Acacia koa: A Review of its Diseases and Associated Fungi
Acacia koa (koa), among the most prominent overstory species of native Hawaiian forests, is affected by a number of diseases, including those caused by rust fungi, wood-rotting fungi, root-infecting fungi, and diseases categorized as seedling blights, foliar infections, and vascular wilts. A number of fungi occurring saprophytically on koa substrates are also known. Symptoms of other apparent diseases and disorders of unknown origin, or whose cause has not been clearly demonstrated, are often manifest as leaf spots or other foliar abnormalities. Endemic pathogens which have evolved with their host may be responsible for many of the heretofore observed disease conditions, and as such usually do not threaten koa populations. However, a condition tentatively referred to as "koa decline" may represent an exception. This condition is characterized by slow to rapid wilt and death of apparently healthy, vigorous trees of all ages, occurring in more or less well defined disease centers. This phenomenon is particularly prominent in upper-elevation koa forests on the slopes of Mauna Loa on the island of Hawai'i. Other apparent decline problems on O'ahu and elsewhere in the Islands have been reported, some associated with insects. The relationship of these observations to the koa decline on the Big Island has yet to be determined, and the question as to whether "koa decline" represents a complex of disease conditions or can be more closely attributed to a single, specific cause requires further study.
Download this file:
Download this file
—
PDF document,
2650Kb
Details
Author(s): Donald E. Gardner
Event:
Koa: A Decade of Growth
1996 - Honolulu Hawai’i
