Control of Small, Medium, and Large Soybean Loopers on Soybeans in Alabama, 1983

Abstract

Abstract This field test was conducted on soybeans planted in Cahaba sandy loam soil at the Plant Breeding Unit of Auburn Univ., Tallassee, Ala. Five treatments and an untreated check were replicated four times in a randomized complete block design. Each 0.012 acre plot was four rows wide (40-in. row spacing) and 40 ft long. Treatments were applied on 8 Sep. with a high clearance boom sprayer equipped with three TX6 hollow-cone nozzles per row operating at 50 lb/in2 and delivering 9 gal/acre. Insect populations were sampled by placing a standard 3-ft beat sheet between the rows and beating the plants on both sides. Larvae were identified and assigned a classification of small (instars 1 to 2), medium (instars 3 to 4), or large (instars 5 +); they were then counted and recorded. Three samples from each plot were taken 1, 4, and 7 days postspray 9, 12, and 15 Sep. At 1 day postspray, both Lorsban (1.0 lb (AI)/acre) and a tank mixture of Lorsban (0.5 lb) and Ambush (0.05 lb) effectively reduced numbers of small and medium soybean loopers. On the second sampling date (4 days postspray), the Lorsban-Ambush mixture plots and the plots treated with Orthene (0.75 lb) had fewer large soybean loopers than the untreated check. By 7 days postspray, the only treatment effective in reducing numbers of small soybean loopers was the Lorsban-Ambush mixture. The Lorsban-Ambush mixture. Scout (0.015 lb), and Lorsban (1.0 lb) all effectively reduced numbers of medium loopers, but no significant differences were detected among treatments on large loopers. Overall, the Lorsban (0.5 lb) and Ambush (0.05 lb) mixture was the most effective treatment against soybean loopers.