Aphid Control on Burley Tobacco, 1991

Abstract

Abstract Ten treatments were evaluated for control of the tobacco aphid on burley tobacco at the Southwest Virginia Agricultural Experiment Station, Glade Spring, VA. Tobacco was transplanted on 23 May in plots 2 rows (8 ft) wide and 30 ft long. The soil type was an Emory silt loam. A randomized complete block was utilized and treatments were replicated 4 times. Plots were separated by single, untreated, border rows and blocks were separated by vacant 5-ft alleys. Except for insect control, production practices conformed to recommendations of the Virginia Cooperative Extension Service. On 24 May, after transplanting, transplant water (TPW) treatments wee applied to individual plants in designated plots at 8 fl oz/plant (340 gal/acre). Foliar treatments were applied on 18 Jul with a CO2-pressurized backpack sprayer delivering 25 gal/acre through 3, TX-10 hollow cone nozzles/ row at 60 psi. During application, the weather conditions were cloudy and calm and the temperature ranged from 75 to 80°F. It rained 0.14, 0.72, 0.20, 0.10, and 0.44 inches at 3, 5, 6, 7, and 8 d, respectively, after the foliar treatments were applied. Aphid infestations on the upper 4 leaves of 10 plants/plot (5 plants/row) were rated on a scale of 0 to 7, where 0 = 0 aphids, 1 = 1-10 aphids, 2 = 11-50 aphids, 3 = 51-100 aphids, 4 = 101-500 aphids, 5 = 500-1,000 aphids, 6 = 1,001-5,000 aphids and 7 = more than 5,000 aphids. Counts were made on 10 Jul, immediately before application of foliar treatments on 18 Jul, and on 22, 25 Jul, 1, and 8 Aug. On 18 Jul the growth of tobacco in each plot was rated on a scale of 0 to 10 where 0 = all plants dead and 10 = large uniform plants. Data were analyzed using ANOVA. Significantly different means were separated using DMRT.