Although the rains have not been enough to start any major epidemics of foliar diseases on wheat, now is the time to start scouting in case of any local outbreaks. Several foliar diseases that are caused by fungi, including Septoria leaf blotch, powdery mildew, and tan spot, can affect wheat. There are also three different rust fungi that can infect wheat. Leaf rust, Puccinia recondita, is the most common rust disease and has the most destructive potential of the foliar diseases.