July 30, 2015
Oak, maples, alder, willow, poplar, apple, hawthorn, elm and linden. However, many plants, including some conifers, are eaten.
Look for larvae to hatch in late April to early May as Bradford pear or Amelanchier are blooming. Larval development takes about seven weeks. Females are creamy white with a wingspan of about 2 inches; males are brown with darker bands. Females cannot fly — they call in males with pheromones, mate, and lay eggs near their pupation sites. Egg masses are laid in July to August.
When using insecticides to manage gypsy moth, target young larvae. Although the caterpillars can be a nuisance, insecticide sprays are not necessary to protect trees if there is less than 30 percent defoliation.
Pheromone traps can be used to time the emergence and flight of adult male gypsy moths. Look for and destroy egg masses in late summer and fall. Gypsy moth has many natural enemies, including predators, parasitoids and pathogens. NPV (a virus), shown infecting the caterpillar in the photo, may cause a significant drop in populations within a couple of years of an outbreak.
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