Control of Fall Armyworm in Whorl Stage Sweet Corn, 1987

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Abstract A small-plot field experiment was conducted to screen insecticides for control of leaf-feeding damage to sweet corn seedlings by the fall armyworm. Sweet corn was planted 11 Aug in an Appling loamy coarse sand. The experiment was a randomized complete block design with 2-row plots, 20 ft long and 38 inches wide, with 5-ft alleys, replicated 5 times. Full-cone sprays were applied at 30 psi, directed over the whorl in a final volume of 25 gal/acre. Sprays were initiated when plants were in the 4th leaf stage at a time when 50% showed leaf feeding symptoms of 1st instar larvae. Plants were sprayed on 2, 9, and 16 Sep. On 9 and 28 Sep, all plants in each plot were rated for fall armyworm damage using the following 0-7 damage index: 0, no damage; 1, slight leaf feeding, but no indication of bud damage; 2, moderate leaf feeding, but no bud damage; 3, heavy leaf feeding and no bud damage; 4, slight to moderate feeding and slight bud damage; 5, moderate to heavy leaf feeding damage and moderate to heavy bud damage; 6, heavy leaf feeding and severe bud damage; and 7, plant virtually destroyed.