You Are Here: Management Updates 2005 Archive September 12, 2005

Date: September 12, 2005
Category: Diseases
Subject: Gray Leaf Spot Update

Since the URI notice, gray leaf spot has appeared at various sites in Massachusetts. The fungus was probably carried up here by the hurricane weather front. We would like to collect isolates at UMass for research purposes. If you have gray leaf spot, please send a specimen to Robert Wick, Dept. PS&IS, 270 Stockbridge Road, Fernald Hall, UMass, Amherst MA 01003. You will not be charged a fee for the diagnosis.

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. If you are considering using chlorothalonil and you are in a Zone II area please see http://www.mass.gov/agr/pesticides/water/faq.htm

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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