You Are Here: Management Updates 2003 Archive November 7, 2003

Date: November 7, 2003
Category: Diseases
Subject: Gray Leaf Spot, Avoiding Fungicide Resistance

Gray leaf spot (GLS) of perennial ryegrass, caused by the fungus Pyricularia grisea, seems to be an occasional problem in New England. Since its confirmation in 1998, we have had significant disease in only three of the five years. On the other hand, it can be a devastating disease when conditions are conducive. It is mostly a problem on golf course fairways and roughs so far. For unknown reasons it does not seem to be an important disease of ryegrass lawns and athletic fields at this time. We also know that fungicide resistance is a potential problem with the use of some of the most effective fungicides for this disease, i.e. the QoI/strobilurins (Compass™, Heritage™, Insignia™). Dr. Paul Vincelli from the University of Kentucky, where the disease is more common and severe, has just published a fact sheet on fungicide use for GLS with ways to avoid fungicide resistance. You can read it by visiting the Disease Fact Sheets section of this web site

- Submitted by: Dr. Gail Schumann