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 (AM) 1927, increased to 12,500 watts. KOA became an NBC affiliate in 1929, and the network took over operation of the station from GE shortly thereafter. On July 7, 1934, power was raised to the current level of 50,000 watts. In 1941, NBC, which had been operating the KOA and KGO in San Francisco for GE since October 1, 1929, also took over ownership of the stations. NBC continued to own KOA until June 1953 when it sold the station to Metropolitan Television Company, whose principal stockholder was Bob Hope. GE repurchased the station in 1968 and continued to own it