// The Problem
Microdochium patch (Microdochium nivale) can be a tough problem on cool-season turf in late winter through early summer. This disease is also known as “Fusarium patch” in older references or as “pink snow mould,” though it can develop when snow is absent.
// What to Look For
Symptoms start off as small water-soaked spots on turf that expand and turn grey or tan with a red-brown or dark, greasy-appearing margin. Fluffy white mycelia can often be observed at the edge of the patches and dead tissue is sometimes covered by pink spore masses.
Wet conditions during maximum daytime temperatures of 7° - 20 °C favour this disease and explosive outbreaks can occur when daytime temperatures are in the low to high teens with overcast, foggy or wet weather. It is most common on cool-season turf, especially annual bluegrass, but can occasionally occur even on warm-season turf such as bermudagrass. This disease is favoured in shaded or poorly-drained locations and excessive nitrogen fertility conditions.
// Bayer Solutions
Cultural practices that reduce leaf wetness duration such as dew whipping and rolling have shown to contribute to disease reduction. In areas like the Pacific Northwest, the disease must be managed with a programmed approach. Interface Stressgard and Trilogy Stressgard fungicides with Stressgard Formulation Technology are outstanding solutions for Microdochium patch, both providing excellent preventive and curative activity. Interface and Trilogy can also help turf recover from pink snow mould damage following snow melt. Interface contains two fungicidal modes of action and provides plant health benefits for turf growth promotion under cool and low-light conditions when Microdochium patch is most active. Interface provides great disease control plus improved turf colour and density when you need it – in cool, wet weather.
Apply Interface at 128 - 160 mL per 100 m2 as a preventive or early curative treatment. Trilogy may be applied at 100 - 177 mL per 100 m2 in areas of particular high disease pressure. In late-curative situations with high disease pressure, tank-mix Interface or Trilogy with a contact fungicide (such as chlorothalonil) to help manage resistance development. Rotate applications with non-dicarboximide or QoI fungicide products when multiple applications are used in the season for Microdochium patch control to discourage resistance development.