Snow mold-crop-environment interactions

Abstract

In temperate, boreal, and sub-arctic zones, plants such as winter cereals, grasses, and perennial forages must survive harsh winter conditions, frequently encountering exposure to lethal and sublethal low temperatures. However, in many regions, a deep, persistent snow cover insulates the root and crown zone, maintaining soil temperatures between 0° and -10°C despite very low ambient temperatures, thereby protecting plants against low temperature injury.1,2 The protracted snow cover creates a dark, humid environment with constant temperatures that prevents photosynthesis and drastically reduces plant metabolism. These conditions favour development of psychrophilic fungi known as snow molds, which can cause extensive damage to agricultural, ornamental, and native plants. In this article, we outline the adaptations that plants and snow mold fungi have made to survive and thrive in a nival environment, and discuss the dynamic nature of the snow moldplant interactions under snow, including the interaction between freezing tolerance and snow mold resistance.