Enhancing Biological Control to Stabilize Western Orchard IPM Systems
Fruit and Vegetable Insect Research
2012 Annual Report
1a.Objectives (from AD-416):
The overall objective is to improve the sustainability of apple, pear, and walnut cropping systems in the western U.S., by developing knowledge and tools that would allow growers to take full advantage of biological control in their orchards.
1b.Approach (from AD-416):
• Objective 1: Evaluate the sublethal effects of newer pesticides on key natural enemies in laboratory assays, and in apple, pear, and walnut orchards
• Objective 2: Characterize the phenology of key natural enemies using banding studies in the fall and orchard sampling during the spring and summer
• Objective 3: Evaluate semiochemicals as a method of monitoring natural enemy presence, abundance, and phenology; assess effectiveness of this tool in evaluating the effects of inseticides on natural enemies; and compare sampling efficacy of these products to results of sampling done using beating trays
• Objective 4: Develop methods in gut contents analysis to monitor predation of codling moth by generalist natural enemies, and confirm gut contents results using video monitoring. Documents Reimbursable agreement with Washington State University (CSREES Specialty Crops Research Initiative). Log 37158. Formerly 5352-22000-017-48R (6/10); 5352-22000-019-24R (1/11).
Enhancing biological control to stabilize western orchard IPM systems.
The reduction in use of broad spectrum insecticides for control of codling moth and other pests in apples and pears have provided an opportunity for enhancing biologic l control in orchards by preserving beneficial predatory and parasitic insects. To measure the value of predatory insects in apple orchards, USDA-ARS scientists in Wapato WA used polymerase chain reaction (PCR) to detect DNA sequences of codling moth from the gut or whole bodies of potential predators collected from apple orchards from 2006-2011. Thirteen species of spiders, 3 predatory ground beetle species, the European earwig, and one species of Opiliones were analyzed, over 3000 specimens in all. Within the spider complex, 7 of the 14 species had recently consumed codling moth and together the community of spiders showed more than 14% predation on codling moth. More than 10% of ground beetles and earwigs showed evidence of predation on codling moth within 48 hours of capture. Barrier traps were used to estimate the abundance of ground dwelling predators and we found 1-2 predatory ground beetles per square meter of the ground cover in two orchards. These data indicate that the beetles are abundant enough to contribute to the control of codling moth in orchards managed with biorational pest control products. The research described in this report addresses aspects of objectives 1 and 4 of the parent project plan.