S14 - Session O1 - Biocontrol of the box tree moth, Cydalima perspectalis, with macro-organisms

Authors: Elisabeth Tabone *, Emeline Morel, Etty Colombel, Caroline Eyssan, Jean-Marc Deogratias, Maxime Guerin

The aim of the SaveBuxus project is to improve knowledge of the invasive Lepidopteran boxwood pest, Cydalima perspectalis , and to propose new effective biocontrol methods that are environmentally and human health friendly. The Biocontrol laboratory contributed to this project by researching macro-organisms such as oophagous parasitoids. The first laboratory tests allowed the isolation of three interesting strains of Trichogramma. However, field trials have shown that Trichogramma alone are not sufficient to control the box tree moth and the costs of using Trichogramma are quite high compared to those of using Bacillus thuringiensis (entomopathogenic bacteria commonly used against that pest). Then, collections were made in natural boxwoods to select native auxiliaries (parasitoids and predators) that would have spontaneously established on the box tree moth. In parallel, the potential of predation of several commercialized insect species was studied. These are polyphagous arthropods, commercialized to protect plants against other pests. All this allowed us to select the most efficient predator ("POL") against the box tree moth, among 18 tested species. In order to determine a strategy of use in situ , the predation of POL on C. perspectalis eggs and young larvae was studied. This was done according to different parameters: shape and size of the boxwood, quantity of POL, density of the pest, climate, etc… All this work was done at Inrae UEVT Antibes and at the Astredhor Sud-Ouest site, thanks to OFB and Valhor funding (donated by Plantes&Cites). Now, we have developed a biocontrol strategy for the box tree moth, which is effective (80%), economically and technically affordable for all users (professionals and individuals), without pest resistance and allowing a sustainable regulation of box tree moth populations in JEVI.