What conditions make grass more susceptible to brown patch disease?

Brown patch disease, caused by the fungus Rhizoctonia solani, thrives under specific environmental conditions that create a favorable environment for its development. Grass becomes particularly vulnerable to this disease when there is high nitrogen content present alongside damp conditions.

High nitrogen levels can promote lush, rapid growth of grass, making it more tender and easier for diseases to establish. When combined with damp conditions—such as excessive moisture from rainfall or high humidity—these factors create an ideal breeding ground for the fungus. The excess moisture enhances fungal activity and mycelial growth, leading to the characteristic circular patches of browning grass.

In contrast, high heat and low humidity, low sunlight exposure, and frequent mowing do not contribute to the disease's prevalence in the same way. High temperatures can stress grass but might not independently support brown patch without the damp conditions that facilitate fungal growth. Similarly, while low sunlight can weaken the grass, it does not directly create the moisture necessary for brown patch to thrive. Frequent mowing typically promotes healthy grass growth and does not inherently favor brown patch disease unless combined with other stress factors.