Tomato hornworms


Material Information

Tomato hornworms
Physical Description:
Benson, Mary F
United States -- Bureau of Entomology and Plant Quarantine
Bureau of Entomology and Plant Quarantine, U.S. Dept. of Agriculture ( Washington, D.C. )
Publication Date:

Record Information

Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 030255613
oclc - 86173760
System ID:

Full Text


a, Moth (or adult) with wings spread; b, egg; c, larva, dark form;
d, pupa (or resting stage); e, larva of the other species, light
form. (a about three-fourths natural size; b about 4 times
natural size; c, d, and e about one-half natural size.)

(See other side for life history and control)

Bureauof Ent.mnlov and Plant Quranine Picture Sheet No. 1
L'ntcJd Ste.t D.parmcnt r Agricultre cture e t o.


TOMATO ITORNWORMS 3 1262 09082 4839
( I',',,t,,p,',,e,' spp.)

Life 1History
The eggs of tomato hornworms are laid on the under side of the
leaves. These eggs hatch in from 6 to 8 days. The resulting larvae
feed on the leaves and sometimes on the fruits. The larva reaches
full growth in 3 or 4 weeks, during which time it passes through
five or six stages, or instars. The full-grown larva then burrows
several inches into the ground and changes to a pupa, or resting
stage. The pupa may remain in the soil all winter and transform
to the moth stage in the spring, or, if weather conditions are suit-
able, the moth may emerge from the pupa after the expiration of
from 2 to 4 weeks. In any event, the emerging moth makes its way
to the soil surface and deposits eggs on tomato plants for the next
brood of hornworms.


Hand-pick the hornworms from infested plants in gardens or
small fields.
There is no entirely satisfactory method for the control of to-
mato hornworms in large fields. Dusting the tomato plants with a
mixture composed of equal parts of calcium arsenate and hydrated
lime will prevent damage to some extent. The dust mixture should
be applied directly to all parts of the plants. The treatments should
begin early in the season and be repeated at weekly or 10-day inter-
vals until the earliest formed fruits on the plants are about half
Caution: Do not apply calcium arsenate, or any other insecticide
that may leave a harmful residue, to tomato plants after the earliest
formed fruits are approximately half grown, unless it is known defi-
nitely that washing or wiping will remove all harmful residues from
the fruit before it is marketed or consumed.

.Jun l""it7 I'. S. Government Printing Office
For sai1 ihy the ti i-'riiteliidenlt of Doculmenlts, Washington, D. C.-Price 5 cents