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Dasineura tortilis

Gall midge Dasineura tortilis

Description

Dasineura tortilis is a gall midge species from the family Cecidomyiidae, primarily affecting alder trees (Alnus spp.), including Alnus glutinosa, A. incana, and hybrid forms. This monophagous insect is widespread across Europe, with its presence confirmed from Scandinavia to southern regions. The species completes one generation per year, with larvae overwintering in the soil. Adults emerge in spring to lay eggs on young leaves. Feeding activity by larvae induces the formation of galls, characterized by folded or curled leaf margins, sometimes affecting the entire leaf. Initially green, the galls turn reddish-brown as the larvae develop. Severe infestations may compromise the aesthetic appearance of host trees and can marginally reduce their vitality. The galls, though small and localized, may lead to discoloration and premature leaf drop in heavily affected specimens.

Symptom

Galls appear as folded or upward-curled leaf margins, often reddish-brown in color. The affected areas thicken, especially around the midrib and lateral veins. The galled tissue eventually dies, turning dark brown and brittle.

Tree Species: Alder

Part of a plant- attacked: Leaf / Needle

Pest significance: Less harmful

Pest Category: Insects

Invasive Species: No

Present in EU: Yes