Impact of Bacillus thuringiensis on Nontarget Lepidopteran Species in Broad-Leaved Forests

Bacillus thuringiensis variety kurstaki ( Btk ) is the only commercially produced biological insecticide available for use in suppression and eradication programs against the gypsy moth, Lymantria dispar (L.). There have been few multi-year laboratory and field studies designed specifically to evaluate the impacts of Btk on non-target native lepidopteran species. The susceptibility of lepidopteran larvae to Btk must often be evaluated on a species-by-species basis.