Keep Your Eyes Open
The best time to assess your turf's state of health is before mowing the lawn. While you are out picking up fallen twigs or removing other items from the ground, stop to take a careful look at any areas that appear wilted or off-color or that otherwise stand out from their surroundings. If you do note changes, don't rush to blame them on disease; there are numerous other possibilities. For instance, a general browning-out of a cool-season grass during high summer is likely just summer dormancy, the grass's protective response to drought and heat. Dull, wilted, bluish gray turf is the grass's signal that it needs water. General yellowing and stunted growth may be attributable to a lack of iron or nitrogen. Ragged leaf tips and a whitish cast usually indicate that your mower blades need sharpening.

Consider the kinds of activity that have recently occurred in your yard, as well. Perhaps the bright green rings surrounding dead grass are courtesy of the neighbor's dog, and the brown patches near the garage could be the result of a gasoline spill. While problematic, these eyesores are limited in scope and can usually be rectified with fertilization, irrigation, or spot reseeding. If your turf's decline cannot be explained by such causes, look more closely.