During the mid 1980s, Iowa State University researchers described a sampling program that used yellow sticky traps for monitoring adult corn root worms. The Pherocon AM trap, then available commercially, served as the basis for a sampling program. This program was pro­ posed as a practical means for commercial corn growers to predict the need for soil insec­ ticides to protect a subsequent year's corn crop from corn rootworm larval damage. Using this decision tool, farmers were expected to apply insecticides only when needed instead of preventively. Since then, a trap called the Multigard, from an additional supplier, has been used to monitor beetle populations. Both traps are yellow, rectangular cards coated with adhesive. The traps differ in color, however; the Pherocon is canary yellow and the Multigard is a fluorescent yellow.