Effects of gamma radiation and Bacillus thuringiensis on F₁ progeny of Cydia pomonella

The codling moth [Cydia pomonella L. (Lepidoptera: Tortricidae)] is the main pest in most apple orchards in Syria. It causes billions of dollars in loss of fruit crops every year. The present work examined the effects of gamma radiation and Bacillus thuringiensis (BT) on F₁ progeny of C. pomonella. The experimental design was based on two factors, namely F₁ offspring produced by males irradiated at a dose of 150 Gy, and artificial diet of BT-treated larvae. The first offspring of unirradiated and irradiated C. pomonella males, F1, were from parents treated with a commercial formulation of Bacillus thuringiensis BT (Dipel^® 2X). F₁ progeny of unirradiated was significantly less susceptible to BT than that of irradiated parents. The results showed high mortality in F₁ progeny of C. pomonella when gamma radiation and BT were applied together. The LC₅₀ in F₁ progeny was 2.5 ppm for irradiated parents, while it was 13 ppm for unirradiated ones. A significant reduction in the fecundity and egg hatchability of F₁ progeny of irradiated parents compared to unirradiated ones was observed. This study demonstrated that for F₁ progeny the combination between Inherited Sterility Technique and BT can be useful to achieve an integrated pest management program of codling moth.