Interactions Among Root Disease Pathogens and Bark Beetles in Coniferous Forests

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Journal/Book Title/Conference

Pages 142-148 in DJ Morrison (ed) Proceedings of the 7th International Conference on Root and Butt Rots, Aug 9-16, 1988, Vernon BC. International Union of Forestry Research Organisation, VIctoria, Canada

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At least two interactions exist among these important groups of organisms: (1) that of the bark beetles as vectors; and (2) that of root pathogens as predisposers of trees to beetles. Bark beetles might be important vectors of root decay fungi, but there is as yet little supporting evidence. However, some beetles may have primary roles as vectors on non-decay pathogens such as Leptographium wageneri, L. procera, and L. terebrantis. Possible of greater importance is predisposition of trees by the pathogens. Evidence continues to build supporting the relationship, and there is a suggestion that beetles can maintain a relatively high populations level in areas with above average disease activity. A few studies have shown effects on host physiology that may be related to increased susceptibility to bark beetles, and one of two have even suggested effects on primary attraction. A review of the literature in both forest pathology and forest entomology shows a serious deficiency in research on these interactions and their significance in resource management.