Drosophila Suzukii Control in Tart Cherries, 2016*

This trial was conducted to evaluate the efficacy of several rates and timings of various insecticides against spotted wing drosophila (SWD) in tart cherry. Single tree plots were established in a 21-yr-old ‘Montmorency’ cherry planting (Tart Cherry 4, 15 × 20 ft spacing) at the 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 the first trap catch and were reapplied on 7-day intervals until 10 Aug (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 the fungicides Topsin, Bravo Weatherstick, Indar, Elite, Rally, Kocide 3000, Gem 500, Rally 40, Indar, Bravo Weatherstik, Cuprofix Ultra, and Badge. Alion and 2, 4-D Weedar were banded below the trees for weed control. Applications of test materials were made as outlined in Table 1.

Four pound samples of ripe fruit were hand-picked from each replicate plot on 7, 14, and 20 Jul from one-tree plots. 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 pounds brown sugar to 5 gal water. The larvae were allowed to float and were subsequently counted. Data are presented as pupae per pound of fruit. Transformed treatment means were analyzed using ANOVA and means separation by Tukey’s HSD at P = 0.05.

In the 7-Jul evaluation, Imidan, Imidan/Exirel, Grandevo + R56, Rimon, Dimilin, and the two Harvanta treatments all provided significant protection from SWD larval infestation, compared to the untreated check (Table 1). In the 14-Jul evaluation, all treatments except Movento/Leverage, Grandevo + Tactic, Grandevo + Tactic/Pounce significantly reduced the incidence of SWD larvae in fruit. In the 20-Jul evaluation, only Imidan/Exirel and Harvanta (16.4 oz rate) provided significant fruit protection against SWD.

Author notes