Abstract:

Abstract：Based on historical data of pest observatory in Tiantai County, Zhejiang province from years 1969 to 2009, the key factors affected on rice brown planthopper (Nilaparvata lugens St?l) were analyzed using stepwise regression prediction. The results showed that the key factors affected the amount of the occurrence incidence of rice brown planthopper on the generation which caused the most damage on rice were mainly depended on the amount of incidence of brown planthopper from its last generation, the amount on behalf of the lamp luring from 2-3 generations, the amount of the incidence from rice field in early stage of rice growth. The stepwise regression formulas were calculated for different rice cropping systems at different month on rice growth seasons. On the double rice cropping system, the stepwise regression equation is Y1 =- 8.9742 - 0.2484X1 + 0.5705X3 - 0.4806X4 + 0.0309X9 + 0.24205X10 for the amount of incidence occurred in late September, and Y2 = 0.74638 + 0.3303X1 - 0.28X2 - 1.3136X3 + 1.7233X4 - 0.2762X10 + 0.7946X11 for the amount of incidence of brown planthopper occurred in late October. On the single rice cropping system, Y3 = 4.1037 + 0.64817X2 - 1.564X4 + 1.4128X6 + 0.1762X7 - 0.0238X8 + 0.0752X9 for the amount of incidence occurred in late August, and Y4 = 2.2717 + 0.3217X1 - 0.4132X2 + 0.3418X4 + 0.3458X5 + 0.6962X10 for the amount of incidence of brown planthopper occurred in late September. Stepwise regression equations can be used as the occurrence trend of short-term forecasting applications on rice brown planthopper. Appropriate adjustments should be considered during the production application process depending on rice varieties with insect resistance changes and indications of insecticide-resistance to change of control effect.