2013 Annual Report
Seasonal fly abundance was monitored using two trap types. Seven sweet cherry orchards and one commercial nectarine orchard were trapped for spotted wing drosophila in 2012 in four towns in the Yakima Valley using Contech and Haviland traps. One trap of each type was hung in each orchard; traps were on different trees approximately 5 m apart. Traps were deployed on 10 May and checked weekly up to the present. Trap solutions were replaced weekly. Numbers of males and females were counted, and data entered into the WSU spotted wing drosophila website weekly throughout the season. Results showed that the fly is present in low numbers in the Yakima Valley, with greatest abundance from August to October. The presence of fly larvae in different non-commercial fruit in the Yakima Valley was determined in 2012. Backyard sweet cherries and wild choke cherries, blackberries, Oregon grape, currants, rosehips, black hawthorn, serviceberry, plum, crabapple, twinberry, bittersweet nightshade, and snowberries were collected in five towns in the valley to determine if they were utilized by the fly and thus need to be monitored for the pest as reservoir hosts that could be sources of infestations in orchards. Individual plants were sampled 1-4 times over the season either when ripe or ripening and ripe. Fruit were held on screens above tubs with slightly moist soil for insect emergence. After about 2 weeks, the soil was poured into containers. Containers were sealed and held at 20-24 °C. The soil inspected for adult flies after 3-4 weeks. Of all fruit samples, only sweet cherries and blackberries were found to have spotted wing drosophila larvae.