Evaluation of Application Method for Aphid Control by Imidacloprid on Connecticut Shade ToBacco, 1997

Abstract

Abstract Preplant broadcast, transplant drench, or band application treatments of Admire 2°F (imidacloprid) were evaluated for tobacco aphid control in a cloth-covered shade tent at the CT Agricultural Expt. Station Valley Laboratory in Windsor, CT. Admire 2°F was applied at 0.17 lb (AI)/acre (1.0 oz per 1000 plants based on 10,800 plants/acre) for all treatments. The soil was an Entic Haplorthod (71.8% sand, 23.0% silt, 5.2% clay, pH = 6.0 and OM = 4.0%). On 29 May, plots were fertilized with 145 lb N/acre of cottonseed meal-based 10-8-10. On 2 Jun, plots were broadcast with Lorsban 4 E at 1.5 lb (AI)/acre and Ridomil 2 E at 1 lb (AI)/acre and spiked to incorporate. On 3 Jun, preplant Admire 2°F in 100 gal/acre water was broadcast to appropriate plots in a 39-inch swath using a TeeJet 8004E nozzle at 18 to 20 psi and spiked. Tobacco was transplanted on 4 Jun to rows 39 in apart with a 1-ft spacing within rows. There were 5 replicates of 4-row plots each per treatment (total 20 plots, 15 X 15 ft each). Plots were separated by an untreated border row. Plots were irrigated 5 Jun with 0.4 inches water. Admire 2°F was applied on 6 Jun as a soil drench using a backpack sprayer with a TeeJet TG-3 nozzle at 15 psi to deliver 20 ml/plant in two 10-ml applications 2 cm to each side of every plant. Admire 2°F was band applied at sidedress in 70 gal water/acre to appropriate plots on 20 Jun (with 59 lb N/acre) or 30 Jun (with 69 lb N/acre) to 6 inches on either side of rows using a backpack sprayer with a TeeJet 8004-E nozzle and incorporated by mechanical cultivation and hoeing. One leaf each from 10 plants per row was removed on 29 Jul, 7 Aug, 14 Aug, and 22 Aug and rated for apterous tobacco aphids (scale: 0 = no aphids or winged only; 1 = 1 aphid per leaf; 2 = 2-10 aphids 3 = 11-100 aphids and 4 = more than 100 aphids per leaf). Treatments were compared within dates by the nonparametric Kruskal-Wallis Test and the Bonferroni Test.