Prairie Tent Caterpillar Identification and Tent-Building Behavior
This colony-forming caterpillar builds silk tents in tree forks that expand as the colony grows, and infestations often go unnoticed until a tree is heavily defoliated.
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Host trees and identification
The prairie tent caterpillar (Malacosoma californicum lutescens) is mostly found on chokecherry, plum, willow, ash, poplar, and rose trees. Mature larvae reach 50 mm in length, most displaying a pale blue coloring with an interrupted white stripe bordered by two reddish-orange stripes along the back.
Eastern tent caterpillars are similar but differ by having a continuous white dorsal stripe and a dark head. Both species produce reddish-brown moths with two oblique whitish stripes on the forewings and a wingspan of 37 to 50 mm.
Life cycle and tent-building
Eggs hatch when new leaves emerge in spring. Larvae form colonies and construct silk tents around tree forks and branches, expanding the tent as the colony grows — infestations can eventually enclose entire branches or trees.
Prairie tent caterpillar adults emerge in late summer (August in Nebraska) and lay flat egg masses on twigs. Eastern tent caterpillar adults emerge in June and July instead. Both species produce one generation per year.
Damage and impact on tree health
Larvae skeletonize leaves outside their tents. Infestations are often spotty and go unrecognized until entire trees have been defoliated. Severely affected trees show reduced vigor and poor aesthetics, but they are rarely killed by tent caterpillar feeding alone.
