Catalpa Sphinx Caterpillar
Contact: Eric Day, Manager, Insect Identification Laboratory
Publication Number 444-247, August 1996
Catalpa Sphinx Caterpillar
Lepidoptera: Sphingidae, Ceratomia catalpae (Boisduval)
Plants Attacked
Catalpa only.
Description of Damage
Catalpa sphinx caterpillars are major defoliators of catalpa.
With their chewing mouthparts, they strip away large portions of
the leaves. In heavy infestations they can completely defoliate
the entire tree. Apparently trees on high ground with poor soil
are rarely, if ever, attacked. In some years, depending on the
region, many trees will have all their leaves stripped away by
the end of the summer. This may be followed by years with no
defoliation observed at all. The fluctuation between outbreak
and no defoliation is largely due to the activity of parasites.
Identification
Catalpa sphinx caterpillars have a distinctive black "horn" on
the end of their abdomen. Mature caterpillars have black heads
and a broad black stripe running the length of their back. The
sides of the caterpillars are white or pale yellow and sometimes
have black spots or vertical bands. There are pale forms that
are more greenish and in some cases will have a row of black
spots down the back or will lack the black stripe. The adult is
a brownish-gray sphinx moth. Eggs are laid in clusters of up to
1000 eggs on the underside of the leaves.
Life History
Catalpa sphinx overwinter as pupae in the soil and the adults
emerge in May and lay eggs on new leaves. Each caterpillar molts
five times; the final molt is into a pupa. There are two
generations in Virginia, but some years a partial third is seen.
The second generation is usually larger and in "good" years the
caterpillars can cause defoliation at the end of the summer.
Control
Although the caterpillars can cause complete defoliation, in some
instances control is usually not warranted because of the
sporadic fluctuations in the population from year to year and the
ability of the trees to grow new leaves. If control is desired,
follow the recommendations in Virginia Cooperative Extension
Publication 456-017, The Pest Management Guide for Horticultural
and Forest Crops.
Remarks
Catalpa sphinx caterpillars, "catalpa worms," make excellent fish
bait and at one time catalpas were grown in Florida in order to
harvest the worms and sell them to fishermen.
Prepared by: Eric Day and D. Ames Herbert, Department of
Entomology, Virginia Polytechnic Institute and State University,
Blacksburg, Virginia 24061-0319.