Foliar Sprays to Control Corn Earworms and Fall Armyworms in Sweet Corn, 1977

‘N & k 199’ sweet corn was planted, 10-inch spacing in 3-ft rows, on Jun 13’77. Treatment plots were replicated 3 times and arranged in a randomized block design. Each plot consisted of three rows 25 ft long with a single untreated row adjacent to each treatment plot. Insecticides were applied to the ear and to an area about 15 inches above and below the ear with a D. B. Smith 5-gallon, knapsack, hand-operated, compressed-air sprayer at the rate of 25 gal/acre at 40 psi pressure, using a Spraying Systems Cone Jet Y-8 nozzle. Treatments were initiated at first silk on Aug 5 and continued at 2-3 day intervals through Aug 15, a total of 5 applications in all. Twenty-five ears were harvested from each replicate on Aug 19 and checked for earworms and fall armyworms. The following categories were selected for evaluation of earworm injury: 1) Clean - no evidence of earworm; 2) Medium - injury less than 1.5 inches below tip; ear could be clipped; and 3) Severe - damage well below ear tip and of such nature that ear could not be clipped or salvaged for use. Heavy fall armyworm feeding undoubtedly destoryed many earworm eggs and small larvae. Fall armyworm injury was evaluated by classifying the ears as Damaged or with Severeinjury - all ears in the severe group were a total loss.