You Are Here: Management Updates 2003 Archive May 9, 2003

Date: May 9, 2003
Category: Diseases
Subject: Spring Problems, Fusarium Patch, Yellow Patch, Leaf Spot, Take-All

The continuing cool, wet weather is causing a variety of turf problems. The predominant problem this spring has been cold injury and/or desiccation after the snow melt. In many areas, the turf came out of the winter well, but then began to show symptoms of cold injury and desiccation, particularly the Poa annua (annual bluegrass). Jim Skorulski, USGA Agronomist, discussed this in his regional report:

http://www.usga.org/green/archive/regional_updates/northeast/april03/april_archive.html

The moist, cool conditions have favored various disease-causing fungi. Fusarium patch (pink snow mold) has been active. At this time of year, it usually looks like small greasy to coppery spots that can be easily streaked, causing confusing symptoms. Yellow patch (cool-season brown patch) can pop up suddenly as rings of various sizes. As with Fusarium patch, it is most favored by high N fertility. It is also most common where there is excess thatch. It does not usually require treatment, especially if a couple of warm days are coming that will stop the disease as well as a fungicide. Leaf spot, that can progress into melting-out, is also favored by cool, wet weather and high N fertility. Lawns with severe leaf spot disease should be overseeded with some of the improved cultivars with excellent leaf spot resistance. Take-all patch, which is most common on younger bentgrass, can occur even on established bentgrass where soil pH is high and when remains cool and wet. Unlike the previously listed diseases, take-all is a root disease. Azoxystrobin (Heritage™) is the best fungicide for the disease, but it must be watered in to reach the roots where the pathogenic fungus is.

- Submitted by: Dr. Gail Schumann