Armyworm Control in Corn, 1985

Test plots were established in 2 no-till fields in Maryland. ‘Dekalb XL61’ field corn was planted 20 Apr near Hebron in Wicomico County and Pioneer 3358’ was planted 8 May near Sunnybrook, Baltimore County, Md. At both locations the row spacing was 30 inches and at the time of treatment the corn was in the 4-leaf stage. Pretreatment precounts at the Baltimore County field averaged 2—3 worms/plant. Pretreatment counts at Wicomico County were 0.5 worms/plant. Treatments were applied 28 May at Wicomico County and 3 Jun at Baltimore County. All ;>lots were 4 rows × 25 ft arranged in a randomized complete block design. There were 3 replicates in Wicomico County and 1 in Baltimore County. Sprays were applied by hand held C02 backpack sprayer calibrated to deliver 20.4 gal/acre at 40 psi. Granules were applied by shaker can. On 29 May in Wicomico County and on 5 Jun in Baltimore County, 40 corn plants from the 2 center rows were searched, and the number armyworms found on and around the plants was recorded.