BOLLWORM 
( Heliothis armigera (Hbn.)) 
Life History 
The boll worm damages cotton wherever it is grown in the United 
States, but the losses are usually greatest in Texas, Oklahoma, and 
Louisiana. It also feeds on many plants besides cotton, especially corn 
and tomato, and is known as the corn earworm and the tomato fruit- 
wonn. Cotton is not the preferred food plant. Bollworm infestations 
usually develop rather late in the season, about the time corn silks are 
drying out and after dusting the boll weevil control has been completed. 
Each bollworm destroys a large number of squares and bolls, and when 
bollworms are numerous a crop of cotton can be ruined in a very short 
time. Damage o^ten occurs so late in the season that the plants do not 
have time to mature another crop of bolls. 
The bollworm moths prefer rapidly growing, succulent cotton in 
which to lay their eggs. The eggs are laid singly on the tender growth 
and newly formed squares. They are smaller than the head of an 
ordinary pin, and pearly white when first laid, but change to a dark color 
before hatching. The small larvae, or “worms,” feed for a few days 
on the tender buds or leaves and on the outside of squares before burrow- 
ing into squares or bolls, usually near the base. Large worms feed 
almost entirely inside the bolls, so that it is very difficult, if not im- 
possible, to control them. Full-grown larvae enter the soil and change 
to the pupal, or resting, stage. There are several broods a year. The 
last brood passes the winter in the underground pupal cells. 
Control 
When it is about time for bollworms to appear, examine the tops of the 
plants frequently for eggs and small worms. When 20 to 25 eggs that 
are beginning to hatch, or this number of eggs and very small worms, 
are found per 100 plants, it is time to begin dusting. Successful boll- 
worm control requires heavy applications of dust while the eggs are 
hatching and before the worms enter the bolls. 
At 5-day intervals apply 10 to 15 pounds per acre of a 10 percent DDT 
dust, a dust containing 5 percent of DDT plus sufficient benzene hexa- 
chloride to give 3 percent of the gamma isomer, or a 20 percent toxaphene 
dust. Calcium arsenate, lead arsenate, and cryolite are less effective. 
AVhenever the red spider must also be controlled, any mixture contain- 
ing organic insecticides should . include at least 40 percent of sulfur. 
Use more pounds per acre when the infestation is heavy and the plants 
are large. Two or three applications will usually control a brood of 
bollworms, but there may be more than one brood or a steady movement 
of egg-laying moths to cotton from other crops, with no distinct broods. 
In such cases several additional applications may be needed to keep the 
plants covered with insecticides to kill the newly hatched worms. Lady- 
bird beetles and other natural enemies or extremely hot, dry, windy 
weather often destroys enough eggs and young bollworms to control 
a threatening infestation without the use of insecticides. Nicotine or 
benzene liexachloride may be added to the insecticides to prevent aphids 
from becoming injurious. 
Caution. — Insecticides are poisonous and should be handled with 
care. Store in a dry place where children and animals will not have 
access to them. 
Revised April 1949 IT. S. Government Printing Office 
For sale by the Superintendent of Documents, Washington 25, I 
832050° — 49 
1. C. Price 5 Cents 
