Gray leaf spot has been identified on perennial ryegrass fairways in northern Kentucky. It is likely that outbreaks will occur in southern Indiana with the next rainstorm (or it may already be established). If the turf that you manage has a history of the disease, this would be a good time to consider apply a fungicide to preventing uncontrollable outbreaks. Several years ago we published results of a field trial comparing efficacy of a variety of products. This was a great test, because gray leaf spot severity increased rapidly in the unsprayed plots over a 4 week period. If you are considering fungicides for gray leaf spot control, you are advised to use the table below to help with the decision-making process.
Other information on gray leaf spot can be found at https://turf.purdue.edu/wp-content/uploads/2010/07/BP-107-W.pdf.
