Although your diagnosis may be correct, remember that many turf diseases look like brown patch. Properly identify the disease by taking a sample to your county extension service. They’ll need a patch that contains some healthy turf, as well as the dead brown area, to make a definite diagnosis. If your lawn does indeed have brown patch, let the disease run its course. Like all fungal diseases, brown patch is condition-dependent – it flares up when the conditions are hot and humid and recedes when the weather turns cooler. Control the severity of brown patch by avoiding heavy nitrogen applications in spring and autumn. Water in the morning, so the grass doesn’t stay wet overnight. To prevent brown patch from spreading when it is active, remove grass clippings.