Erysiphe euonymicola

Powdery mildew Erysiphe euonymicola

Description

Erysiphe euonymicola is a fungal pathogen responsible for powdery mildew on Euonymus plants, commonly known as spindle or burning bush. This fungal disease can significantly impact the aesthetic value and health condition of Euonymus species, which are popular ornamental plants in gardens and landscapes.Erysiphe euonymicola thrives in conditions where high humidity and moderate temperatures prevail. Overwintering occurs through mycelium in buds or as cleistothecia (sexual fruiting bodies) in plant debris.Management and Control: Remove and destroy infected plant debris to reduce sources of overwintering inoculum. Plant Euonymus with adequate spacing to ensure good air circulation, which helps reduce humidity levels around the foliage. Application of fungicides can be effective in managing powdery mildew. Planting resistant varieties or species of Euonymus can be an effective long-term strategy. While complete resistance is rare, some varieties may exhibit partial resistance to the fungus.The aesthetic value of Euonymus plants is often a key consideration in landscaping, and powdery mildew can severely diminish this by causing unsightly foliage and reducing plant vigor. In commercial nurseries, severe infestations can also impact the marketability of plants, leading to economic losses.

Symptom

The powdery mildew caused by Erysiphe euonymicola manifests as white to grayish powdery spots on the surfaces of leaves, stems, and sometimes flowers. These spots can coalesce to cover large areas of the plant. Infected leaves may turn yellow, brown, or purple. Leaves and young shoots can become distorted and curl. Severely infected plants may exhibit stunted growth. In severe cases, the infected leaves may drop prematurely, weakening the plant.

Tree Species: Spindle

Part of a plant- attacked: Leaf / Needle

Pest significance: Harmful

Pest Category: Fungi

Invasive Species: No

Present in EU: Yes