Summer is almost here, and the heat is on. We have had a very wet, rainy spring, and deep moisture and humidity bring some challenges. Powdery mildew and root rot are the beginning of the gardener’s concerns currently. Large, leafed plants like gourds, squash, and pumpkins are particularly susceptible to powdery mildew. It grows as a fungus on the leaves, a powdery grey film on the leaves, or a white coating on the leaves and stalks.