Will glyphosate resistance in weeds revert to susceptible?
Current evidence suggests the frequency of glyphosate resistant individuals in a population will decline with time if glyphosate is not used. However, it would take many years of no glyphosate use for the proportion of resistant plants to return to the very low levels needed for glyphosate to be effective on that population again over repeated applications. Therefore, once a population is resistant to glyphosate it should be assumed that glyphosate will not be a fully effective control option for that population again. As a result, rotations of herbicides that give glyphosate a rest in some years can be very valuable in reducing the risk of glyphosate resistance. It is likely that glyphosate will continue to be used to control other susceptible weed species in the paddock even after resistance in one species has developed. There will be no decrease of glyphosate resistance if there is continued selection pressure.
