There is a need to keep the more environmentally friendly, cost-effective herbicides in use. We have initially modeled various ways to delay herbicide resistance in 1978, using population genetics and dynamics models that factor in use patterns, as well as various parameters relating to the properties of the herbicides. These models were continuously updated over thee years in conjunction with leading ecologists, population dynamicists, and applied mathematicians and are the basis of most policy making around the world dealing with this area.