GREEN COVE SPRINGS – Many residential homes in our county, especially those in housing developments, have their yards sodded with St. Augustine grass. This species is water needy and has a few major issues that can occur but has become the standard for many lawns because of its appearance and abundance. These diseases appear to be in full swing due to the weather so here is some quick information on how to decide what is going on.

Cultural Issues

Many issues with turfgrass come from them being established or managed incorrectly. First of all, St. Augustine grass of any variety needs a minimum of 4 hours of full sun per day to thrive so areas in the shade will always have issue. In addition to this, many soils around structures and in yards are a mixture of fill dirts and many do not provide adequate drainage for the grass. Always check your root system as well. If your lawn is watered too frequently or is on poor soil, you may have a very shallow root system that makes your grass very likely to have issues during drought. Remember that St. Augustine grass should also be mowed at a height of 3.5” – 4”.

In regards to water, you should only irrigate as needed and always by the regulations put forth by the St. Johns River Water Management District. Also, check your system to ensure it is providing good coverage and is only putting down between a half-inch to three-quarters of an inch per application. More water can cause poor root systems, diseases and weed problems.

It is important to check all of your management strategies to make sure that a disease is actually the culprit and it is not a broken sprinkler head, scalping from being mowed too short, or sod dying out due to shade or excess water.

Common diseases

One of the common diseases of St. Augustine grass is called Large Patch, which can be identified by dying patches within the lawn and brown, rotting damage to leaf blades and stems. This is worsened by excess fertilization and is common in humid months. Another disease that is likely becoming active now is gray leaf spot, which causes small gray lesions to form on the leaf blade with eventual die back. Both can be prevented and controlled by fungicides but proper management is the best way to keep them from becoming a major issue.

Another major disease that is mostly found in stressed or very wet turfgrass is Take-all root rot. This can kill large swaths of turfgrass quickly by killing and actively rotting the roots and stems. Fungicide treatment is not as effective for this disease and the best way to control it is to keep your turfgrass happy and stress-free.

If you need help with issue identification, bring in a sample or email in some pictures of the areas and the grass blades close up to aid in identification and recommendations. For more information on these issues and their control, see the St. Augustine grass for Florida Lawns factsheet at http://edis.ifas.ufl.edu/lh010 and the Turfgrass Disease Management factsheet at http://edis.ifas.ufl.edu/lh040.

With any chemical control be sure the product is labeled for turfgrass and follow all directions found on the label, it is the law.

If you have any questions contact the University of Florida/IFAS Extension Office at (904) 284-6355 or email them to IF-SVC-Clay-MG@ad.ufl.edu. Visit clayextension.eventbrite.com to see and register for upcoming classes or call the office for more information.