Disease cycle and epidemiology (Silver leaf)

• The fruiting bodies are produced on dead wood in autumn and spores (basidiospores) are released from these during wet weather and when temperatures are above freezing.
• Spore release occurs from autumn to the following June.
• The spores are spread by wind and rain and infect wood through pruning wounds, bark splits, pruning stubs, grafts, etc.
• Infection of wounds more than one month old is uncommon.
• Apple trees are most susceptible to infection from September-May.
• In June, July and August, trees are much less susceptible to infection as they are actively growing and capable of forming barriers in the wood against fungal invasion.
• Silver leaf does not spread from tree to tree through the soil and silvered leaves are not a source of inoculum.
• Spread of the disease on pruning implements is also unlikely.