Influence of Several Herbicides for Broad-Leaved Weed Control and Tween 20 on the Phytotoxicity of Paraquat

Paraquat at 0.28 kg/ha provided excellent control of barley (Hordeum vulgare L.), wheat (Triticum aestivum L.) and oats Avena sativa L.) when applied at the four-leaf stage of growth. Applications of paraquat in tank mixtures with ester formulations of 2,4-D, MCPA, bromoxynil or bromoxynil/MCPA did not affect paraquat activity on the grasses. Tank mixtures of paraquat with dimethylamine formulations of 2,4-D and MCPA resulted in a permanent reduction of paraquat activity on the annual grass species. Sequential applications of 2,4-D amine or MCPA amine in relation to paraquat did not reduce paraquat activity on the annual grass species. Control of rapeseed (Brassica campestris L.) with 0.28 kg/ha paraquat was not acceptable and was variable. However, excellent control of rapeseed was obtained when one of several herbicides for broad-leaved weed control were combined with paraquat.