“This fungus is believed to survive the winter by staying on the surface of the new host plant, such as on bark or buds.[4] In the spring, new buds are infected by the conidia as the leaves emerge from the buds. The disease does not occur every year, as it requires a minimum of 3mm of rainfall followed by at least 12 days during which the developing conidia remain damp and at temperatures below 19°C.[5][6] The fungus has higher infection rates following cooler, damper winters.”