Introductions of the African parasitoid Psyttalia lounsburyi in South of Francefor classical biological control of Bactrocera oleae

Abstract: Psyttalia lounsburyi is an African parasitoid of the olive fruit fly Bactrocera oleae. Itsintroduction in France has been made with two different objectives: i) controlling the olive fruitfly in France, and ii) testing how intraspecific hybridization affects the demographic success ofsmall introduced populations. For this, we introduced two parental strains of P. lounsburyioriginating from either Kenya or South Africa, and a hybrid strain resulting from their admixture.In this paper, we report the first years of research and progress toward our two objectives. In 2006and 2007, intensive field surveys were carried out to locate 60 suitable release sites in South ofFrance. During fall 2007, before the introduction of P. lounsburyi, a first set of olive samples wascollected to assess the density of B. oleae and the diversity of indigenous natural enemies. Theyear 2008 was dedicated to parasitoid mass production, release, and a second set of sampling. Insummer, a total of about 43,000 individuals P. lounsburyi were introduced in the 60 sites.Individuals of the genus Psyttalia were found in some samples, suggesting the ability of thereleased parasitoids to locate B. oleae in French olive trees and to complete their preimaginaldevelopment into these hosts. However, molecular identification of the recaptured individualsneeds to be done to confirm these results. More sampling is also necessary to test the ability ofAfrican P. lounsburyi to overwinter and establish in South of France.