Bipolaris Disease on Warm-Season Lawns

Bipolaris is an interesting fungal lawn disease that shows up in turf when the environmental and cultural conditions are just right, like a perfect storm.

Thankfully, you can diagnose and mitigate this grass disease on your own. Here are Super-Sod's bullet points for bipolaris disease diagnosis and a lawn treatment plan.

Bipolaris Lawn Disease Diagnosis

Typically, we recommend sending grass samples to your local county extension office for accurate diagnosis. Bipolaris turf disease is an exception to that rule. If the following conditions are present, you can assume the issues are caused by Bipolaris fungus and take quick steps to cure the disease and heal your lawn.

• Look on your grass leaf blades for purplish brown to black spots with tan centers (see examples below). After initial infection as revealed by the spots, the grass will "melt out" and rot at the crown, roots, and rhizomes, creating bare spots in the lawn.
• These are the four conditions that trigger bipolaris turf disease:
  
  • 10 hours per day with water/moisture on the leaves;
  • Then . . . bipolaris becomes more severe when the ground dries out;
  • High Nitrogen fertilization coupled with low Potassium levels;
  • We especially see this disease after excess Nitrogen is applied, then the lawn is scalped.

Bipolaris Lawn Disease Treatment

If you see purplish brown to black spots with tan centers or rotting areas and your turf has been subjected to the outlined conditions, here is a treatment plan for getting rid of Bipolaris in your grass:

• Watering Time: Irrigate your lawn only in the morning around sunrise. There are nuances to morning watering that can be found in: How and When to Water Your Lawn.
• Specialized Fertilizer: Apply high Potassium fertilizer as soon as symptoms appear. We recommend at least 3 times more Potassium (K) than Nitrogen (N). We keep 5-10-30 (N-P-K) fertilizer in stock to serve you.
• Professional-grade Fungicide: Our fungicide has two modes of action to cure and prevent future infections. Protection lasts for 14-28 days, so reapply the fungicide if environmental triggers persist.
• Mowing: Mow weekly to avoid scalping your turf. Read our article coaching you how to Master Lawn Mowing: Top 7 Tips for a Lush and Healthy Lawn

Bipolaris disease is one reason Super-Sod advises against over-application of fertilizer and cautions against scalping (the best way to avoid scalping is to mow weekly).

We carry the appropriate fertilizer and fungicides in our stores.

Bipolaris Lawn Disease Examples

For visual reference, here are two pictures of bipolaris turf disease. The first picture shows purplish-brown to black spots with tan centers to help you positively identify the first signs of infection.

Bipolaris Identification: Look for purplish brown to black spots with tan centers.

Scalping when mowing can trigger Bipolaris disease.

Come by your local Super-Sod for high Potassium fertilizer and professional-grade fungicide to treat Bipolaris as soon as possible. We also ship products or you can order ahead online and simply come by and pick up your products.