One of my clients has a problem with a persistant burnout in the St. Augustine lawn (about 3 foot patch). A book I have it mentions St. Augustine can have a problem with St.Augustine Decline (SAD) virus. Thatch not a problem as the rest of the lawn is immaculate and lush. I was thinking at first the cleaning lady dumped her clorox bucket but its been several months now with same prob. The lawn was installed in the early 80s so its possible newer varieties have come along that are resistant to SAD virus. Thanks, Aloha, P.Y.S.