Abstract:

Hyphantria cunea were effectively controlled by using Chouioia cunea as a major biological control agent. In parasitic wasp successively released areas where 4 consecutive generations of H. cunea were studied, the damage caused by Fall Webworm decreased but in control areas the damage had no change. The parasitism rates in pupae of Fall Webworm caused by C. cunea reached to 50%～70% after 2 years of Control effort. Because of no pesticide used in these areas, Where almost all the natural enemies were protected, overall parasitism rates of all parasitic insects in pupae of Fall Webworm reached to 83.26%～ 95.82%. The results obtained by calculating the relational grade among parasitism rates of different insect natural enemies showed that C. cunea released by man was the major factor in biological control of the Fall Webworm and had little influence on other insect natural enemies. The damage caused by Fall Webworm was effectively reduced by all of natural enemies acting together.

Key words: Hyphantria cunea, Chouioia cunea, Biological control, Insect natural enemy, Relational grade