Abstract:

In this study, the parasitoid Dastarcus helophoroides (Coleoptera： Bothrideridae) was released for sustainablly controlling the longhorn beetle Batocera horsfieldi (Coleoptera： Cerambycidae), an important stem-borer in poplars in the south of China. Adults and eggs of D. helophoroides were released in the fields at nine plots in the Hunan and Hubei Provinces. Control effect was evaluated by two investigation indexes, I.e., infested trees number and larvae density. Results showed that, releasing both eggs and adults was able to effectively control B. horsfieldi. Among three plots of releasing the parasitoid eggs, the mean correction reducing rate of the longhorn beetle larvae per tree was 83.27%, and the mean correction reducing rate of infested trees was 74.33%. Among six plots of releasing the parasitoid adults, mean correction reducing rate of the longhorn beetle larvae per tree was 84.23%, and the mean correction reducing rate of infested trees was 75.65%. The controlling results by releasing adults of the parasitoid were a little better than releasing eggs of the parasitoid by comparing the controlling effect in the first and second year, however there was no significant difference between them. Considering higher cost of mass rearing the parasitoid adults than the eggs, it is suggested to release the parasitoid eggs for controlling the severe-damaged longhorn beetle in forests.

Key words: Batocera horsfieldi, parasitoid, Dastarcus helophoroides, field control effect, poplars