Fighting weed resistance

Overreliance on a single herbicide can cause resistant weeds to develop. This puts the ability to grow a crop in a specific field in jeopardy. When resistant weeds develop, farmers face the additional costs required to control them—unplanned herbicide applications, intense manual labor, and in extreme cases, total crop loss.

Integrated Weed Management (IWM) practices help to preempt these issues and result in successful management of resistant weed populations. These include regular rotation of pesticides with different modes of action. By featuring a unique mode of action, Glufosinate-ammonium is ideal for use in rotation with broad spectrum-herbicides such as the commonly-used Glyphosate.

Glufosinate-ammonium as part of the solution

Glyphosate Resistance in Europe 2013

Weeds compete with crops for soil nutrients, moisture, sunlight, carbon dioxide and space. This weakens the crops and considerably reduces the quality and volume of yields. They are also hosts for insects and diseases, and decrease the efficiency of fertilizer use and irrigation systems. Weeds resistant to commonly used herbicides are becoming an increasingly serious problem in certain regions of the world. In Europe, parts of France, Italy, Portugal and Greece, Spain, Poland and the Czech Republic have been affected as a result of over-reliance on certain herbicides such as Glyphosate.

A survey conducted in the US in 2013 showed that 51 % of farmers representing 71 million acres of row crops in the US say they have Glyphosate resistance on their farms, up from 34 percent of farmers surveyed in 2011.1

To protect their produce, farmers are increasingly turning to diverse herbicides and crop solutions with modes of action, and taking proactive steps to manage weed resistance. Integrated Weed Management (IWM) programs optimize crop rotation and crop protection products. As Glufosinate-ammonium works in a different way than the herbicides that have become susceptible to weed resistance, it is ideal for rotation with them or mixtures. It is able to control herbicide-resistant weeds at the same time helping to reduce the buildup of such resistance in the first place.

Did you know?

  • There are currently 437 unique cases of herbicide resistant weeds globally.2 Weeds have evolved resistance to 22 of the 25 known herbicide sites of action.3
A recent US study showed that Integrated Weed Management improved the quality and increased winter wheat yields by 23%.4
  • Herbicide resistant weeds have been reported in 83 crops in 65 countries. In Europe, seven of the largest agricultural producing countries have reported weed resistance to Glyphosate. In Spain and in Italy more than three weed species have developed resistance, which threatens productivity and calls for better availability of herbicide solutions to farmers.
1 | Stratus Agri-Marketing 2013.
2 | International Survey of Herbicide Resistant Weeds, October 2014,
3 | International Survey of Herbicide Resistant Weeds, October 2014,
4 | Frank L. Young et al., Integrated Weed Management Systems Identified for Jointed Goatgrass (Aegilops cylindrica) in the Pacific Northwest, Weed Technology 24, October–December 2010, pp. 430-439.
The sun rises on crop diversity

Maize (corn) monocultures are a common sight on Hungary’s Northern Great Plain. But as with any monoculture herbicide resistance is always a potential danger. In 2010 Istvan Szolomajer discovered Panicum riparium growing on his fields. Initially, Istvan and his fellow farmers used ALS inhibitors to control this weed, but after several years of application, there was strong evidence of an emerging resistance problem. Istvan’s solution to the resistance problem was to replace maize monoculture with crop diversity – changing from monocot to dicot crops and from spring to winter crops, for example. This year, he has been growing sunflowers on 100 ha, winter wheat on 50 ha, and maize on most of the remaining 200 ha under cultivation. This crop diversity has brought Istvan welcome relief from resistant Panicum riparium. Close cooperation with Bayer staff in Hungary has been a crucial factor in Istvan’s diversity strategy.

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How safe is Glufosinate-ammonium to the environment?

The herbicide is rapidly degraded by micro-organisms in the soil, making water contamination very unlikely. Risk to birds, bees, aquatic organisms, earthworms and other soil organisms is also very unlikely if the product is used according to label instructions.

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