Campbell Vaughn: Identify grass fungus, then treat it wisely

There is fungus among us, especially in our warm season grasses. Diseased grass has been the bulk of our office calls the past couple of weeks. There are about 10 types of diseases that we see regularly; some are easy to spot while others are more difficult to pinpoint.

 

Look for browning of grass in patches (round and irregular), yellowing, actual spots on the leaf/blade, or chlorosis. Chlorosis is a condition in which leaves produce insufficient chlorophyll. As chlorophyll is responsible for the green color of leaves, chlorotic leaves are pale, yellow or yellow-white. If the damage is not from chinch bugs or army worms, it is most likely fungus.

Where did the fungus come from and how do you get rid of it? The simple explanation is that the fungus is already there and it is just being opportunistic. If the conditions are right, the disease is going to take advantage of the situation. This time of year it is mainly the warm days, cooler night temperatures and high moisture levels that activate the fungus. The pH levels and amount of nitrogen in soil can also play a large role in fungus growth.

If you start seeing the disease in your lawn, try these things first.

Turf grass doesn’t need the moisture you were adding through irrigation in July. Turn down or turn off your watering system. Natural dew is already adding moisture to the soil. Lower humidity and higher pressure from the departure of Hurricane Matthew can help dry out soil, keeping the fungus contained.

If you can identify the fungus, you will know better how to treat it, but you might need help. For example, Dollar Spot is a fungus that is pretty easy to identify because you will see a bunch of circular straw color patches that look like polka dots throughout your lawn. On the other hand, Take-All Root Rot and Large Patch can look similar.

UGA has a great website for helping identify disease in turf. Search online for: UGA Turfgrass Diseases in Georgia: Identification and Control and see what might be ailing your yard. This website will go step by step (with pictures) to properly isolate or identify the disease in your turf.

You can also email photos to us at augusta@uga.edu to help pinpoint the problem. Remember the better the picture, the better we can help you. Take several photos and include something to give us an idea of the scale, like your hand or a person standing nearby.

Most disease in turf reacts well to fungicides. Myclo­butanil is the active ingredient in a good general purpose fungicide found in the product Immunox. It can take care of a lot of diseases, but be careful because it is not a cure all. If you misdiagnose your disease, myclobutanil might not work and the fungus may keep running while you think you have treated it.

Find the right fungicide for the right disease. If a disease looks rampant, find a mixture of active ingredients with products such as Pillar G Intrinsic or Headway. These two products will be found at your local specialty stores such as Ewing Irrigation or Site One. Be sure to follow instructions carefully. Fungicides usually don’t hurt our warm season turf, but can hurt your pocketbook if applied incorrectly.

Raking thatch (dry vegetation) is a good way to eliminate fuel for disease. Removing thatch will allow for better air flow, which is good for grass and not for disease. If the disease is minor, skip the fungicides and consider top dressing your yard with an organic top dress and possibly adding a beneficial microbial content to your yard to promote the “good stuff” to out compete the bad. Your lawn will thank you later.

At this time of year:

Put pre-emergence on lawns and, if you can find the right product, also on ornamental beds. This is a good way to keep winter weeds down. Plan to reapply in March.

Turn down or turn off the amount of water you are subsidizing in your yard. The plants don’t need it, but the diseases do.

Last, applications are being accepted through Oct. 21 for the UGA Master Gardener class. Classes will meet from 9:30 a.m.-noon Tuesdays and Thursdays Jan. 5-March 21. Call (706) 821-2350 or email uge3245@uga.edu for more details.

 

REACH CAMPBELL VAUGHN, THE AGRICULTURE AND NATURAL RESOURCES COOPERATIVE EXTENSION AGENT FOR RICHMOND COUNTY, BY E-MAILING AUGUSTA@UGA.EDU.

 

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