What is the common cause of Large Patch in warm-season grasses?

Large Patch, also known as Rhizoctonia solani, is primarily caused by excessive nitrogen combined with wet conditions, particularly in warm-season grasses. This fungal disease thrives in environments where nitrogen levels are high and moisture is plentiful, which creates ideal conditions for the pathogen to spread rapidly. Warm-season grasses, such as zoysia and bermudagrass, are particularly susceptible to this condition, especially during the transition from warm to cool temperatures.

For warm-season grasses, over-fertilization with nitrogen can lead to excessive leaf growth, making the grass more vulnerable to diseases. Coupled with wet conditions, which can include factors like heavy rainfall or poor drainage, the roots and the lower portions of the grass plants become compromised, making them a prime target for the disease.

Understanding the conditions that foster the growth of Large Patch allows for better management strategies, such as avoiding over-fertilization with nitrogen and ensuring proper drainage to minimize wet conditions. This knowledge can help turf managers maintain healthier lawns and ornamental areas.