OILSEED RAPE growers looking to use propyzamide products for grass-weed control have been reminded they have until the end of January cut-off to do so.

The deadline was introduced because after this date shading by the developing crop canopy could reduce weed control efficacy, explained Interfarm‘s technical manager, David Stormonth.

Beyond the end of January target grass-weed roots may also be below the residual layer in the soil, reducing herbicide effectiveness further, he said.

Where weed roots are well developed, adding a graminicide would help control success, he noted.

But while propyzamide products such as Propose and Flomide can be used in frosty weather, Dr Stormonth urged growers to check the labels of any tank mix partners carefully.

“If you still have crops to spray, use the higher rates on the label, which are 2.1l/ha for Flomide and 1.7kg/ha for Propose. The higher rate will assist the residual soil activity,” he said.