Association of Plagithmysus bilineatus (Coleoptera:Cerambycidae) and Phytophthora cinnamomi with the Decline of 'Ohi'a-lehua Forests on the Island of Hawaii

Two organisms, an endemic cerambycid beetle Plagithmysus bilineatus and a widespread root fungus Phytophthora cinnamomi, have been associated with the decline of ohia trees on the island of Hawaii. While neither organism appeared to trigger epidemic ohia decline, each was an integral part of the complex decline syndrome. The two organisms we studied acted independently, but attack by the cerambycid was apparently encouraged by rootlet mortality or crown loss brought on by unknown stress factors. Forest Sci. 25:187-196.