Bleeding canker. Yellowing of leaves on a horse chestnut tree (Aesculus hippocastanum). This pathogen destroys bark, cambial tissue and the phloem (su

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Bleeding canker. Yellowing of leaves on a horse chestnut tree (Aesculus hippocastanum). This pathogen destroys bark, cambial tissue and the phloem (sugar conducting tissue). If the damage spreads around the trunk, then more general effects will be seen, namely yellowing of leaves, early leaf fall, failure to fruit and damage to the crown of the tree. Research suggests that a bacterium may be responsible. The disease affects trees ranging in age from young saplings to mature trees. It is estimated that some 35,000 to 50,000 trees are already infected over a widespread area. Photographed in Regent's Park, London, UK.

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Size: 5120px × 3401px
Photo credit: © GEORGETTE DOUWMA/SCIENCE PHOTO LIBRARY / Alamy / Afripics
License: Licensed
Model Released: No

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