Tracking changes in the susceptibility of forest land infested with gypsy moth. Forest Service research paper (Final)

The report questions the forest land subject to intensive outbreaks of gypsy moth (Lymantria dispar L.) which become less susceptible to defoliation. A model for estimating the lifelihood of gypsy moth defoliation has been developed and validated. It was applied to forest-inventory plot data to quantity trends in the susceptibility of forest land in south-central Pennsylvania during a period of intensive infestation. Results show that even though susceptibility of the region's forest apparently has declined, the potential for future infestations remains relatively high.