Abstract:

To understand the influence and action evaluation of the functional groups of natural enemies on jujube trees by intercropped herbage at jujube orchards, a systematic survey was made at Taigu, Shanxi Province. The systematic survey showed that there were significant difference (P<0.05) of the diversity and dominance of functional groups of natural enemies on the trees at the two types of jujube orchards. The result suggested that jujube orchard with herbage have obvious effect to the succession of functional groups of natural enemies on the trees. There were different community parameters of functional groups of natural enemies in the different developing stages of jujube trees. The jujube orchard with herbage could improve the recovering and rebuilding of the population of functional groups of natural enemies which had been severely reduced by spraying of the widespectrum insecticides. So the jujube orchard with herbage is of great benefit to the biological control of pests. The controlling effects of functional groups of natural enemies to pests were estimated according to sizes of ratio of S_n/S_p、E_I/P_I and d_s/d_m. The results from the sizes of ratio suggested that there were better controlling abilities of functional groups of natural enemies to pests in the jujube orchard with herbage than that without herbage. The result from relativity mensuration showed that the study of natural enemy community was conducted by using functional groups instead of species.

Key words: jujube field intercropped with herbage, functional groups of natural enemy, diversity, dominant, natural enemy action