If only a few small trees or shrubs are infested, picking the bags off by hand and disposing of them may provide satisfactory control. This approach is most effective during fall, winter, or early spring before the eggs contained in the bags have hatched.

The best time to apply an insecticide is while the larvae are still small (less than 1/2 inch long), usually in June, and most vulnerable to insecticides. Carefully inspect susceptible landscape plants, especially evergreens, for last year's bags. Young bagworms are harder to see; look closely for the small, upright bags, which have the appearance of tiny ice cream cones constructed of bits of plant material. Preventive treatment is often justified on plants that were heavily infested with bagworms the previous year.

Several products are available for homeowner and professional use. Contact your local Cooperative Extension office for insecticide recommendations.