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FS ShieldForest Health Protection, Southern Region


Malscosoma americanum (F.)

Importance.- The eastern tent caterpillar is primarily an aesthetic problem and has little adverse effect on the host trees. Species of the genus Prunus are preferred hosts, with black cherry being the primary, uncultivated host.

Identifying the Insect. - Full-grown larvae are between 2 to 21/2 inches (50 to 65 mm) in length. Caterpillars have black heads, with long, light brown body hairs. The back has a light stripe, bordered on each side with yellowish-brown and black wavy lines. The sides are marked with blue and black spots. Moths have a wingspread of about 2 to 21/2 inches (50 to 65 mm) and are yellowish-brown, with two narrow, light lines across the front wings.


Larva. (Click for detail. JPG 34K).

Identifying the Injury. - The larvae construct a white web or tent in the crotch of a small branch. They consume the entire leaf, except the midrib.

Typical tent on cherry

Typical tent on cherry.
(Click for detail. JPG 31K).

Biology. - Overwintering eggs hatch about the time black cherry buds open in the spring. Young larvae begin to construct a tent and enlarge the structure as they grow. Full-grown larvae construct tough, silken cocoons. Moths emerge in early summer and lay eggs in shiny, dark brown masses around small twigs or branches of host trees.

Control. - Control is not normally necessary. Defoliated trees usually refoliate after being attacked. Chemicals can be used to protect fruit trees, or tents containing the caterpillars may be picked off and destroyed.