Sulfur has been used to manage powdery mildew for centuries, but it is effective mainly as a preventive. Fungicides are typically not needed during the hottest part of the year when the powdery mildew fungus is inactive, and using fungicides at this time may damage the plant foliage. The surface of an infected plant has a powder-like appearance (Fig. Powdery mildew spores can germinate and infect crape myrtle in the absence of free water on the plant tissue, as long as there is adequate humidity in the air. To remedy this situation, you will need to apply fungicide. Some fungicides, both natural and synthetic, are available to help control powdery mildew. Spray your crepe myrtle with fungicides as soon as you see mildew on the leaves. Powdery mildew thrives in hot, humid environments and will not live as well when the air flows freely through the branches. All Rights Reserved. We have intentionally placed the review of the most effective fungicide at the end of the review because its the diagnosis which comes first and foremost. The best way to prevent powdery mildew on crape myrtles is to grow resistant varieties in open, airy sites that receive at least six hours of direct sunlight every day. The wind carries the powdery mildew spores to other plants. on the crape myrtle. They flourish in U.S. Department of Agriculture plant hardiness zones 7a through 9a. Once the roots are established, the tree rarely requires supplemental water. Our work makes a difference, in the lives of Texans and on the economy. genus of trees and shrubs are reliably hardy in zones 6 to 9, depending on the species, variety or cultivar. You may use a generic fungicide that contains propiconazole, tebuconazole, thiophanate-methyl, myclobutanil or triadimefon. Plan the perfect garden with our interactive tool →, Mississippi State University Extension: Powdery Mildew on Crape Myrtle, North Caroline State University Cooperative Extension: Crapemyrtle aphid, University of Georgia Cooperative Extension: Crape Myrtle Culture, University of Calfiornia Sonoma County Master Gardeners: Lagerstroemia Spp. Getting rid of fungus takes wit! Powdery mildew occurs most often on young, actively growing plant tissues (Fig. Download a printer-friendly version of this publication: Powdery Mildew on Crape Myrtles, View more Gardening & Landscaping information ». To remedy this situation, you will need to apply fungicide. For more information about crape myrtle varieties: Aggie Horticulture – Information about varieties that have powdery mildew resistance and are good choices for Texas. What is the best Fungicide for Powdery mildew? The ascoma survives the winter on leaves or plant debris and produces spores in the spring that can re-infect crape myrtles. Powdery mildew occurs most often on young, actively growing plant tissues (Fig. Do you have a question -or- need to contact an expert? Mildew thrives in warm, moist conditions. It is used frequently in southern gardens because the hot summer climate allows it to thrive. It can completely cover and severely damage new plant growth. Garden Safe is a 3-in-1 formula tripling up as an antifungal, insect powder, and a miticide. In order to diagnose your plant correctly you need to know as much as possible about plant diseases, and most of our guide is devoted to that matter! 1). Roth earned a Bachelor of Arts in French literature from Brandeis University and Master of Library Science from Simmons College Graduate School of Library and Information Science. The Mississippi State University Extension recommends pruning back your crepe myrtle during its winter's dormancy for best results. Warm days and cool nights (60° to 80°F) favor development and spread of powdery mildew. Our guide unites the scientists recommendations and experienced farmers tips. • Powdery mildew is one of the most common problems of crape myrtle • Surfaces of infected leaves, stems and flower buds become covered with a white or grayish powdery, mealy-to-dusty growth (Fig. Alternate using formulas with different active ingredients to prevent the crepe myrtle from developing a resistance to any one kind of fungicide. Use it for roses, ornamental plants, potted seedlings, and shrubs. Crepe myrtle (Lagerstroemia Indica) is a popular, easy to grow tree in the right setting. Erica Roth has been a writer since 2007. The crape myrtle is a popular woody ornamental plant. However, crepe myrtle benefits from an occasional watering during hot, dry weather, especially while the tree is blooming. Application intervals vary; if the aphids reappear, treat the tree again to prevent another round of black mold. Follow the instructions included with your fungicide of choice. Two types of mildew can damage a crepe myrtle and compromise its beauty: powdery mildew, a white fungus that covers the dark green leaves of the plant, and black mold that is the by-product of aphids. Always read all directions and labels before using any chemical control. It grows in thin layers on the surface of buds, flowers, leaves, and shoots. Avoiding excess fertilization also helps reduce susceptibility to powdery mildew. And that's what crepe murderers have helped to do this year. A variety of chemicals can control powdery mildew, including neem oil, sulfur-based sprays, propiconazole, potassium bicarbonates and tebuconazole. The fungus Erysiphe lagerstroemiae causes powdery mildew. Mildew is a fungus. Garden Safe – Best Organic Fungicide for Powdery Mildew. Control Prevention is the best management method. Powdery mildew spores can germinate and infect crape myrtle in the absence of free water on the plant tissue, as long as there is adequate humidity in the air. Prevention is the best management method. It is a dark, spherical structure about the size of a small poppy seed and easy to see among the whitish mildew.