Now is the time to effectively control large patch to prevent widespread damage through the winter and next spring.
Grasses affected
Previously, large patch was only thought to affect zoysia (once called zoysia patch), but we now know it affects all warm-season turfgrasses including seashore paspalum and bermudagrass
Favorable conditions
Optimal conditions for large patch development include cool-to-mild temperatures (50 degrees F to 86 degrees F) coupled with high soil moisture and extended periods of overcast weather. Though, like all pathogens, some activity may still occur outside of this range of environmental conditions
Cultural management:
Aeration: Improved soil drainage and regular summer aeration is effective in reducing large patch
Nitrogen: Recent research (Miller et al., 2016) showed 0.75 pounds N/1000 square feet applied in fall or spring to zoysiagrass did not increase large patch, in contrast to older information. Instead, positive turfgrass responses from N were found to occur on Meyer zoysiagrass in spring, and the net result was a reduction of large patch symptoms
Control with fungicides:
DMI fungicides: The preferred mode of action for soil-borne pathogens like this
Apply in a minimum of 2 gal/1000: Recent research at University of Tennessee indicates fungicides only need to penetrate as far as the leaf sheath to be most effective, so apply in high water carrier volumes or apply ONLY 0.1 inch or less irrigation after application when using a lower water carrier volume
