Suitability of African gramineous stemborers for development of Cotesia flavipes and C. sesamiae (Hymenoptera: Braconidae)

Four cereal stemborers occurring in Kenya, Chilo partellus (Swinhoe), Chilo orichalcociliellus Strand (Lepidoptera: Pyralidae), Busseola fusca (Fuller), and Sesamia calamistis Hampson (Lepidoptera: Noctuidae), were exposed to females of the larval endoparasitoids Cotesia flavipes Cameron and Cotesia sesamiae (Cameron) to assess their acceptability for oviposition and suitability for development of the parasitoids. There was no difference in the acceptability of the 4 hosts exposed to Cotesia flavipes. In contrast, Cotesia sesamiae preferred S. calamistis larvae, followed by the 2 Chilo species; B. fusca larvae were the least attacked by Cotesia sesamiae. The suitability of the 4 hosts also varied with the parasitoid species. Neither parasitoid species developed in B. fusca and egg encapsulation was observed. Both Chilo species and S. calamistis were suitable hosts for the development of Cotesia flavipes. However, higher immature mortality was observed in S. calamistis than in Chilo partellus. There were no differences in the mean number of progeny per female or the sex ratio. The most suitable host for Cotesia sesamiae was S. calamistis, followed by the 2 Chilo species which were equally suitable. When 3rd, 4th, 5th, and 6th instars of Chilo partellus were exposed to Cotesia flavipes females, immature parasitoid mortality was highest in 3rd-instar hosts