[Effects of imidacloprid on arthropod community structure in tobacco field]

The effects of imidacloprid on the structure of arthropod community and its sub-communities were analyzed. The results showed that after applied imidacloprid, the species number of arthropod community and its pest sub-community was influenced, but that of its natural insect enemy and spider sub-community was not influenced obviously. The individuals of arthropod community and its pest sub-community in both treatment plot (II) and control plot were decreased after the application of imidacloprid on May 23 to June 13, and the decline degree in treatment plot was larger than that in control plot. The individuals of arthropod community and its pest sub-community at treatment plots had a large decrease, and that in control plot had a large increase after imidacloprid application on June 14. Twice applications with imidacloprid did not reduce the number of the individuals of natural insect enemy and spider sub-community obviously. The individuals of tobacco aphids who were dominant in tobacco field decreased obviously within a period of time after application, and hence, the dominant concentration of arthropod community and its pest sub-community declined, and the diversity and stability increased.