Lawn Fusarium Patch
Wet lawn developing pink and yellow patches of damage? Could be fusarium patch. Find out what it is and what to do about it.
What is it?
A grass disease caused by the fungus, fusarium nivale that attacks lawns when they are wet from conditions such as rain, snow, or poor surface drainage.
What does it look like?
Areas of damage are between 2 inches and 1 foot diameter and will be pink around the edges with a pale yellow center. Blades will be a light tan color and stick together easily. Occasionally, a white cottony growth appears on blades.
How does it manifest?
Fusarium patch fungi often will grow beneath the snow, and spread as it melts. This is the reason for its other name: pink snow mold. Often only the blades will be affected, but occasionally in sever disease crowns become affected and kill of the lawn. Fusarium patch thrives in humid weather where daytime temperatures remain beneath 65° F.
What can you do about it?
At the first sign of disease in the spring, treat the lawn with a fungicide containing benomyl, methyl thiphanate, or iprodione. Repeat a second application in 14 days. Treat the lawn twice more in the fall while daytime temperatures remain below 60° F and conditions are wet. You can discourage fusarium patch by mowing your lawn until growth stops in the fall, and by applying high nitrogen fertilizers in late fall.