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Ambermarked birch leafminer

Ambermarked birch leafminer - Tunnel containing several larvae
  • Latin name: Profenusa thomsoni (Konow)
  • French name: Tenthrède mineuse de Thomson
  • Order: Hymenoptera
  • Family: Tenthredinidae





Damage, symptoms and biology

The presence of small, light-coloured blotches on the upper surface of leaves in July and the browning of the foliage later in the season are characteristic of attacks by the ambermarked birch leafminer. Depending on the severity of the damage to the foliage, the weakened tree may become more susceptible to other insects, but generally does not die from attack by this leafminer.

The ambermarked birch leafminer has only one generation each year. The eggs are laid inside the leaf. On hatching, the larvae begin mining the leaves, feeding on the interior tissue, causing them to turn brown. When fully grown, they leave the mines, drop to the ground and construct cocoons in which they overwinter.

Life cycle (East of the Rockies)

Life cycle (East of the Rockies)
Stage/Month J F M A M J J A S O N D

Other information

Long known in Europe, the ambermarked birch leafminer is probably an introduced species and, until 1955, it was confused with the birch leafminer in Canada. First reported in Quebec in 1959, this insect occurs throughout Canada.

The ambermarked birch leafminer prefers shaded or semi-shaded foliage on small trees. Open-growing ornamental birches are generally less susceptible to attack by this species.

Large numbers of larvae in mined leaves result in a shortage of food, which quickly puts an end to an infestation. Because the damage occurs late in the season and because even a severe infestation seldom lasts more than one year, control measures are generally unnecessary.

Canadian Forest Service Publications

Ambermarked birch leafminer

Diet and feeding behaviour

  • Phyllophagous : Feeds on the leaves of plants.
    • Miner: Feeds inside the blade of a leaf, between the epidermal layers, or beneath the bark of plants, by first excavating a mine into these tissues.
Information on host(s)

Main host(s)

Grey birch, white birch, yellow birch


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