Seed Protectants Safen Sorghum (Sorghum bicolor) Against Chloroacetamide Herbicide Injury

Abstract

Alachlor at 3.4 and 6.7 kg ha-1, metolachlor at 2.8 and 5.6 kg ha-1, and propachlor at 4.5 and 9.0 kg ha-1were applied to grain sorghum in field experiments conducted in 1981 and 1982. ‘Dekalb E-59’ and ‘Pioneer 8311’ grain sorghum were tested with and without the seed protectants cyometrinil and flurazole in both experiments. ‘Funk's G-1350’ was tested with and without cyometrinil and CGA-92194 in one experiment. Alachlor and metolachlor caused serious injury (stunting and, in some instances, reductions in stand and yield) to grain sorghum without the seed protectants. Less severe injury to grain sorghum occurred with alachlor and metolachlor at high rates even in the presence of the seed protectants. The three seed protectants were equally effective in preventing crop injury. Only minor injury to grain sorghum, with or without the seed protectants, occurred with propachlor at both rates. Overall, early-season weed control was 81 to 100%; however, propachlor at the rates tested was noticeably weaker than alachlor and metolachlor against some annual grasses.