EASTERN TENT CATERPILLAR

MEET THE PEST

Eastern tent caterpillars become a pest when they feed on deciduous trees and cause defoliation. They construct a tent of silk on one or more branches of a tree. The tent provides protection against weather conditions and predators. The caterpillars feed during the day, and at night, they return to the tent for protection.

The caterpillar is approximately 2 2 inches (6 1/4 cm) long, hairy and black with a cream coloured stripe down its back. Blue spots, as well as, brown and yellow lines can also be seen along the sides of the caterpillar's body.

LIFE CYCLE

The life cycle of the eastern tent caterpillar consists of egg, larva, pupa and adult stages. In June or July, the female adult, a reddish-brown moth, lays numerous eggs (up to 300) on a branch. The eggs are held together by a sticky substance, and the following spring when the leaves begin to unfold, the eggs hatch into the larval stage. It is the larval stage (caterpillar) of the life cycle which causes damage. In approximately five to seven weeks, the caterpillars reach maturity. In early July, the caterpillar spins a cocoon and pupates for two weeks. After emerging as an adult, it mates and lays eggs within a period of 24 hours. Only one generation of Eastern tent caterpillars is produced each year.

MONITORING

Monitor for eastern tent caterpillar presence at different times of the year. Check for cocoons during summer, silky tents during the spring and egg masses in fall and spring. If present, begin a control program using one or more of the following methods.

PHYSICAL

Begin control at night when groups of caterpillars will be gathered together inside a tent. Cut the tent open and hand pick the caterpillars. The removed caterpillars can be placed in a bucket of soapy water or crushed. This is most effective because large numbers can be removed at once.

Remove egg masses by scraping the clusters with a knife. Prune trees in late fall or early spring to keep populations low.

BIOLOGICAL

Some natural enemies of tent caterpillars are birds and rodents.

CHEMICAL

If physical and biological measures are not effective, use a pesticide which will have a minimal impact on both you and the environment. Apply a dormant oil in late winter to kill the eggs before they hatch. An insecticidal soap is another option for control of the eastern tent caterpillar.

If the above measures are not effective, consult with an expert at a garden center for pesticides available. Before using pesticides, consult the Backyard Bug Brigade Brochure which contains information on safe pest control. Open the tent and spray the pesticide directly on the caterpillars late in the day when they are gathered inside.

Always use a registered domestic class pest control product labelled for tent caterpillar control and carefully follow the label directions.