January - April: Remove and destroy egg masses
March - April: Treat egg masses with biologic oil
May - August: Manage gypsy moth caterpillars, pupae, and moth populations
Inspections - Ongoing
We need everyone’s help in detecting gypsy moth populations and keeping this insect from spreading to new neighborhoods. Failure to inspect household articles for gypsy moth life stages prior to movement from a regulated area is a violation of U.S. Department of Agriculture quarantine regulations and may result in significant civil penalties.
To be most effective in minimizing defoliation, Btk - Bacillus thuringiensis var. kurstaki (commonly found in soil and on plants) - is applied by aerial spraying when the caterpillars are less than 1 inch long. When caterpillars eat Btk the protein crystals dissolve in their digestive system and become toxic. Within 1 to 2 days they die.
As caterpillars get larger, the efficiency of Btk diminishes. Btk has a reported residual activity (i.e., how long it remains potent) of about 1 week and is broken down by sunlight. Btk is only known to be toxic to feeding caterpillars of moths and butterflies and is quite safe to humans, birds, fish, pets, beneficial insects and other non-target organisms.