Thin, poorly established oilseed rape crops could come under threat from mayweeds, cleavers and sow-thistles, according to Dave Ellerton of ProCam.

A strong oilseed rape crop could shrug off most weeds, he explained. “However, where the crop is poorly established or patchy, mayweeds, sow thistles and cleavers are starting to grow well with recent moisture. This may lead to harvesting delays as well as threatening yield.”

Growers have two options: Galera (clopyralid + picloram) or Dow Shield (clopyralid).

Providing most cleavers and mayweeds had germinated then Galera was the best option,” Dr Ellerton said. “Timing in the autumn is less critical than trying to hit the narrow spring window of before buds are visible above the crop canopy.”

Autumn applications of Galera also left the opportunity to follow-up with Dow Shield in the spring.

Galera can only be used once per crop, and is best applied at 0.35 litres/ha when weeds are actively growing, for control of mayweeds and thistles, and suppression of cleavers, according to manufacturer Dow AgroSciences.

Dow Shield (clopyralid) at 0.35-0.5L/ha can be used more than once and is a better solution where just mayweeds and thistles are the problem. The higher rates of Dow Shield need to be used with bigger, or hardened-off, weeds.