A survey of egg-parasitoid species associated with 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. Given that the average female fecundity exceeds 300 eggs, population suppression prior to larval eclosion is critical to prevent massive infestations and minimize losses. The use of egg-parasitoids represents a biologically optimal control strategy, as they effectively attack non-migratory eggs and egg masses while avoiding the drawbacks of chemical pesticides, such as resistance, residue, and pest resurgence. Therefore, systematic field investigations are needed to identify and collect native dominant parasitoids of D. houi for subsequent mass rearing and release.

This study reports eight parasitoid wasp species emerging from D. houi eggs: Eupelmidae : 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; Scelionidae: Telenomus dendrolimi (Matsumura); and Trichogrammatidae : Trichogramma chilonis Ishii. Among these, five species— A. gastropachae , A. huangi , A. dexingensis , A. fulloi , and T. chilonis —are newly recorded as parasitoids of D. houi in Fujian Province, China. We compared key biological characteristics, including parasitism rate, longevity, offspring quantity, and sex ratio, across all eight species. Based on this analysis, T. dendrolimi was identified as the dominant egg-parasitoid.

This study fills a critical gap in the systematic investigation of D. houi egg-parasitoids in Fujian, China. Our findings provide a scientific basis for the mass rearing and field release of these parasitoids, thereby supporting the biological control of D. houi in Chinese forests.