PMN Crop News Homepage   

Posted 16 May 2010. PMN Crop News.

Pesky Tent Caterpillars Emerging

Source: University of Missouri Press Release.

Columbia, Missouri (May 4, 2010)--This is the time of year when you might find your trees and shrubs under attack from the eastern tent caterpillar, a native defoliator, said a University of Missouri Extension horticulturist.


Fortunately, control of tent caterpillars is usually simple, and natural predators often curtail outbreaks before they can inflict severe damage, said Mary Kroening. However, heavy infestations can weaken a tree by destroying a substantial number of leaves.

Tent caterpillars build their tightly webbed tents in the crotch of various trees and shrubs. Their favorites are fruit trees such as wild cherry, plum, apple and crabapple, Kroening said.

They also feed on ornamental trees such as ash, birch, maple, oak and poplar. The insects rest during the day within the tent and crawl out at night to chew leaves and developing fruit. As each caterpillar leaves the nest, it will spin a strand of silk as it travels.

“Tent caterpillars overwinter in the shiny brown egg masses glued to twigs. The eggs usually hatch at about the same time as the tree buds begin to break open,” she said. The emerging larvae will crawl toward the trunk of the tree until they find a suitable site to form a tent.

You can easily dislodge and destroy larvae and nests using a broom or heavy water spray. Dislodged tent caterpillars usually cannot get back onto the tree and often will fall prey to robins and other ground-feeding birds.

If tent caterpillars persist from year to year, you can prune egg masses from the limbs in the fall.

Mary Kroening