You Are Here: Management Updates 2005 Archive September 7, 2005

Date: September 7, 2005
Category: Diseases
Subject: Gray Leaf Spot

Dr. Nathaniel Mitkowski, URI, has identified gray leaf spot from a golf course in Massachusetts north of I-495 and east of Rt. 3.  This is a devastating disease of perennial ryegrass; tall fescue has also been reported to be a host. In the south and mid-Atlantic states where gray leaf spot is more common, resistance to strobilurins has been reported. Thiophanate methyl would be the next best choice. Banner Maxx™ (propiconazole) plus Daconil™ (chlorothalonil) or Bayleton™ (triadimefon) plus Daconil™ are reported to be less effective than strobilurins and thiophanate methyl but resistance to this combination would not be a problem. Scout for this disease in taller ryegrass in the shade. Have the disease confirmed in a plant disease diagnostic clinic. Avoid irrigation toward evening so that you do not prolong the leaf wetness duration.

Submitted by: Dr. Robert Wick

DISCLAIMER - As always, it is the responsibility of the applicator to verify the registration status of any pesticide BEFORE applying it. Different states have different regulations as well. The author and the University of Massachusetts are not liable for any consequences of any pesticide "recommendations". Mention of any trade name is not to be considered endorsement of a product.

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