Abstract: In order to evaluate biocontrol effect of an invasive pest, the fall webworm Hyphantria cunea, by the parasitoid Chouioia cunea (Hymenoptera: Eulophidae), life tables of four generations of the pest were consecutively studied for two years in Yantai, Shandong Province. Two experimental sites were selected where the fall webworm was still a big problem but not so serious as some years ago. In one of the sites the parasitoid was released twice in each fall webworm generation , at the beginning and peak period of pupation, while the other site served as the control. The average data of observations for the 1st generations of the fall webworm in two years were combined to make one life table for the test site and the average data of the observations for the 2nd generation of fall webworm were used to make another life table. Similarly, the average data of observations from the control site were used to make two other life tables. The results show that the trend indexes of population (I value) of 1st and 2nd generations of the fall webworm at the test site, 0.29 and 0.14 respectively, were significantly lower than that at the control site, 8.74 and 4.48 respectively. The pest population clearly declined at the test site and appeared to have been effectively controlled by the parasitoid.

Key words: Hyphantria cunea, Chouioia cunea, life table, biological control