Gypsy moth caterpillars are nearing the end of their feeding period and are pupating to emerge as moths. Delta traps, orange-red or green triangular cardboard traps about 10 inches long and 4 inches per side, are being placed in Illinois by federal and state personnel. The traps are open at each end and sticky inside to capture any moth that flies in. The attractant is a synthetic compound that mimics the pheromone released by the female gypsy moth to attract the male. By collecting the males, it can be determined if gypsy moths are present and roughly how numerous they are.

Participating in a federal and state regulatory program, these personnel have trespassing rights to enter property and place the traps. They will remove the traps in July or August.