Good Fruit Grower

May 15

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In field trials in Washington, Oregon, and Mississippi with cherries, blueberries, blackberries, and raspberries, the new four-component lure never failed to catch large numbers of flies, Landolt reported. It was used in a dome-style trap with a large bottom entrance, which Landolt believes is more effective than traps where insects enter through funnels or holes in the top or sides. The lure was effective early in the season, when fly populations are low, as well as later in the season when ripening fruit competes for the fly's attention. Landolt said he and Cha moved well beyond the initial goal of trying to come up with chemicals that would be as attractive as wine and vinegar. By altering the amounts and ratios of the chemicals, they roughly doubled the attractiveness of the lure. "Now, we're quite a bit better than wine and vinegar consistently," he said. Other insects Another advantage of the new chemi- cal lure is that it attracts far fewer nontar- get insects. In traps with wine and vinegar or other food baits, the liquid can be com- pletely filled up with insects of many kinds, and most of those are not spotted wing drosophila flies. In contrast, where the new lure is used, the drowning liquid is usually clear, with primarily spotted wing drosophila and just a few other insects in it, Landolt said. In field tests, the new lure attracted far fewer noctuid moths, muscoid flies, yellowjackets, and other drosophila species than the wine and vinegar (see table above). "It's not absolute, but the difference is very great," Landolt said. Landolt and Cha are now finalizing work to determine the optimal release rates for each of the four chemicals. Trécé has a new lure called the Pherocon SWD Dual-Lure on the market this season that uses the four chemicals and can be used with apple cider vinegar or a neutral drowning solution, such as water with antifreeze or soapy water (see "SWD bugs California growers"). The con- trolled release lure lasts for up to 30 days. Scentry is developing a version of the lure called V2. Landolt expects the Cha lure will be useful to growers not only for monitoring the arrival of the pest in an orchard, but for assessing how well treatments have controlled the insect. He'll be working with other entomologists to figure out how the lure can be useful in integrated pest management programs. • Nontarget insect trap catches The table shows the mean number of insects trapped per week in traps baited with a mixture of wine and vinegar versus traps with the Cha lure. Insect Wine and vinegar Cha lure Spotted cutworm moth 10.7 0.3 Bertha armyworm moth 6.7 0 *EPWIWXEFPI¾] 0MXXPILSYWI¾] +IVQER]IPPS[NEGOIX ;IWXIVR]IPPS[NEGOIX 3PMZIHEVXQSXL 8VYIEVQ][SVQQSXL SOURCE: Peter Landolt, USDA-ARS PHOTOS BY TJ MULLINAX Dr. Dong Cha and colleagues at the USDA in Yakima, Washington, identified chemicals that attract spotted wing drosophila and developed dispensers that would release the chemicals consistently over a period of time. GOOD FRUIT GROWER MAY 15, 2014 29 Spotted wing drosophila flies are suspended in alcohol at the USDA lab in Yakima, Washington.

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