Survey of hymenoptera parasitoids fauna in tea fields with different pest management systems, and their seasonal prevalence

We surveyed Hymenopteran parasitoid fauna, noting seasonal changes, in three tea fields at our research center and three commercial tea fields with different pest management systems. During this period, 12182 and 6953 parasitoids were captured in traps at the research center and in commercial fields respectively, and identified to Family level. At the research center, 19 families, such as Encyrtidae, Aphelinidae, Trichogrammatidae, Mymaridae, Braconidae, Charipidae, were identified. In the commercial tea fields 18 families were identified. Significant differences in parasitoid family composition were found between different pest management units in both research center and commercial fields. Classification groups that had a large number of captures were Arrhenophagus albitibiae Girault, Pteroptrix orientalis (Silvestri), Aphelininae, and Aphidiinae, and so on. The number of Megaphragma sp., the egg-parasitoid of Scirtothrips dorsalis Hood, was also significant. Peaks of parasitoid occurrence frequently synchronized with those of host numbers, even in cases in which the boundaries between successive host generations were unclear. At the research center, there were significant differences in trap data between different management units for the catches of 13 species or families, and four species or taxa group in the commercial tea fields showed significant differences. While the influence of pesticides on the differences in parasitoid trap data were not clear, we suspect that parasitoids such as Megaphragma sp. may be harmed by pesticides. We selected five candidate indicator species, i.e., A. albitibiae, P. orientalis, Thomsonisca indica, Trichogramma dendrolimi, and Megaphragma sp., for environmental conservation in tea fields.