Recent wet, rainy weather has created some weed management challenges for Indiana growers.  In this article we will hit on a few key points to consider based on current challenges. Delayed weed control in corn.  Indiana corn growers rely heavily on premixes in corn that contain some combination of group 15 herbicides (metolachlor, acetochlor, pyroxasulfone), atrazine, mesotrione (Callisto), clopyralid (Stinger), and bicyclopyrone.  Rain will not have completely washed all of the herbicide away, but may have compromised overall activity.  Scout fields as soon as possible to determine if weeds are escaping.  Obviously giant ragweed is a big concern, but wet conditions and dilution of atrazine can result in failures to control velvetleaf, burcucumber, morningglories, waterhemp, cocklebur and others.  If corn is less than 12 inches tall and you haven’t used all of the atrazine allowed by the label, it would be wise to add atrazine to the other postemergence herbicides[Read More…]