Koa wilt trees. Outrigger canoe racing, often in koa canoes, is still a popular and highly competitive sport of cultural significance. Koa wilt Koa wilt is a relatively new disease to Hawaii, discovered in 1980. Koa wilt is caused by a forma specialis of the fungus "Fusarium oxysporum", which is now abundant in Hawaiian soils and infects the native Acacia koa tree, a once-dominant species in the canopy of Hawaiian forests. Fusarium oxysporum f.sp. koae is believed to have been brought into Hawaii on an ornamental acacia plant. Fusarium fungi clog the tree xylem, causing significant wilt and mortality among these beautiful
Acacia sensu lato fragrant timber used for ornaments. "A. seyal" is thought to be the shittah-tree of the Bible, which supplied shittim-wood. According to the Book of Exodus, this was used in the construction of the Ark of the Covenant. "A. koa" from the Hawaiian Islands and "A. heterophylla" from Réunion are both excellent timber trees. Depending on abundance and regional culture, some "Acacia" species (e.g. "A. fumosa") are traditionally used locally as firewoods. It is also used to make homes for different animals. In Indonesia (mainly in Sumatra) and in Malaysia (mainly in Sabah), plantations of "A. mangium" are being established to