Effects of insecticides on insect pest-predatory natural enemy communities in middle-season paddy fields
Effects of four insecticides including triazophos,shachongshuang,abamectin and Bt+imidacloprid on the insect pest-natural enemy communities in middle-season paddy fields in the Yangtze-Huaihe regions of Anhui Province were studied.The results showed that all the four insecticide treatments had significant effects on dominant insect pest population growth.Triazophos had greater effects on community diversity than the others,and abamectin and Bt+imidacloprid had the least effects on community diversity.The average values of community diversity in triazophos,shachongshuang,abamectin and Bt+imidacloprid treatment plots were 1.509,1.537,1.770 and 1.782,respectively,all of which were significantly lower than that in blank control plot(the average value of community diversity was 1.945).After two weeks of the insecticide treatment,the community composition in shachongshuang treatment plot was similar to that in triazophos treatment plot,and which was significantly different from that in Bt + imidacloprid treatment plot.As a result,the authors suggested that abamection is better than the others to control insect pests in middle-season paddy fields.