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Bayer Solutions Solution sheet Microdochium Patch – Warm Season // The Problem Microdochium patch, Microdochium nivale, can be a tough problem on both warm- and cool-season turfgrass during fall, winter and spring. This disease was formerly known as “Fusarium patch” in older references. Microdochium patch is a newer disease of warm-season turf primarily because seashore paspalum and ultra dwarf bermudagrass are now seeing greater use on golf courses. In particular, seashore paspalum can be highly susceptible during periods of wet, cool conditions. Ultra dwarf bermudagrass is vulnerable when it is in a state of slow growth or semi-dormancy. Careful diagnosis of Microdochium patch is important because it can be an aggressive disease of warm-season turf, and the symptoms can be confused with other cool temperature diseases such as leaf spot and Pythium blight. What To Look For On seashore paspalum, Microdochium patch symptoms are dark brown to bronze, irregular-shaped spots that progress to patches. The patches are 0.25-2 inches in diameter, but may expand up to 8 inches across with a red-brown or dark, greasy-appearing margin. Young- est leaves will appear water-soaked, and mature leaves will look yellow to brown in color. Confirmation of the disease can be made by incubating a sample in a cool, moist container/plastic bag overnight. Microdochium nivale will sporulate on infected leaves and stolons and the resultant spores/conidia are multi-celled and crescent-shaped. Wet conditions during maximum daytime temperatures of 45-68°F favor the development of Microdochium patch. This disease is favored in shaded or poorly-drained locations and conditions of excessive nitrogen fertility. Microdochium patch is most severe on slowly-growing turf with heavy thatch. In heavily thatched situations, the turf becomes spongy or even matted down, creating an ideal micro-environment for disease development. On bermudagrass greens, Microdochium patch outbreaks can occur during the winter months when turf is semi-dormant and not growing. In warmer tropical or sub-tropical climates in the United States, the disease can be continuously active fall through spring as long as air temperatures and extended periods of leaf wetness remain conducive for its development. Any injury in the fall or winter will be long-lasting until growth resumes in the spring. // The Solution Cultural practices can be used to improve warm-season turf health and reduce the likelihood of Microdochium patch. To reduce Micro- dochium, avoid excessive fertilization especially in spring, maintain adequate potassium, maximize drainage, minimize thatch, improve air movement, and minimize shade. Interface® Stressgard® fungicide is the premier solution for Microdochium patch, with excellent preventive and curative activity. Interface Stressgard contains two fungicidal modes-of-action, the QoI trifloxystrobin and the dicarboximide iprodione. It provides plant health benefits for turf growth promotion under cool and low-light conditions when Microdochium patch is most active. Interface Stressgard is a systemic fungicide without plant growth regulator effects. Apply Interface Stressgard at 4-7 fl. oz. per 1,000 sq. ft. as a preventive or early curative treatment. 26GT® is also effective for Microdochium patch control, but does not have the added benefits of trifloxystrobin and Stressgard Formulation technology. In late-curative situations with high disease pressure, tank-mix Interface Stressgard with a contact fungicide to help manage resistance development. Additionally, rotate fungicides with different modes of action (refer to the FRAC code) when multiple applications are used to address Microdochium patch. Microdochium Patch Solutions Solution1 Rate (per 1,000 sq. ft.) Application Interval Interface® Stressgard®2, 3 4.0 - 7.0 fl oz 14 - 21 days 26GT®2, 4 4.0 - 8.0 fl oz 14 - 21 days 1See the product labels for complete use and instructions. Always read and follow label instructions carefully. 2See product label for any additional state registrations before use (Fusarium patch, aka Microdochium patch, aka Microdochium nivale).3Do not apply more than 30.0 fl. oz./1,000 sq. ft./year or 6 applications/year. 4Do not apply more than 35.0 fl. oz./1,000 sq. ft./year or 6 applications/year. Microdochium patch severely affecting an ultra dwarf Irregular patch symptoms caused by Microdochium nivale on an ultra bermudagrass golf green in Texas. dwarf bermudagrass golf green in Texas. (Dr. Maria Tomaso-Peterson, Mississippi State University) (Dr. Maria Tomaso-Peterson, Mississippi State University) Pink-colored sporodochia or spore-bearing structures On a turfgrass leaf blade, crescent-shaped spores/conidia are attached of Microdochium nivale on a dead leaf blade of turfgrass. to a sporodochia of Microdochium nivale. (Bayer) (Dr. Maria Tomaso-Peterson, Mississippi State University) ALWAYS READ AND FOLLOW LABEL INSTRUCTIONS Bayer Environmental Science, a Division of Bayer CropScience LP, 5000 CentreGreen Way, Suite 400, Cary, NC 27513. For additional product information, call toll-free 1-800-331-2867. Not all products are registered in all states. Bayer, the Bayer Cross, Interface, Stressgard and 26GT are registered trademarks of Bayer. © 2019 Bayer CropScience LP. ES-1018-GWS-475-A-R1.
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