This week at the Wonderful World of Weed Man we will be continuing on our “Your Lawn May Have the Sniffles!” lawn disease series.  Last week we talked about powdery mildew.  It is common this time of year, so if you are seeing it, check out that article to see how best to treat it.  Today, we are going to focus on fighting blight!

As lawn fungus goes, blight can be a catchall term for many variations of leaf blight.  We see a few of the variations every year.  Particularly Pythium Leaf Blight as well as Ascochyta Leaf Blight.  I know, I know, that is a mouthful.  For today’s purposes we are going to discuss Ascochyta Leaf Blight.  If you are interested in Pythium Leaf Blight, we have a great resource on our website about it.

We tend to see Ascochyta Leaf Blight most often in the beginning of summer when temps spike, or at tail end of the summer when it cools down, but we get a warm spell.  The symptoms develop more commonly during hot, droughty periods that were preceded by cool, rainy conditions.  As most lawn diseases this leaf blight is just another type of fungi that lives in the soil thatch year-round and develops when conditions are just right for it to thrive.

When the leaf blight shows up on the lawn, it looks very much like your lawn is dying.  If you don’t know what to look for you might think that your lawn was ‘burned’ or ‘bleached’.  The leaf blade of the grass will turn straw colored very quickly.  The overall appearance of the lawn (in the affected areas) will look like its drought stressed or dead.


Leaf blight, in comparison to drought stress or a dying lawn, can appear overnight or within a day or two.  Leaf blight, fortunately is not a blight on the crown or root portion of the grass plant.  It generally affects only the blade, and does not kill the crown or root of the plant.  If you look carefully at the grass blade, it will be straw colored from the tip down, but will be green at the base.  Because it is not damaging the crown or root, the lawn will recover on its own.

Conditions that bring on this disease can be the following

  • Mowing during the heat of the day seems to be one of the factors that cause this disease to become active.
  • It mainly affects bluegrass and it is usually on lawns that were mowed too short, or too often.Blight.jpg
  • Dull Mower blades will contribute to the severity of the disease. Your lawn mower can even spread the disease around on its wheels or mower blade as it moves up and down your property.  – you can see in this picture how mower wheels spread the disease around:


As stated previously this leaf blight will recover on its own within 2-3 weeks.  If you want to improve the recovery time, or prevent the issue altogether you can try the following:

  • Reduce thatch (where fungus spores like to lay in wait) by aerating your lawn regularly.  This will allow better water flow deeper into the soil.
  • When the disease is present reduce your mowing frequency, and increase your mowing height.
  • Avoid mowing during wet weather and/or the hottest part of the day.
  • Collect your mowing clippings to reduce the spread of the disease and/or the severity of the disease
  • Fungicides in this instance are very expensive, and literally unhelpful, as the damage has already been done.  Again the lawn will recover on its own.

If you are seeing any type of leaf blight in your lawn, and need some help with it, don’t hesitate to call the Weed Man! 208-888-9911  #wecareforyourlawn