What to do this week –By Mark Govan, Host “Florida Gardening”
January is the time of year many of our plants have gone dormant. Turf grasses, ornamental bedding plants, and even our vegetable gardens have either slowed down their growth or are at the end of their growth cycles. Although you may think that finally you can take a break, there are still a few things you need to be looking for this time of year. In this article I will tell you about a particularly nasty turf grass disease you either have seen or will be seeing right now. I have also decided to include some photos I have taken to help you distinguish this problem from other problems. Let us get started.
Winter Brown Patch or Rhizoctonia is a fungus disease of our Southern Turf Grasses and is causing major problems for many of us now. Even though we generally worry about this disease during the rainy season, nighttime cool temperatures combined with heavy dew have caused a severe outbreak of this disease in many homeowner lawns. Watering at night, excessive nitrogen fertilizers, and increased thatch in your lawn can cause this fungal diseases to kill your turf grass in as little as two to three short weeks.
Look for areas of the lawn that turn brown and in many cases these brown areas appear to grow in a circle. As the disease spreads, these circular patters seem to coalesce into large areas with a distinct border where the unaffected grass and the diseased grasses meet. Sometimes the areas in the center on the patches may look like they are recovering with green grass starting to grow again. However, this particular disease spreads very quickly and the most active areas of the fungus are at the edges of the circle. These outer edges sometimes may have a yellow hue to them and may have an odor of decay you can smell.
Lawn mowers that cut large commercial properties or even residential properties can easily spread this fungus from lawn to lawn on the decks of their mowers. In the old days, the mowers were required to pick up the grass clippings and dispose of them. This was a big help in reducing the spread of Winter Brown Patch and Summer Brown Patch. Unfortunately, as landfills filled up with yard waste, new requirements were put into place to eliminate grass clippings from the landfills. New efficient mulching mowers were created to eliminate this waste and reduced the cost to landscapers of hauling the clippings to the dump. By returning the clippings to the soil, nutrients were added back in the lawn which helped reduce the amount of fertilizers needed to keep lawns green but also created additional problems such as fungal diseases.
In a few short weeks time, this fungus can kill an entire St. Augustine lawn and you may be required to replace it. Homeowners should walk their lawns weekly to look for this disease before it spreads and there is massive turf loss. Call your pest management professional to look at your lawn and identify this problem before treatment is made to be sure you have this disease. Other problems may mimic this disease such as drought as noted in the picture below. Notice in this picture the green area is surrounded by dead grass, the exact opposite of how this disease progresses. If you want to treat this disease yourself I will give you instructions below.
Fungicides such as Bayleton, Daconil, Funginex, and K-Phite are good control products for this disease. You can find most of these products at your local garden center but be sure to read the label for each of these products before you use them. Be aware that not all fungal problems can be controlled with one product or one application. You will need to repeat the application in about fourteen days. This is why I highly recommend you hire a professional pest control company to properly identify this problem and let them control this problem for you. Remember, if you lose a ten by forty piece of turf grass due to this fungus, you could wind up paying more to replace the sod with new grass than it would have cost you to have hired a professional company to watch over your lawn for an entire year.
Cultural considerations or environmental conditions may also have an impact on control. If we are getting a lot of rain you may need to do additional applications. If you have excessive thatch in your lawn or your lawn is spongy when you walk on it, this may contribute to this disease spreading very quickly. Make sure you are properly fertilizing your lawn with an Enhanced Efficiency Fertilizer. EEF’s release their nitrogen slowly to the turf grass generating less loss of nitrogen and quicker uptake of nutrients into the grass. Fertilizers containing slow release nitrogen or polymer coated fertilizers release nitrogen over time reducing the risk of Winter Brown Patch due to quick releases of nitrogen.
You can have a direct impact on the condition of your lawn and surrounding plants simply by walking your yard on a regular basis and looking for issues before they become a problem. Look for the telltale yellow halo on the outer edges of this fungal problem and notify your pest control applicator immediately if you have a concern. Being proactive can save you tons of money and time if you catch the problems early. Proper fertilization and watering will also help keep this disease at a minimum. Use the fungicides I mentioned above if you are going to control Winter Brown Patch yourself and be sure to read the entire label before any application. Thanks for your time this week and remember, without plants we would not be here!