An orange-brown, slightly raised stem canker may develop and cause branch … Most active at temperatures between 60 and 80 degrees Fahrenheit, the fungus succumbs to strong sunlight and temperatures above 95 F. Prevention measures include planting euonymus shrubs in full sun with room for good air circulation, watering them from above and feeding with slow-release fertilizer. It may defoliate a shrub. You can use a fungicidal spray to treat the plant. Although this disease is unattractive, it is not life-threatening. As the disease advances, the lesions merge and the foliage yellows, dies and drops. Look for a fungicide marketed as "all purpose" or "garden treatment" and apply it at regular intervals, starting in early spring, according to the directions on the package. Bacterial crown-gall disease on an euonymus shrub is hard to miss. Disease Symptoms Pathogen/Cause Management; Anthracnose: Small spots pepper leaves of evergreen euonymus. Diseases of the Euonymous Shrub. Informational table showing disease name, symptoms, pathogen/cause, and management of Euonymus diseases. The rain-loving disease surfaces as tiny brown leaf and twig spots. Fungal scab diseases attack Japanese euonymus varieties, including "Green Spire." In large numbers, they block the passage of moisture and nutrients throughout the plant. This particular disease, which is rather common according to Clemson University, is caused by either the Cercospora detructiva fungus, the C. euonymi fungus or both. Prevent crown gall by guarding against insect infestations of the Euonymus, as the bacteria that cause crown gall can enter the plant on the bodies of insects. Euonymus shrubs are nothing if not versatile. Symptoms consist of a flat, white to gray growth primarily on the upper surfaces of the leaves, which can be partially rubbed off. These can vary widely in appearance and even growth. Anthracnose is a disease that affects a wide range of woody ornamental plants, including those in the Euonymus family. Diseases. diseases is obviously warranted since results have been so variable and the diseases are so important. Columnar, evergreen "Green Spire" (Euonymus japonicus "Green Spire"), at 6 to 8 feet high and 1 to 2 feet wide, is ideal for containers or narrow spaces. Horticultural or neem oils sprayed according to the label specifications at temperatures below 90 F eliminate existing infections. This stubborn disease covers leaves with white fungal strands and may curl or scar tender leaf shoots. Updated: July 31, 2016. The primary symptom is the development of large, round galls, which swell up on the branches of the plant. Powdery mildew results from the Oidium euonymi-japonici fungus. Affected areas of the plant can be pruned off if the galls are limited to one area. Euonymus Diseases; Euonymus Diseases. The genus Euonymus is a large group of plants composed of shrubs, vines and ground covers, according to Clemson University. Copyright Leaf Group Ltd. // Leaf Group Lifestyle. Prune off infected areas and remove any dropped leaves from the soil. Although euonymus (Euonymus spp.) The white males are oval shaped, measure 1-2mm long and are generally to be found hanging around on the undersides of leaves. Variegated-leaf euonymus shrubs have a heightened risk of contracting anthracnose. Sometimes, the middle of the brown areas becomes greasy and gray in color. Treating the disease means cutting out the galls and a minimal amount of surrounding wood so that air can dry the exposed tissue. Spray the plant with an insecticide if you notice increased insect activity on your shrub. This insect has a soft flattened body that is covered by a shell or scale. Anthracnose is a disease that affects a wide range of woody ornamental plants, including those in the Euonymus family. Euonymus plants are highly susceptible to crown gall, which is a disease caused by several different types of bacterium. Over-watering and improper spacing may contribute to the development of fungal diseases and following good cultural practices can often prevent outbreaks. It became established in Britain on the south coast of England during the 1950s. It is now found in gardens throughout Southern Britain. Make sure the ingredients contain thiophanate-methyl, and follow the instructions on the label for the size and age of your Euonymus plant. Plan the perfect garden with our interactive tool →, shrub-euonymus image by Jeffrey Zalesny from, Clemson University: Euonymus Diseases & Insect Pests. Euonymus shrubs are nothing if not versatile. This is a fungal disease of Euonymus plants, meaning it is caused by one or more types of fungi. The most popular with home gardeners are the evergreen shrubs, such as the attractive Euonymus japonicus. The result is a stunted, weak shrub with dying branches of yellow leaves. For more information on growing euonymus refer to HGIC 1063, Euonymus. The imposing shrub illuminates gardens with red-violet, late-summer berries and rose-red autumn leaves. As a result, Euonymus shrubs often lose their leaves, even those that are evergreen. If your euonymus shrubs' leaves exhibit pale-brown, circular lesions, suspect Cercospora fungus. Any dropped leaves should be removed immediately, as the fungi can overwinter in the soil. Cercospora seldom requires fungicide application. This is a fungal disease, but instead of infecting only the leaves, the fungi, which are from the Colletrotichum species, attack the wood as well. Hot, dry weather eliminates it. Delay feeding until the shrubs’ new spring foliage is completely open and the threat of rain has passed. In other cases, the spots drop out of the leaves, or the leaves shrivel up and drop off the plant. Save For Later Print. Look for spongy raised areas, or galls, on its roots and stems and around its base. The primary symptom of the disease is the appearance of small brown marks on the leaves. Powdery Mildew: Powdery mildew is the most common and possibly the most difficult disease to control on euonymus. When plants begin to show signs of infection, you may need to use chemicals to fight the disease. In other cases, the spots drop out of the leaves, or the leaves shrivel up and drop off the plant. Anthracnose can be fatal in severe cases, especially if the plant is stressed from environmental conditions. Spring rain splashes scab spores from infected leaf litter onto new leaves and stems, where they cause tiny, orange-bordered pale-gray spots. They infect plants through cracked or wounded tissue. Articles. It is caused by the fungus Oidium euonymi-japonici. Hardy from U.S. Department of Agriculture plant hardiness zones 4 through 9, euonymus may be evergreen or deciduous, and are popular choices for hedges, borders and screens. 4 H e r - 416 Sp e 2 Me d 8 No. Any dropped leaves should be removed immediately, as the fungi can overwinter in the soil.