Submitted to: California Olive Committee Annual Research Report
Publication Type: Other
Publication Acceptance Date: 2/5/2010
Publication Date: 2/9/2010
Citation: Yokoyama, V.Y. 2010. Biological and Cultural Control of Olive Fruit Fly in California---Utilization of Parasitoids from USDA-APHIS-PPQ, Guatemala and Cultural Control Methods. California Olive Committee Annual Research Report. pp. 62-71.
Interpretive Summary: Olive fruit fly has become a key pest in California olives since it was first found in Los Angeles in 1998. Losses in production of olives used for canning in the Central Valley have been prevented with bait spray treatments in commercial orchards, but economical and environmentally friendly techniques are under investigation as substitutes for sprays. A biological control program using a small parasitic wasp reared on larvae of another fruit fly was imported from Guatemala and released in several olive growing areas. The releases were successful based on recovery of the wasp’s offspring from olive fruit fly larvae. A method was evaluated to ensure that the wasps were imported without risk of contamination by the fruit fly host used to produce them. The procedure based on host irradiation did not affect the longevity and flight endurance of the wasp. The immature stages of olive fruit fly, including the newly emerged adults showed strong tendencies to travel over long distances without flight. Cultivation methods were studied to contain the movement of these stages in olive orchards. The work supports the development of practical and sustainable techniques to control an economic pest in olives harvested for canning and oil valued at $90 million annually in California.
Technical Abstract: The parasitoid Psytallia humilis = P. cf. concolor (Szépligeti) was reared on sterile Mediterranean fruit fly, Ceratitis capitata (Wiedemann), larvae at the USDA, APHIS, PPQ, Moscamed biological control laboratory in San Miguel Petapa, Guatemala and shipped to the USDA, ARS, Parlier, for biological control of olive fruit fly in California. Parasitoids were released in olives infested with olive fruit fly in the Sacramento, San Joaquin, and North and Central Coast of California. Subsequent generations of parasitoids were recovered from olive fruit fly pupae in most locations, except when infested olives were scarce such as found during winter. Numbers of olive fruit fly were very low in Central Valley except for Lodi based on adult trap captures and fruit collections, but higher numbers of the pest were found in foothill locations. Irradiation of the host at different doses did not affect survival of P. humilis in laboratory tests at different temperatures and with and without water and honey for food. Life span was significantly increased by the presence of water and honey for food, and cool temperature at 15°C versus 35°C. The parasitoid showed high dispersal capacity with continuous flight in different air temperatures and air speeds. Female and male parasitoid flight time ranged from 4-20 min and 3-14 min, and the longest flights ranged from 53-110 and 20-52 min, respectfully. An olive fruit fly colony has been reared on formulated diet for >40 generations but the larval stage was not acceptable for oviposition when exposed to parasitoids in mesh and waxed cages. Yellow pan and cone traps were obtained for testing as potential olive fruit fly attract-and-kill traps. Olive fruit fly newly emerged adults were shown to travel over long distances without flight.