Scientists at the Agricultural Research Service are looking to sabotage the love life of gypsy moths by using aircraft to “seed,” with tiny sex-attractant dispensers, the tree canopy where the insects mate.

The scientists want to disrupt mating to prevent caterpillar offspring, which are responsible for defoliating trees.

The air-dropped dispensers are little more than soft plastic beads or flakes less than three millimeters in size. They would be sprayed by aircraft as an insecticide-free defense against isolated or low-level gypsy moth infestations.

Held to tree leaves by a glue-like substance, the dispensers saturate the surrounding air with a synthetic version of the female moth’s chemical sex attractant or pheromone. This thwarts the males’ ability to home in on the real chemical beacon from females.

In the researchers’ studies, the pheromone applications prevented nearly 100 percent of the moths from mating. As a result, the number of fertile egg masses on pheromone-protected trees was cut by 75 to 100 percent compared to trees in untreated plots.

Scientists are studying various ways to distribute the dispensers for maximum effectiveness and ease of application from aircraft.

Originally from Europe, the gypsy moth attacks many species of trees in a region stretching from New England west to Michigan and south to North Carolina. It is the worst insect pest of trees in the eastern U.S.

Scientific contact: Kevin Thorpe, USDA-ARS Insect Biocontrol Laboratory, Beltsville, Md., phone (301) 504-5689