Cypress canker
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| Cypress canker | |
|---|---|
 Asexual fructifications of cypress canker disease | |
| Causal agents | Seiridium spp. |
| Hosts | Cypress trees |
| Distribution | Europe, North America, Australia, New Zealand |
Cypress canker is a disease affecting Cupressus species, caused by one of several species of fungus in the genus Seiridium. Infection causes die-back of twigs and branches in susceptible cypress trees,[1] with rapidly increasing amounts of damage and the death of the tree.
The first epidemic of cypress canker was recorded in California in 1928, with Monterey cypress (Cupressus macrocarpa) being affected. Within a few years the local populations of this tree had been killed. The species is widely traded as an ornamental tree and the disease had soon spread worldwide, probably with nursery stock. Within five decades the disease had reached New Zealand, France, Chile, Italy, Argentina, Greece, most of Europe, Canada, North Africa, South Africa and Australia. The causal agent of this pandemic spread was the pathogenic fungus Seiridium cardinale, with Seiridium cupressi and Seiridium unicorne sometimes being involved, but being less aggressive; other pathogenic fungi can also cause cankers in cypresses.[2]
Hosts
Besides Monterey cypress, other trees attacked by the fungi that cause this canker include Cupressus sempervirens, Cupressus pygmaea, Cupressus lusitanica, Platycladus orientalis, Chamaecyparis lawsoniana, Calocedrus decurrens, Juniperus chinensis and Juniperus sabina. Even when a species is susceptible, environmental factors are important in the development of the disease. In California, for example, Monterey cypresses growing on the coastal ranges were found to be much less affected than those growing in inland areas where the climate was of a Mediterranean type.[3]