OILSEED RAPE growers are being urged to step up control of volunteer cereals and weeds earlier than normal this autumn.

While crops have established well, weeds and volunteers have also emerged quickly in good conditions and are now competing heavily, said Interfarm’s technical manager David Stormonth.

Independent trials have found 80 cereal volunteers per square metre can cause up to 20% yield loss, he said.

“Dealing with this problem in a cost effective manner will mean the use of a suitably priced graminicide such as Co-Pilot (quizalofop-p-ethyl),” he suggests.

While most volunteers have emerged and the first split doses of many cheaper graminicides have been applied, there is a wide choice of post-emergence products, added Frontier’s Bob Mills.

Where blackgrass is an important target he suggests growers opt for slightly more expensive products such as Aramo (tepraloxydim) or Laser (cycloxydim).

Many crops are already large enough to accept residual-acting post-emergence products, but growers should wait for cooler conditions, he said.

For a summary of oilseed rape graminicides available this autumn and an update on herbicide prices, see this week’s FARMERS WEEKLY magazine (7 October 2005).