Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/10/2007
Publication Date: 4/20/2007
Citation: Yokoyama, V.Y. 2007. Biological and cultural control of olive fruit fly in california. 9th Annual Exotic Fruit Fly Symposium, April 25-26, 2007, Fresno, California. p. 72
Technical Abstract: Olive fruit fly, Bactrocera oleae (Gmelin), monitored with ChamP traps captured the highest numbers of adults in olive trees, Olea europaea, in October in an inland valley location, and in September in a coastal location. Significantly more adults were captured in Pherocon ® AM traps than ChamP traps when both were provided with ammonium bicarbonate baits and pheromone lures. A significantly greater number of females were captured in Pherocon ® AM traps with baits and lures, than traps with lures alone. Fruit volume increased by 4 times from mid-June to mid-November. Olive fruit fly completed development from the egg to the adult stage in fruit with a mean volume of 0.17cm³, the maximum number of ovipositional sites per fruit occurred in October, and the greatest number of pupae and adults were reared from fruit collected in September and October. In the following year, the highest numbers of pupae were collected from non-harvested fruit in March when high numbers of adults were captured in the same orchard. Mortality of 1-5, 6-8, 9-11, and 12-14 d-old immature insects in olives was 19-75, 13-58, 5-27, and 0-7% when exposed to 15ºC and 65% relative humidity (RH), and was 14-31, 8-32, 16-38, 4-22% when exposed to 25ºC and 35% RH, respectively. Mortality was 100% in all immature stages in fruit exposed to 5ºC and 85% RH and 35ºC and 25% RH. The mean pre-ovipositional period for adult females was 13.0 d; mean peak oviposition occurred at 19.7 d; and, mean egg laying ended after 63.7 d at 23ºC. The mean number of adults captured in Pherocon ® AM traps was higher in olive trees with irrigation water at the base (39.9 adults per trap per week) than in olive trees without irrigation water (27.7 adults per trap per week) in the absence of fruit in the canopy. Percentage mortality of olive fruit fly 3rd instars was greater than young (0-4 d-old) and old (9-12 d-old) pupae after immersion in water and sand for 1-5 d, and young pupae were in general more susceptible than old pupae. Calculated percentage parasitism of olive fruit fly 3rd instars by Psyttalia cf. concolor (Szépligeti) imported from Guatemala in field cage tests ranged from 4% in a dry and warm inland valley area, to 29% in a humid and cool coastal area. In laboratory tests at constant temperature, parasitoid adult survival decreased with an increase in temperature when provided with water (48 d at 15°C and 12 d at 35°C) or with no water (4 d at 15°C and 0 d at 35°C). In greenhouse tests, at fluctuating diurnal and nocturnal temperatures, parasitoid adult survival with food and water was 21 d at approximately 26°C and 4 d at approximately 36°C, and without food and water was 4 d at approximately 26°C and less than or equal to 1 d approximately 36°C. Releases of parasitoid adults in 2006 were conducted in Orland, San Juan Bautista, Cayucos, Sylmar, Santa Barbara, and San Diego. Adults (3,613-8,322) were released 1-4 times during October through December at each site. The estimated number of olive fruit fly 3rd instars per fruit that were exposed to parasitoids at each site ranged from <1 in Orland to 1.3 in San Diego. The F1 progeny of released adults were collected in fruit samples from every location and the mean rate of parasitism ranged from 5.6 in Orland to 96.0 in Cayucos.