Effect of Temperature on the Development of the Nonage Stages of Sitophilus zeamais (Coleoptera) in Kunming

Sitophilus zeamais(Coleoptera) feed with corn was studied at constant temperatures of 16,20,24,28 and 32 ℃,in order to give a reference for prevent and control S.zeamais.The results showed that temperature had significant influence on the development duration of each nonage stage of the insect. The development period of eggs,larvae and pupae were shortened with the rise of temperature. The results were (131.901.14), (58.690.35), (37.470.26), (32.090.32) and (30.090.14)d. The development rate of each nonage stage was well fitted to Logistic curves. The threshold of development of eggs,larvae stage,pupae stage calculated by the regression straight line method were 11.14, 10.90, and 10.81 ℃,the effective accumulative temperature of all stages were 141.64, 294.23 and 149.73 ℃d. The regression equation of growth rate and temperature of nonage was:r=exp(0.20T)-exp7.10-(35.05-T)/5.07,while the threshold was 10.78 ℃ and the effective accumulative temperature was 571.16 ℃d. It is known from calculate that maize weevils occurs 5~6 generations in Kunming.