Physiological and histopathological effects of certain insecticidal agents on Bactrocera zonata (Diptera: Tephritidae).

Abstract

The toxicological, biochemical and histological effects of Malathion and Spinosad on the peach fruit fly B. zonata (Saunders) were investigated. The obtained results revealed that, Spinosad was more effective than Malathion against pupal and adult stages. However, the two tested insecticides caused obvious malformations in pupae after treatment by dipping. The adult stage was more susceptible than pupae to the effect of the two insecticides. Also, LC50 values of the tested compounds were higher in female than male adults. The treatment of lab insects with LC50 of Malathion and Spinosad for five generations produced 16 and 4 folds of resistance ratio.The two tested insecticides caused a significant depletion of total protein contents in the whole body tissues of all treated insects. High significant increase in the Glutathione-S-Transferase (GST) and Acetylcholinesterase (AchE) activities of treated adults. The treatment with the two insecticides caused disappearance and appearance of specific protein bands on polyacrylamide gel electrophoresis. Band No. 3 (M.W. 185.73 KDa ) was disappeared in all treated insects. Band No. 4 (M.W. 173.55 KDa) was specific to Spinosad treated females, Malathion and Spinosad treated and resistant males. Band No. 23 (M.W. 28.68 KDa) was specific to treated females and males. Bands No. 6 and 10 (M.W. 148.14 and 119.28KDa) was specific to treated males with Malathion. Histological studies of the Malathion and Spinosad on female ovary of B. zonata at intervals 1-, 2- and 3-weeks old of female life was studied. The results showed effective damage appeared in 1-week old and reached maximum damage in 3-weeks old. Also, the results revealed that the Spinosad had effective damage on female ovary than Malathion. Key words: Bactocera zonata, Toxicological studies, Electrophoratic separation of protein, Glutathione-S-Transferase, Acetylcholinesterase, Histological studies.