A big April flush of wild oats could appear in crops following the harsh winter, growers are being warned.

The cold winter is likely to have broken the natural dormancy of wild oats and stimulated their growth, says ADAS‘s weed expert Sarah Cook.

The winter of 2009/10 was the third coldest since 1977, and previous cold winters, such as 1986 resulted in higher weed numbers in the spring.

“Historically, a greater spring flush of wild oats tends to emerge after a cold winter,” says Dr Cook.

“Frozen soil breaks dormancy and stimulates growth. Germination then occurs when soil temperatures rise to 6-7C.”

But there are a wide range of effective products available to control wild oats, she says, including Broadway Star (florasulam + pyroxsulam) before third node is detectable (GS 32) and Axial (pinoxaden) before flag leaf extending stage (GS 41).

Penetration of the spray into the crop is an important consideration which can be improved by altering spray volume, droplet size and nozzle type.

Hand-rogueing can also keep low populations under control, says Dr Cook.

“The immature plants must be pulled up completely otherwise the remaining tillers will be encouraged to produce further panicles.

“Unripe seeds of wild oats are viable and non-dormant. Therefore, hand-pulled wild oats – even with green panicles – must be removed from the field and disposed of carefully.”