An inoculation screening protocol for cypress canker in Cupressus macrocarpa
New Zealand Plant Protection
Cupressus macrocarpa clones selected for rural woodlots and forest plantations may not always be adequately exposed to populations of the cypress canker disease pathogens prior to release. In order to develop a direct method for testing field selections, wounds made on seedlings of nine families were inoculated with two isolates of Seiridium unicorne. Disease severity, as measured by lesion length, varied between fungal isolates and between host families. Higher temperatures (23°C/17°C,
... (23°C/17°C, day/night) encouraged greater stem infection, and initially more foliage browning, than cooler temperatures (12°C/8°C). Inoculation of side branches suggested a technique for simultaneous screening of cypress clones against multiple pathogen isolates using single plants. Conidia were less effective as inoculum than mycelium in agar. Incidence of plants bearing fruit bodies of S. unicorne varied between fungal isolates, and fruitbodies of S. cardinale or Lepteutypa cupressi appeared on some plants inoculated with S. unicorne. A routine inoculation screening procedure may be feasible if consistency between test runs can be demonstrated.