Since the fall RWA flight is expected six to eight weeks after planting, such treatments may not last long enough. The risk of significant fall infestations is generally considered to be low in Colorado. Fall Aerial or Ground Applications of Foliar insecticides These should be considered if more than 10 to 20 percent of the plants in a field show RWA damage and weather conditions are expected to remain favorable for an extended period. To determine the level of infestation, walk a diagonal or zigzag pattern across the field and stop at least 10 times to examine 20 consecutive plants. It also is best to examine some damaged plants for RWA, but they may be difficult to find on cooler days or during bad weather.
Scout fields every two weeks in the fall.
Visit a field more often if a RWA infestation is detected. Fall control generally has been more effective than spring control. The risk of increased winter injury and some loss of yield potential if treatment is delayed until spring needs to be balanced against the possibility that RWA overwintering success will be low. These are recommended according to the guidelines below. Plants with even a single infested or damaged tiller should be considered infested.