Koa wilt They are a dominant forest species. Koa wilt has been found on the islands of Kauaʻi, Oʻahu, Maui, and Hawaiʻi. Most diseased trees are found at elevations below 3,000 feet. However, it has also been observed at elevations as high as 7,000 feet. Fusarium, the primary cause of Koa wilt, May be found in a variety of environments but thrives with the high temperatures and moist soils of Hawaii. It survives in the soil. "F. oxysporum" is a soil-borne pathogen, and currently sanitation, controlling the initial inoculum, is the best means to control it. One should avoid bringing infected soil
Oʻahu ʻamakihi assigned to "Chlorodrepanis" based on the phylogenetic analysis of mitochondrial and nuclear DNA sequences. It tends to stay in the wetter southern area of Oahu, and in the valley near Wahiawa and Mililani. It can easily be spotted in two major parks, the Honouliuli Preserve, and the Wa'ahila Ridge State Recreation Area. It tends to stay in forest, but has - at least to some extent - adapted to non-native forest types. It will nest and forage in wooded urban areas, but prefers native habitats where koa ("Acacia koa") dominates. It mainly occurs at altitudes above , but in some