It is critical in resistance weed management (to combat or prevent it) to use multiple herbicide sites of action. This requires paying close attention to sites used and planning for the future. The Take Action Herbicide-Resistance Management initiative has launched a new site of action chart and mobile lookup tool. This tool helps to quickly identify herbicide sites of action by product trade name or active ingredient. And because an objective in weed control should be site of action diversification, the tool will also provide a list of products with the same site of action that would not provide the diversification recommended. One should avoid repeat applications of herbicides belonging to the same site of action group. But, simply including herbicides that belong to multiple sites of action may not be sufficient. The different sites of action must also be effective against herbicides-resistant or troublesome weeds. The chart also includes the number of species that have shown resistance to the site of action. One must be aware and consider if a certain weed species has resistance to a site of action.