Preventing herbicide resistance is far more cost effective in the long term than having to mitigate a resistance problem after it develops. Rotating crops and herbicide modes of action are recognized as keys to preventing the onset of resistance to certain important herbicides. The repeated use of any herbicide mode of action, in the absence of alternatives, results in a monoculture for weed control and greatly increases the likelihood of resistance developing. Employing a diversity of weed control measures across the landscape over time greatly facilitates preventing herbicide resistance. A diversity Relatively few herbicides are labeled for use in forage of weed control measures across the landscape greatly facilitates
HERBICIDE RESISTANCE
the prevention of herbicide
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resistance.
sorghums. While herbicide resistance is not now considered a “hot topic� in forage sorghum production, there are characteristics of the production systems that could favor the onset of resistance to key classes herbicides. Foremost among these are the repeated use of only one mode of action, especially in a no-till or minimum-tillage system. Tillage can be considered a weed control mechanism which helps mitigate resistance. However, in conventional tillage systems, producers should strongly consider rotating their herbicide modes of action from year to year. Recent experience in other crops indicates that herbicide resistance in weeds can occur in a variety of crops and cropping systems and forage sorghum producers are therefore not immune to the problem. The following table lists the herbicides labeled for use in forage sorghums, their mode of action, and the likely risk for resistance development with repeated use. Producers should consider this information closely when planning their weed control programs from year to year. This includes forage sorghum as well as previous and future crops. Currently, there are 331 herbicide resistant weed biotypes documented worldwide and the list grows longer each day.