Back to the Wild: The Parasitoid Community of Lobesia botrana (Lepidoptera: Tortricidae) in a Grapevine-Free Natural Environment

Abstract

The European grapevine moth (EGVM), Lobesia botrana (Lepidoptera: Tortricidae), is one of the major concerns for vineyard managers in the Mediterranean area. It is a polyphagous moth, which develops on a wide variety of host plants, among which the spurge flax, Daphne gnidium (Thymelaeaceae), very likely represents its originary wild host plant. In this study, we investigated the parasitoid complex of L. botrana feeding on D. gnidium during a three-year sampling in a natural reserve in Tuscany, Italy, where this plant is extremely abundant while the grapevine is absent. A total of 24 species of parasitoids were obtained from eggs, larvae, and pupae of EGVM, belonging to 6 families of Hymenoptera and a family of Diptera. The ichneumonid wasp Campoplex capitator was the most abundant larval parasitoid. Four species of the genus Trichogramma were obtained from parasitized eggs during the first year of sampling, with a peak in the parasitisation during the EGVM 3rd generation. Some of the main EGVM parasitoids on spurge flax were also observed in vineyards, although a certain degree of redundancy was observed in the wild, due to several less frequent “satellite” species exploiting the same host. Overall, this research sheds light on the parasitoid community and dynamics of this important moth pest in a grapevine-free natural ecosystem, discussing the possible role of natural areas as ecological reservoirs of pest natural enemies.

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“…Trichogramma species are the most widely exploited and used for pest management across the world. There are 230 recorded species and the highest numbers of species have been described from the USA, India, Brazil, China, Russia and Portugal (Jalali et al, 2016;Carlos et al, 2022;Di Giovanni et al, 2022) However, it has been proven that the low effectiveness of some Trichogramma applications in biological control is due to the selection of unsuitable species and their application in unfavourable ecological conditions (Reda, 2004;Moreau et al, 2009). Therefore, native species are preferred over exotic species because of their possibility of adapting to climate, habitat and host conditions (Hassan, 1994;Smith, 1996).…”