Efficacy of Selected Insecticides for Control of Soybean Looper 1, 2015

Soybean was planted on 8 Jun in Jefferson County, Arkansas. Plot size was four rows by 50-ft long planted on 38-inch rows, arranged in an RCB design with four replications. Insecticides were applied with a Mud-Master sprayer equipped with a multiboom delivering 10 gpa at 40 psi through 8002 dual flat fan nozzles with 19.5-inch spacing. Crop oil concentrate 1% v/v was added to all treatments. Insecticide application occurred on 17 Aug. Soybean looper densities were determined by taking 25 sweeps per plot with a 15-inch diameter net. Samples were taken on 20, 25, 28, and 2 Sep, 3, 8, 11, and 16 days after treatment (3 DAT, 8 DAT, 11 DAT, 16 DAT), respectively. Data were analyzed with ANOVA and means were separated using a Duncan’s New MRT (P < 0.10) (Table 1).

At 3 DAT, all of the insecticide treatments reduced soybean looper densities below those in the untreated check. At 8 DAT, all insecticide treatments, except Karate, resulted in soybean looper densities below that in the untreated check. At 11 DAT, all of the insecticide treatments, except Karate, resulted in significantly lower soybean looper densities than the untreated check. Also, Intrepid Edge (4 and 5 oz/acre) resulted in lower soybean looper densities compared with all other treatments. At 16 DAT, all of the insecticide treatments, except Karate and Steward, resulted in lower soybean looper densities than the untreated check. All treated plots, except those treated with Karate, had lower season total soybean looper densities than those in the untreated check. Intrepid Edge at 5 oz/acre resulted lower season total looper densities than all other insecticides, except Intrepid Edge at 4 oz/acre.

This research was supported by industry gifts of products and research funding.