Your Lawn During the Fall Season
Dr. Mario A. Villarino, County Extension Agent for Agriculture and Natural Resources.
Several recent calls to the Hopkins County Extension Office were related to St Agustine grass lawns dying. There are three main reasons that can be attributed to poor conditions in St Agustine lawns, all affected directly by the soil conditions of the lawn. The first two are spring-summer diseases: take all root rot and chich bug damage. Take-all root rot is a fungal disease that causes weak, brown, dead patches in turfgrass. In Texas, the disease severely affects St. Augustinegrass and bermudagrass. Take-all root rot is caused by a fungus that lives in the soil. The fungus lives in many parts of Texas and is commonly found in both diseased-looking and apparently healthy-looking turfgrass. It lives in thatch, which is a layer of plant roots, stolons (shoots that grow horizontally along the ground surface), and decaying plant matter. The fungus can produce spores but spreads mainly through the roots and stolons. The disease is not usually transported by mowers or foot traffic; it is more likely to be spread when infected grass, thatch, or soil is moved elsewhere. The most obvious initial symptom is yellowish foliage that eventually turns brown and wilts. The turf thins out, leaving brown, irregular patches from 1 foot to more than 20 feet in diameter. As a field diagnosis, look at the roots of infected grass, which are usually short, blackened, and rotten, making it easy to lift the stolons from the soil.
Chinch bugs are about the size of a sesame seed and move fast, which makes it difficult for the untrained eye to recognize them. To confirm the presence of chinch bugs on your turfgrass: Mix 1 to 2 tablespoons of liquid dishwashing detergent in 1 gallon of water. Use a watering can to pour the mixture evenly over a 1-square-yard area of the affected turf. Look closely for chinch bugs. Within minutes, they will begin scurrying about. The adult bugs are black and about 3/16 inch long, with distinctive shiny, white wings; the immature nymphs are smaller and reddish, with a whitish band across the back. If many chinch bugs appear, they are probably the main cause of the turf problem. In some cases, the turfgrass may be afflicted by both chinch bugs and take-all root rot. If so, you must act against both culprits, and you may need to apply both an insecticide and a fungicide.
The third disease is called large patch. Unlike those infected with take-all root rot, grass blades with large patch can be slipped easily from the stolon because the fungus has rotted the stems. Infected leaves often have a slimy, dark brown lesion at the base of the leaf. Another difference is that large patch first appears in the fall and continues until early spring. The infected turf recovers quickly as temperatures rise in the spring. Have the soil tested, then fertilize on the basis of the test results. If excessive thatch has built up (more than ½ inch thick), the lawn becomes spongy and tends to scalp when mowing. The thatch can be reduced by using a vertical mower, aerating the soil with a core aerifier, and mowing at the proper height (2½ to 3½ inches for St. Augustinegrass; 1 to 2 inches for bermudagrass). Applying too much nitrogen encourages thatch to accumulate, making the turfgrass more vulnerable to disease outbreak and other environmental stress. For more information of lawn care, please contact the Hopkins County Extension Office at 903-885-3443 or email Mario at mavillarino@ag.tamu.edu.
Program Updates
Our yearly Dairy Outreach Program Area Training will be conducted at the SouthWest Dairy Museum October 31, 2012. Permitted Dairies are encouraged to participate. 4 DOPA credits will be offered. The cost of the training will be $10 per person lunch included. Our yearly pesticide applicator training is scheduled for November 7, 2012 at the regional civic center. The topics for this year are of special interest for herbicide applicators and beef producers. Call the Hopkins County Extension Office for more details. The cost of the event is $25 lunch included. New pesticide applicator applicants are encouraged to participate in our multi-county pesticide applicator training scheduled for November 7, 2012. Private landowners seeking pesticide applicator licensing will have an opportunity to get the mandated training and exam in our single day. The cost of the PAT training is $10. No lunch is included. For more information on these or any agricultural topics please contact the Hopkins County Extension Office at 903-885-3443 or e-mail me at mavillarino@ag.tamu.edu.
