(F39) CORN (FIELD): Zea mays L. 'Pioneer 3733' Northern corn rootworm; Diabrotica barberi (Smith and Lawrence) Western corn rootworm; Diabrotica virgifera virgifera (LeConte) Cornell University E.J. Shields and A.M. Testa Department of Entomology Ithaca, N.Y. 14853 Phone: (607) 255-8428 Email: [email protected]
CORN ROOTWORM CONTROL IN FIELD CORN, 1994: Experimental plots measuring 37 rows x 30.5 m (100 ft) were planted at Musgrave Research Farm, Aurora, N.Y., on 21 May, and Agway Research Farm, Tully, N.Y., on 26 May, with a 2row corn planter at 31,000 seeds/acre, and fertilized with 400 lb of 10-10-10 fertilizer banded at planting. Soils were silt loam with 4% organic matter. Soil PH at the Aurora site was 8.1 and 6.5 at the Tully site. Each treatment was a single row by 100 ft. Thirty-seven treatments were replicated four times in a CRB design. Supplemental nitrogen was provided with a preplant incorporated application 300 lb urea. Granular insecticides were applied at planting (AP) with Noble granular applicators mounted on the planter. Stand counts were taken 100 row ft on 22 June in Aurora. Five plants in each row were dug and the roots washed before rating root damage using the Iowa 1-6 root rating scale on 5 August in Aurora and on 5 Aug in Tully. Treatments were mechanically harvested in Tully only, on 27 Oct with a single row silage chopper (New Holland model 707), and the silage from each treatment row was collected and weighed. Means were seperated using Fisher's LSD. Significant differences were observed at 0.05 level between treatments in root ratings and silage yield (Tully) and root ratings and stand counts (Aurora).