ARS | Publication request: Biological control of olive fruit fly, Bactrocera oleae, in Israel

Submitted to: European Meeting in the IOBC/WPRS Working Group
Publication Type: Proceedings
Publication Acceptance Date: April 27, 2011
Publication Date: October 9, 2012
Citation: Argov, Y., Kuslitzky, W., Hoelmer, K.A. 2012. Biological control of olive fruit fly, Bactrocera oleae, in Israel. European Meeting in the IOBC/WPRS Working Group. 79-85.

Technical Abstract: Bactrocera oleae, the olive fruit fly (OFF), is a key pest of olives in most olive-growing countries in the Mediterranean basin and elsewhere. It significantly reduces yields and degrades the quality of the oil extracted from infested fruit. Olive growers have traditionally used systemic organophosphate insecticides to control the pest, but it is anticipated that these pesticides will be banned in the near future. Biological control with imported OFF parasitoids could help manage fly populations. To increase the production of parasitoids that are entirely mass-reared on Israeli flies, two OFF lines were established on an artificial diet: 1) the wild Israeli flies “Yael” line (100% "Israeli" genome), and 2) progeny of a laboratory strain imported from Crete and crossed with the Israeli wild strain. Four crosses were made and the resulting colony, the “Argov” line, had a 93.75% "Israeli" genome. Two species of OFF parasitoids were imported to Israel and maintained in culture: three lines of Psyttalia lounsburyi (originally from Kenya: Burguret forest and Marmanet forest; and from South Africa: Cape Prov.), and Psyttalia sp. nr. concolor (also called P. humilis) (from Namibia). Because it proved difficult to rear the Psyttalia spp. on B. oleae, the cultures were instead maintained on medfly. Field releases of the imported parasitoids started during November 2008 and were continued from June to November 2009 and 2010. A total of 37,000 individuals of P. lounsburyi were released on 67 occasions at 22 sites, and a total of 97,000 individuals of P. nr. concolor were released on 77 occasions at these 22 sites. During 2007, 2008 and 2009 a survey was conducted to document the indigenous and any imported parasitoids attacking OFF in Israel. In 2007 the total parasitism rate in fruit samples reached 11%. Seven species of parasitoids emerged from olive fruits, dominated by the braconids P. concolor (local species) and Diachasmimorpha kraussii (previously released against Ceratitis capitata). All other species belonged to the Chalcidoidea. During 2008, the pooled parasitism rate in fruit samples reached 15%, including 63 individuals of Fopius arisanus (also previously released against C. capitata). In 2009 the total parasitism rate reached 25.6%.