Things You'll Need
Powdery mildew eradication spray
Powdery mildew is a fungus that grows on plants like fruit trees, roses and other garden plants. According to the University of Washington, powdery mildew looks like baby powder was sprinkled over the leaves of the plants, although in some cases it also causes dark spots. Unfortunately, powdery mildew can survive the winter and attack new plant growth in the spring if it is not properly cared for. To get rid of a powdery mildew infection on your garden plants you need to spray it with a fungicide or oil that will kill the disease.
Remove any dead or severely damaged foliage from the plant with the powdery mildew infection using the pruning shears and dispose of it immediately. Do not compost it as it may spread to other plants.
Purchase a powdery mildew eradication spray from your local plant nursery. They come in many kinds and include plant oils like jojoba or neem oil, fungicide like AQ10 or horticultural oils like JMS Stylet Oil, Saf-T-Side Spray or Sunspray Ultra-Fine Spray Oil, according to the Master Gardeners of Santa Clara.
Spray the powdery mildew eradication spray all over the plant or plants with the infection. If the plant is potted, move it to a sunny location as the heat will help kill the powdery mildew. If the powdery mildew infection persists after the first spray, spray the plant again 3 to 5 days later until the powdery mildew if eradicated.