Submitted to: Fruit Flies of Economic Importance International Symposium
Publication Type: Proceedings
Publication Acceptance Date: April 7, 2008
Publication Date: October 22, 2008
Citation: Yokoyama, V.Y., Rendon, P., Sivinski, J.M. 2008. Biological Control of Olive Fruit Fly (Diptera: Tephritidae) by Releases of Psyttalia cf. concolor (Hymenoptera: Braconidae) in California, Parasitoid Longevity in Presence of the Host, and Host Status of Walnut Husk Fly. Proceedings of the 7th International Symposium on Fruit Flies of Economic Importance, September 10-15, 2006, Salvador, Bahia, Brazil. pp 157-164. Interpretive Summary: Biological control of olive fruit fly, an invasive pest that threatens the olive industry in California, was implemented with a parasitoid, Psyttalia cf. concolor, imported from Guatemala. The parasitoid was released in olive trees infested with olive fruit fly in a coastal and an inland valley location during the fall of 2005. Parasitism and control of the pest was higher in the cool and humid environment of the coast than in the arid and dry conditions of the inland valley. Subsequent generations from the released parasitoids were collected from infested olives showing that the parasitoid may eventually become established in California. The parasitoid was shown to live for longer than a month, and also attacked another fruit fly pest, walnut husk fly, in greenhouse and laboratory tests. The imported parasitoid shows great promise as a biological control agent for olive fruit fly and in an integrated control program that will help protect the production of canned olives and olive oil in California that is valued at $68 million annually.
Technical Abstract: The larval parasitoid, Psyttalia cf. concolor, collected from tephritids infesting coffee in Kenya and reared on Mediterranean fruit fly, Ceratitis capitata Weidemann, in Guatemala by USDA-APHIS, PPQ, was imported into California for biological control of olive fruit fly, Bactrocera oleae (Gmelin), in olives, Olea europaea. Free releases of the parasitoids were made in olive trees infested with olive fruit fly at a coastal and inland valley location during the fall of 2005. The relative humidity during the releases was significantly higher at the coastal location. Mean percentage parasitism ranged from 0.5 to 4 and 1.5 to 30 at the coastal and inland valley locations respectively, based on same season recovery of the F1 generation. One parasitoid was found in infested olives in the next crop of the following year in San Jose. Survival of the parasitoid in the greenhouse in the presence of olive fruit fly infested olives was not significantly different than in the presence of non-infested olives. The greatest number of progeny was produced from female parasitoids that were 12-16 d old. In laboratory tests, a few individuals of the parasitoid successfully completed one life cycle in walnut husk fly, Rhagoletis completa Cresson, infested English walnuts, Juglans regia L.