Control of Spotted Wing Drosophila in Blueberries, 2016*

This trial was conducted to evaluate the efficacy of several rates and timings of various insecticides against SWD in Blueberry. Two bush plots were established in a mature ‘Jersey’ blueberry planting (4 × 12 ft. spacing) at the Nye farm, located ∼3 miles southwest of Trevor Nichols Research Center in Fennville, MI. Treatment plots were replicated four times and set up in an RCB design. Applications began 20 July at first SWD trap catch and were re-applied on 7 d intervals (Table 1). Test materials were applied with an FMC 1029 airblast sprayer calibrated to deliver 50 GPA at 2.5 mph. No foliar maintenance pesticides were applied to the test plots during the trial.

Fruit were hand-harvested on 2, 9 and 16 Aug. Samples were weighed in grams, with weights then converted to pounds. The fruit samples were evaluated through the Washington State Department of Agriculture brown sugar method as follows. Blueberries were crushed in a solution of 7 pounds brown sugar to 5 gallons water. The larvae were allowed to float and subsequently counted. Due to differences in sample sizes, data are presented as larvae per pound of fruit. All data were analyzed using ANOVA and means separation by Tukey’s HSD at P = 0.05.

While numerical trends differed, due to variability there were not statistically significant differences between treatments in the 2 Aug fruit evaluation (Table 2). In the 9 Aug evaluation VST006340, Captiva + Imidan, Imidan, Grandevo + NuFilm, and Grandevo + NuFilm + Pyganic all significantly reduced the incidence of SWD larvae in fruit. In the 16 Aug evaluation all treatments significantly reduced SWD larval counts in fruit.

Author notes