Pest Corner

Insects are coming to life throughout Missouri and I am noticing the emergence of a native tree defoliator, the eastern tent caterpillar. Tent caterpillars build their tightly webbed tents in the crotch of various trees and shrubs, with their favorites being fruit trees such as wild cherry, plum, apple, and crabapple. They also feed on ornamental trees such as ash, birch, maple, oak, and poplar. These insects rest during the day within the tent, and crawl out of the tent at night to chew on leaves and possibly developing fruit. As each caterpillar leaves the nest, it will spin a strand of silk as it travels and it is assumed this helps the caterpillar find its way back to the nest. Tent caterpillars over-winter in shiny brown egg masses glued to twigs, and eggs usually emerge at about the same time as tree buds begin to break open. When abundant, tent caterpillars can destroy a substantial number of leaves, and can weaken a tree. Tent caterpillars are usually kept under control by natural enemies, which typically prevent tent caterpillar outbreaks from persisting long enough to cause serious damage. Tent caterpillar larvae and nests can easily be dislodged from trees and destroyed using a broom or heavy water spray. Once caterpillars are knocked off the tree or out of the nest, they usually cannot get back onto the tree and fall easy prey to ground feeding birds such as robins. If tent caterpillars are persistent from year to year, egg masses can be pruned out of the limbs in the fall, which reduces insect numbers the subsequent year.

For more information on web producing insects, refer to MU Extension Guide G7271
http://muextension.missouri.edu/explore/agguides/pests/g07271.htm.

Mary Kroening
KroeningM@missouri.edu