Effects of Bacillus thuringiensis kurstaki on the midgut cells of the Thaumetopoea pityocampa (Lepidoptera:Thaumetopoeidae) larvae

Ill EFFECTS OF BACILLUS THURINGIENSIS KURSTAKİ ON THE MIDGUT CELLS OF THE THAUMETOPOEA PITYOCAMPA (LEPIDOPTERA: THAUMETOPOEIDAE) LARVAE (M.Sc. Thesis) Meltem UZÜNHISARCIKLI GAZI UNIVERSITY INSTITUTE OF SCIENCE AND TECHNOLOGY June 2002 ABSTRACT In this study, the effects of Bacillus thuringiensis var. kurstaki, a microbial insecticide, on midgut epithelial cells of Thaumetopoea pityocampa (Lepidoptera: Thaumetopoeidae) larvae were studied. Fourth instar larvae foods are sprayed with 3 x 10s bacteria/ml. 1, 3, 6, 12, 24, 48, 60 hr and 4 days after bacterial treatment, midgut epithelial cells of T. pityocampa larvae were studied under transmission electron microscope as compared with control group. 1, 3 and 6 hr after bacterial treatment, no differences was detected in the structure of midgut epithelial cells when compared to control group. Swelling in mitochondria in certain epithelial cells and formation of vacuoles in their cytoplasm were noticed at 12 hr after treatment. A decrease in the number of microvilli, an increase in the number of vacuoles taking place in the cytoplasm and swelling in epithelial cells were detected at 24 hr after bacterial treatment. Melting in nucleoplasma and an increase in the number of autophagic vacuoles in the cytoplasm of epithelial cells were of considerably noticed at 48 hr after treatment. Swelling in - iJJ :asvok ıKeyword: Bacillus thuringiensis = Bacillus thuringiensis ; Elektron mikroskobu = Electron microscope ; Mikrobiyal insektisitler = Microbial insecticides ; Orta bağırsak = Midgut ; Çam keseböceği = Pine processionary moth