Histopathological Effects of Bacillus thuringiensis on Larvae of the Indianmeal Moth and the Almond Moth1, 2, 3

Abstract
Histopathological studies demonstrated that the midgut epithelium in larvae of both the Indianmeal moth, Plodia interpunctella (Hübner), and the almond moth, Ephestia cautella (Walker), was damaged within 1/2 to 1 h after they ingested spores and parasporal crystals of Bacillus thuringiensis Berliner subsp. kurstaki. Midgut epithelial cells progressively degenerated until the midgut was totally disrupted and the larvae died. Larval death preceded extensive septicemia, and thus, apparently was caused by the gut wall's loss of integrity.