Control of Green Peach Aphid on Tobacco, 1983

Thiodan and malathion dusts, standard insecticides for aphid control on tobacco in this region, were compared with three formulations of acephate. Tobacco plants grown from seed in multipot trays, were transplanted on 22 Jun. to a field of Merrimac sandy loam on the Valley Laboratory farm. Cultural practices throughout the growing season were standard for cigar binder tobacco with plants 24 in. apart in rows that were 39 in. apart. Each plot consisted of seven plants in a single row with a border row between each plot. Each randomized treatment was replicated four times. Insecticides were applied 8 Sep. when the aphid population appeared vigorous and more or less uniformly covering the test area. Acephate 75 SP combined with pecanshell meal to make a dust, and the malathion and thiodan dusts were applied with a Chapin handcranked duster. The acephate liquid formulation was applied with a Solo backpack sprayer using a cone nozzle and 20 lb/in2. The acephate mist treatment was applied with a knapsack KWH power-driven mist blower. For the post-treatment count, taken on 14 Sep., all stages of aphids were recorded in three 4.7cm circles (leaf tip, middle and base) on the lower surface of two leaves from each of two plants in every plot.