I recently discovered a number of brown patches in my lawn and was totally floored when I discovered the culprit. I immediately went online to find a number of potential causes which included:Fungal Diseases (e.g., Brown Patch): Fringes of irregular, spreading brown patches that thrive in hot, humid weather or over-watered areas. Heat & Drought Stress: Widespread fading or irregular brown patches during prolonged dry spells. Gary McCoy Gary McCoyAccording to fairwaylawns.com, dog urine is highly concentrated in nitrogen and causes small, defined circular spots. So, if you've got these brown patches, and a Lily of your own, you've got some choices to make, or just do what I've decided, and learn to live with it.