Submitted to: California Olive Committee Annual Research Report
Publication Type: Other
Publication Acceptance Date: January 28, 2011
Publication Date: February 3, 2011
Citation: Yokoyama, V.Y. 2011. Development of Biological and Cultural Control of Olive Fruit Fly in the Central Valley of California. California Olive Committee Annual Research Report. 46-57. Interpretive Summary: Olive fruit fly is a key pest of olives produced for canning in the Central Valley of California. Surveys were conducted in the eastern side of the valley in search of reservoirs of the pest in olive groves. Wherever high numbers of olive fruit fly were detected, parasitic wasps were imported from Guatemala and released for biological control of the pest. Additional species of parasitic wasps were imported into a quarantine facility to evaluate their ability to attack olive fruit fly and one showed positive results. The non-flying stages of the pest were studied in laboratory devices that showed olive fruit fly could travel for a long time over the ground and methods were considered to stop dispersal across orchard floors. A yellow corrugated plastic, inverted pan was constructed and designed to function as an attract-and-kill trap to reduce bait spray applications for olive fruit fly adults, and testing was initiated to evaluate its effectiveness. The research provides California growers with new control strategies for olive fruit fly in the only U.S. state that produces canned olives.
Technical Abstract: The eastern side of the Central Valley of California where olives are grown for canning was surveyed for olive fruit fly, Bactrocera oleae (Rossi), infestations. The pest was found for the first time in unusually high numbers in Merced. The a parasitic wasp, Psyttalia humilis (Silvestri), was imported from the USDA-APHIS-PPQ Moscamed biological control laboratory in Guatemala and released for biological control of olive fruit fly infestations in Oroville, Woodland, Lodi, Merced, Exeter, Bakersfield, and Grapevine. Subsequent F1 progeny of the released adults were reared from olive fruit fly pupae showing the capacity of the parasitoid to adapt to the same environmental conditions as the fruit fly host in California. Two other parasitoids, Fopius ceratitivorus and P. cosyrae, were imported into the quarantine facility at Univ. of Calif. Berkeley and only P. cosyrae developed successfully in olive fruit fly larvae. Olive fruit fly adults from field infestations in central California were used to rejuvenate a laboratory colony that had been reared through 48 generations. Pre-flight olive fruit fly adults, newly emerged from pupae, escaped from the bottom to the top of 22-24 in vertical columns of sand that weighed 41-45 lbs, or traveled horizontally to the opposite end of 25 ft pipes. Over solid surfaces, the third instar larvae crawled an average of 79 ft at an approximate speed of 1 ft per hr; pre-flight adult males walked an average distance of 49 ft at a speed of 118 ft per hr; and females walked about 32 ft at a speed of 104 ft per hr. A yellow corrugated plastic, pan trap baited with olive fruit fly male spiroketal lure and ammonium bicarbonate female bait with GF120 sprayed on the underside is currently under investigation for control of olive fruit fly in an olive orchard.