Brown Patch

Brown patch is a very common fungal disease in lawns. It begins as irregularly shaped brown patches and then spreads outward. The fungus is most active where lawn and patch collide and often this area is a darker green than the lawn. As the fungus spreads the centers of the patch may begin to recover and/or weeds may invade the area. This causes the patch to have a doughnut-like appearance.

Pathogen:
Rhizoctonia solani is the pathogen of brown patch and it loves lush, tender growth. To prevent the appearance of this pathogen avoid over-fertilizing the lawn. The pathogen may also be spread by mowing equipment. If you are mowing a large area, or several lawns, sterilize any equipment that may have come in contact with brown patch before moving on to an uninfected area.

Environment:
Brown patch will usually show up after a few cool, overcast, rainy days. Providing good drainage and removing excess thatch will help prevent brown patch development. Most importantly do not water in the evenings, early morning is best.

Hosts:
Tall fescue, Kentucky bluegrass, St. Augustine, and centipede grass are vulnerable to brown patch. Tall fescue and Kentucky bluegrass are common turfgrasses in the Nashville area. It is best to plant a mixture of 3 or more resistant varieties just to cover your bases. St. Augustine and centipede grass are primarily southern coastal turfgrasses and will not survive well in the Nashville area.

Management:
Several days of dry weather will suppress brown patch. So, check the weather forecast before applying chemicals. Fungicides containing chlorothalonil (Daconil), mancozeb, tiophanate-methyl (Thiomyl, Domain), or triadimefon (Bayleton) are effective against brown patch. Always apply according to label directions.

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