The study showed that in the early growth stage of cucumber in spring,the predation on Bemisia tabaci egg was the key factor for controlling B.tabaci population,and the exclusion index of population control was 1.7333.In the late growth stage of cucumber in spring,summer and autumn,the predation on B.tabaci elder nymph was the critical factor for controlling B.tabaci population,and the exclusion index of population control was 4.5372,4.0429 and 7.9021,respectively.From spring to autumn,the index of population development trend was decreased from 21.0610 to 5.8523,because of the increasing controlling effect of the predators,and the exclusion index of population control was from 4.0560 to 17.8662.
