I have not received the phone calls yet on this issue, but I know they will come soon. Large patch is a fungus that attacks warm season grass (Bermuda, centipede, St. Augustine) during cool, wet periods. Although it has been unseasonably warm, it has been wet and cooler weather is coming. This fungus attacks the plant roots and kills the grass in a distinct circular patch.
Large patch disease is favored by:
• Thick thatch
• Excess soil moisture and poor drainage
• Too much shade which stresses turfgrass and increases moisture on turfgrass leaves and soil
• Early spring and late fall fertilization
Cultural practices are very important in control. Without improving cultural practices, you may not acheive long term control.
• Use low to moderate amounts of nitrogen, moderate amounts of phosphorous and moderate to high amounts of potash. Avoid applying nitrogen when the disease is active
• Avoid applying N fertilizer before May in Georgia. Early nitrogen applications (March-April) can encourage large patch
• Water timely and deeply (after midnight and before 10 a.m.). Avoid frequent light irrigation. Allow time during the day for the turf to dry before watering again
• Prune, thin or remove shrub and tree barriers that contribute to shade and poor air circulation. These can contribute to disease
• Reduce thatch if it is more than 1 inch thick
• Increase the height of cut
• Improve the soil drainage of the turf
• Apply lime if soil pH is less than 6.5 Chemical control options can be found in the UGA Homeowner Pest Control Handbook. Fungicides should be sprayed this fall and this spring. Look for products containing Thiophanate methyl (Cleary’s 3336, Scotts Lawn Fungus Control) or Myclobutanil (Spectracide, Immunox Lawn Disease Control – RTU, Concentrate, and Granules)
For more information or questions, contact Effingham County Agent Sam Ingram at 754-8040 or firstname.lastname@example.org.