Influence of Acetamide Herbicide Applications on Efficacy of the Protectant CGA-43089 in Grain Sorghum (Sorghum bicolor)

Abstract

The influence of acetamide herbicide applications on efficacy of CGA-43089 [α-(cyanomethoximino)-benzacetonitrile] in grain sorghum [Sorghum bicolor(L.) Moench] was studied under field conditions. Acetamide herbicides applied preplant and incorporated on a Haynie very fine sandy loam caused more grain sorghum injury in 1979 than in 1978. Reductions in plant population, plant height and yield, along with delay in maturity, were severe for acetochlor [2-chloro-N-(ethoxymethyl)-6′-ethyl-O-acetotoluidide], metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide], and alachlor [2-chloro-2′,6′-diethyl-N-(methoxymethyl)acetanilide]; moderate for diethatyl [N-(chloroacetyl)-N-(2,6-diethylphenyl)glycine], xylachlor [2-chloro-N-(2,3-dimethylphenyl)-N-(1-methylethyl)acetamide], and butam [2,2-dimethyl-N-(1-methylethyl)-N-(phenylmethyl)propanamide]; and did not occur for propachlor (2-chloro-N-isopropylacetanilide) treatments. Acetamide herbicides caused less grain sorghum injury on a Reading silt loam than on a Haynie very fine sandy loam in 1979. CGA-43089 applied as a seed treatment protected grain sorghum grown on soils treated with metolachlor, alachlor, diethatyl, or xylachlor. Metolachlor-triazine combinations at five locations in Kansas reduced yields at two locations. CGA-43089 provided protection from metolachlor injury at those two locations.