Mildews are a fungal disease that affects a wide range of plants, especially those that are stressed or have become dry at the roots. The symptoms are light grey powdery patches on the leaves, shoots and flowers, sometimes turning brown as they mature. The lower leaves are often the most affected, but mildew can appear on any part of the plant that shows above the ground. As the disease progresses, the spots get larger and thicker as massive numbers of spores form, and the mildew spreads up and down the length of the plant.
