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Fireblight

Fireblight is a disease caused by the bacterium erwina amylovora. It affects rosaceous trees and shrubs with apple-like fruits, principally Malus, Pyrus, Crataegus, Sorbus, Cotoneaster, Pyracantha and Photina species.

Fireblight can kill flowers, fruit, shoots, spurs, twigs, branches or whole trees. It originated in the USA but was first recorded in the UK on pear trees in Kent in 1957. Since then it has spread slowly to affect most areas of England and Wales and has continued to spread northwards. Fireblight also occurs in many countries which export susceptible tree and shrub nursery stock to the UK. EU legislation is in place to minimise the disease in commerce.

Symptoms

Most obvious between June and September and after leaf fall, they include:

  • wilting or dead blossoms
  • numerous dark brown, dead leaves hanging on one or a number of twigs or branches
  • rapid wilting and dieback of shoots, especially after damaging storms
  • dark green or brown bark on young shoots, often looking water-soaked and contrasting with the normal healthy bark
  • reddish-brown stained inner bark in affected twigs and branches (the bacterium may spread from a branch and girdle the main stem; in this case, foliage on part or all of the crown will wilt and die but the bark stain will be absent from all but the directly infected parts)
  • a glistening whitish slime or mucilage (later darkening to cream, yellowish or brown) exuding from affected tissues during wet, warm weather (best seen before sunrise)
  • bark cankers or patches of cracked bark.

Report a diseased tree