We are seeing a greater occurrence of crop injury following herbicide use than is typical. These responses aren't limited to any single product or class of herbicide. A major factor leading to many of these crop injuries is the environmental conditions encountered earlier in the season. The cool, wet weather placed the crops under considerable stress, thereby reducing their tolerance to herbicides. When it finally did warm up, we went into a period with high temperatures and high humidity, which enhanced herbicide activity.

There has been considerable buggy-whipping (onion-leafing) of corn following postemergence herbicide applications. This is a response characteristic of growth-regulator herbicides, but it also has occurred following applications of ALS-inhibitors (Accent, Basis, Exceed, Permit, etc.). The injury appears to be most common following applications of an ALS product with a dicamba product. Both of these classes of herbicides are systemic and accumulate at the growing point where they may influence leaf initiation. When these corn leaves emerge from the whorl several weeks after application, they are unable to unfurl properly. Combinations including Basis seem to have induced this response more than the other ALS-inhibitors, probably due to Basis having a narrower margin of safety than the other products and because Basis was applied earlier in the season when the corn was under greater stress.