Cercospora microsora

Lime leaf spot

Description

Cercospora microsora, commonly known as lime leaf spot, is a common fungal pathogen from the family Mycosphaerellaceae. It primarily infects linden trees (Tilia spp.), with most species being susceptible. The fungus overwinters on fallen leaves and spreads via conidia during the growing season, leading to circular, grayish spots on leaves, petioles, and sometimes flower bracts or young shoots. These spots range from 1–3 mm in diameter, with a lighter center and a darker margin. Under favorable conditions, spots can merge, forming larger necrotic areas.

This pathogen is widely distributed across Europe and is commonly found on trees of all ages. Although it primarily causes aesthetic damage by reducing leaf quality and appearance, severe infections may lead to premature leaf drop, potentially impacting the tree's vitality and photosynthesis.

Symptom

Circular gray spots with lighter centers and darker edges appear on leaves, petioles, and flower bracts. Severely affected leaves may develop larger necrotic areas, dry out, and drop prematurely.

Tree Species: Lime

Part of a plant- attacked: Leaf / Needle, Branch

Pest significance: Harmful

Pest Category: Fungi

Invasive Species: No

Present in EU: Yes