Barclay Crop Protection

Green stubbles prompt spring crop warning

Spring crops sown in 2010 could face troublesome and difficult-to-control weed populations unless consideration is given to interim treatments to prevent weeds growing too big, growers have been warned.

The rapid greening of winter stubbles brought about by unseasonably warm autumn

weather has seen an unusually vigorous greening-up of stubbles, says Bryan Pickles,

technical agronomist with Barclay Crop Protection.

"A lot of fields are a lot greener than we would normally expect at this time of year," he

says. "By the time growers are ready to drill spring crops next year, weeds in some fields

will be huge," Mr Pickles warns.

"The planned crop will dictate whether it's broad-leaved or grass weeds that growers need

to be wary of. Broad-leaved species such as mayweed have proved particularly responsive

in the current conditions, and while grass-weeds such as black-grass and meadow-grass

have in many cases taken a while to get going this autumn, growers will be only too aware

that they're now rapidly making up for lost time.

"Ploughing will be the preferred option for many fields next spring, but on its own, this

could have the effect of simply transplanting the larger weeds. Timeliness of establishment

is critical in the spring, yet some of these weeds could be very difficult - and expensive - to

control by then, and there's every chance drilling dates could be missed.

Mr Pickles suggests that in exceptional circumstances, growers might consider applying an interim treatment of Gallup (glyphosate). To help growers decide whether such an application is necessary, the company has developed a treatment guide to assist in the decision-making.

"Growers need to get out into any fields they're worried about and assess the weed growth stage. If you've grass-weeds that are beginning to tiller, then speak to your agronomist about suitable rates and timings for Gallup; likewise, any broad-leaved weeds with more than four true leaves.

"If grass-weeds and broad-leaved weeds have reached only a maximum of three leaves or less, then ploughing - as soon as conditions allow - will be sufficient to prevent the weeds causing significant problems in the next crop."

A decision tree summarising the options is available from Barclay's website at

www.barclay.ie