Lawn fungus? - Ask Extension
At my home in west Portland, near Cedar Mill, I had lawn damage the last couple years with irregular dead spots that left a black, hard surface. Grass...
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Lawn fungus? #867677
Asked May 09, 2024, 12:23 AM EDT
At my home in west Portland, near Cedar Mill, I had lawn damage the last couple years with irregular dead spots that left a black, hard surface. Grass seed and fertilizer didn’t help, the spots persisted. This year I’m having some success getting grass to grow in those areas after using lime, fertilizer and a bagged soil mix (Scott’s Lawn Soil). I’m wondering if it was a fungus, possibly caused by over watering.
In addition to reducing my watering is there a general or broad spectrum fungicide I can apply to prevent this from returning?
Also, any suggestions about how often to water given the hot, dry summers we’ve been having.
Thanks!
Multnomah County Oregon
Expert Response
Could you send me a past photo of the black, hard surface symptoms?
If you fertilize your lawn in the spring and fall fungicides are not needed. Fungi attack turfgrass when it is under or over fertilized. The best thing to do to prevent this is fertilize in the spring and fall months, which are periods of peak growth and development. Be sure to avoid fertilizer application in the winter and summer, when growth is slow, or stress is significant.
Scotts and Bayer both sell some broad-spectrum fungicides that could be applied when symptoms start to develop. Common active ingredients that work well for turfgrass fungi include chlorothalonil and propiconazole.
