Canadian Forest Service Publications
Factors influencing the regional dynamics of butternut canker. 2018. Sambaraju, K.R.; DesRochers, P; Rioux, D. Plant Dis. 102: 743-752.
Issued by: Laurentian Forestry Centre
Catalog ID: 38954
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Butternut (Juglans cinerea) is an important component of native biodiversity in eastern North America. Of urgent concern is the survival of butternut whose populations are declining rapidly in large part due to an exotic pathogen, Ophiognomonia clavigignenti-juglandacearum, that causes butternut canker. The disease presently occurs throughout the range of butternut in North America, causing branch and stem cankers, dieback, and tree mortality. Despite the existential threat posed by O. clavigignenti-juglandacearum to butternut, a detailed understanding of the factors that drive cross-scale disease patterns is lacking. Therefore, we investigated the association of a range of factors, including tree attributes, topography, and weather, with butternut canker spatial dynamics at different scales using data collected in the province of Quebec, Canada. Trunk canker damage and dieback showed distinct geographic patterns. Bark phenotype was not significantly associated with trunk canker damage. Results suggest that open or dominant trees may show less dieback than intermediate or suppressed trees. Probability of the presence of trunk canker and percentage dieback were proportional to the tree diameter at breast height. Temperature was positively associated with disease severity at a 1-km2 scale. Our results provide strong evidence that multiple factors, notably weather, influence butternut canker epidemiology.
Plain Language Summary
In this article, the researchers studied the factors that influence the prevalence of butternut canker based on data collected across the province of Quebec. Here are the main results:
- There is no significant association between the type of bark (smooth or rough) and trunk damage.
- Open or dominant trees show less dieback than intermediate or suppressed trees.
- The probability of canker presence on the trunk and the percentage of dieback are proportional to the tree’s diameter at breast height.
- Day temperature is positively associated with disease severity. In Canada, the butternut is threatened by an exotic disease: butternut canker. The disease currently occurs throughout the butternut’s range in North America, causing branch and stem cankers, dieback, and tree mortality.