In the Garden:
Take-all root rot causes a general dieback of affected turf grasses.
Take-All Root Rot
Growing a beautiful lawn has its challenges. There's the need to water, the challenge of weed invasions, and various insects and diseases that can show up to hamper your dream of a beautiful green carpet. However, in recent years we have been dealing with a particular disease here in the south that affects St. Augustine grass and bermudagrass but can also attack zoysia and centipede. This disease is called take-all root rot or take-all patch.
Unlike most other turf diseases, it doesn't just do some aesthetic damage, leaving the turf to recover. It kills turf, and as its name implies, it can take out a large part of a lawn. It's caused by a fungus that gets the upper hand when turf is stressed. Drought, shade, and weed killers are all common causes of turf grass stress that may lead to take-all infection.
This disease kills roots and runners, leaving the lawn declining quite rapidly in the heat. Unlike chinch bugs, symptoms don't usually begin adjacent to a curb or sidewalk but are rather random in location and irregular in shape and progression throughout the lawn.
There are two basic approaches to dealing with take-all: prevention and treatment. Avoid stressing your lawn and you will likely avoid this disease becoming a factor. Broadleaf weed killers are very stressful to St. Augustine, for example, when temperatures rise into the mid 80s. Avoid using these products after the cool spring period gives way to rising temperatures.
I let my lawn get very drought stressed a couple of years ago during the long, hot summer season. The next year I experienced a serious take-all problem. Once you have the disease in the lawn, your control options are cultural and chemical. First of all, you will want to provide adequate soil moisture without overwatering to help the grass plants survive with their limited root systems. Avoid overfertilizing but make sure and provide moderate nutrition to help keep the plants reasonably vigorous.
Research in several Texas trials has shown that peat moss applied at a rate of one 3.4-cubic-foot bale per 1,000 square feet was effective in suppressing take-all. One trial showed that the inclusion of iron in the peat application was even more effective. There are special rolling drum spreaders for applying peat moss, and some lawn care companies have compost blowers that can be used.
After applying the peat moss, water the area well. Applications can be made at any time, but in lawns with take-all problems it is especially important to make the applications in early fall to mid-fall or mid-spring.
There are several chemical treatments available through lawn care companies or over the counter at garden centers for this disease. These have shown some effectiveness, but in some cases they can inhibit grass regrowth. All things considered, I find the peat moss approach to be the most natural and effective option. Just remember to avoid stressing the grass or you'll be providing take-all the opportunity to strike again.
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