Invasive species in Hawaii and health-related problems. The introduction of mosquitoes to Hawaii has resulted in the spread of avian malaria, and increases the risk of dengue and west Nile virus (not known to be in Hawaii yet). Other native species can be affected by invasive species diseases as well, such as the once-dominant koa tree being killed by koa wilt, which is believed to have been brought into Hawaii on an ornamental acacia plant, and the 'ohi'a tree, now being affected by Rapid Ohia Death. Invasive predators can severely reduce the population sizes of native species, or even drive them extinct, because native
Koa wilt to the Hawaiian islands. It ranges in size from 15 to greater than 50 feet with a canopy spread of 20 to 40 feet. It has a showy white flower and blooms sporadically. Mature leaves are sickle shaped. Koa wilt is typically a fatal pathogen for its host. In only a few months, a tree may lose its entire canopy and die. Trees less than fifteen years old are typically the most susceptible. Symptoms include stains in cambium, roots, and sapwood as well as chlorosis (yellowing), canopy dieback, brown and wilted leaves, oozing sap, and bark cankers. The Koa wilt