The Invasive Species, Bactocera olea

University of California Agriculture and Natural Resources

COOPERATIVE EXTENSION

Contact:Bill Krueger, UCCE Glenn County

(530) 865-1107 - whkrueger@ucdavis.edu

William H. Krueger, UCCE, Glenn County

Table olives are currently produced on 12,000 acres in Glenn and Tehama Counties. This industry has a total value to the local economy of 175 million dollars. In 1998, the Olive Fruit Fly (OLF) (figure 1) was trapped in the Los Angeles area. It spread rapidly and can now be found virtually anywhere olives are grown in California. OLF lays eggs in the olive fruit (figure 2) that hatch into maggots that feed and tunnel through the fruit (figure 3). Damaged fruit are susceptible to attack by secondary decay organisms (figure 4). Damage is mostly internal and difficult to remove in the packing shed. The potential consequences of infested fruit on marketing mandates a very low tolerance. As the OLF population continues to develop, it remains to be seen if olive growers will be able to meet these requirements. The survival of this industry is dependent upon developing and adopting effective and economical control methods.

Research funded by California Olive Committee (COC), University of California, USDA and CDFA is currently underway to find efficient and economical methods for controlling OLF under California conditions. UC Cooperative Extension in Glenn and Tehama Counties is conducting research and educational programs to provide growers with the most effective and economical tools. This effort is a good example of how UCCE can function collaboratively with other agencies, individuals and private industry to bring the resources of the University to bear on locally important issues. Our activities can be divided into outreach and research and are described below.

ResearchCoordination of USDA researchers specializing in sorting of agricultural products resulted in COC funding for investigating methods of mechanically sorting infested fruit. Potentially this could increase the tolerance for infested fruit and make IPM programs more feasible.

Collaborative research with UC Entomologist Frank Zalom and UC graduate student Hannah Burrack is underway in Glenn County and has been supported by a COC grant which has provided $5000 annually for two years. In 2004, research demonstrated superior performance for the plastic McPhail trap (figure 8) for monitoring OLF populations in local orchards compared to the standard yellow sticky trap. Local pesticide dealers were encouraged to make these traps available. As a result, many growers have switched to this type of trap.

ConclusionThe table olive industry in California is at risk. Work being done locally by CE is serving to catalyze efforts underway by individuals, agencies and private industry to combat this invasive species and make the results of this work accessible to the growers. These activities are critical to the continued survival of the table olive industry in California.

Figure 1. Adult Female Fly

Figure 2. Ovipositional Stings in Fruit Figure 3. Small Larvae and Feeding Traces Figure 4. Olive Fly Larvae in Decaying Fruit

Figure 5. Media Day – Chico Enterprise Record article

Figure 7. Commercial Orchard BrochureFigure 6. Ornamental Tree Brochure

Figure 8. McPhail Trap Figure 9. OLIPE Trap Figure 10. Attract and Kill Trap

Figure 11. Surround Spray

Olive Fly information and links posted on the Glenn County CE website include updated trap results, the publications described above, UC IPM Pest Management Guidelines, 2005 UC Recommendations For Controlling Olive Fly, sources of OLF trapping materials, instructions for OLIPE traps, UC Backyard Orchard publication on OLF and other links with useful information.

Work with local Agricultural Commissioners resulted in GF 120 (the only pesticide currently available for commercial growers) being available for non commercial trees.

Technical advice was provided for Glenn and Tehama Counties Olive Pest Control Districts.

The outreach program described above is being partially funded by a CDFA grant of approximately $7500 annually for three years administered through the Tehama County Agricultural Commissioner’s office.

During 2005 alternative control measures including the standard GF 120 Spinosad spray, homemade OLIPE bottle traps (figure 9) for mass trapping, attract and kill traps (figure 10) and Surround spray (figure 11) for repelling OLF are being compared in a replicated trial.

Outreach

The Sacramento Valley Olive Day was held in Tehama County in 2004 and Glenn County in 2005 with a primary focus on OLF. Researchers presented results to growers. Each meeting had an attendance of approximately 200 and was supported by local processors.

Media Day (figure 5) was organized and presented to local media to encourage the removal of non- commercial olive trees to minimize the risk to commercial orchards.

Newsletters with up to date information on OLF were produced 4 times annually and sent to a mailing list of approximately 330 growers and industry personnel.

FlyersControlling Olive Fruit Fly in Non-Commercial Orchards (figure 6) provides information on OLF for homeowners and caretakers of ornamental olive trees. This is important because of the threat that uncontrolled populations in these trees pose to commercial orchards. The publication was distributed at the 2005 Olive Day, has been given out at our office and is posted on our website. Additionally, 700 copies were mailed to non-commercial olive growers by the Glenn County Olive Pest Control District.

Controlling Olive Fruit Fly In Commercial Orchards (figure 7) presents the latest information on controlling OLF for commercial growers. It was printed in English and Spanish on the same publication because of a significant Hispanic population among olive growers. It was mailed to all of the olive growers in Glenn, Tehama and Butte Counties and is posted on our website. To date 1300 copies have been printed. It will be updated and redistributed in 2006.

Website:

http://ceglenn.ucdavis.edu

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