Physemocecis hartigi

Gall midge Physemocecis hartigi

Description

Physemocecis hartigi is a gall-inducing midge that forms distinctive, lenticular galls on linden trees (Tilia spp.), particularly on Tilia cordata, Tilia platyphyllos, and their hybrids. This monophagous species is widely distributed across Europe. The lifecycle is either univoltine or bivoltine, with larvae pupating in the soil. Galls are formed on the leaves, typically appearing in late spring or summer.

While the damage is primarily aesthetic, the formation of multiple galls per leaf can reduce the photosynthetic area and impact the ornamental value of the host tree. Repeated infestations may lead to premature leaf drop, but significant harm to the overall vitality of mature trees is uncommon.

Symptom

Small, flat, lenticular galls are visible on the upper side of leaves, often in clusters. Each gall contains a white larva, which exits through an opening on the underside. Vacated galls dry and remain as scars.

Tree Species: Lime

Part of a plant- attacked: Leaf / Needle

Pest significance: Less harmful

Pest Category: Insects

Invasive Species: No

Present in EU: Yes