Abstract: By mathematic statistics,the paper analyzed the relations between the occurrence degree,early dates of brown planthopper and climatic-biological factors in single late rice in Shanghai.The results showed that the occurrence of early dates significantly correlated with rainfall days from April 16 to 30 and average ridge position of sub-tropical high-pressure on 500 hPa layer from 110? to 150癊 of the last October,and their coefficients were -0 6307 and 0.4781,respectively.The occurrence degree related to mean minimum temperature from January 1 to February 10 and rainfall amount in July,and their coefficients were -0.5218 and 0.5203,respectively; while the coefficient for average ridge position of sub-tropical high-pressure on 500 hPa layer from 110? to 150癊 of last December was -0.5374.When El Nino appears strong in spring,brown planthopper occurrence in Shanghai single late rice will be serious during that exact year.When El Nino appears medium or plus in autumn,the occurrence situation will be serious during the following year.The analysis also showed that La Nina had no obvious relations with the occurrence degree.

Key words: Photosynthetic bacteria(PSB), Most probable number(MPN), Bacteria counting, Application effect