Mass rearing of Bracon hebetor (Hym.: Braconidae) on wax moth, Galleria mellonella (Lep.: Pyralidae) with varying density of parasitoid and the host

Rearing methods for Bracon hebetor (Say) (Hym., Braconidae) were investigated in the series of laboratory experiments designed to enhance the yield of the mass rearing of this parasitoid for biological control of lepidopteran field and stored product pests. In these experiments, the effects of parasitoid and host densities on fertility and sex ratio of B. hebetor were assessed. In parasitoid densities, ۵۰ last-instar greater wax moth (GWM) Galleria mellonella (L.) larvae were placed per container and ۱, ۲, ۴, ۸ or۱۰ pairs of B. hebetor (one male and one female) were released in each container. In host density study two pairs B. hebetor were introduce in six different densities (۱۰, ۲۰, ۳۰, ۴۰, ۵۰ and ۶۰) of host, GWM per container. A density of ten male-female pairs of B. hebetor produced a higher number of progeny (۲۰۵ ± ۷.۰۷ adults) on ۵۰ last instar larvae of GWM. Similarly, in a host density experiment, a density of ۶۰ last instars GWM larvae produced a significantly higher number of parasitoid progeny (۱۴۲.۰  ±  ۸.۷۵ adults), followed by ۵۰ last instar larvae (۱۴۱.۰ ± ۸.۳۴ adults) among the tested host densities when two pairs of B. hebetor were used. The sex ratio of progenies was male-biased in all studies and there were no significant effects on sex ratio in various parasitoid and host densities. In mass rearing experiment, total number of emerged parasitoids per ۲۰۰ wax moth larvae was ۱۰۹۱ ± ۸۲.۳۸ adults with mean parasitism rate of ۹۸ ± ۰.۸%.

Keywords:

Biological control , mass rearing , Bracon hebetor , parasitoid density , host density