Q. I believe I am dealing with some fungal outbreak on my
new lawn. About a month ago I started to see faint circles of stressed lawn. They
range from 24 to easily 48 inches wide. They are certainly not dog urine spots.
I know the difference. Also confident
it’s not a watering problem. All spring and early summer the lawn has been
healthy and looking great. But now these circles are appearing everywhere. Am I going to need to just throw in the towel
and start over?
A. This is most likely a fungal disease called Summer
Patch. Buy a lawn fungicide at your local nursery that either says it controls
Summer Patch or (less likely) as well as necrotic ring spot disease.
Patch. Buy a lawn fungicide at your local nursery that either says it controls
Summer Patch or (less likely) as well as necrotic ring spot disease.
Fungicides
are primarily preventive so making an application now during this hot weather
will arrest the disease from going any further but not reverse the damage done.
Look for a turfgrass fungicide that states it will control Summer Patch
disease, Fusarium diseases or “frog eye” on the label. Follow the
label precisely in application. If the label states it also controls Necrotic
Ring Spot as well, so much the better.
are primarily preventive so making an application now during this hot weather
will arrest the disease from going any further but not reverse the damage done.
Look for a turfgrass fungicide that states it will control Summer Patch
disease, Fusarium diseases or “frog eye” on the label. Follow the
label precisely in application. If the label states it also controls Necrotic
Ring Spot as well, so much the better.
This is
a “hot weather” disease of lawns and favors soils that stay wet and don’t drain
readily. Since this is a hot weather disease, you can always expect it to occur
when temperatures are rising and become particularly aggressive during the
“summer monsoon” season where relative humidity takes a bump along
with high temperatures.
a “hot weather” disease of lawns and favors soils that stay wet and don’t drain
readily. Since this is a hot weather disease, you can always expect it to occur
when temperatures are rising and become particularly aggressive during the
“summer monsoon” season where relative humidity takes a bump along
with high temperatures.
Next
year anticipate an outbreak to start in June and make your preventive fungicide
application then or when you start to see those “faint circles” appearing.
year anticipate an outbreak to start in June and make your preventive fungicide
application then or when you start to see those “faint circles” appearing.
I would
aerate the soil now as well. You can use a simple hand aerator that you can buy
at the nursery or you can rent a power aerator from a local rental company. Don’t
use the shoes with the spikes on the bottom. They are a gimmick.
aerate the soil now as well. You can use a simple hand aerator that you can buy
at the nursery or you can rent a power aerator from a local rental company. Don’t
use the shoes with the spikes on the bottom. They are a gimmick.
Remember
this problem area in the future. Prior to the onset of hot weather, aerate to
improve water drainage from the area around grass roots. Mow the lawn at its
minimum acceptable height (usually 1 1/2 inch for tall fescue) to improve air circulation
in the stand of grass.
this problem area in the future. Prior to the onset of hot weather, aerate to
improve water drainage from the area around grass roots. Mow the lawn at its
minimum acceptable height (usually 1 1/2 inch for tall fescue) to improve air circulation
in the stand of grass.
Avoid
excessive applications of nitrogen fertilizers but keep the lawn fertilized
“adequately”. This will usually mean about half the label rate
mentioned for lawns on the fertilizer bag.
excessive applications of nitrogen fertilizers but keep the lawn fertilized
“adequately”. This will usually mean about half the label rate
mentioned for lawns on the fertilizer bag.
This is
particularly true if you are mulching the clippings back into the lawn with a
mulching mower. Returning the clippings to the lawn with the mulching mower has
no bearing on this disease in a lawn.
particularly true if you are mulching the clippings back into the lawn with a
mulching mower. Returning the clippings to the lawn with the mulching mower has
no bearing on this disease in a lawn.