Increased levels of wild oats are being seen across the country this season, following an open autumn and winter allowing weeds to over-winter, and dry conditions leading to poor herbicide uptake.
Wild oats are notoriously difficult to target due to their more protracted germination period, and the dry winter will not have helped, according to Lynn Tatnell, weed biologist at ADAS.
She says the increase in populations is one of the dangers growers face who do not consider wild oats as a threat in the autumn, excluding them from their pre-emergence herbicide programme.
She says: “They then start becoming more visible in late spring, but by this time they are large and hard to control.”
Those that have applied pre-ems could also be seeing poorer control due to dry conditions meaning weeds cannot take them up, says Ms Tatnell.
“However, with conditions generally being quite dry the weed might be struggling too,” she adds.
“We would still urge people to hand rogue wild oats where they can to stop seed return.”
ADAS has seen a large increase in the number of wild oats being sent in for annual resistance testing in recent years.
“It may be that people have had black-grass tests done in the past and are now willing to check other species, or just that oats really are on the increase,” Ms Tatnell says.
“It is always worth testing them for resistance or hand rogueing before seed shed. We also ask people to monitor movement of patches in their fields, as this can indicate population increases perhaps due to resistance.”
James Southgate, field technical manager at Syngenta, says the increase in wild oats in spring crops could also be a result of early spring drilling leading to extended germination time.
He says: “Much of the wild oat burden is being seen in spring barley due to warm conditions in February leading to early drilling and earlier germination.
“This means numbers of broadleaf and grass-weeds like wild oats have increased.”
It is important to take out wild oats as early as possible at T1 rather than T2, says Mr Southgate, because the bigger they get, the more difficult they are to control and the more effect they have on yield.
He adds: “For winter crops, if people have not done anything yet they need to soon. Winter barley growers have until before GS41 to apply Axial Pro (pinoxaden) and clodinafop-propargyl or pinoxaden in winter wheat.”