Recommendations and Prevention

To reduce the risks of developing herbicide resistance, several agricultural practices must be combined. The ideal prevention strategy hinges on good growing practices and appropriate use of herbicides. To increase their efficacy, these measures should be coordinated at regional level.

Agronomic recommendations

  • A varied rotation with spring crops allows differentiated sowing dates and/or intercropping.
  • It is very important to diversify weeding practices. In addition to mechanical weeding, tillage (ploughing, stubble ploughing, false seed-bed) helps to control weeds.
  • Staggered sowing dates inhibit the emergence of weeds that are specific to the crop in question.
  • Planting competitive varieties and increasing sowing density enables the crop to compete more successfully with the weeds.
  • Mowing the weeds before heading prevents pollen or seed production and stops the spread of resistance.
  • Prevent the spread of weed seed between fields and regions by using crop seed that is free from undesirable seeds, and ensure that farm machinery does not act as a vector between plots.

Chemical control recommendations

  • The most important thing is to alternate herbicides with different modes of action (refer to the HRAC groups instead of the trade names) and/or use mixtures of herbicides with different modes of action.
  • It is also essential to apply the manufacturer’s recommended dosage and use the herbicides at the optimum stage of weed susceptibility and during the best possible weather conditions.
  • Chemical weed control must achieve a minimum efficacy rate of 95%.
  • Monitor the relative efficacy of the herbicides based on past experience. This could give indications of the development of any new resistance in the treated plot.