Would appreciate help with lawn black spots in attached photo. My lawn is 30 years old. Black spots started to appear about 6 years ago in one corner of lawn. Now they have spread all over the lawn. The blackness does not seem to be growing on the soil. It seems to be attached to grass stems & leaves. It is a matted thing, with spongy appearance, & slightly slimy/sticky. It is worse in wet weather.
About 3 years ago I put white lime on the blackness. It cured it for a while, but it came back again. March 2012 I sprayed bluestone on moss patches, & scarified the lawn a few weeks later in dry weather. The blackness is not dead moss.
The lawn is not low-lying. It is not boggy. It is on good soil. It has a nice slope for water run-off. It does not show pools of water.
Any ideas on a cure. Any danger it will eventually kill the grass.
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