Good Fruit Grower

March 1

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GOOD TO KNOW A research report from Alan Knight, USDA Agricultural Research Service, Yakima, Washington New traps and lures for tree fruit pests Researchers aim to improve monitoring techniques for several key orchard pests. G TABLE 1 enerations of growers have monitored the key pests in their orchards. Over the years, traps and lures available to growers have evolved. Yet, the goal has always been to develop easy-to-use, sensitive, and selective trapping systems. Sorting through pails baited with fermenting fruit juice filled with a writhing mass of flies, wasps, lacewings, and moths of various sizes has been the visual incentive for entomologists to develop new technologies. While the broad goal for any trapping program is similar, the specific focus can vary for different pests, such as codling moth, oriental fruit moth, the Pandemis and obliquebanded leafrollers, and spotted wing drosophila. Codling moth can be adequately monPercent traps itored with a high-load sex pheromone catching any lure within sex- pheromone-treated Leafroller location and damage leafroller orchards, but the combination of sex Orchard clean, and isolated 0 pheromone and pear ester improves the from sources of leafrollers reliability of monitoring in orchards where Orchard clean, adjacent to cherry 50 mating disruption is used and allows or other infested host female moth populations to be tracked. Orchard with overwintering larvae, 50 However, with oriental fruit moth, sex but sprayed, with no fruit injury Orchard infested, with fruit injury 100 pheromone lures do not work under Monitoring leafroller in traps with CM-DA Combo plus acetic acid lures for codling moth LR Risk None / low Low / moderate Moderate High FIGURE 1. Ajar trap for oriental fruit moth with exclusion holes. mating disruption, and orchards are often still monitored with an open bait bucket. In the case of leafrollers, pheromone traps often catch too many moths, and catch is not indicative of infestations inside the orchard. Similarly, spotted wing drosophila can be trapped with apple cider vinegar in very high numbers around infested orchards. Farm managers have used a variety of trap designs with little coordination even among researchers or extension specialists to help interpret catch numbers from this ensemble of traps. Research to develop effective monitoring tools for tree fruits has a long history at the U.S. Department of Agriculture���s Agricultural Research Laboratory in Yakima, Washington. Dr. Frank Howell, who passed away in 2012, was instrumental in the development of the standard wing trap baited first with virgin female moths and then with synthetic sex pheromone lures for codling moth. More recent studies have focused on developing several innovative new monitoring approaches for pests: the use of a single trap to monitor codling moth and leafrollers, a new trap design to monitor both sexes of oriental fruit moth in mating-disruption-treated orchards, and a new trap design for spotted wing drosophila. One trap for codling moth and leafrollers Adding acetic acid to the Pherocon CM-DA Combo lure clearly increases catches of male and female codling moths. In response, Tr��c��, Inc., developed the Pherocon AA lure. Over the past few years, we have noticed low catches of leafrollers in traps placed in some orchards. To address this, we developed a new AA lure that has a much higher release rate to be most effective for leafrollers. A two-year project funded by the Washington Tree Fruit Research Commission with Dr. Jay Brunner at Washington State University and Dr. Rick Hilton at Oregon State University found that, in most cases, catches of leafrollers in these traps were indicative of the presence or risk of infestation of either leafroller (Table 1). However, some exceptions were also noted. False negatives (traps failed to catch) sometimes occurred when overwintering larvae were found, but no subsequent adults were captured. This was likely due to the subsequent use of insecticides to control the larval population. Another occurrence was when damage in some Medford pear orchards was misidentified as leafroller 32 MARCH 1, 2013 GOOD FRUIT GROWER

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