Weed Resistance Assessment Program (WRAP)
The phenomena of herbicide resistance is not a new concern; triazine resistant weeds were first reported in the late 1960's. Since then, resistance has developed to many other important classes of herbicides. Although there are isolated infestations of triazine resistant weeds across Iowa, these weeds are not considered a major problem in the state. Recent shifts in herbicide use patterns has increased the potential for the development of resistant biotypes. This paper will describe factors which influence the development of resistance and how weed management programs can be manipulated to minimize the potential for resistance.