A higher-than-normal number of reports of wild oats in wheat and barley crops this season means growers should be on their guard for this damaging grass weed, Syngenta is urging.
Be prepared to treat this season’s wild oats on time, growers are being urged, to stop them growing large and cutting into yield.
Attention to detail with control timing could be especially important, the company says, to prevent large weeds slicing into yield.
“It isn’t clear whether it’s the mild winter which has led to increased wild oat growth,” says Syngenta field technical manager, Iain Hamilton, “or because black-grass herbicides were applied early last autumn, which allowed wild oats to germinate afterwards. But either way, we’ve had more reports of wild oats in winter wheat and winter barley crops than usual for this time of year.
“With many of these wild oats now over-wintered and therefore well-established, it will be important to control them before they grow too large.”
According to Mr Hamilton, just five wild oats per metre squared can cause a 5% yield loss, and the longer that wild oats are left uncontrolled in crops, the more yield damage they cause.
Trials plots have shown that yield dropped by 1.2 t/ha when wild oat treatment was delayed until flag leaf, compared with spraying earlier before growth stage 30, he says. But significantly, it also costs less to control wild oats earlier, rather than later, if using the herbicide Axial, he points out, because a lower dose can be used against smaller weeds.
“Once germination has finished, Axial can be applied at 0.2 l/ha for wild oats between one leaf unfolded and the end of tillering, or 0.3 l/ha if wild oats are between stem extension and the flag leaf stage.
“In the interests of removing weed competition as early as possible, research also shows that Axial gave faster control than using a fop-based herbicide. Axial also maintains control in cold conditions, in case the weather turns cold again,” he explains.
For early removal in wheat and barley, Mr Hamilton suggests treating wild oats once germination is complete but before the crop canopy grows too tall and closes over, which can shield weeds from the spray.
“Wild oats are one of the most competitive weeds affecting UK cereals,” adds Mr Hamilton. “Each wild oat plant can produce 75 seeds and, if you let them slip through the net, seeds can persist in the soil for more than five years.
“For best control, it is also important that application technique is correct. Axial can be used in both wheat and barley, but it must be used with the correct dose of Adigor adjuvant. Best advice is to spray at around 100 l/ha of water, using Adigor at 1% of the spray volume – so, for example, 1 litre in 100 l/ha or 1.25 litres in 125 l/ha,” he says.
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