Koa wilt it starts to produce microconidia, eventually clogging the xylem. Once the Koa tree dies, the fungus invades all tissues and, upon reaching the dead plant surface, sporulates profusely producing macroconidia and chlamydospores. The fungus can survive saprophytically in the soil, as either mycelium or as any of its three spore types mentioned. The chlamydospores, as the resting spores, survive the longest in the soils, usually under cold conditions. Koa trees occupy dry to mesic areas on the islands of Kauaʻi, Oʻahu, Molokaʻi, Lānaʻi, Maui, and Hawaiʻi in elevations of 80 to 8,000 feet with 0 to 100 inches of rain.
ʻAnianiau Its call is a pair of notes, "tew-weet", while its song is a trill of "wee-see, wee-see, wee-see". Anianiau are found in mesic and wet forests at elevations above . The highest densities occur above . Dominant tree species in its habitat include koa ("Acacia koa"), ōhia lehua ("Metrosideros polymorpha"), ōlapa ("Cheirodendron trigynum"), and lapalapa ("C. platyphyllum"). The anianiau mainly feeds on nectar from the flowers of plants such as ōhia lehua ("Metrosideros polymorpha"), ōhelo ("Vaccinium" spp.), and alani ("Melicope" spp.). It will also take arthropods from trees, shrubs, or vines. The anianiau breeding season ranges from February to June.