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Manage broadleaved weed resistance - Nufarm UK

Manage Broadleaved weed resistance

Resistance to broadleaved weed herbicides is growing. There are virtually no new actives with an alternative mode of action. It is important we use broadleaved weedkillers wisely to prevent a build of of problems

The extensive use of acetolactate synthesis inhibitors (ALS) in the UK has led to the appearance of broadleaved weed resistance problems in both Europe and the UK. In the eastern counties there are reports of broadleaved weeds such as poppies showing resistance to this group of herbicides. ALS inhibitors include the sulfonylureas and a number of other groups including triazolopyrimidines e.g. florasulam. Many people are not aware that treatments for the control of Blackgrass, such as Atlantis, are ALS inhibitors and also have activity against broadleaved weeds ‘Nufarm are seeing increased use of phenoxy herbicides which offer an alternative mode of action for control of difficult weeds’ according to Richard Dyason, Technical manager for Nufarm.

Nearly 70% of cereal crops receive at least one application of an ALS inhibiting herbicide either in autumn or spring. Almost 90% of spring cereal crops receive at least one treatment with an ALS mode of action. ALS herbicides are increasingly being used in the break crops placing further selection pressure onto weed populations

Herbicide resistant Blackgrass has frequently hit the headlines because of its impact on cereal production. Now resistant broadleaved weeds are becoming significant and it is for this reason that Nufarm together with Farm Business magazine carried out a broadleaved weed resistance survey in spring 2012. Results confirmed farmers were having difficulty controlling Poppies with ALS products particularly in the Midlands, Lincolnshire and Norfolk. In Scotland Chickweed control was more of an issue


  • Concentrated MCPA formulation which can be used in the spring up to before flag leaf emergence in winter wheat
  • Alternative mode of action to the ALS inhibitors to help manage resistance
  • Boosts control of difficult weeds such as Poppies
  • Helps control Thistles


  • Bromoxynil based contact herbicide
  • Controls difficult weeds such as Fat Hen and Orache not always controlled by other herbicides
  • Ideal spectrum for weed control in spring barley
  • Non ALS mode of action
Nufarm market a range of products with a different mode of action to the ALS herbicides. These products mimic the natural plant hormones called auxins. These products have been around for 60 years with few occurances of resistance. Examples of these products are listed here:

Duplosan KV

  • Contains mecoprop-P. Works in cooler conditions from March 1st onwards
  • Controls some difficult overwintered weeds such as Cleavers and Chickweed
  • Often mixed with ALS products to improve weed control spectrum in spring cereals

High Load Mircam

  • Contains dicamba and a good concentration of mecoprop-P.
  • Ideal for use in spring cereals but also useful for clean-up of winter cereals in the spring
  • Controls volunteer weeds, Chckweed, small Cleavers, Fat hen, Polygonums and many other species, many of which are not well controlled by the ALS herbicides