Yellow Grass: Fungi Part 2
Spring and fall are the most common times for fungal lawn issues. Irrigating your sod late in the day makes your grass particularly susceptible to fungal growth. Fungicide applications are most critical/beneficial during damp weather in the spring, early summer, and fall when temperatures are between 70º and 80ºF.
Brown Patch is the most common fungus across all the varieties we carry; however, Texas A&M has a full list of lawn fungi common in Texas with pictures and recommendations on treatment.
Causes/Prevention:
- Ensure Proper Drainage
- Morning Irrigation ONLY
- Irrigate As Needed Only (once established)
- Avoid Frequent, Shallow Waterings
- Fertilize & Water Appropriately
- Remove Excess Thatch, Leaves, and Debris.
- Mow Regularly
- Avoid Over-Fertilizing.
- Aerate Yearly
- Topdress Twice Yearly
- Avoid high-nitrogen fertilizers during drought & excessive heat.
- Clean Mowing Equipment with Bleach Solution
Resolution:
- Confirm the issue is fungal related by hiring a lawn professional or using Texas A&M’s Earth Wise Guide to Lawn Problems Flowchart
- Cut back on irrigation
- Let lawn dry out completely
- Identify the type of fungus by hiring a lawn professional or using Texas A&M’s Disease Handbook
- Treat with an appropriate fungicide (p 84)
- Always rotate fungicides from different FRAC groups
Other Possible Issues:
- Grub Worms
- Fungus
- Chinch Bugs
If you believe your soil/sod has been infected with a fungus, you need to cut back on your irrigation, letting the area dry out. It is essential that you only water in the morning. Watering in the evening or overnight causes excess moisture to remain in the lawn when overnight temperatures cool down, promoting an ideal environment for fungal growth.
Additionally, it would be best if you treated the yard with a fungicide. Please use Texas A&M’s guides linked above under “Resources” to find the appropriate fungicide. Be advised that once disease symptoms are present, the area will likely need more than one application. As with any chemical product, make sure that you read and follow the manufacturer’s instructions on the product’s label.
Finally, a fungicide with the active ingredients azoxystrobin and propiconazole will control most fungi in our area. We usually recommend Heritage G fungicide, as it is a broad-spectrum fungicide that will target many different types of fungi. That said, do NOT use a fungicide with the same active ingredient more than twice in a row! It is imperative to rotate fungicides from different FRAC groups to prevent resistance (see resources above for instructional video).
