Ascochyta Leaf Blight Symptoms

This lawn fungus is most commonly seen at the start of the summer when the weather changes from a cool damp spring to a hot and dry summer. This is when we start seeing sprinkler coverage issues, or improper watering practices manifested. Ascochyta and Dollar Spot are both symptoms of shallow grass roots which is often a caused by incorrect watering practices. One cause is watering frequently but for short intervals. This will keep the grass roots from growing deeply because they stay close to the surface where the water is. The other cause is by over watering which replaces the air in the soil so the grass roots stay close to the surface so they can breathe. The thing you want to most avoid is applying synthetic pesticides or fungicides to the lawn. Those will hinder more than help. They will kill beneficial microbes in the soil which help the lawn recover. Having a living soil or a healthy population of microbes is what keeps the soil a competitive environment so no one fungus or bacteria can take over.

Is this drought stress or a fungus?

Both will start to show up around the same time, which is usually early June. When the lawn is no longer getting the natural moisture from the cool spring weather we start seeing sprinkler issues; either the lawn lacking the proper coverage or it’s not being watered deeply and infrequently.
Ascochyta and Dollar spot are fungi that are symptoms of short grass roots, whereas drought stress is a lawn that hasn’t been watered properly, which causes short grass roots. The easiest way to tell if you have Ascochyta is if you go to the edge of the newly affected areas and find a blade. The blade of the grass will be green at the crown, brown in the middle, and green on the top. The Ascochyta will be a straw yellow color, but the drought stress will look more like a dull green or a light colored brown depending on the severity. It is possible to have both in the lawn, so getting a proper diagnosis is crucial to fixing the problem. The photo above is drought stress.

Are Ascochyta and Dollar Spot the same fungus?

Basically, the only difference between Ascochyta and Dollar Spot is that the Dollar Spot will have a dark band above the brown middle section. The photo to the left is Dollar Spot. The photo to the right is Ascochyta. Both have the same causes and cures. The first thing we look at is the watering schedule and sprinkler coverage.

I have Ascochyta in my lawn, now what?

Since Ascochyta is a minor stress fungus, it’s not likely that the grass is completely dead since it doesn’t affect the crown of the grass. Depending on the cause of the Ascochyta there are varying recovery times. Luckily it’s easy to fix either way. Step 1: Have a sprinkler audit performed to adjust the watering schedule and check for coverage issues in the lawn. Step 2: Water the lawn consecutively for 3 days to get it out of its stressed state. Then follow the watering schedule set from step 1. Step 3: Aerate your lawn; this will help get the air down into the soil, which will help the microbes breath and alleviate soil compaction. We suggest aerating twice a year for severely compacted lawns, or lawns that are struggling. Step 4: Apply humate; this will help the lawn recover more quickly by making the nutrients in the soil available for the microbes to break down. Step 5: Mow the lawn correctly; do not mow the lawn when it’s wet. You will want to mow the lawn on the highest setting of the mower (at least 3 inches). Bag the grass until the fungus is eliminated. Make sure you are not taking off more than 1/3 of the blade per mow, you may have to mow more frequently, but this will avoid putting additional stress on the lawn.

If the Ascochyta / Dollar Spot was caused by too much water it will take about two weeks to a month to recover. Follow the steps below for the speediest recovery.

Step 1: Have a sprinkler audit performed to adjust the watering schedule and check for coverage issues in the lawn. Often even if the times are set correctly one area may be getting double coverage, which is too much water. Step 2: Aerate your lawn; this will help get the air down into the soil and alleviate soil compaction. We suggest aerating twice a year for severely compacted lawns, or lawns that are struggling. Overwatering and foot traffic are the leading causes of lawn compaction. Step 3: Apply humate; this will help the lawn recover more quickly by making the nutrients in the soil available for the microbes to break down. Humate will also help break down a compacted soil. Step 4: Mow the lawn correctly; do not mow the lawn when it’s wet. You will want to mow the lawn on the highest setting of the mower (at least 3 inches). Bag the grass until the fungus is eliminated. Make sure you are not taking off more than 1/3 of the blade per mow, you may have to mow more frequently, but this will avoid putting additional stress on the lawn.

I’ve followed your watering recommendations why did I get Ascochyta?

There is no absolute prevention from getting Ascochyta. The fungus can travel via water into recently cut or damaged blades of grass. The best way to avoid this is by waiting 24 hours after you water the lawn to mow it and waiting 24 hours after you mow to water the lawn. It typically takes about 24 hours for the lawn to repair the tips from a mow. The healthier the lawn is the less likely it is of getting a fungus or disease. You can achieve the healthiest and strongest lawn by getting on one of our full season programs, which feeds the lawn throughout the season with a 100% organic fertilizer, mowing the lawn tall (3 inches or taller) and by following our 1-2-3-2-1 lawn watering technique.