Foliar Sprays to Control Insect Pests on Late-Planted Sweet Corn, 1987

Silver Queen' sweet corn was planted 13 Jul in a Sassafras sandy loam field. Plots were 4 rows wide on 30-inch centers and 25 ft long. Whorl sprays were applied with a self-propelled, high-clearance sprayer with one nozzle centered over each of the middle 2 rows calibrated to deliver 30 gal/acre at 40 psi operated at 2 mph. Foliar sprays at silking were applied with 4 nozzles/row, directed at the ear zone, using 105 gal/acre at 40 psi operated at 2 mph. The center 2 rows of each plot were treated and the outer 2 rows were untreated guard rows. Sprays were applied on 19 and 25 Aug and on 8, 11, 14, 17, 21, and 24 Sep. At harvest (27 Sep), 20 ears from the center 2 rows of each plot were husked and evaluated for worm damage as fresh-market (clean ears, no damage evident), processing (evidence of tip feeding, but less than 3.6 cm tip damage), and culls (tip damage beyond 3.6 cm to the side and/or bottom). All worms found within the husk or ear were identified, counted, and recorded; all ears were then weighed and total weights were recorded. On 9 Nov, 20 stalks from the center 2 rows of each plot were split from 3 nodes above the ear to 3 nodes below the ear and each 2.5 cm of ECB damage recorded as one cavity.