Control of Spotted-Wing Drosophila in Tart Cherry, 2021

This trial was conducted to evaluate the efficacy of two different rates of Verdepryn and other insecticides in the control of SWD in tart cherry. Single-tree plots were established in a 17-yr-old ‘Montmorency’ cherry planting (15 × 20 ft spacing) at the Trevor Nichols Research Center in Fennville, MI (Tart Cherry 4). Treatment plots were replicated four times and in a RCB design. Applications began 24 Jun at initial infestation with ripe fruit and were applied weekly until 15 Jul (Table 1). Test materials were applied with an FMC 1029 airblast sprayer calibrated to deliver 100 gpa at 2.5 mph. Regular maintenance foliar applications were applied to all treatments and included Avaunt, Bravo Weatherstik L, Captan 80, Indar 2F, Luna Sensation 500 SC, and Merivon 4.17 SC. In addition, Alion and glyphosate were banded below the trees for weed control.

One pound samples of ripe fruit were hand-picked from each replicate plot on 29 Jun, and 6 and 13 Jul. The collected fruit was then evaluated through the Washington State Department of Agriculture brown sugar method as follows. Cherries were crushed in a solution with the ratio of 7-lb brown sugar to 5-gal water. The larvae were allowed to float and were subsequently counted. Data are presented as mean SWD larvae per pound of fruit (Table 1). Although non-transformed means are presented, ANOVA was run on log-transformed data. Transformed treatment means were analyzed using ANOVA and means separation by Tukey’s HSD at P < 0.05.

SWD infestations in the first two evaluations were low, likely because high air temperatures suppressed SWD oviposition. Mustang Maxx significantly reduced the incidence of SWD infested fruit in the 13 Jul evaluation, compared to the untreated check.¹

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