Malacosoma disstria (Lasiocampidae)

forest tent caterpillar

Adults:

Malacosoma disstria, the forest tent caterpillar, adult moth. Light yellow to yellow brown. Forewings are crossed with two lines with space in between often darker to form a band.


Larvae:

Malacosoma disstria larva (caterpillar). Dark brown with bluish head and blue to blue-black sides. Dorsal surface marked with whitish or yellowish keyhole shaped spots and patches of orange lines.


Damage:

Malacosoma disstria larvae feeding gregariously. Larvae feed without building a tent. Spin cocoons in trees in one or more webbed together leaves. (Note: The common tent building caterpillar around campus is probably the western tent caterpillar, Malacosoma californicum).


Principal Hosts:

Feeds on deciduous trees including members of the following genera: Populus, Salix, Alnus, Betula, Prunus, and Quercus.

Economic Importance:

In Canada, some outbreaks of this pest have persisted for 6 years and have been extremely widespread. In 1962 over 139,000 square miles of defoliation occurred in the four western provinces. However, reduced growth and some branch killing are the usually extent of damage.

References and Links:

EAG: 480-481; FC: 187, 189.

See HForest and JP17.

Additional Images of the Northern Tent Caterpillar, Malacosoma californicum pluviale:

Western tent caterpillar nest on branch end. Western tent caterpillar colony. Mature western tent caterpillar larvae. Western tent caterpillar egg masses. Nest of Malacosoma californicum, the Western Tent Caterpillar.


For more information about Malacosoma californicum pluviale, see HForest and JP17.