The Rockdale Gardener

Gardening Posts From Rockdale Cooperative Extension

Large Patch Fungus Killing Warm Season Grasses This Fall

The large patch fungus attacks warm season turf during cool wet periods. The fungus eats at the plants roots, killing the grass in distinct near-circular patches.zoysia large patch (2)

Dr. Alfredo Martinez, UGA’s Turfgrass Disease specialist, has written a really good synopsis of the disease here:

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

Large Patch is fungal disease of warm season turfgrasses such as zoysiagrass. It is favored by cool wet conditions and over-fertilization.

Large Patch is fungal disease of warm season turfgrasses such as zoysiagrass. It is favored by cool wet conditions and over-fertilization.

• Water timely and deeply (after midnight and before 10 AM). 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)

 

***NOTE – When using pesticides, observe all directions, restrictions, and precautions on the pesticide label.  It is dangerous, wasteful, and illegal to do otherwise.  Store all pesticides in their original containers with labels intact and behind locked doors.  Keep pesticides out of the reach of children.

Trade and brand names are for information only.  The Cooperative Extension, The University of Georgia College of Agricultural and Environmental Sciences, does not warrant the standard of any products mentioned; neither does it imply approval of any product to the exclusion of others which may also be suitable.

For a chemical poisoning call the Poison Help line at 1-800-222-1222