HORNWORMS on TOBACCO 
e how to control them 
Hornworms are found wherever tobacco is 
grown. They feed on the leaves of the growing 
plants, cutting holes that may be 3 or 4 inches 
across. They can destroy an entire crop if the 
grower takes no measures to control them. 
In the United States hornworms cause more 
WHAT THEY LOOK LIKE 
Hornworms are the caterpillars, or young of 
large, brownish-gray moths. 
The caterpillars are green (some are brown to 
black), and 3 to 4 inches long when full grown. 
They are called hornworms because of the con- 
spicuous hornlike appendage that is found at the 
end of the body. 
The tobacco hornworm has seven diagonal 
white stripes on each side of the body; the horn 
is curved and red. The tomato hornworm has 
eight V-shaped stripes on each side of the body; 
the horn is straight and black. 
HOW THEY DEVELOP 
The hornworms’ life stages are as follows: 
Egg, larva (caterpillar), pupa, and adult (moth). 
The female moth lays round, green eggs, prin- 
cipally on the undersides of tobacco leaves. The 
eges hatch in about 5 days. 
As soon as they are hatched, hornworms be- 
gin feeding on the leaves. They continue feed- 
ing 2 to 3 weeks. During this time, they molt, 
or shed their skin, 4 or 5 times. When full 
grown, the hornworms crawl to the ground, bur- 
row several inches into the soil, and construct 
cells, in which they transform into pupae. 
The pupae are dark-brown, jug shaped, and 
about 2 inches long. They are a familiar sight 
in a tobacco field when the soil is being plowed. 
The pupal, or resting, stage usually lasts 2 to 
4 weeks; then moths emerge from their pupal 
cases and make their way to the soil surface. 
The moths do not feed on tobacco leaves, but 
1 Protoparce sexta. 
°? Protoparce quinquemaculata. 
damage to tobacco than any other pest. The ~~ 
damage is estimated at $80 million annually. 
Two species of hornworms occur on tobacco— 
the tobacco hornworm’ and the tomato horn- 
worm. 
instead prefer to suck nectar from the flowers of 
jimsonweed and tobacco. Their feeding causes 
no damage to the plants. 
The insects pass the winter in the soil as 
pupae. In May or June, moths emerge and 
mate, and the females lay their eggs. 
Hornworms usually produce 1 to 4 generations 
a season; the number depends on latitude and 
weather. 
HOW TO CONTROL THEM 
You can control hornworms by following rec- 
ommended cultural practices, by handpicking, 
and by applying an insecticide to tobacco plants. 
Cultural practices and handpicking greatly re- 
duce the need for insecticides. 
Cultural Practices 
1. Immediately after harvest plow up or oth- 
erwise destroy all stalks remaining in the field. 
The suckers of these stalks furnish food for a 
large number of hornworms. This practice cuts 
down on insect breeding. 
2. Plow the. field in the fall. This practice 
kills overwintering pupae. The field may be 
seeded to rye or some other suitable cover crop 
after plowing. 
Handpicking 
The control of hornworms by handpicking is 
profitable and should be done whenever prac- 
ticable. 
Insecticides 
You can control hornworms on tobacco by 
applying endrin or TDE to infested plants. 
Either insecticide is available from dealers as 
dust, ready for use, or as emulsifiable concen- 
trates and wettable powders, which can be mixed 
with water ‘and applied as sprays. 
