EPA has granted a request from the Mississippi Department of Agriculture for a Section 18 emergency exemption for the use of methoxyfenozide (Intrepid 2F) to control saltmarsh caterpillars, soybean loopers and armyworms in soybeans.

The emergency exemption, which is now in effect in Mississippi, expires Sept. 30, according to Lester Spell, Mississippi's commissioner of agriculture. “The effort made by producers to control populations of these pests will greatly be enhanced by the availability of this product,” he said.

Manufactured by Dow AgroSciences, Intrepid 2F mimics the action of a natural insect molting hormone and causes larvae to undergo a premature molt within hours of its ingestion. The product is effective against many species of lepidopteran larvae (caterpillars of scaled-wing insects) without harming lacewings, lady beetles, parasitic wasps and other beneficials.

Saltmarsh caterpillars are often called “woolybears” because they take on a characteristic “large, hairy” appearance as they eat plant leaves. Soybean loopers are small light green caterpillars that have a “looping” or measurement movement when they crawl. Armyworms are conspicuous by the stripes along the sides of bodies and distinguishing marks either on the sides or the head.

The pests are difficult to control because of their resistance to certain insecticides already in use, according to entomologists with Mississippi State University.

The state agriculture department has authority under Section 18 of the Federal Insecticide, Fungicide and Rodenticide Act to obtain an exemption from EPA for a nonlabeled use of a pesticide if significant losses of an agricultural commodity are likely and alternative, labeled products are not available or effective.

The department's Bureau of Plant Industry has responsibility for administration of the exemption. Growers can contact the Bureau toll-free at 888-257-1285 for more information.