The holiday season has arrived, but the cooler weather we often associate with this season is lagging behind. The recent unseasonably warm temperatures are the cause of brown patch, a common turf disease in the fall and spring that especially affects St. Augustine turf. This disease might be impacting your lawn.
Symptoms
Brown patch usually comes in the form of expanding circular shapes of discolored turf that can become several feet in diameter. The edge of the patch is typically the most affected while the turf at the center might be thinned out but can still be green. Another symptom of the disease is a gray cottony growth that can be seen between the leaf blades. At first, the affected turf can appear healthy, but when conditions are just right, the turf can decline extremely fast. It can even seem like it crept up overnight.
This disease is most prevalent when daytime temperatures range between 75-85 degrees and nighttime temperatures fall below 68 degrees. These are the exact temperatures we’ve been experiencing in this mild start to winter.
Causes
Besides the temperatures, brown patch can be brought on by the following conditions, which cause the turf’s metabolism to slow down.
- Shorter days with less sunlight
- Consecutive wetness (more than 10 hours a day)
- High humidity and shade
- High amounts of nitrogen
Also, brown patch can become more severe when the turf is cut too short with a dull mower blade.
Control
First, avoid nitrogen applications until turf recovers from the disease.Then, a strict fertilization schedule should be followed that applies slow-release nitrogen fertilizer in small doses to regulate the nitrogen level. Also, irrigation usage should be limited in shaded areas and areas that have consecutive wetness. When irrigation is needed, apply it in the early morning hours to allow the sun to dry the excess moisture throughout the day. Be sure to bag clippings to avoid spreading the disease throughout the lawn. Finally, mow the turf at the correct height with a sharp mower blade.
Recovery
Since brown patch typically only kills the leaf, the turf can make a full recovery as long as secondary problems do not take advantage of the turf’s weakened state. Remember, this is a cultural condition that can be avoided with a prudent watering schedule and good drainage.
