Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: 8/15/2004
Publication Date: 8/15/2004
Citation: Yokoyama, V.Y., Miller, G.T. Systems approaches for control of olive fruit fly: a recent introduction of an exotic pest in california. Abstracts of the XXII International Congress of Entomology, Brisbane, Queensland, Australia, August 15-21, 2004.
Interpretive Summary: The recent introduction of olive fruit fly in California has threatened the destruction of olives used for canning and oil in the state that produces the crop for the entire nation. The biology of the pest was studied in the laboratory and greenhouse and the data showed that the pest is limited by high temperature and low humidity. Cool coastal areas that produce specialty olive products are highly infested while hot interior valleys where the bulk of commercial olives are grown have low infestations. A yellow sticky panel manufactured in the U.S. was used to trap olive fruit fly adults and monitor field infestations. The U.S. made trap was found to be more economical and efficient than a classic imported European type of trap. A high number of adults were trapped in trees in which olive fruit remained after the harvest period and standing water occurred around the trunks. Removal of all non-harvested fruit and standing irrigation water were proposed as methods to reduce orchard infestations. A parasitic wasp was found to reduce larval populations in cage and open field releases and may have great potential to control high populations of the pest in coastal areas. Control techniques that were developed to prevent the spread of olive fruit fly throughout the state include immersion in brine solutions prior to curing the olives for canning and cold storage for at least three weeks after harvest. The systematic combination of all measures to mitigate the occurrence of the pest in orchards and harvested fruit may provide a high level of control and reduce crop losses in the future.
Technical Abstract: Methods to mitigate olive fruit fly, Bactrocera oleae (Gmelin), in olives used for canning and oil were developed after the pest was first detected in southern California in 1998. Greenhouse tests showed that adults would survive without food for 5-12 days at 18ºC and 50% humidity, and only 2-3 days at 35ºC and 30% humidity which is similar to conditions in the major olive growing areas. Immersion in 1% acetic acid brine solutions impeded emergence of the immature stages in fruit allowing containment during shipment. Postharvest cold storage at 2-3ºC for 3-5 weeks reduced larval survival to <1%. 'Manzanillo' fruit was more susceptible to oviposition and supported significantly higher populations than 'Mission' fruit suggesting cultural practices based on cultivar would help reduce infestations. Yellow panel traps were more effective and economical than Champ traps for adult captures. Trees with fruit and standing water had higher adult trap captures (33/trap/week) than trees without (20/trap/week). Trees with unharvested fruit supported very high larval populations (53 pupae/100g fruit in March). Biological control of olive fruit fly by Psyttalia cf. concolor (Szépligeti) resulted in 100% parasitism of olive fruit fly second instars in cage tests and 10% parasitism of field populations in open releases.