update Green Solutions
Large Patch Management // Overview
Large patch is one of the major fungal diseases of warm-season turf and is caused by the soil-borne fungus Rhizoctonia solani AG 2-2 LP. It is the primary disease of zoysiagrass fairways, tees and lawns in the transition zone and is commonly referred to as ‘zoysia patch’. However, large patch can also affect other warm-season turf species such as seashore paspalum, kikuyugrass and bermudagrass. It attacks slowly-growing, warm-season turfgrass in cool, wet weather, and is most common on turfgrass that is semi-dormant or turfgrass that is going into or emerging from dormancy. In the transition zone, the disease is most active in the fall and spring, whereas in warm climates like Florida, the disease can be continuously active fall through spring. // Best Management Practices
Cultural Practices // Improve surface and subsurface drainage
Spray Volume and Watering-In // Recent research at the University of Tennessee suggests applying products in at least 2 gallons of water volume per 1,000 square feet to sufficiently move the active ingredient to the sheath and crown where the pathogen is most active // If applying in less than 2 gallons/1,000 sq. ft., irrigate lightly with 0.1” or less immediately after application to move active ingredient to the crowns and sheaths. Do not over-irrigate and move the fungicide into the soil.
// Aerify to minimize thatch and further improve drainage // Research recently conducted at the University of Missouri showed 0.75 lbs. N/1,000 sq. ft. applied in fall or spring to zoysiagrass did not increase large patch // Positive turfgrass responses from N were found to occur on ‘Meyer’ zoysiagrass in spring, and the net result was a reduction of large patch symptoms
// 2019-2020 Fungicide Programs for Golf Courses Timing for large patch prevention is based on university research and begins in the fall when the average soil temperature at a 2-inch depth taken at 11 am is 72-75°F for five consecutive days. Warm-Season Fairways & Tees
Product 1 and Use Rate per 1,000 sq. ft.
1st app. (Fall) 72-75°F soil temp 2nd app. (Fall) 28 days later
Mirage ® Stressgard ®2 1 fl. oz. Mirage Stressgard 2 1 fl. oz. Mirage Stressgard 2 1 fl. oz.
3rd app. (Spring) 50% turf green-up (no later)
1 See product labels for additional information and follow application instructions 2 Do not exceed 6.5 fl. oz. Mirage Stressgard/1,000 sq. ft./year; In New York only, do not exceed three applications at 1 fl. oz. Mirage Stressgard/1,000 sq. ft.
Large Patch – Zoysiagrass Green Surround. (Bayer)
Large Patch – Bermudagrass Fairway. (Bayer)
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