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Research Project: Biological Control of Invasive Arthropod Pests from the Eastern Hemisphere

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Title: Improvement of mass-rearing procedures for an olive fruit fly parasitoid – duration of exposure to hosts affects production of Psyttalia lounsburyi

Author
item LA SPINA, MICHELANGELO - Vineland Research And Innovation Centre
item DAANE, KENT - University Of California
item BLANCHET, ARNAUD - European Biological Control Laboratory (EBCL)
item Hoelmer, Kim
item PICKETT, CHARLES - California Department Of Food And Agriculture
item Williams, Livy

Submitted to: International Entomophagous Insect Workshop
Publication Type: Abstract Only
Publication Acceptance Date: 9/7/2015
Publication Date: 10/4/2015
Citation: La Spina, M., Daane, K.M., Blanchet, A., Hoelmer, K.A., Pickett, C.H., Williams Iii, L.H. 2015. Improvement of mass-rearing procedures for an olive fruit fly parasitoid – duration of exposure to hosts affects production of Psyttalia lounsburyi. 4th International Entomophagous Insects Conference, Malaga, Spain, 4-9 October 2015. NA.

Interpretive Summary:

Technical Abstract: The olive fruit fly, Bactrocera oleae (Diptera: Tephritidae), causes severe economic damage in California. Control of this fly is currently limited to pesticides. The USDA-ARS European Biological Control Laboratory in Montpellier, France established a classical biological control program nearly 15 years ago, and discovered a promising parasitoid, Psyttalia lounsburyi (Hymenoptera: Braconidae). This wasp is currently produced in a mass-rearing program for release in California. In this system P. lounsburyi is reared on a factitious host, Mediterranean fruit fly, Ceratitis capitata (Diptera: Tephritidae). Our observations indicate that during host exposure to P. lounsburyi a larva is stung several times, but it is unknown if each sting results in oviposition. We report on studies that measure the impact of duration of exposure to hosts on parasitism by P. lounsburyi. Psyttallia lounsburyi wasps were exposed to host larvae for different time intervals (1, 2, 3 and 4 hours) during 3 weeks. Number of pupae, fly adults and parasitoid adults were counted. Subsamples of fly larvae were dissected to count number of sting marks and parasitoid eggs. Differences between exposure times were analyzed, as well the correlation between the number of stings and eggs vs. emerging adult parasitoids. Analysis of results suggests that duration of exposure can affect number of parasitoids produced. The number of parasitoid offspring was much higher when larvae were exposed to fly hosts for shorter time periods, while parasitoid larval mortality was higher for longer exposure times. There was a positive correlation between number of stings and larval mortality; however, the number of parasitoid eggs per host larva was not related to exposure time. Optimization of P. lounsburyi mass-rearing was achieved by reducing the duration of exposure to hosts. This improvement has allowed for a doubling of the parasitoid production with minimal input of additional resources.