A team consisting of scientists from the Agricultural Research Service (ARS), universities, and the industry has identified a new genetic vulnerability to the herbicide tolpyralate in 49 varieties of corn. This marks the first report indicating that weed control could be problematic for a major crop. The discovery offers farmers the opportunity to choose a variety tolerant to tolpyralate or prevent crop losses by using a different herbicide. Tolpyralate belongs to a class of herbicides known as HPPD inhibitors and was registered in 2017. This finding reveals that the corn plants’ rapid metabolism of this herbicide is dependent on specific genetic factors. This information can assist farmers in developing more effective weed control strategies.