The effectiveness of an unregistered material at reducing Drosophila suzukii (SWD) infestation rates in blackberry field plots and its toxicity to adult SWD in laboratory bioassays was tested during the 2015 growing season. Field trials were conducted at the Sandhills Research Station near Jackson Springs, NC, in a 0.11-acre planting consisting of two rows of ‘Ouachita’blackberries. Six treatments, including an untreated check (UTC), were applied to 5-plant plots and were arranged in an RCB design with four replicates per treatment, blocked by row, with two blocks per row. Delegate was the standard material. Some of the treatments were combined with an adjuvant, Syntact, at a concentration recommended by the manufacturer (Table 1).

Applications were made twice, on 11 and 30 Jun. Treatments were applied to both sides of each row to fully cover plants using a CO2-pressurized backpack sprayer fitted with three flat fan nozzles at 45 psi pressure and 50 gal/acre spray volume. The desired application frequency for these materials is 7 days; however, additional applications could not be made due to unseasonably hot weather. Ten to 20 ripe berries, depending on availability, were collected from the middle three plants in each plot pre-treatment and 7 days after treatment (DAT) to measure infestation in the field. Fruit were held in plastic containers vented with fine mesh on the bottom to allow fruit to drain at 20 C, 65% RH, and 12: 12 (L: D) h conditions. After 7 days, larvae and pupae were counted to determine infestation rates per berry. Plant material for bioassays was collected immediately after treatment (0 DAT) and 7 DAT. A small branch with several leaves and three ripe berries were collected in each plot and immediately placed into an individual bioassay arena. Arenas were constructed from 32-oz plastic deli cups fitted with a floral water pick into which the cut stem was placed. Arenas were transported back to the laboratory and provisioned with food and water, whereas berries were placed in a 1-oz portion cup within each arena. Five male and five female reproductively mature SWD adults (≥ 5 days old) were then placed in each arena. Flies were obtained from a laboratory colony maintained for over 50 generations. Arenas were