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GYPCHEK Fact Sheet

What is GYPCHEK and how is it made?

GYPCHEK is the registered trade name of a general use insecticide containing the gypsy moth nucleopolyhedrosis virus (NPV). It is registered for aerial or ground application to control gypsy moths. The current label requires that it only be applied to manage gypsy moth infestations in public pest control programs under USDA Forest Service sponsorship. It is not available to the general public.

GYPCHEK is manufactured under controlled laboratory conditions in which live gypsy moth caterpillars are infected with the NPV. After they die, the caterpillars are blended with water and the virus is filtered out and freeze-dried into a power. It takes about 500 to 1000 infected caterpillars to make enough GYPCHEK to treat one acre. The amount made each year is approximately 5000 to 7000 acres worth. This is a very labor intensive and costly process. Because of this, in 2019 the USDA Forest Service stopped the production of Gypchek.

How effective is it for controlling gypsy moth?

GYPCHEK can effectively reduce moderate to high gypsy moth populations. It takes 10 to 14 days for infected caterpillars to die, so GYPCHEK may not completely protect tree foliage in all cases.

How is GYPCHEK used?

GYPCHEK is mixed in with a water and molasses mixture that contains a powder tree extract that acts as a sunscreen, protecting the virus from ultraviolet light, and a sticker that helps the mixture adhere to the tree leaves.

The mixture is applied by aerial application equipment at the rate of ½ to 1 gallon per acre. Two separate applications applied approximately three days apart are required. GYPCHEK should be applied when the caterpillars are in the first or second instar stage, this is when they are most susceptible.

Is GYPCHEK safe?

The NPV component of GYPCHEK occurs naturally in the environment. It has no harmful effects on people or animals. GYPCHEK is very specific and only affects gypsy moth and will not affect other beneficial insects (including other caterpillars). This makes GYPCHEK a very desirable product to be used in areas where Threatened and Endangered (T&E) species are of great concern.