Like bacteria with antibiotics, weeds naturally develop resistance to herbicides over time. In fact, about 250 weed species have evolved to resist 160 different herbicides, according to the International Survey of Herbicide-Resistant Weeds. These herbicide-resistant weeds have been reported in 86 crops in 66 countries.
Given this inevitable challenge, the crop protection industry set up an Herbicide Resistance Action Committee (HRAC) to identify practices that better manage and delay herbicide resistance. Recognizing that weeds develop resistance to herbicides due to overexposure to them – whether through repeated use of the same herbicide, use of several herbicides that kill weeds the same way or planting of the same crop – HRAC promotes integrated weed management practices to prevent it. These include using multiple herbicides with different sites of action, inspecting fields after herbicide application, cleaning equipment between fields and rotating crops.
HRAC, which is supported by CropLife International, also aims to promote a responsible attitude toward herbicide use, provide the public with a better understanding of the causes and results of herbicide resistance, collaborate between public and private researchers, and communicate among industry stakeholders. It hopes to “weed” out new cases of resistance through these efforts as well as with the industry’s continuous development of new herbicides.