The fungus Discula destructiva causes extensive damage in North America to the native Cornus species, which are an important landscape feature. The disease is known there as anthracnose and was first noted in the 1970s. The fungus is not thought to be native to North America, but its origins are unknown. It was first detected in the UK in the late 1990s and was probably introduced accidentally on infected plant material.
The fungus produces very small, pimple-like fruiting bodies on dead leaves and stems and in wet weather minute spores are released from these and dispersed by rain-splash, wind-blown rain and, probably, by animals and birds. Wet conditions are required for infection.
No other spore types are known and it is assumed that the fungus can remain dormant in affected twigs and bark during the winter, to produce fresh spores the following spring.