Simulated Commercial Insecticidal Trials for Control of Corn Earworm and Fall Armyworm on Sweet Corn in Alabama, 1982

Sweet corn tests were conducted at the Auburn University North Alabama Horticulture Substation, Cullman, AL on both early- and mid-season plantings of Buttersweet corn. Early-season test plots were 6 rows (44-inch centers) x 50 ft, and mid-season plots were 6 rows (44-inch centers) x 25 ft. All treatments were replicated 4 times in a randomized complete block design. Applications were made with a John Blue S 6000 high clearance sprayer operating at 45 psi , delivering 75 gpa through 3 TX26 hollow cone nozzles per row, 1 over-the-top, and 2 on drops at the level of, and directed towards the ears. The early-season test received 9 applications on alternate days beginning at initial silking , Jun 25, through Jul 12. Applications on the mid-season test were initiated on Jul 23 and were made either daily or on alternate days, through Aug 10 (10 or 19 applications). Treatment efficacy was determined through damage ratings and larval counts on 100 ears per plot in the early-season test , and 50 ears per plot in the mid-season test. Ears were shucked, examined for larvae, and rated by the following 1-6 scale: 1 = clean; 2 = slight silk or tip damage; 3 = tip damage of <1.5 inch; 4 = tip damage of >1.5 inch; 5 = side damage; 6 = tip and side damage. Mean damage and larval counts were analyzed using the AN0VA test and compared using Duncan’s multiple range test.