Although gypsy moth larvae will feed on the foliage of hundreds of plant species, oaks and aspens are the typical hosts. In areas of very high population densities, trees may become completely defoliated. When combined with other biotic and abiotic stresses, this can lead to tree mortality. Researchers estimate that less than 20% of trees in northeastern forests will die as a direct result of gypsy moths, but tree mortality can become severe if gypsy moth populations are not managed. Another concern is the loss of economically or ecologically important oak species.
Over the last 100 years, management of gypsy moths has been studied intensely. Small mammals such as the white-footed mouse are the most important predators of the gypsy moth, and are introduced to manage small gypsy moth outbreaks. After its introduction, parasitoids of the gypsy moth from its native Eurasia were introduced to try and manage populations, but most of these introductions either failed or could not reach populations high enough to have a profound impact on gypsy moth populations. A nucleopolyhedrosis virus can control small outbreaks, and an entomopathogenic fungus was recently discovered that can cause considerable mortality in North American populations. Several million acres of forestland have been aerially sprayed with pesticides over the past twenty years to suppress gypsy moth populations.
Zack Lindsey
Robert Mills
Insect Biology & Diversity Fall 2003
