Tighter restrictions on the use of ACCase inhibitor herbicides mean oilseed rape growers need to be extra careful when controlling volunteers and grassweeds this season, Interfarm has advised.

The new rules effectively limit the use of ‘fop’ and ‘dim’ graminicides to one application per crop, meaning low-dose split applications of any particular product are no longer permitted, explained the firm’s David Stormonth.

“However the new regulations allow some flexibility in that a second application of a different ACCase inhibitor product is permitted to control different weeds at different timings.

“In other words a different graminicide can be used at a later timing providing the target is not the same weed.”

In oilseed rape, he suggests an early application of a graminicide (such as Co-Pilot (quizalofop-p-ethyl)) before blackgrass has emerged to control cereal volunteers (when they have 2-3 leaves), followed later by another ACCase product to target blackgrass.

“Whatever the season brings, the choice of graminicide is important and, with only one shot being likely, it is important to make sure that a really effective dose is used,” he added.