Aphid Control on Shade Tobacco with Systemic Insecticides, 1996

Insecticide treatments were evaluated for tobacco aphid control in a cloth-covered shade tent at the CT Agricultural Expt. Station Valley Laboratory in Windsor, CT. The soil was an Entic Haplorthod (71.8% sand, 23.0% silt, 5.2% clay, pH = 6.0 and OM = 4.0%) naturally infested with tobacco cyst nematodes (Globodera tabacum tabacum). On 28 May, plots were fertilized with 126 lb N/acre of cottonseed meal-based 10-8-10, broadcast treated with Lorsban 4E at 1.5 lb (AI)/acre and Ridomil 2E at 1 lb (AI)/acre and spiked to incorporate. On 5 Jun, Vydate L [2.0 lb (AI)/acre in 107 gpa water] was broadcast to appropriate plots in a 39-inch swath using a TeeJet KCL-5 nozzle and raked to incorporate. Tobacco was transplanted on 6 Jun to rows 39-in apart with 1 -ft spacing within rows. There were 20 replicate 4-row plots of each treatment (15 X 15 ft), each with 2 treated pick rows in the center and 2 adjacent treated border rows. Plots were separated by an additional untreated border row. Vydate was band applied at 2.0 lb (AI)/acre to appropriate plots on 7 Jun to 6 inches on either side of rows using a backpack sprayer with a TeeJet 8004-E nozzle and incorporated by hoeing. Admire 2F was applied on 6 Jun as a soil drench at 0.15 lb (AI)/acre (10,800 plants/acre) using a backpack sprayer with a TeeJet TG-3 nozzle at 15 psi to apply 20 ml/plant in 2 10-ml applications 2 cm to either side of plants. Foliai Orthene at 0.75 lb (AI)/acre, in 204 gpa water, was applied on 8 Jul to previously untreated plots and on 16 Aug to plots previously sprayed with Orthene or Vydate using a TG-3 nozzle at 15 psi. One leaf each from 15 plants per row was removed on 16 Aug, 21 Aug, 30 Aug, and 6 Sep (60 leaves per plot) and rated for apterous 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). Ratings from 15 plants per plot were recorded and treatments compared within dates by the nonparametric Kruskal-Wallis Test. Plants were picked at weekly intervals over six weeks (29 Jul, 6 Aug, 15 Aug, 20 Aug and 28 Aug) to remove 18 leaves.