Field Corn, Northern Corn Rootworm Larval Control, 1979

The test field had been in continuous no-till corn for 4 years. Corn was planted no-till in 30 inch, 3 row plots, 95 ft long with 4 replications in a randomized block design. Thirty-five insecticide-rate combinations were compared. The treatments were evaluated by root damage ratings based on the Iowa 1-6 system and on yield. Stand establishment was also observed. Only 3 materials had a stand density of less than 104 per 100 row ft. All treatments except Furadan 4F at 0.25 and 0.5 lb and Furadan 10G at 0.25 lb significantly reduced rootworm danage in comparison with the untreated check. The Furadan 4F and FMC 35001 4E formulations did not perform comparable to these same chemicals formulated for granular treatment. The more than average precipitation during the summer season may have accounted for this reduction in efficacy.