What can mimic herbicide resistance?
There are a few situations that may mimic a resistance problem. Consider if the weed is naturally tolerant to the herbicide. For instance, Pinnacle will not control nightshade in soybeans. This is not a case of resistance. Weeds that emerge after a non-residual herbicide application are also not resistant, but they could appear to be resistant if their time of emergence was not considered. Adverse weather like drought could cause weeds to survive a herbicide application, but is also not resistance. Application errors such as spray skips, the wrong herbicide rate, etc. also need to be ruled out as mimics of resistance.
