Ben Lowe is an Agrovista agronomist based on the East Coast of Scotland, supporting customers from Dundee up to South Aberdeenshire. With a specialism in row crops, he explains what growers should be currently considering when it comes to early potato herbicides and weed control.
14/05/2020
Ben Lowe, agronomist for Agrovista
“Although we’re all a little tired of talking about the weather, the main thing I’m keeping my eye on at the moment is soil moisture, because it’s key in ensuring we get the best out of residual chemistry.
Pre-emergence herbicides
Potato growers will be looking to apply pre-emergence herbicides, and to make sure these work most efficiently, moisture on the ridges is needed. And by moisture, we don’t want too much either, because this will wash away the active ingredient, or move it into the crop and cause damage.
Following the loss of diquat, timing of pre-emergence products will be more important than ever, as growers are lacking fast-action contact herbicides. The threat of weeds such as annual meadow grass in Scotland and blackgrass in England will mean it’s likely that pre-ems will be sprayed sooner rather than later.
A useful pre-emergence product is flufenacet-based Artist®. Not only does this target grass weeds, but it also controls broad-leaf weeds such as cleavers and fat-hen.
Forecasting and tools
Using forecasting and tools such as weather stations and soil moisture probes help me to plan for my customers, especially during the COVD-19 restrictions. For those with their own weather stations, this gives site-specific remotely-accessible data, which provides invaluable insight into the potato plant’s development. If this data is field-specific, even better due to the huge variances we experience in rainfall.
Grass weeds
Ultimately, if growers have grass weeds in their crop now, it’s a red flag for harvest. Grasses cause clumping in the bed, meaning the soil needs more agitation which impinges on harvest practicalities. It also of course impacts seed return for following rotations.
Canopy closure
One of the best ways we can overcome weeds naturally is by getting the crop to canopy closure as soon as possible. Blocking weeds’ access to sunlight through a vigorous crop will supress them before we’ve even thought about chemical control.
Also worth bearing in mind during planting is ensuring the soil is fine, firm and clod-free, again to improve herbicide efficacy. Although this isn’t relevant now, it will be pertinent come next year.
But for this year, organisation will be key as we continue to work together to overcome the challenges of COVID-19. Keeping in regular contact with agronomists, albeit at distance, will help to mitigate supply chain issues. And without diquat, it’s likely the whole weed management programme will need to be adjusted for many.”