Optimisation of Habrobracon hebetor mass-rearing: effects of host species, host density and parasitoid density

Habrobracon hebetor (Say) (Hymenoptera: Braconidae) is a gregarious ectoparasitoid wasp with global distribution. Its short generation cycle and wide host range make it an important natural enemy of lepidopteran pests in field and storage systems, contributing to biological control and integrated pest management. To determine the parameters for mass rearing of H. hebetor, this study investigated the effects of different hosts—Corcyra cephalonica (Stainton) (Lepidoptera: Pyralidae) and Ephestia elutella (Hübner) (Lepidoptera: Pyralidae)—as well as varying host densities and parasitoid densities. Under laboratory conditions, the study focused on offspring emergence and the paralysis and parasitism of E. elutella within a 5-day period. Compared with E. elutella, C. cephalonica produced significantly more females, males, and total wasps, as well as a more favourable sex ratio, identifying it as the superior host. The optimal treatment comprised 70 pairs of H. hebetor per 500 C. cephalonica, yielding 730.33 females, 606.67 males, and 1,337 total wasps approximately 13 days after introduction. Offspring at this density paralyzed and parasitised 176.20 and 22.20 E. elutella individuals, respectively, within 5 days. With E. elutella as the host, the best density was 50 pairs of H. hebetor per 600 E. elutella, producing 436.33 females, 610.00 males, and 1046.33 total wasps approximately 13 days after introduction. Offspring at this density paralyzed and parasitised 179.80 and 21.60 E. elutella individuals, respectively, within 5 days. Overall, these findings provide technical guidance for large-scale rearing and practical use of H. hebetor in storage environments.