A Scottish body has issued advice in the face of spiralling problems with weed control.

According to Scottish Agronomy, weed control has been more challenging over the last two seasons and in response have been trying new techniques with growers and conducting trials to find the way forward.

Scottish Agronomy’s Eric Anderson cites annual meadow-grass, black-bindweed, cleavers, fumitory, knotgrass and volunteer oilseed rape as weeds that now demand a more considered approach.

“The good news is that with careful selection of product mixes - according to the weed spectrum in each field - and timely application, they can largely be dealt with,” he said.

“Experience in 2009 - the first season without PDQ - also showed just how effective it was against annual meadow grass (AMG); it is now the main problem weed for many growers.”

Last year Scottish Agronomy ran trials to assess herbicides’ efficacy against high AMG populations; dry spring conditions added further challenge. Best results were from Artist (flufenacet + metribuzin) at 2.5 kg/ha while the herbicides Defy (prosulfocarb) and pendimethalin proved very sensitive to lack of soil moisture.

ased on their trials work and the advisory team’s recent experiences, Anderson advises growers to now aim for control with one contact and a residual mix applied two to three weeks after planting.

“Post emergence options are very limited so the main thing is to go early. Allow the ridge to settle and time the spray when the largest sprouts are still 2cm to 5cm below the soil surface. Growers with larger areas to cover need to start as early as possible to avoid getting caught by the weather.

“On heavier soils weed control should be fairly straightforward using metribuzin or Artist based programmes. In challenging AMG or cleavers situations the flufenacet component of Artist adds the extra residual activity needed,” he added.

Scottish Agronomy warned that varietal and soil type restrictions must be taken into account in tackling the problem.