Frequency of Comandra Blister Rust Infection Episodes on Lodgepole Pine

摘要

Comandra blister rust is a damaging canker disease of lodgepole pine in the Central Rocky Mountains. Our knowledge of previous blister rust outbreaks and the effects of weather and climate on rust epidemiology has not been sufficient to explain the frequency and severity of disease outbreaks. Thus, we sought to describe the seasonal and annual frequency and duration of meteorological conditions favorable for infection of lodgepole pine, to relate infection episodes to various weather phenomena, to observe new canker appearances on young trees, and to age existing cankers on mature trees. We examined comandra blister rust outbreaks for three areas in the Central Rockies Beaverhead in southwestern Montana, Shoshone in western Wyoming, and Medicine Bow in south-central Wyoming. We defined periods suitable for comandra blister rust infection of lodgepole pine (potential infection episodes), based on published criteria, and identified as continuous periods longer than 6 hours during the months of July, August, and September when temperature ranged between 10 and 20 degrees C and the air was nearly saturated. Synoptic daily weather maps were examined to classify weather systems associated with potential infection episodes.