ARS | Publication request: Evaluation of imported parasitoid fitness for biocontrol of olive fruit fly in California olives

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: August 20, 2011
Publication Date: N/A

Technical Abstract: A parasitoid, Psyttalia humilis (Silvestri), was reared on irradiated Mediterranean fruit fly (Medfly), Ceratitis capitata (Weidemann), at the USDA, APHIS, PPQ, Moscamed biological control laboratory in San Miguel Petapa, Guatemala, and imported into California for biological control of olive fruit fly, Bactrocera oleae (Rossi). Irradiation of Mediterranean fruit fly larvae to rear large numbers of parasitoids prevents the accidental introduction of fertile hosts in parasitoid shipments and the effect on parasitoid fitness needed evaluation. Parasitoids reared from hosts irradiated with 40-70 Gy did not show differences in longevity in laboratory tests at 15-35°C when provided with or without water and honey for food versus parasitoids reared from fertile hosts. Parasitoid flight times were similar for adults reared from irradiated or non-irradiated hosts. Parasitoid longevity was similar to olive fruit fly in tests at temperatures and humidities that simulated seasonal and regional climates in California. Parasitoids that were reared from irradiated Medfly were released in olives trees infested with olive fruit fly primarily in the Central Valley of California in 2009-2010 and subsequent generations of the parasitoid were recovered from the host. The findings are related to the capacity of the imported parasitoid to adapt, survive, and reproduce under the same environmental conditions where olive fruit fly occurs as a pest and in California olives grown for canning. The results support the use of irradiated host to provide security in mass rearing and release of parasitoids for biological control.