Growers are being advised to adopt a thorough control strategy to combat a resurgence in wild oats reported on some farms.
Agronomists say there are several reasons why this fiercely competitive grass weed has become more prevalent – including the recent increase in spring cropping and changing weather conditions.
Spring cereals have largely replaced oilseed rape in areas susceptible to cabbage stem flea beetle and dry weather. But some replacement crops have most likely been planted on fields with a history of wild oats.
Independent agronomist Sarah Symes says some cultivation systems have created a favourable environment for wild oats to thrive. “Growers who have ploughed a lot in the past tend to get more wild oats than those who use a direct drill, min-till system.”
Ms Symes also points out that dry weather is been another factor contributing to a proliferation of wild oats. “Weeds become really waxy and don’t take up the crop protection products properly – and this is true for wild oats too.”
Growers should adopt an appropriate control strategy as soon as possible, says Ms Symes. The prevalence of this grass weed could continue to increase year on year if small populations are left untreated, she adds.
This is because seeds can remain viable in the soil for up to 20 years. Rogueing – or manually pulling out the weeds – is a straightforward and cost-effective way of nipping small populations of wild oats in the bud.
More severe outbreaks can be cleared up early on with the use of the crop protection product Foxtrot EW – a herbicide specially formulated for the post-emergence control of grass weeds in wheat and barley.
Foxtrot EW should be used in spring barley when the weeds are at the 3-4 leaf stage, says Ms Symes. “It has to be used on its own – but it’s not harsh on the crop if used under the right conditions, when crops aren’t stressed.”
Foxtrot EW is a contact acting herbicide and is more effective on actively growing plants, says Adam Espir of suppliers FMC. “Getting application timings and rates right will be essential to ensure you don’t have problems later with regrowth,” he adds.
Foxtrot should be applied at a rate of 0.8 litres per hectare in at least 200 litres/ha of water. Larger weeds or more dense populations should be tackled with up to one litre of product in 300 litres/ha of water.
“As spring arrives and weeds start growing, growers should think about treating any problem fields in good time to give their crops the best chance to thrive this season,” says Mr Espir.