Biological and Cultural Control of Olive Fruit Fly in California---Utilization of Parasitoids from USDA-APHIS-PPQ, Guatemala

Authors: Yokoyama, Victoria

Submitted to: California Olive Committee Annual Research Report
Publication Type: Other
Publication Acceptance Date: 1/15/2009
Publication Date: 1/20/2009
Citation: Yokoyama, V.Y. 2009. Biological and Cultural Control of Olive Fruit Fly in California---Utilization of Parasitoids from USDA-APHIS-PPQ, Guatemala. California Olive Committee Annual Research Report. p. 91-97.

Interpretive Summary: Olive fruit fly is a destructive pest of olives in California, causing serious economic losses in the nation’s domestic supply of canned fruit and oil. A biological control program designed to reduce pest numbers was implemented with the importation of thousands of parasitic wasps from Guatemala. The parasitic wasps were released into infested olive orchards throughout California to attack and reproduce in olive fruit fly. The results showed varying levels of parasitism and under certain conditions a large decrease in olive fruit fly infestations in olive fruit. The work supports the use of biological control to suppress a key pest in olives and to protect an annual crop valued at $90 million annually.

Technical Abstract: The parasitoid Psytallia cf. concolor (Szépligeti) was reared on sterile Mediterranean fruit fly larvae at the USDA-APHIS-PPQ, Petapa Quarantine Laboratory in Guatemala and shipped to the USDA-ARS, Parlier, for wide-spread release and biological control of olive fruit fly in California. As many as 37,000 parasitoids were received per shipment and released in olives infested with olive fruit fly in San Diego, San Luis Obispo, Tulare, Santa Clara, San Joaquin, Santa Barbara, Napa, Glenn and Butte Counties. The first or second generation of parasitoids from released adults was recovered from olive fruit fly pupae in most locations. Olive fruit fly populations were very low in interior valleys based on trap captures and fruit collections, but an unusually high population was found in Lodi. The number of olive fruit fly larvae in fruit exposed to the parasitoid was about 59% lower than in non-exposed fruit in the Solvang location. More parasitoids were recovered from olive fruit fly in fruit collected in the upper tree canopy than in the lower canopy. A proposal was submitted to the Guatemala Ministry of Agriculture for entry of US fruit fly species into the Petapa Quarantine Laboratory for parasitoid host tests.