Cooler weather means soil conditions are now ideal for controlling grassweeds in oilseed rape with residual herbicides, according to Makhteshim Agan.
“Residual chemistry applied from now on will be active through the winter, boosting levels of weed control,” said the firm’s technical manager, Stuart Hill.
Three years of trials found that mid-November and December applications of the carbetamide products Carbetamex or Crawler resulted in over 90% blackgrass control – compared with 65% from January and 40-50% from February applications.
The addition of a contact graminicide to control larger grassweeds will be particularly important this season, he added. In the same trials, adding a graminicide increased December control to 95% and January efficacy to 90%.
Recent frosts should have opened up advanced canopy’s, and improve spray penetration, but where cover is still lush, water volumes should be kept high and an appropriate adjuvant should be used if necessary, he noted.