You Are Here: Management Updates 2002 Archive May 16, 2002

Date: May 16, 2002
Category: Diseases
Subject: Fusarium Patch, Yellow Patch, Take-All Patch, Fairy Ring

The continuing cool, wet weather has favored the activity of fungi that love these conditions. Fusarium patch (pink snow mold) is still active in northern New England. It can take on a variety of appearances from small greasy patches to coppery patches to tan patches or rings. If you are not sure about your diagnosis, try closing a cup-cutter plug with disease in a plastic bag with a moist paper towel in a cool place overnight. The white to slightly pinkish mycelium should appear on infected leaf blades. This fungus produces an abundance of spores that are easily streaked by mowers causing more disease and even more confusing symptoms. Excessive N fertility makes disease more severe.

Yellow patch (cool-season brown patch) continues to be active on putting greens, tees, and even home lawns. This disease, too, is favored by cool, wet weather and high N fertility. It causes a lot of tip blighting but is rarely serious. Both yellow patch and Fusarium patch will disappear with the arrival of warm weather.

There are many reports of leaf spot on bentgrass, but no diagnoses have been made. Where the effect is throughout an area uniformly, the cause may be cold injury. The continuing cold nights may delay the growing out of the injured tissue.

Take-all patch has been diagnosed in samples from MA and NY. This root disease of bentgrass is favored by cool, wet weather. It is most common in new bentgrass plantings, but can occur in compacted soils especially where pH is on the high side. Ammonium sulfate in spring and fall can help lower pH in the root zone. Improve drainage and relieve compaction to avoid root stress. Azoxystrobin watered-in to the root zone immediately after application (while still wet on the leaves) has been very effective for take-all.

The soil moisture is apparently favoring the growth of fairy ring fungi resulting in hydrophobic soils and plants with drought symptoms on putting greens. Attention to excess thatch, wetting agents, and some hand watering will help the plants recover. Reports on the use of fungicides for fairy ring have not been very promising.

- Submitted by: Dr. Gail Schumann