Koa wilt 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 and iconic Hawaiian trees. The host for Koa wilt is Acacia koa, a tree that is native and endemic
Scotorythra paludicola State Park. Laboratory feeding trials of these larvae showed that they could complete their development at the same rate on both the normal host ("Acacia koa") and the invasive tree ("Falcataria moluccana"). Three other exotic tree species, "Acacia confusa", "Prosopis pallida", and "Leucaena leucocephala" were not suitable host plants and all the larvae tested on these species died after 5 days of feeding. Scotorythra paludicola Scotorythra paludicola, the koa looper moth, is a moth of the family Geometridae. It was first described by Arthur Gardiner Butler in 1879. It is endemic to the Hawaiian islands of Kauai, Oahu, Maui and