General Information
Common name: Hornworm
Scientific name:
Manduca spp.
Lepidoptera:Sphingidae
Synonyms: Tomato hornworm, Tobacco hornworm
Host plants
Tomato, pepper, eggplant, potato, tobacco, dill
Distribution
South and Central America, Asia, USA
Damage
Larvae are
defoliators, initially attacking the upper portion of plants and consuming foliage, blossoms and green fruits. They usually consume the entire leaf and are capable of high levels of defoliation. The highest
foliage consumption occurs during the final
instar because of its large size.
Description
Eggs are spherical to oval in shape and measure about 1.50 mm in diameter. The colors vary from light green to white. Eggs are deposited both on the lower and the upper surface of foliage.
The larva is cylindrical in form and bears five pairs of
prolegs in addition to three pairs of
thoracic legs. The larva has a thick pointed structure or horn located dorsally on the terminal abdominal segment. It is about 12 cm long. The tomato hornworm has a dark-green horn with black sides, while that of the tobacco hornworm is red. The white striping along their sides also differentiates the two caterpillars. The white striping form a V-series on tomato hornworms, while these are diagonal dashes on the tobacco hornworm. Larvae blend in with the foliage and are not easy detected. They cause considerable damage at the end of the larval period.
The pupa is large and elongate-oval in form, but pointed at the posterior end. It measures 45 to 60 mm in length. The pupa bears a pronounced maxillary loop, a structure in the upper jaw, which encases the mouthparts.
Adults of both species are large moths with stout, narrow wings. A moth has a wingspan of about 1 cm. The forewings
are much longer than the hind wings. Both species are dull-grayish or brown in color. The sides of the abdomen are usually marked with six orange-yellow spots in the tobacco hornworm and five spots in the tomato hornworm. The hind wings of both species bear alternating light and dark bands. Adults are known as
sphinx and hummingbird moths.
Important species
Cassava hornworm (
Erinnyis ello)
A newly hatched larva is pale green with a black horn and is about 6 mm long. The matured larva is whitish-green with yellowish body spots and more pronounced black and red spot on its abdominal segment. The thoracic-feet are pinkish, and thrice annulated with black. The abdominal feet are pale reddish with a black band and whitish
claspers. A larva can reach a length of 8-10 cm.
Larvae generally eat the younger leaves of cassava, often stripping growing shoots. In severe attacks, the whole plants and even entire plantations may be defoliated.
An adult female has pale-gray forewings while those of male are darker. Both hindwings are red with dark-gray marginal bands. The adults fly only at night time and tend to migrate in swarms. The females lay their eggs in masse.
Control measure
Hornworm baculovirus
Baculovirus erinnyis is a hornworm larva
virus. This virus is used to control cassava hornworm larvae in Brazil. The larvae are collected in the field, liquefied in blenders and mixed with water. The same mixture is then sprayed to the infested plants. Upon application, the virus can kill 90-100% hornworm larvae.