BENAZOLIN FOR SELECTIVE WEED CONTROL IN WHEAT AND OILSEED CROPS

In field tests conducted between 1963 and 1969, wheat, Triticum aestivum L., flax, Linum usitatissimum L., Argentine rape, B. assica napus L., and Polish rape, B. campestris L., were tolerant to benazolin (4-chloro-2-oxo-3-benzothiazolineacetic acid). Wild mustard, Sinapia arvensis L., and redroot pigweed, Amaranthus retroflexus L., were controlled. Control of other weeds encountered in these tests was usually unsatisfactory. There was sufficient difference in tolerance of wild mustard and both species of rape to make selective control possible. In years when growing conditions were favorable, benazolin gave good control of wild mustard in rape at 0.56 kg/ha. When crop stands were poor due to dry, unfavorable weather a rate of 0.84 kg/ha was required. This sometimes caused light but visible injury to the rape, although crop yields were not significantly reduced. The selective properties of benazolin may make it possible to grow rape on land infested with wild mustard.