The 2013 Herbicide Guide for Iowa Corn and Soybean Production (WC 94) can now be accessed from the Iowa State University Weed Science web page. The publication provides an update of new herbicide products as well as an herbicide effectiveness chart for herbicides used in soybean and corn. Herbicide site of action and injury symptoms are described and information about herbicide group numbers is included. A list of prepackage mixtures of herbicides is included. The current herbicide resistant weed situation in Iowa is described and a discussion about Palmer amaranth is provided.