This fall, the weather has been ideal for golf and mainly for reducing pathogen activity. Signs of mini-ring and take-all root rot are appearing on bermudagrass putting greens, but the pathogens were more active when soil temperatures were higher and during rainfall in summer and early fall. Currently, most of North Carolina is abnormally dry or in a moderate drought. Fungal pathogens respond to temperature and moisture, and although the temperatures have been suitable, the moisture levels have not. If a disease is present, it is probably due to poor infiltration from irrigation cycles or overwatering.

Additionally, the pathogen may have been active earlier this year and bypassed fungicide treatments, or there may have been gaps in the fungicide program. Unfortunately, not much can be done right now if mini-ring and take-all root rot have developed. It is important to monitor leaf spot and Pythium blight on ultradwarf bermudagrass putting greens. Under persistent cloudy, wet weather, QoIs or phosphite applications will not effectively control Pythium blight. If those conditions are forecast, use a product specifically designed for Pythium, such as Subdue MAXX, Banol, Serata, or Segway.

The upcoming forecast for NC doesn't currently favor leaf spot or Pythium blight, but it does indicate chloroplast masking. We call this chloroplast evacuation, which happens when turfgrass plants stop producing chlorophyll as light levels decrease, revealing other pigments, such as anthocyanin (the purple pigment in plants). With the forecasted cold nights, bermudagrass putting greens are likely to develop purple spots that may resemble a disease. However, if you examine the leaf tips, you'll see they are purple; unlike leaves affected by leaf spot or Pythium blight, where the whole leaf shows damage. Based on the forecast, we wouldn't expect much leaf spot or Pythium blight activity, but we do expect purpling caused by the cold temperatures. If you suspect a disease is present, please feel free to reach out.