Dasineura acrophila

Gall midge Dasineura acrophila

Description

Dasineura acrophila is a gall midge that forms characteristic galls on ash trees (Fraxinus spp.), including Fraxinus excelsior (European ash), F. angustifolia (narrow-leaved ash), and F. ornus (manna ash). This species is monophagous, focusing exclusively on ash trees, and is distributed across Europe, including southern and central regions. The lifecycle includes one generation per year, with larvae overwintering in the soil and emerging in spring.

The galls are pod-like structures created by the thickening and upward folding of the leaflets along the midrib. Each gall contains multiple white larvae. While the damage is primarily cosmetic, severe infestations can reduce photosynthetic capacity and overall vitality of affected trees.

Symptom

Pod-like galls form on leaflets, thickened and folded along the midrib. Larvae inhabit these structures, leaving behind cast skins and frass after exiting. Upper leaf surfaces may show swelling. In comparison to Dasineura fraxini, which forms smaller galls on leaf veins and petioles, D. acrophila produces more prominent and visible galls, predominantly on leaflet midribs.

Tree Species: Ash

Part of a plant- attacked: Leaf / Needle

Pest significance: Less harmful

Pest Category: Insects

Invasive Species: No

Present in EU: Yes