A Brown Patch of Lawn Fungus

Types

• Brown patch is a common infectious fungal disease in grass. Although unsightly, brown patch is not typically destructive except in tall fescue and perennial ryegrass. Necrotic ring spot is a fungal disease in lawn grass most active during the spring and fall months. Bluegrass is susceptible to leaf spot diseases, which is caused by the fungus Bipolaris sorokiniana.

Symptoms

• The symptoms of fungal diseases in lawn grass include brown patches in grass that vary in size, fungal web-like growth on grass, smoke rings on grass, lesions on grass blades and brown spots on individual grass blades. Certain fungal diseases cause brown patches that are known as frogseye spots.

Control

• Keeping your grass healthy and stress-free prevents fungal diseases. Avoid over-watering and using fertilizers with high concentrations of nitrogen; certain fungal diseases such as brown patch worsen with fertilization. Set your lawnmower at a height no higher than 2 1/2 inches and avoid using fungicides or herbicides unless instructed to do so by your local extension office.