Brown Patch: Symptoms and Control
High humidity, along with high soil temperatures and high soil moisture, can lead to several different turfgrass diseases, including brown patch. Brown patch is very common, producing damage in the spring, summer, and fall. However, it is most active and severe in the summer. The good news about brown patch: it is a very treatable disease even in a curative situation.
Brown patch appears on turfgrass as smoky-colored circular patches with dark, purplish rings around the perimeters of the patches. The patches vary in diameter from 4 – 8 inches. Under extreme conditions and in early morning, dewy conditions, you may also see grey mycelium in the darker ring area.
Prevention: Cultural and Chemical
During the timeframe when brown patch can be most prevalent, do these practices to reduce disease incidence.
- Avoid overwatering.
- Use fertilization practices that enhance growth in a slow-release manner. Avoid excess mineral nitrogen.
- Utilize phosphites in your spray program.
- Utilize products that enhance soil biology.
- Enhance airflow by removing trees in the offseason or use fans.
- Needle tine aerification.
- Make sure that drainage is adequate.
Brown patch preventative applications should begin early June through early September when conditions are prime for it to occur. Preventive products that contain FRAC 11 (Strobilurin/QoI) fungicides, such as Armortech’s Zoxy-T, Bayer’s Exteris Stressgard, and BASF’s Lexicon, are best.