Acceptability and suitability of the European Ostrinia nubilalis Huebner for Macrocentrus cingulum Brischke from Asia and Europe

We examined whether Macrocentrus cingulum (Hymenoptera: Braconidae) of Asian origin could serve as a biological control agent of the maize pest Ostrinia nubilalis (Lepidoptera: Crambidae) in Europe. M. cingulum is already present in Europe, where it does not parasitize O. nubilalis but Ostriniascapulalis, a related species feeding on wild dicotyledons. In contrast, M. cingulum have been imported from Europe and Asia into North America (where O. nubilalis had been accidentally introduced from Europe), and does parasitize O. nubilalis there. We conducted laboratory infestations to assess host acceptability (parasitoid's propensity to oviposit) and suitability (parasitoid's ability to develop) of European O. nubilalis for M. cingulum of European and Asian origin, and of Ostriniafurnacalis (their original host) for Asian M. cingulum. Asian M. cingulum parasitized European O. nubilalis as readily as O. furnacalis, and developed equally well in terms of: % female cocoons, time to first emergence from the cocoon, total number of adult offspring, % female offspring and adult longevity. Adult female parasitoids were significantly larger when emerging from O. nubilalis, mixed-sex and male cocoons were significantly more and less frequent, respectively. The acceptability of O. nubilalis was significantly lower for European than for Asian M. cingulum, and its suitability was zero. Asian M. cingulum appears a potential candidate for introduction as a biological control agent of a major maize pest, European O. nubilalis, provided environmental impact studies, economic analyses, and foreseeable interactions with other biological control agents such as the egg parasitoid Trichogramma brassicae (Hymenoptera: Trichogrammatidae) are satisfying.