A survey of egg-stage parasitoid species within Dendrolimus houi (Lepidoptera, Lasiocampidae) in Fujian, China

Dendrolimus houi Lajonquiere is a polyphagous defoliator with strong adaptability causing significant damage to hundreds of hectares of pine forest. The larvae primarily damage coniferous tree species. Moreover, the female adult has afecundity on average exceeding 300 eggs per individual, indicating population suppression before larvae hatching and massive infestation is critical to minimise losses. Fortunately, egg-parasitoids have been found to be a biologically optimal choice for attacking non-migration eggs or egg masses without chemical resistance, residue and resurgence. Therefore, it is necessary to collect and sift native dominant parasitoids for mass rearing and field releasing after intensive field investigations. However, systematic investigation on the native egg-parasitoid species of D. houi is currently needed to be undertaken. In this paper, we reported eight parasitoid wasps within D. houi eggs: Mesocomys albitarsis (Ashmead), Mesocomys trabalae (Yao et Yang), Anastatus ( Anastatus ) gastropachae Ashmead, Anastatus ( Anastatus ) dexingensis Sheng et Wang, Anastatus ( Anastatus ) fulloi Sheng et Wang, Anastatus ( Anastatus ) huangi Sheng et Yu, Telenomus dendrolimi (Matsumura) and Trichogramma chilonis Ishii, of which, A. gastropachae , A. huangi , A. dexingensis , A. fulloi and T. chilonis were new parasitoid species of D. houi recorded in Fujian Province, China. We also compared biological characteristics such as parasitism rate, longevity, offspring quantity and sex ratio amongst these eight parasitoid wasps and built a system on dominant species evaluation by assigning scores. Finally, T. dendrolimi was selected as the dominant egg-parasitoid of D. houi . This study fills the gap in systematic investigation of D. houi egg-parasitoids in Fujian, China, provides a scientific basis for artificial mass rearing and field release of parasitoids and supports biological control of D. houi in Chinese forests.