Answer: Brown patch attacks turf in your area primarily in spring and fall when the weather is cool and rainy. It is seldom seen in summer unless the turf is being really overwatered and overfertilized.
I suspect what you are seeing is Take-All Patch, which unlike Brown Patch actually kills the turf in irregular areas.
The best way to manage Take-All Patch is by several cultural steps. First, cut back on watering to once every 5 days, applying an inch of water to wet the soil thoroughly when you water. A coffee can has straight sides and makes a suitable sprinkler gauge to determine how long it will take to apply an inch.
Second, reduce fertilizing to a minimum. At most, apply a light fertilization in mid-April and again in early October using a product with a 3-1-2 ratio. Avoid herbicide treatments to kill weeds as these can stress turf dramatically increasing Take-All Patch problems. This includes "Weed-and-Feed" fertilizers.
Finally, apply sulfur dust (wettable sulfur for spraying) at a rate of 10 pounds per 1,000 square feet in early September to slightly acidify the thatch and runner zone at the soil surface. Water in well after applying the sulfur.
Good luck with your lawn!
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