Crepe Myrtle Diseases Pictures

Crepe Myrtle Diseases Pictures

Crepe Myrtle Diseases Pictures: Myrtles (Lagerstroemia indica) are essentially small, unproblematic trees. The most common problems are powdery mildew, Cercospora leaf spot, aphids, Japanese beetles, and sooty mold. More information on the successful cultivation of crepe myrtle can be found in HGIC 1008, Crape Myrtle and HGIC 1009, Crape Myrtle Pruning.

Crepe Myrtle Diseases Pictures Powdery Mildew

Powdery mildew: Powdery mildew is one of the most common crepe myrtle problems caused by the fungus Erysiphe Lagerstroemia. Dusty white to grayish growth patches appear on the surface of new leaves, flowers, and shoots. Heavily infected flowers may not open, and the infected parts of the plant are deformed and atrophied. The disease is most severe in shady and humid locations, especially where plants are overcrowd and have poor air circulation. The fungus development is favor by high nighttime humidity and dry, mild conditions during the day, as is often the case in spring and fall.

Prevention and treatment: The most effective control measures include placing plants in full sun, removing shoots from the base of the plant, and planting resistant varieties. Sensitive varieties of pancake myrtle should be avoid. Removal of diseased twigs and branches may be possible if only a few shots are infecting. Remove sprouts (suckers) at the base of the plant as they appear, as they are highly susceptible to powdery mildew. Once these shoots become infected, the fungus quickly spreads to the upper parts of the plant.

Resistant plant varieties: The degree of resistance to powdery mildew for a particular type can vary from place to place and may depend on specific environmental conditions.

Varieties to Avoid Crepe Myrtle Diseases Pictures

“Grey’s Red,” “Orbin’s Adkins,” “Carolina Beauty,” “Wonderful White,” “Raspberry Sundae,” and “Potomac.”

If the disease is severe enough to warrant chemical control, select a fungicide that contains one of the following: myclobutanil, propiconazole, thiophanate-methyl, or copper-based fungicides (see Table 1 for specific products). Multiple applications may be require. Apply all chemicals according to label directions.

Cercospora spot: Cercospora lythracearum leaf spots can appear on crepe myrtles caused by the fungus Cercospora. This disease generally occurs during periods of hot and humid weather. Yellow spots (⅛ to ¼ inch in diameter) appear on the upper surface of the leaves, with grayish-white sporulation of the fungus on the lower surface of the leaves. The disease can cause almost complete defoliation of the plant in late summer and a drop in susceptible cultivars.

Prevention and treatment: Select resistant varieties for new plantations. The types “Fantasy,” “Tonto,” “Tuscarora,” “Tuskegee,” and “Velma’s Royal Delight” have shown resistance to Cercospora staining in field trials. The degree of resistance can vary from place to place and may depend on particular environmental conditions. Ensure good air circulation and avoid crowding of plants. If the disease is severe enough to warrant control chemicals, thiophanate-methyl or myclobutanil, as used for powdery mildew, will control the Cercospora leaf spot (see Table 1 for specific products). Apply all chemicals according to label directions.

Also Read: Atlanta Center For Dermatologic Diseases