Study On The Climatological Condition And The Risk Assessment Of Planthopper Disaster

This article studies the key factors and the key periods of meteorologic factors to the occurrence of rice planthopper from three levels and three sides,and then make the disaster risk assessment in the whole China.The result shows that, the key factors and the key periods that affect the occurrence of rice planthopper in ShanDong province, is precipitation of the middle ten days of Jul., air temperature of the first ten days of Aug. and precipitation of the last ten days of Aug..Quantified the impact-function of air temperature to the brown planthoppers population in the second rice, the two key periods are during the forepart period of the development of the brown planthoppers population, that suggests that the outbreak or not of the brown planthoppers is determined by the suitable of the forepart period-the accumulation period-of the brown planthoppers population.According to the correlation study between the rate of rice area and degree attacked by rice planthopper in China and the five character indexes of the West Pacific subtropical high from 1971 to 2001 , the intensity of the subtropical high is the important factor ,and the period during Jul. to Oct. is important period to the occurrence of rice planthopper in China.the disaster risk assessment analyzes the occurrence ratio of the planthopper,and give the estimation of the probility for disaster risk levels of 5% 10%, 15 %, 20%, 25%, 30%, 35%, 45 %, 50% .This article selects the more suitable means to analyze, and the result is useful for the science management, the effective prevention and the integration prevention during the rice-growth process, and serves for the crop growth under the market economy.