Pea growers need to choose pre and post-emergence weed control options carefully this season and be prepared to use a wider mix of active ingredients, experts have advised.

Relatively benign winter conditions and good seedbed conditions mean some may consider sowing peas early this season, but this could create a wider window for weed emergence, said the Processors and Growers Research Organisation’s, Jim Scrimshaw.

“Any pre-em residual herbicide may need to work hard. Low soil temperatures may favour weed development rather than crop. Under these conditions using a contact material with the residual could be of use prior to crop emergence.”

Soils need to be moist for residual sprays to be most effective and activity could drop off if there is warm, dry weather in late-March and April, he noted.

With approvals for Bullet (cyanazine + pendimethalin), Batallion (terbuthylazine + terbutryn) and Fortrol (cyanazine) due to cease at the end of June next year under the ongoing EU review of approved products, growers need to consider alternatives, he said.

Options include the new pre/ early post-em Skirmish (terbuthylazine + isoxaben), early post-em Impuls (bentazone + pendimethalin), or Blois (linuron + trifluralin) – a new pre-em available this season, he said.

“If crops are drilled early, in good moist, and well-firmed seedbeds then early weed take-out using a pre-em is good practice. In this respect, Blois gives flexibility in costs. But, with later drilled crops, an early post-em may be all that is needed.

“It really is a case of testing new materials as part of a control programme and weighing up their cost-effectiveness in any situation.”