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BIOGRASS
02-25-2010, 02:12 PM
I have used Heritage to treat Necrotic Ring Spot in the past and have been somewhat happy with the results that have come from using it. Have any of you used other applications like Headway? Any other types? Please let me know for I have 4 lawns that I am going to renovate that have NRS.

quackgrass
03-13-2010, 02:12 AM
I don't use fungicides for necrotic ring spot anymore. They are too expensive and don't cure the problem.

Typically you will find NRS on lawns that are about 2-5 years old, generally it is a sodded KB grass that was placed on an imported layer of clay someone mistook for top soil.

The host lawn is usually one that was fed a highly soluble NPK diet for 1 or two years then left to starve because its owner moved onto another project.

Necrotic ring spot will take hold of this anemic grass and the worst possible thing is to fertilize it with a quick release synthetic because the fungus will actually go little shop of horrors on you because it loves soluble nitrogen.

So now you have a turf that is too weak to defend itself but can't be fed right? Wrong! You need to feed it with an organic fertilizer containing microbes. For some unknown reason, the microbes which consume the organic fertilizer and turn it into soluble N are antagonistic to the NRS fungus. The other benefit is that the turf gets fed without the NRS stealing the food. (sort of like the Red cross :laugh:) Compost puts a complete smack down on NRS for good.

The areas that are killed need to be seeded with a more resistant cultivar of grass then you should top dress these areas with compost.

Don't put the lawn on any quick release ferts for a long time but maintain high fertility. Use milorganite, chicken poo etc.

Aerate regularly (before top dressing) for better drainage. NRS loves perched water!

Water infrequently as possible but deeply, shallow roots are not good.

Hope that helps, its worked better than fungicides for me.

RigglePLC
03-13-2010, 09:25 AM
I am not a fan of fungicides for necrotic ring spot. I would favor heavy and repeated overseed with a top quality disease-resistant rye/blue mixture. Prepare the site with power raking or double aeration. For just a few spots I favor to cut out the spot and patch it with new sod.
I don't disagree with Quack, but don't worry about what type of fert you use. A top quality slow release type is fine.