Do Torymus sinensis (Hymenoptera: Torymidae) and agroforestry system affect native parasitoids associated with the Asian chestnut gall wasp?

Publication date: Available online 31 January 2018 Source:Biological Control Author(s): Chiara Ferracini, Sandro Bertolino, Umberto Bernardo, Carmelo P. Bonsignore, Massimo Faccoli, Ester Ferrari, Daniela Lupi, Stefano Maini, Luca Mazzon, Francesco Nugnes, Anna Rocco, Fabrizio Santi, Luciana Tavella The Asian chestnut gall wasp, Dryocosmus kuriphilus Yasumatsu, is one of the most serious pests of Castanea spp. worldwide. Since local parasitoids did not effectively control this exotic pest, the Chinese parasitoid Torymus sinensis Kamijo was released in Japan and Europe resulting in a successful control of the invader. A survey of native parasitoids usually infesting oak gall wasps but associated with D. kuriphilus was carried out, sampling chestnut galls in Italy in 2013. The effect of predictive variables (years since T. sinensis release, oak occurrence, type of chestnut formation, latitude) on composition and density of native parasitoid populations was modelled with Generalized Linear Models. In total, 4,410 chalcid parasitoids were recorded, and the most abundant species were T. flavipes Walker, Eupelmus spp., and Bootanomyia (= Megastigmus) dorsalis (F.). Introduction of T. sinensis and oak occurrence influenced native parasitoid richness, conversely to the latitude of the study area. In particular, every additional year of presence of T. sinensis was proved to determine the loss of about 14% of native species, and 32% of their population density. A positiv...
Source: Biological Control - Category: Biology Source Type: research