Recommendations regarding chlormequat (e.g. Manipulator)

*Originally published by the Canadian Malting Barley Technical Centre

  • Farmers should consult their grain buyer, as well as thoroughly review their contract, with regard to the use of Chlormequat chloride on malting barley. Many malting barley buyers in Canada will not accept malting barley treated with Chlormequat chloride.
  • To avoid potential market access issues, malting barley treated with Chlormequat chloride should not be delivered into the commercial grain system without the knowledge of the grain buyer. 
  • Producers are encouraged to investigate the cost/benefit of using Chlormequat chloride in their area (see study by L.A. Perrott, S.M.Strydhorst et al, link below).
  • Given risks associated with the use of Chlormequat chloride (e.g. Manipulator) on malting barley in relation to customer acceptance, market access and potential impact on malting barley quality, the CMBTC recommends producers not use Chlormequat chloride on malting barley until such time as these risks have been addressed.

Background information

  • In 2019 the plant growth regulator Manipulator (Chlormequat chloride) was registered for use on barley in Canada.  
  • In March of 2020, it was reviewed under the Canada Grain Council’s Domestic MRL Policy (link below) as administered by Cereals Canada, which resulted in the classification of Chlormequat chloride (e.g. Manipulator) as “Green/no recommendations” status for barley, with an exception for use on malting barley for which it is classified “Amber/Be informed” status, which signals: Be informed. Treated grain may not be accepted by some grain buyers. Consult with your grain buyer before using this product.
  • Chlormequat chloride/Manipulator is listed under “Products of Concern” in the 2020 Keep it Clean! campaign*with the following statement highlighted in the information sheet: “Before using chlormequat on malt barley, growers are advised to check with their grain buyer to confirm contract obligations and acceptance.” 
  • In a study entitled Effect of Cultivar and Agronomic Management on Feed Barley Production in Alberta Environments by L.A. Perrott et al, the investigators found that advanced management techniques had negligible effects on lodging and grain quality in 10 feed barley cultivars evaluated. Advanced management included supplemental post-emergence N, the plant growth regulator (PGR) chlormequat chloride (CCC), and two foliar fungicide applications.
  • A study published in 2020 by McMillan et al (reference below) found that chlormequat-treated barley produced malt with somewhat reduced levels of enzymes and poorer endosperm modification, although the effects were relatively small.  

*Keep it Clean! is a multi-platform communications campaign aimed at farmers and designed to emphasize the importance of using only registered crop input products and always according to label instructions; this is to ensure Canadian grain is market ready and doesn’t create any market access issue.

Referenced links:
  • Canada Grains Council Domestic MRL Policy link:
  • Effect of Cultivar and Agronomic Management on Feed Barley Production in Alberta Environments – Published in the Canadian Journal of Plant Science June 21, 2018. L.A. Perrott, S.M. Strydhorst, L.M. Hall, R.C. Yang, D. Pauly, K.S. Gill, and R. Bowness.
  • Effects of plant growth regulator application on the malting quality of barley (2020). McMillan, T., Tidemann, B., O’Donovan, J., and Izydorczyk, M.S. Journal of the Science of Food and Agriculture 100:2082-2089