Emerger becomes the foundation of weed control

Across 60 hectares of Maris Piper grown mainly on sandy soils and with a wide weed spectrum, Emerger (aclonifen) has become the basis for achieving season-long weed control.

For farm manager Adrian Howell from North Norfolk, reliable and effective weed control is essential.

“I've been using Emerger (aclonifen) since its introduction in 2019. It has proven to be a reliable residual that has become the basis of our weed control programmes because it mixes well, has a broad spectrum of activity, is less constrained by soil moisture than some other residuals and is crop safe,” says Mr Howell.

Over the years, he has learned how to best use it and what partners he needs to mix it with for effective weed control.

“First, it is different to linuron, so growers need to think differently about how they use it. I always apply Emerger in a mixture with prosulfocarb, which bolsters control of cleavers, and metribuzin, as this has the widest weed spectrum of any herbicide authorised for use in potatoes.

“As we grow Maris Piper, post-emergence applications of metribuzin are not an option available to us and I try to avoid rimsulfuron wherever possible as it can be hard on the potato crop. As such, I have to focus efforts at the pre-em stage,” Mr Howell says.

A typical tank-mix would be 1.5 L/ha of Emerger with 3 L/ha of prosulfocarb and 0.25 L/ha of metribuzin applied seven to 14 days ahead of expected emergence.

“Timing is always prioritised to promote efficacy and even coverage of the ridges. In practice this means spraying on a still day with no wind, and preferably, soon after a shower of rain so moisture is in the soil to activate the chemical and promote weed germination,” he says.

“Emerger has become the favoured residual because of its broad spectrum of control and is cost-effective too. The dominant weeds are fumitory, annual nettle, black bindweed, fat-hen and knotgrass. Groundsel can be a problem weed too, but on a patchy basis. The sandy soils are fully irrigated from tuber initiation onwards and we have not identified any crop safety issues or experienced a drop off in persistence,” he says.