Foliar Sprays to Control Lepid0Pteran Larvae on Late-Planted Sweet Corn, 1981

Abstract

Abstract ‘Silver Treat’ sweet corn was planted Aug 1 to 8 Sassafras sandy loam field. Plots were 4 rows wide on 30-inch centers and 25 ft long. Whorl sprays were applied with a trctor-mounted boom sprayer with one nozzle centered over the row calibrated to deliver 55 gal/A at 40 psi; foliar sprays at silking were applied with a tractor-mounted boom sprayer with 4 nozzles/row, directed at the ear zone, which delivered 170 gal/A at 250 psi. Whorl treatments were applied aug 29 and Sep 4. Foliar sprays at silking were applied Sep 21, 25 and 29 and Oct 2. Twenty plants from the middle 2 rows were evaluated on Sep 11 for armyworm damage. The categories for armyworm foliar feeding damage are as follows: (0) no damage; (1) slight damage; (2) 10% damage; (3) moderate damage, 25% of whorl destroyed; (4) heavy damage, 50% of whorl destroyed; and (5) severe damage, skeletonized, whorls destroyed. At harvest (Oct 15) 20 ears from the middle 2 rows of each plot were evaluated for ‘worm’ damage as “none” (clean), “tip” (less than 1.5 inches tip damage) and “side”. O Oct 24, 20 stalks from the middle 2 rows of each plot were split from tassel to soil surface; each inch of European corn borer damage was recorded as one cavity.