Powdery Mildew

    Related Articles

    There are many different powdery mildew fungi. The fungus spores overwinter on fruit trees. In spring, the fungus begins to grow, and spores are released to travel on the wind to young leaves. Powdery mildew thrives where cool nights follow warm days. Insufficient sunlight and poor air circulation favor the development.

    Target Plants

    Bee balm, begonia, clematis, dahlia, euonymus, hydrangea, lilac, pansy, phlox, rhododendron, rose, sunflower, zinnia, bean, grape, pea, potato, pumpkin, squash, strawberry, tomato, apple, dogwood, peach, crepe myrtle, maple, oak, and sycamore trees.


    A white or gray powdery fungus appears on foliage and flowers. Round, white spots on upper leaf surface expand and merge, covering both sides of leaves. Infected leaves turn yellowish-green to brown. New growth may be stunned, curled, and distorted. Infected blossoms may not set fruit; fruit may develop a rough skin or be covered with the powdery fungus. Fruit drops early or is dwarfed.


    Some weeds get easily infected with powdery mildew, such as henbit. Plant resistant selections. Give plants sufficient light and air circulation. Water plants from underneath rather than above to keep leaves dry.


    Reduce nitrogen fertilizer. Pick off and destroy infected leaves and flowers. Spray ornamentals with horticultural oil, triforine (funginex), thiophanate-methyl (Thiomyl, Domain), azadirachtin (Neem), or triadimefon (Bayleton). Spray fruits and vegetables with wettable sulfur or horticultural oil. Discard infected flowers of annuals and leftover produce in fall.

    Video Credits: California Garden TV – Advice for All Climates
    Image Credits: Pollinator, WikiMedia


    Other Topics

    Rufous-sided Towhee

    Overview The Rufous-sided Towhee (Pipilo erythrophthalmus) is a spectacular large, long-tailed, red-eyed sparrow is known as Red-Eyed Towhee,...


    History & Overview The Pudelpointer is a versatile and healthy working gundog suitable for work in the fields,...


    History & Overview The Barbet is a medium-sized, sturdy, intelligent, independent dog. With approximately 300 dogs in the...

    Health Problems In Chinchillas

    Eye Infections Chinchillas are usually healthy, robust animals, and if fed properly and housed in a clean environment,...

    25 Dogs Breeds That Are Good With Children

    Overview We urge you to think hard before you bring that cute, cuddly puppy home only to find...