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Pemphigus bursarius

Poplar-lettuce aphid

Description

Pemphigus bursarius, known as the poplar-lettuce aphid, is a monophagous species that primarily infests black poplar (Populus nigra) and occasionally other poplar species. In the spring, the aphids induce the formation of pouch-shaped galls on the petioles of poplar leaves. Later in the season, winged generations migrate to secondary hosts in the Asteraceae family, including lettuce (Lactuca sativa), where they colonize the roots and can cause significant damage.

This species is widespread across Europe, North America, and parts of Asia and Africa. While the galls on poplars rarely cause serious harm, they can impact the tree’s aesthetics. However, on secondary hosts like lettuce, P. bursarius can become a serious pest, causing root damage, reduced growth, and even plant death in severe infestations. Additionally, aphids excrete honeydew, leading to sooty mold development, which further weakens host plants.

Symptom

On poplars, purse-shaped galls (1–2 cm) appear on leaf petioles, often green to reddish in color

Tree Species: Poplar

Part of a plant- attacked: Leaf / Needle

Pest significance: Less harmful

Pest Category: Insects

Invasive Species: No

Present in EU: Yes