Disease Management
Diseases can occasionally cause significant problems in forage crops. Root diseases and crown diseases (caused by Pythium spp, Rhizoctonia spp, Fusarium spp), leaf blights, or leaf spots (such as Bipolaris leaf spot caused by Bipolaris and/or Drechslera spp, and dollar spot caused by Clarireedia spp) have been cited as occasional problems.
Diseases must be confirmed by a pathologist. If you need more tailored recommendations for your operation, please consult with your local County Extension Agent.
For more information on leaf spots, see University of Georgia Extension publication C887, Leaf Spot Diagnosis and Management in Bermudagrass Forages.
Management Options
Well-managed pastures and hayfields are generally free from most disease problems. If a disease outbreak occurs, the best option is to harvest or clean off the affected material as soon as possible. Prevention is critical for protecting forage stands against disease. Below is a list of best management practices that specifically relate to disease prevention.
Apply potash as soon as possible
Nearly every diseased stand of grass has a low soil K level, especially with respect to the N than has been applied. It may take several weeks to see the effects of the potassium, especially if the grass is really stressed. Potassium is a critical nutrient for disease prevention and should be applied at green-up and mid- to late-summer.
Adjust soil pH
Potassium will become less available to the plant when the soil pH is outside of the neutral zone (6.0 - 7.0). If the pH is low, the plant cannot take full advantage of the potash that is being applied.
Maintain a frequent harvest or grazing interval
Actively growing forages should be grazed or harvested approximately every 28-35 days to optimize forage yield and quality. Frequent removal of the forage mass will also prevent forage diseases. Potassium moves from older to younger leaves as the plant grows, which leaves the older leaves more susceptible to disease.
Minimize the Thatch Layer
Thatch is the layer undigested plant material that can build up on the soil surface. This layer can tie up nutrients and may contain abundant decaying material that serves as a spore reservoir. Burning is the ideal way to remove the thatch, but the bermudagrass must be completely dormant before the burn or you risk severe injury to the stand.
Avoid over-irrigation
Diseases thrive in warm and wet environments. Although we cannot control the weather, we can adjust irrigation. Irrigation is only needed to supplement ~ 75% evapotranspiration for economical forage production. Evapotranspiration includes water loss from both the soil (evaporation) and plant (transpiration).
Note on Chemical Control
Unfortunately, there are currently no legal and cost-effective chemical control options to use on pastures or hayfields in Georgia. We are limited to cultural control options detailed in this circular. Updated pesticide recommendations will be made if such products become available, however none are anticipated in the upcoming years.