I've been getting calls the past three weeks concerning Take-all patch infestations in lawns.
This fungus is most active in spring and fall, but is usually less common once we get into cooler weather in November. It's more of a problem this year because of the above-average rainfall, and because it's been warmer than average for much of the month.
Take-all patch first appears as circular to irregular straw-colored to light brown thinning patches of turf, six inches to three feet in diameter. As the disease progresses, patches come together, eventually killing large areas of the lawn. The patches can reappear and cause extensive damage in subsequent years.
Take-all patch is sometimes confused with brown/large patch, which has similar symptoms. These two diseases can be differentiated by pulling on a yellow or brown blade of grass. A blade infected with brown patch will give some resistance when pulled on, but a blade infected with Take-all patch will easily pull from the ground.
Integrated management is the best approach to preventing and controlling Take-all patch.
Maintaining a pH below 6.5 will reduce the severity of the disease. If your soil pH is above 6.5, acidifying fertilizers such as ammonium sulfate can be used to lower it. Conversely, you don't want the pH to be too low (4.5 - 5.3), as this will tie up most of your nutrients where they are not available to the grass.
If your lawn is infected, take a soil sample to your local extension service office.
One of the keys will be the potassium level. I can almost guarantee that when a grass has a disease problem like Take-all, the potassium levels will be low. Potassium is essential in growing grass. It helps in the prevention of disease and encourages winter hardiness.
I recommend a 16-4-8 fertilizer in the absence of a soil test. At least the grass is getting 8 percent potassium.
It is obviously too late to apply fertilizer with potassium for this year, but going ahead with a soil sample now will show you what fertilizer to use next spring.
You can treat Take-all with fungicides now. Research has shown that the only effective times to treat are in the fall and again during early spring. Treat with Immunox Lawn Disease Control (myclobutanil) or Bayleton or Bayer Advanced Fungus Control for Lawns (triadimefon).
It may be too late to treat your lawn, with cold weather approaching, but it certainly wouldn't hurt if you did so one more time. You definitely need to do so again next spring while the grass is coming out of winter dormancy.
Other factors to consider when treating for Take-all is to never fertilize the grass before April 15. Fertilizing in March can actually make it worse.
It will be beneficial if you aerate the lawn after complete green-up (after May 1). Topdressing with sphagnum peat moss also seems to help. Apply 3.8 cubic feet per 1,000 square feet. You might also try top dressing with compost, which has anti-fungal properties.
SID MULLIS IS THE DIRECTOR OF THE UNIVERSITY OF GEORGIA EXTENSION SERVICE OFFICE FOR RICHMOND COUNTY. CONTACT HIM AT (706) 821-2349 OR SMULLIS@UGA.EDU.
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