Effect Of Heat Stress On Thermotolerance And Heteromorphosis Of Hind Wing In Insecticide-susceptible And-resistant Plutella Xylostella (L.)

The diamondback moth, Plutella xylostella (L.), is one of the most destructive pests of cruciferous vegetable and has been reported to produce serious resistance to organophosphates, pyrethroids, carbamates, acylurea insect growth regulators, Bacillus thuringiensis(Bt), antibiotics, etc. Thermotolerance and effect of heat-hardening during pupa on emergence and heteromorphosis of hind wing were studied in insecticide-susceptible and-resistant Plutella xylostella (L.) which selected by Beta cypermethrin in laboratory.Heat resistance of1-day-old insecticide-susceptible and-resistant adults was greatly elevated by a2h exposure to33.5℃or acclimation at33.5℃from larva to pupa. After heat shock at44.0℃, insecticide-susceptible and-resistant adult survival changed from48.9%to67.8%(hardening),87.8%(acclimation) and34.4%to57.8%(hardening),71.1%(acclimation), respectively. Besides, knockdown resistance was significant improved by acclimation, only71.1%and84.4%in insecticide-susceptible and-resistant adults were knockdown compared to100%in control or after hardening.Emergence rate was decreased by exposing1-day-old pupa to heat-hardening, especially the resistant pupa. After a16h exposure to40℃, the insecticide-susceptible and-resistant emergence rate was75.0%and53.9%, respectively, and both lower than60.0%by a48h exposure to38℃. Different temperature and times were decisive to the adult with abnormal wing and mutation types were observed in the hind wing.