A weed screen trial at the Drummonds open night on Thursday 18 June brought the seriousness of the grass weeds situation to life for farmers.

Back in the autumn, the team planted barley, winter wheat, winter oats, wild oats, barren brome, sterile brome, Italian ryegrass, annual meadow grass and perennial grasses.

Half the plots were treated with pre-emergence herbicides and half the plots were treated two months later with post-emergence herbicides.

They have been monitored throughout the season and agronomist Frank Glynn said that the value of pre-emergence herbicides has been very visual.

Message

Speaking at the company’s open evening, he said: “Our message to all our growers is, if you’re going to sow it, it has to be good enough to spray it the following day.”

Frank said this is now happening with beans and winter barley – people purchase their seed and herbicides on the same day. The results have been very positive in winter barley, but winter wheat has issues.

If there is an issue with grasses or broad-leaved weeds, pre-emergence has to happen.

“We have seen huge problems this year with stuff that didn’t get sprayed in the backend. That’s the scary part. What we’re dealing with now is a lot of old chemistry and the only way the efficacy of it is any good is if it's pre-emerged.”

He noted that farmers this year were applying “heavy lifters” such as Pacifica and Allister in late March and April due to wet conditions and this was too late to apply the products.

Doing too much

“You’re asking them [herbicides] to do way too much and that’s where resistance starts,” he added.

Grass weeds appear to be much worse this year and there are high numbers where crops did not get a spray in the autumn.

Frank said the levels of weeds in winter wheat is “scary”, but he added that farmers are taking steps to reduce the problems.

Italian ryegrass, annual meadow grass and patches of blackgrass look to be the most common in his area and he was adamant that the control of these weeds is not in a bottle - it’s a mixture of cultural and chemical control.

Farmers are rogueing crops for grass weeds. They’re also spraying off patches with glyphosate and mapping where the weeds are on their farms so they can monitor them.

“There’s no one ignoring it anymore. They know the possibility of what it can do. You need to have maybe a couple of stale seedbeds and hold off for later sowing in that field. Early sowing is a big, big problem when you have blackgrass.”