Trial success for potato weed controls

Scottish Agronomy trials show combination of product mixes and early application yields results.

Potato growers can tackle hard-to-control weeds by selecting product mixes and timing applications carefully, trials by Scottish Agronomy, have shown.

The company trialled new techniques after the removal from the market of pesticides such as PDQ (diquat and paraquat) made weed control more challenging.

Senior agronomist Eric Anderson said annual meadow grass (AMG), black-bindweed, cleavers, fumitory, knotgrass and volunteer oilseed rape all now require a more considered approach. "But the good news is that with careful selection of mixes according to the weed spectrum in each field, and timely application, they can largely be dealt with."

Growers should aim to mix one contact product with one residual herbicide and apply two to three weeks after planting, the trials showed.

Anderson said: "Post-emergence options are very limited so the main thing is to go early. Allow the ridge to settle and time the spray when the largest sprouts are still 2cm to 5cm below the soil surface.

"Growers with larger areas need to start as early as possible to avoid getting caught by the weather," he added.

Scottish Agronomy ran trials last year to assess herbicides' efficacy against high AMG populations - with the dry spring conditions adding to the challenge.

"Experience in 2009 - the first season without PDQ - also showed just how effective it was against AMG, which is now the main problem weed for many growers," said Anderson.

The best results were from Artist (flufenacet + metribuzin) at 2.5 kg/ha, while the herbicides Defy (prosulfocarb) and pendimethalin provide very sensitive to lack of soil moisture.

Anderson said: "On heavier soils weed control should be straightforward using metribuzin or Artist-based programmes. In challenging AMG or cleavers situations the flufenacet component of Artist adds the extra residual activity needed."

"However, growers must take account of varietal and soil type restrictions; on light to very light soils and sands you need to be aware of soil textural variation within fields," he added. "AMG growth stage is likely to be the main consideration in contact herbicide choice."


Situation Residual herbicides
Challenging AMG Artist 2.5kg/ha + linuron* 1.2 litre/ha
Challenging cleavers Artist 2.5kg/ha
General broad-leaved Linuron* 1.2 litre/ha + 70% metribuzin 0.75kg/
haweeds (+Gamit (clomazone) 0.25 litre/ha
where sporadic cleavers)
Light/very light soils Defy 4 litre/ha + 70% metribuzin 0.25kg/ha
Sands Defy 4 litre/ha + linuron* 1.2 litre/ha

* Approved formulations of 500g/litre linuron

Have you registered with us yet?

Register now to enjoy more articles and free email bulletins

Sign up now
Already registered?
Sign in

Before commenting please read our rules for commenting on articles.

If you see a comment you find offensive, you can flag it as inappropriate. In the top right-hand corner of an individual comment, you will see 'flag as inappropriate'. Clicking this prompts us to review the comment. For further information see our rules for commenting on articles.

comments powered by Disqus

Read These Next

What is being done to develop biocontrols against orchard pests?

What is being done to develop biocontrols against orchard pests?

The SIVAL horticultural trade show in Angers, France, this week (16-18 January) heard about several initiatives to promote more environmentally sustainable orchard growing.

What does the 25-year plan mean for growers?

What does the 25-year plan mean for growers?

Published on 11 January, the Government's long-awaited 'A Green Future: Our 25 Year Plan to Improve the Environment' brings together a number of policy strands into a single framework that will impact many sectors, not least fresh produce, over the coming decades.

What will 'embracing change' mean for horticulture?

What will 'embracing change' mean for horticulture?

At the Oxford Farming Conference, whose theme was "embracing change", Defra secretary Michael Gove expanded on what a post-Brexit UK agriculture and land-use policy will look like and how it will impact farmers and growers.

Follow us on:
  • Facebook
  • LinkedIn
  • Twitter
  • Google +
Horticulture Jobs
More Horticulture Jobs

Pest & Disease Tracker bulletin 

The latest pest and disease alerts, how to treat them, plus EAMU updates, sent direct to your inbox.

Sign up here

Professor Geoffrey Dixon

GreenGene International chair Geoff Dixon on the business of fresh produce production

Read Professor Geoffrey Dixon