In August and September we saw many Take-all Root Rot samples brought in to our Diagnostic Desk by frustrated homeowners. Periods of heavy rainfall and a stressed lawn trigger this disease which appears in summer and early fall.
Yellow and light green patches of St. Augustine lawn that eventually thin and die are the symptoms our walk-in customers described. Roots show the symptoms before the leaves do. By the time the leaves turn yellow, the disease has been destroying the roots for weeks or even months.
This disease is more easily prevented than controlled. Reducing stress on the lawn in the areas of mowing, fertilizing and herbicide applications is important. Proper watering, with a Rain Sensor Shutoff for sprinkler systems, helps in prevention.
There is no chemical control for Take-all Root Rot unless you are treating preventatively.
For more information, please see this University of Florida link: http://edis.ifas.ufl.edu/pdffiles/LH/LH07900.pdf