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.
Primitive koa finch Primitive koa finch fossils have been found on Maui and Oahu. It is believed that it inhabited lowland dry forests and savannas, where dominant plant species included "ka palupalu o kanaloa" ("Kanaloa kahoolawensis"), "aalii" ("Dodonaea viscosa"), "loulu" ("Pritchardia" spp.), and "koaia" ("Acacia koaia"). Unlike other species of "Rhodacanthis", "koa" ("Acacia koa") was not present in significant numbers in its habitat. The primitive koa finch was a granivore, with a bill adapted to eat the hard seeds and pods of legumes, especially "ka palupalu o kanaloa" ("Kanaloa kahoolawensis") and "koaia" ("Acacia koaia"). It may have also taken caterpillars and "aalii" ("Dodonaea