Abstract: By means of the life table of acting factors combinations and the theory of modern population system control,this paper evaluated the efficacy of different combinations of application dosage and times of granulosis virus on Plutella xylostella control.The results showed that with gradually recovered natural enemies,the second generation of Plutella xylostella in the field of spring flowering Chinese cabbage would increase 4.1 times if no control methods were carried out to the first generation.After applying a suspension of 0.25LE/L(Larval equivalent)two times,the egg and larval numbers of the second generation Plutella xylostella were reduced significantly,but the index of population increase was still beyond 1,while applying a suspension of 0.5 LE/L two times or 1LE/L one time at the peak of 2nd instar larvae of the 1st generation could significantly reduce the egg and larval numbers,and the index of population increase was only 0.13.Therefore,if used appropriately, the granulosis virus originated from Plutella xylostella could control the damage of Plutella xylostella effectively.

Key words: Hibernating generation, Microvelia horvathi, Hunger tolerance, Temperature, Density