Evaluation of Selected In-Furrow At-Planting Granular and Liquid Insecticides for Control of Thrips in Peanut, 2014 * Open Access

Selected granular and liquid insecticides applied in-furrow were evaluated for control of thrips in peanut. ‘Bailey’ peanut was planted 8 May at the Virginia Tech Tidewater Agric. Res. & Ext. Ctr., Suffolk, VA, using 36-inch row spacing. Seed was not treated with any insecticide. The granular Temik treatment was applied into the seed furrow at the time of planting using tractor-mounted inverted polypropylene jars with lid holes calibrated to deliver exact amounts via gravity. Liquid Velum Total treatments were applied into the seed furrow at planting at 5 gpa using a microtube mounted between the disc openers, pressurized by CO ₂ at 51 psi. A RCB design was used with four replicates; plots were 4 rows by 35 ft. Thrips injury to plants was determined by visually rating injury using a 0–10 scale, where 0 = no injury, 1 = 10% leaves injured, 2 = 20% leaves injured, 3 = 30% leaves injured, 4 = 40% leaves injured, 5 = ≥ 50% leaves injured and ≤ 5% terminal buds injured, 6 = ≥ 50% leaves injured and 25% terminal buds injured, 7 = ≥ 50% leaves injured and 50% terminal buds injured, 8 = ≥ 50% leaves injured and 75% terminal buds injured, 9 = ≥ 50% leaves injured and 90% terminal buds injured, and 10 = dead plants. Peanut stand was determined on 27 May by counting all plants in two rows of each plot. The number of plants with visual symptoms of Tomato spotted wilt (TSW) was determined by examining two rows per plot on two dates. Peanuts were dug on 3 Oct. Yields were determined by combining peanuts from two rows of each plot on 14 Oct and adjusting to 7% moisture. Data were analyzed using ANOVA and LSD statistical procedures.

Peanuts treated with Temik (at 7 lb/acre) had significantly higher yield than those treated with Velum Total (at 18 oz/acre) or untreated plants ( Table 1 ). The Temik treated plots also had the numerically lowest thrips injury rating on all four sample dates. While Velum Total (at 14 oz/acre) had a lower thrips injury rating than Velum Total (at 18 oz/acre) on three of four sampling dates, the treatments had no significant difference in yield. There was no significant difference among treatments in TSW hits on either sampling date.

Author notes