Powdery Mildew Disease

While different fungal species are behind powdery mildew, Erysiphe australiana is one of the most common problems for crape myrtle trees. The effects of powdery mildew can be devastating to your trees and lawn—photosynthesis is obstructed, nutrients are underutilized, growth is stunted, and finally, the plant becomes overwhelmed and dies. The lawn care professionals at Fairway Lawns can help contain powdery mildew and get your yard healthy again! Contact us today!

How to Identify Powdery Mildew

Powdery mildew looks exactly as it sounds; it’s a white or greyish powdery substance that covers the leaves, stems, and flower buds of a plant, but identifying it can be tricky. Many people mistake it for downy mildew, which is very similar, except it grows only on the underside of plant leaves. Powdery mildew; however, covers the entire leaf. Young shoots and leaflets are most susceptible to this fungal infection, as well as rapidly growing, lush foliage that has been overfertilized.

Here’s what powdery mildew looks like on crape myrtle trees:

Small-to-large, irregular-to-circular white/grey patches on leaves

Stunted leaves that may only grow a third of the normal size and are abnormally thickened

Pinhead fruit growth first appears white, turns to yellow, then to brown or black

Reddish discoloration under the white coating

Curling or twisting on new foliage before fungus growth is evident to the untrained eye

Stunted flower stems

Buds fail to develop flowers under severe disease levels

Defoliation may occur

Causes of Powdery Mildew

It can ruin a wide variety of plants like crape myrtle trees. Unique from other fungal plant diseases, powdery mildew prefers warm, dry climates. Humid areas that are constantly under stress make a perfect environment for the fungus to grow. Temperatures between 60-72 degrees also promote the proliferation of powdery mildew, along with poor air circulation and insufficient lighting.

While fertilizers play a huge part in plant health maintenance, it is important to note that applying too much can lead to the development of powdery mildew, which usually preys upon new plant growths. When trees grow too aggressively as a result of over-fertilization, a powdery mildew outbreak can occur. This is why it’s crucial to monitor the supply of nutrients to the plants to control results.

Powdery Mildew Control and Treatment

In the beginning, fungi form spores that spread through the wind and contaminate other plants. The disease is fairly easy to contain with the right techniques, for example, fungicides for powdery mildew can help arrest an outbreak. Fungicides provide the greatest effectiveness when applications are started soon as the disease infection occurs. That is why it is best to take action as soon as symptoms are noticed!

Having your trees inspected by Fairway Lawns will ensure your trees have the best chance of surviving this fungal disease. You can count on our experts to identify and manage powdery mildew or any other lawn disease your yard is suffering from.


Before any symptoms escalate or even begin, it is always wise to take preventive measures for your crape myrtle trees, such as:

  • Avoid heavy applications of fertilizer during the summer growing season
  • Space plants apart to ensure good air circulation
  • Practice selective tree pruning to maintain an open canopy to improve air flow
  • Plant trees in full sun (6 hours minimum)
  • Remove sprouts (suckers) at the base of the tree as they occur (sprouts are very susceptible to powdery mildew and once infected, the fungus easily spreads to the upper portions)
  • Remove and destroy all infected plants, leaves, and branches (do not compost debris because remnants of the fungi can remain in composted materials and spread through the air)


Don’t take chances with the health and beauty of your trees and turfgrass, contact us at Fairway Lawns today for professional lawn treatment services. We can help manage powdery mildew as well as provide all of the other lawn care and tree and shrub care services you need!

Schedule your free estimate by filling out our online form.

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