If they are, some species of hardwood trees could be at risk for defoliation in 2001. A newsletter published earlier this month by the state's Insect and Disease Laboratory notes that the population appears healthy. Charlene Donahue, an entomologist at the Hospital Street laboratory, said gypsy moth caterpillars in Maine have been devastated by a specific virus and a specific fungus. The last serious outbreaks of the leaf-eating caterpillars occurred in the early 1980s and early 1990s. The caterpillars, which are in the process of turning to moths now, prefer to feed on oak and poplar tree leaves.
Female moths are unable to fly because of the numerous eggs they carry.
Donahue said two types of traps are used to attract adult male moths. Pheromone, a hormonal substance, is the bait that lures the insects to the cardboard boxes. Even though no traps are set near the laboratory here, moths show up there because they can smell pheromone in and around the building, she added. Traps are placed in Kennebec County and other parts of Maine. Only scattered defoliation has been reported this year in southern and central Maine.