Image Source: Adrian Klasovsky
Pest of the Month – Koa Rust (Atelocauda digital)
Hosts: Infects a wide range of Acacia species, including A. koa, mangium, auriculiformis, aulococarpa, crasicarpa, leptocarpa, mearnsii, and polystacha.
Distribution: Occurs on all major Hawaiian islands except Lāna‘i.
Damage: This rust disease is not fatal to koa trees. Severe symptoms (witches’ brooms) are mainly confined to several or more branch terminals. Seedpods can be severely affected. The rust can destroy all seedpods on a given tree by attacking the pods while still green, and do so yearly. The disease symptoms can vary significantly among koa genotypes and locations.
Control: Removal of witches’ brooms and diseased seed pods might help to delay disease development on newly planted, uninfected plants. Avoid moving rusted plants to any other locations, especially areas where the disease is not reported to occur.
Source: CTAHR publication
