Large Patch on Zoysia
Zoysia is a warm season turf grass that is suited for use on home lawns in the Kansas City area. Zoysia is widely considered one of the more insect and pest free turf grasses homeowners can use in their lawns. However, it is not without some problems.
Large patch of Zoysia is a disease that can wreak havoc on any lawn during relatively cool and wet conditions. The disease is most common in the early spring and late fall as the turf is entering winter dormancy or breaking dormancy. Large Patch is commonly associated with turf in shaded areas or areas that tend to stay moist in the summer months. These patches can develop each spring and fall in the same locations unless proper control measures are taken. The disease forms irregular patches that can range in size from 2 feet to up to 20 feet in diameter.
The spring patch symptoms appear as light brown sunken areas that are slower to recover from dormancy than surrounding turf. As the soil temperatures rise throughout the summer, the disease is suppressed until the return of more favorable conditions in the fall. The fall disease symptoms are bright orange patches of matted turf. The patch attacks the leaf sheaths near the thatch layer of the turf. The disease does not damage the roots or stolons during the infection process so rarely does this disease completely kill large areas of zoysia grass.
Large patch on Zoysia – Picture by B. Fresenburg
Controlling large patch in zoysia can be accomplished with cultural practices as well as chemical applications. Excessive soil moisture should be avoided so as to not promote large patch. Poorly drained areas should be corrected and turf grass areas should not be over watered.
Thatch should also be kept in check with zoysia grass lawns. Thick thatch layers serve as overwintering sites for the disease. Verticutting and core aerification should be performed each year to limit thatch accumulation and eliminate disease habitats.
Several fungicides can be used for preventing large patch from becoming a problem. These fungicides can be sprayed in the fall each year to reduce the disease pressure plus give some residual control in the spring.