Hellebore leaf miner

This leaf mining fly became established in Britain in the 1990s, The larvae  can extensively tunnel
foliage of stinking hellebore, Helleborus foetidus.

Hellebore leaf miner

Quick facts

Common name: Hellebore leaf miner
Scientific name: Phytomyza hellebori
Plants affected: Stinking hellebore Helleborus foetidus
Main symptoms: Brownish black blotches and lines develop on the foliage during winter
Most active: August to March

What is hellebore leaf miner?

Hellebore leaf miner is a small fly with larvae that tunnel inside the leaves of Helleborus foetidus.

Symptoms

  • Only Helleborus foetidus is affected by this insect
  • The mines in the leaves are initially brownish-black blotches, but later become sinuous, whitish-brown tunnels
  • When numerous most of the foliage can be affected by spring
  • Leaf mining occurs during late summer to early spring

Control

Although the mines can be unsightly, H. foetidus plants are not greatly harmed and so the damage can be tolerated.

Non-pesticide control

  • Heavily mined leaves can be cut off and destroyed during the winter before the adult flies emerge

Pesticide control

  • Pesticides are unlikely to control of this insect

Biology

  • This hellebore leaf mining fly was first found in Britain in 1999 and is now widespread in England and occurs in parts of Wales
  • Eggs are laid on the foliage and the larvae begin feeding inside the leaves during August
  • The mines are not fully developed until the new year. Pupation takes place within the leaf mines


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