By Matt Giese, M.S., technical services manager for Syngenta

• Cultural practices |
• Research trials |
• Lawn Disease ID Guide

Brown patch is a disease that is caused by the pathogen Rhizoctonia solani. All turfgrass species are susceptible to its infection, but tall fescue and perennial ryegrass are most at risk. Tall fescue and ryegrass lawns in the transition zone, Mid-Atlantic, Midwest and Northeast can be exposed to brown patch under summer conditions with high humidity and nighttime temperatures above 65° F.

Brown patch symptoms can vary depending on grass species and mowing height. On wide-bladed turf species like tall fescue, leaf lesions develop with tan centers and dark brown margins. These leaves will die quickly, leaving a blighted area of lawn.

Generally, brown patch disease is more severe during extended periods of hot, humid weather (low and high temperatures above 70° F and 90° F, respectively). Poor soil drainage, lack of air movement, over-watering and low nitrogen also contribute to brown patch development.

The following cultural practices will help mitigate brown patch:

• Avoid night watering to reduce periods of leaf wetness
• Plant turfgrass species tolerant of low-light exposure in shady areas
• Aerate high-traffic areas in the fall to increase soil drainage and reduce soil compaction
• Apply adequate nitrogen to cool season turf in summer
• Keep records of previous outbreaks and their locations

Preventive solutions

Combining cultural management techniques with preventive fungicide applications is the best strategy to manage these turf diseases. R. solani can concentrate itself in the thatch and in areas of past infection, which is why it’s important to keep accurate records of disease history. Curative fungicide applications will stop progression of the disease, but turf recovery may not be visible until the following spring.

Headway^® fungicide is an excellent choice for preventive control of brown patch. Headway contains the active ingredients azoxystrobin and propiconazole and delivers broad-spectrum control of brown patch, as well as all major turf diseases. There are two formulations to choose from:

• Liquid sprayable formulation: Headway can be applied at a rate of 1.5 to 3.0 fl. oz./1,000 sq. ft. up to a 28 spray interval. Applications are best timed prior to disease symptoms. Use of the higher rate may be necessary for curative applications.
• Granular formulation: Headway G fungicide provides the same level of disease control as a spray. Application rates of 2 to 4 lbs. of product/1,000 ft.² provide 14 to 28 days of disease control. As with the liquid formulation, applications are best timed prior to disease symptoms.

When you need to combat brown patch and insect pressure at the same time, Caravan^® G insecticide offers the convenience of a fungicide and insecticide in one product. It contains the same active ingredient found in Heritage^® fungicide and Meridian^® 25WG insecticide. While timing and geographies vary, one application of Caravan G made in June or early July can yield season-long grub control and three weeks of preventive brown patch control.

Brown Patch, Rutgers University

Help inform your customers about brown patch and ensure they’re able to help you identify it with the free Lawn Disease ID Guide. This brochure offers a quick resource for not only identifying turf diseases, but also solutions for treating them. Order now.

For more information on controlling brown patch and other turf diseases, contact your local Syngenta territory manager.