St. Augustine Decline (SAD) is a virus causing a chlorotic mottling or stippling of St. Augustinegrass leaves. It is also called Take-all Patch. St. Augustinegrass and centipedegrass are the only turfgrasses that the virus is known to affect. The virus is widespread in Texas.
The best control for the virus is to introduce resistant varieties of St. Augustinegrass into the lawn. Presently, Floratam, Floralawn, Raleigh and Seville are SAD-resistant varieties of St. Augustinegrass. Simply plug the resistant variety into the existing lawn on 2- or 3-foot centers. The resistant grass will crowd out the diseased grass over a period of a year or more. There are no chemical controls for SAD.