The Vintage Rosery
Brown Patch is a fungal problem and is prevalent in wet weather anytime before or after the heat of the summer. There are fairly well-defined circles of yellowing, followed by browning grass, expanding outward.
Culturally, poor drainage (or excessive watering), close mowing, high-nitrogen fertilizers and alkaline (high pH) soils encourage Brown Patch. So, improve the drainage, raise your mower deck, use organic fertilizers and apply sulfur to lower the pH. Water less frequently, but deeper, and only in the morning. This allows the grass blades to dry more quickly, making it less inviting for the fungus.
To treat the fungus, add a granular product called Actinovate, which is a beneficial streptomyces bacteria that will colonize the grass roots and protect them from a pathogen such as Brown Patch. Apply Actinovate at one pound per 1000 square feet of problem area.
Another solution is using corn meal as a fungicide, applying it at a rate of 20 pounds per 1000 square feet. Texas A&M has been testing corn meal and found that corn meal works by feeding and stimulating a fungal species (in the genus Trichoderma) that feeds on other (non-beneficial) fungal species. In one trial, they found that after spreading yellow corn meal, Trichoderma built up rapidly over a 5 to 10 day period. The resulting high Trichoderma population was able to destroy vast amounts of non-beneficial fungi. They further found that the level of control with corn meal is influenced by 1) soil moisture, 2) temperature, and 3) pesticides used (or not used). Applications of certain synthetic chemical based fungicides inhibited Trichoderma, which would limit the usefulness of corn meal.
Water in your corn meal with Compost Tea. Soil should already have a diverse variety of beneficial bacteria and fungi. If Trichoderma is lacking, the soil is most likely deficit in other species of beneficial fungi as well. Compost tea provides that diversity, with hundreds of species of fungi, bacteria and protozoa.
Grubs are the larvae of certain species of beetles. Grubs eat grass roots, killing the grass. One application of beneficial nematodes should take care of your grub problem. As a preventive, reapply beneficial nematodes once a year. At $20 per 3,000 square feet of coverage, it is an inexpensive solution.
Mushrooms indicate a lack of nitrogen. People that are trying to grow mushrooms will provide the mushrooms with rotting sawdust or rotting logs. Generous moisture and a lack of direct sunlight can help too.
In the horticultural world "rot" almost always mean "composting". To properly compost, you need a certain mixture of carbon heavy organic matter (wood, dried leaves, straw, etc.) and nitrogen heavy organic matter (manure, grass clippings, table scraps, weeds, etc.). If you get just the right mix, you get hot composting happening. Too much nitrogen and it gets a little stinky. Too much carbon and the composting takes a very long time.
To get rid of mushrooms, you just need to get your lawn to out-compete them. Grass loves a nitrogen rich soil. Mushrooms love a carbon rich soil. Lawn fertilizer has heaps of nitrogen and hardly any carbon. Time to fertilize!
Chinch bugs can cause extensive damage very quickly, including a total kill. Lawns suffering from chinch bug infestation show large patches of irregular, yellowish, stunted, wilted grass.
Typically, chinch bugs infect St. Augustine lawns during the hot, dry periods. Texas summers fit the bill. High-nitrogen fertilizers are a major factor of increased Chinch Bug activity, as is the use of chemical pesticides on the grass.
To check for chinch bugs, push a bottomless can into the ground near the edge of a dead patch of lawn and fill it with water. (Don't check the brown areas, as they already finished there and have moved on.) If chinch bugs are present, they will float to the surface within a few minutes. Look for fast moving bugs approximately 3/16 to 1/8 inch in length with black bodies and white wings.
If you do have chinch bugs damaging your lawn, use 2 - 3 repeated applications of diatomaceous earth (d.e.) for small infestations, pyrethrin spray, or a pyrethrin/d.e. powder, for larger infestations. Treat all of the lawn in the vicinity of the yellowing or browning lawn that is in full sun.
Synthetic chemical insecticides will kill chinch bugs. However, they also kill their natural predators and parts of the soil microbiology. A stable, organically maintained lawn should not see symptoms of chinch bugs.
After an infestation, be sure to inspect for chinch bugs the following year starting in July.