Control of Spotted Wing Drosophila in Jersey Blueberries, 2018

This trial was conducted to evaluate the efficacy of several rates and timings of various insecticides against Spotted Wing Drosophila (SWD) in Blueberry. Two-bush plots were established in a mature ‘Jersey’ blueberry planting (4 × 12 ft spacing) at the Nye farm, located approximately 3 miles South West of Trevor Nichols Research Center in Fennville, MI. Treatment plots were replicated four times and set up in an RCB design. Applications began 23 July at first SWD trap catch with ripe fruit and were re-applied on 3- and 7-day covers (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.

Fruits were hand-harvested on 2, 16, and 23 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 and floating SWD larvae were 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.

All treatment programs provided significant fruit protection on the 2 Aug evaluation, compared to the untreated check (Table 1). Only Lannate LV/MustangMaxx/Imidan/Brigade, Grandevo (3lb) + NuFilm, Danitol, Entrust, Argyle, and Imidan/Verdepryn/MustangMaxx programs significantly reduced SWD infestation 16 Aug compared to the untreated check. All treatment programs provided significant fruit protection on the 23 Aug evaluation, compared to the untreated check.¹

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