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Erysiphe (= Microsphaera ) syringae

Lilac powdery mildew

Description

Erysiphe syringae (synonymum: Microsphaera syringae) is a specialized fungal pathogen that causes powdery mildew on various lilac species (Syringa spp.). It occurs widely across Europe, particularly in regions with warm and humid summers. The fungus overwinters as cleistothecia (closed fruiting bodies) on fallen leaves or as mycelium on buds and young twigs. Infections typically start in spring and may recur in several cycles during the growing season. Heavy infestations reduce the ornamental value of lilacs and may lead to premature leaf drop. The species is common in European parks and gardens.

Symptom

White powdery coating on the upper side of leaves, often forming a continuous layer; leaves may curl or turn yellow.

Tree Species: Lilac

Part of a plant- attacked: Leaf / Needle

Pest significance: Less harmful

Pest Category: Fungi

Invasive Species: No

Present in EU: Yes