. 417.
1954.
2. BROGDON, JAMES E. Control of insect pests of flue-cured tobacco. Fla.
Agr. Ext. Ser. Cir. 129. 1955.
3. CHAMBERLIN, F. S., and A. H. MADDEN. Insect pests of cigar-type to-
baccos in the Southern districts. USDA Cir. 639. 1944.
4. KUITERT, L. C., and A. N. TISSOT. Control of budworms and hornworms
in flue-cured tobacco. The Fla. Ent. 32:4: 171-177. 1949.
5. MADDEN, A. H., and F. S. CHAMBERLIN. Biology of the tobacco horn-
worm in the Southern cigar-tobacco district. USDA Tech Bul. 896.
1945.
6. NETTLES, W. C., and J. M. LEWIS. Tobacco insects and diseases. Clem-
son Agr. Col.-USDA Bul. 109. 1954.
7. RABB, R. L., F. E. GUTHRIE, H. E. SCOTT and C. F. SMITH. Tobacco
insects of North Carolina and their natural enemies. N. C. Agr.
Exp. Sta. Bul. 394. 1955.




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