Evaluation of Karate Z for Control of Bird Cherry-Oat Aphids in Winter Wheat, 2016

A selected insecticide treatment of Karate Z 2.08CS was evaluated for control of bird cherry-oat aphid and suppression of barley yellow dwarf virus transmission in winter wheat at the Fisher Delta Research Center Lee Farm (Hayward, MO). Wheat was planted in 15 Oct. The test was arranged in an RCB design with four replicates. Individual plots were 30 × 150 ft and planted at a rate of 100 pounds of seeds per acre. Foliar treatments were applied with a high clearance sprayer calibrated to deliver 10.8 gpa at 32 psi with 80,015 flat fan nozzles. Broadcast foliar application was made in 1 Feb. Plots were sampled by visually inspecting the leaves of 10 random plants per plot, beginning at stage 5 on the Feekes scale, or when the wheat was beginning to elongate. On each date, 10 randomly selected plants per plot were inspected for the presence of aphids and the total number of aphids recorded. Aphid densities were determined in 19 Feb, 18 days after treatment (18 DAT), 23 Feb (22 DAT), 1 Mar (29 DAT), 8 Mar (36 DAT), and 15 Mar (43 DAT). On each date, plants were observed for barley yellow dwarf virus by examining all of the wheat within an arm’s reach in each plot. Data were subjected to ANOVA and means were separated using a protected LSD.

There were no significant differences among treatments at 18 and 22 DAT. Karate Z significantly reduced the total number of aphids compared with the untreated check at 36 and 43 DAT (Table 1). No barley yellow dwarf virus was observed in the trial. This research was partially supported by industry gifts of pesticide and seed.

Author notes