Cereal growers must balance the urgency of their mounting spring workload with the need to maximise all opportunities for achieving good weed control in the next few weeks, says ProCam head of crop production Nick Myers.
For many, large black-grass plants should be the priority with worries that the longevity of some of the autumn residual chemistry used has been reduced by the warm, wet winter conditions, he says.
“Although residuals did a good job, there are survivors to clean up and there have been reports of recent black-grass germination, so in some situations there’s an urgent requirement for a spring herbicide top-up.”
The fall in grain prices makes the financial decision to spray again a difficult one, especially given the level of grass weed resistance to contact herbicides and the other fieldwork that needs to take place, he acknowledges.
“Crops have generally established well and should be competitive so it may be that low levels of black-grass are tolerated this year. In later drilled wheat crops, where good use of stale seedbeds and pre-emergence herbicides was made, there may be no need for further action.”
For those who need to do a follow-up there may be some value in adding a residual element to the contact herbicide to boost control if sequences and time permit, he advises.
“There are choices for this, such as flufenacet + DFF, as well as pendimethalin. Of course, the later that this application is made, the value of adding a residual falls away.”
For the contact herbicides to work well, both growing conditions and application technique must be right, Nick Myers points out.
“The weeds have to be actively growing for the best results. Where black-grass is the main target, it’s important to get every bit of control that you can from this treatment.”
If necessary, broad-leaved weeds can be controlled at the same time by following manufacturer advice on approved tank mixes, he adds.
“The main target is going to be cleavers and there are options for dealing with them at both early and later timings.
“There are also concerns about continued aphid activity in crops due to above average winter temperatures.
“There is a potential BYDV risk. If you’re finding aphids in the crop, a spring insecticide could still be worthwhile and could be tied in with the weed control pass.”