Necrotic Ring Spot Control: How To Get Rid of Necrotic Ring Spot

Necrotic Ring Spot is a fungal disease that can kill turfgrass if there is no intervention. Caused by Leptosphaeria korrae, a fungus known to infect the roots of turf, Necrotic Ring Spot infests lawns across the country, particularly during cool and wet weather.

Characterized by rings of dead grass, Necrotic Ring Spot creeps up often in places that are not well-fertilized. There are various reasons that Necrotic Ring Spot may appear on your lawn but for the most part, it usually occurs through overwatering or poor mowing practices.

If left untreated, Necrotic Ring Spot can begin to spread through spores and can overtake a lawn. Common types of grass that can be severely affected by Necrotic Ring Spot include Kentucky Bluegrass and Bentgrass as well as Ryegrass, Red Fescue and Tall Fescue.

If you have discovered Necrotic Ring Spot on your lawn, moving forward with a treatment program is crucial. Our DIY treatment guide below was compiled by lawn care specialists and will guarantee the removal of necrotic ring spot from your lawn if you follow the steps carefully.

Identification

Before you can proceed with treatment, you need to be certain that you are seeing necrotic ring spot on your lawn and not some other disease. Here are some facts and characteristics about necrotic diseases and what it looks like to help you with identification.

• Necrotic Ring Spot is often confused with another lawn disease known as Summer Patch, so much so that the were once thought to be the same disease.
• The main factor that differentiates the two are the times of year the diseases start to develop. Necrotic Ring Spot tends to develop in late spring or Fall whereas Summer Patch develops in the summers, as its name makes clear.
• When Necrotic Ring Spot is present, it is usually when the weather is cool and wet around the spring and fall seasons.
• The symptoms of the disease initially appear as small clustered patches of gray-tan colored turf between 6 to 8 inches in diameter.
• During conducive conditions, the patches develop an irregular donut shape with dead grass on the outside and a patch of healthy grass in the middle.
• Due to Necrotic Ring Spot being a root disease, initial above-ground symptoms start with discolored leaf tips followed by a collapse of the leaf and decline of the entire turf.
• Infected roots are affected by stunted growth and look worn and dead compared to healthy roots.

Refer to the image above and our description to help you in identifying Necrotic Ring Spot. If you are still not totally sure, you can contact us and we'll help you in correctly identifying your issue.

Inspection

After you have confirmed that you are dealing with necrotic ring spot, you can proceed with inspection. During this phase you will locate the areas where necrotic ring spot is prevalent and check for conditions that may be helping the disease to thrive.

Where to Inspect

Necrotic Ring Spot is known to infect popular lawn cool-season grasses such as Kentucky Bluegrass and Annual Bluegrass on golf courses, sports turf, professional landscapes, and residential lawns.

Playing fields and landscapes which have a mixture of Annual Bluegrass and Creeping Bentgrass may suffer from a blotchy or scattering appearance as a result of necrotic ring spot taking hold on the land. Necrotic ring spot often is seen as a disease of turfgrass that is on the younger side, but disease development can also occur in older turf (30 years or more).

What To Look For

Look for scattered patches of discolored or dead grass in areas of your lawn that are particularly shaded or having poor drainage. When it is summertime, look for spots that dry out easily in the heat as summer stress can exacerbate Necrotic Ring Spot.

Treatment

Before handling any chemicals, we suggest wearing the proper safety equipment for the job to prevent chemicals from coming in contact with your eyes or skin. Gloves, safety goggles and long-sleeved clothing should suffice.

Our top recommendation to control Necrotic Ring Spot is Patch Pro. This product contains the active ingredient propiconazole that works systemically to treat common diseases like Necrotic Ring Spot and keep it from spreading. Patch Pro is also cost-effective and one of our more affordable fungicides.

Step 1 - Measure & Mix Patch Pro

To determine how much Patch Pro you need, you will need to calculate the square footage of your treatment area by measuring and multiplying the area's length x width. The label says to use 4 fl. oz. per gallon of water per 1000 sq. ft. For example, if you measured a 2,000 sq. ft. area , this means you need 8 oz. to treat your yard mixed with 2 gallons of water. Mix the Patch Pro in a 20-gallon hose-end sprayer for large volume treatments.

We recommend mixing Patch Pro in a 20 gallon hose-end sprayer to make large volume treatments to a yard and to provide sufficient enough water for the Patch Pro to reach the root system of your turf.

Make sure the sprayers control valve and water pump are off and then attach the hose-end sprayer nozzle to the hose. Remove the reservoir and then add the proper amount of Patch Pro and the proper amount of water. For large volume applications, use 2 or more gallons per 1,000 sq. ft. for the product to reach the roots. The product will mix with the water and create an even emulsion. Reattach the reservoir to the nozzle and turn the water to the hose on. You are now ready to spray.

Step 2: Apply Patch Pro To Affected Areas

To spray, push forward on the control valve of the hose-end sprayer. Apply Patch Pro to infected areas spraying to wet but not to the point of runoff. The key is to focus on low lying areas of the yard that get a lot of shade as they are more susceptible to Summer Patch. You will also want to make sure to spray other vegetation around the infected area to prevent spores from spreading.

Apply liberally on the affected areas. The key is to act quickly and apply the fungicide where the Necrotic Leaf spot has been observed. Sprays should be applied when weather conditions favor pathogen activity in the soil, for example when soil temperatures at the 3” depth range between 60 - 70˚F. These soil temperatures are usually seen in the spring and fall months when the weather is generally mild and wet. So it is important to apply Patch Pro in spring or fall depending on your local conditions.

28 days later, a second application should be conducted. The disease that causes Necrotic Ring Spot is soil-borne, so it is important that the Patch Pro applications make it down deep into the soil where the grassroots are. This can be helped with irrigating the lawn before or after application or aerating the lawn before application.

Prevention

If you don't want Necrotic Ring Spot to make a comeback on your lawn, there are a few things you can do to lessen the chances of reinfestation.

• Rake and dethatch your lawn in spring, reduce shade by trimming tree branches and aeration in the Spring and/or fall will encourage deep rooting, improving the chance of turfgrass survival and recovery.
• Relieve summer stress through a regular watering routine of 1 to 1.5 inches of water a week.
• Implementing a balanced nitrogen fertilizer program and raising mowing heights to 3” will reduce demands on the root system and help lessen the chances of turf decline during hot dry conditions.

Key Takeaways

What is Necrotic Ring Spot?

• Necrotic Ring Spot is a turf disease caused by fungal spores in the air which can actually lie dormant for 30 years and all of sudden become active and infect your lawn with the disease.

How to Get Rid of Necrotic Ring Spot

• Our top recommended fungicide to control Necrotic Ring Spot is Patch Pro. It is highly effective against the disease and an affordable option.

Preventing Necrotic Ring Spot Reemergence

• Once your lawn has been treated, keep Necrotic Ring Spot away with a consistent lawn care and maintenance program which includes aeration, fertilizer application, and regular watering and mowing.