Much like Downey Mildew, Powdery Mildew can become a problem during periods of warm days and cool evenings, such as we are currently experiencing.  This fungal disease is found quite often on the upper leaf surfaces of many of our vegetables, such as squash, cucumbers, and melons as well as many of our ornamentals, such as crape myrtles, hydrangeas, and numerous herbaceous varieties, as a grey film.  Symptoms include early decline of the plants and fewer fruits.  Treatment is similar to that for Downy Mildew.