Host selection for the mass production of Trichogrammatoidea cryptophlebiae (Nagaraja, 1979) (Hymenoptera: Trichogrammatidae)

The generalist egg parasitoid Trichogrammatoidea cryptophlebiae (Nagaraja, 1979) (Hymenoptera: Trichogrammatidae) is mass-reared in South Africa on Thaumatotibia leucotreta (false codling moth). However, alternative tortricid hosts may improve or enhance production. This study assessed the suitability of Cydia pomonella, Cryptophlebia peltastica and Lobesia vanillana as alternative hosts for the parasitoid through no-choice and choice trials. Host acceptance, emergence, superparasitism, unsuccessful emergence, sex ratio, and offspring morphology were measured. In no-choice assays, T. leucotreta and L. vanillana yielded the highest parasitism, while C. peltastica showed significantly less parasitism. Emergence was highest from C. pomonella and C. peltastica, but high superparasitism in these species resulted in increased unsuccessful development compared to the other species. Lobesia vanillana, the smallest host, classified by egg size, produced significantly smaller offspring of the parasitoid. Morphological analyses showed limited differences in forewing length, but significant host- and sex-dependent variation in hind tibia length. Choice trials revealed a consistent preference for T. leucotreta, particularly eggs that had been irradiated, suggesting its continued suitability for mass production of T. cryptophlebiae. These findings highlight key host-related traits affecting T. cryptophlebiae biology and rearing potential and confirm L. vanillana and C. peltastica as physiological hosts.