Ceratocystis huliohia wilt

Ceratocystis huliohia is a fungal pathogen responsible for a severe form of vascular wilt in forest trees. It is taxonomically classified as an ascomycete, and it colonizes the xylem of host plants, effectively choking the tree by disrupting the hydraulic conductance of the vascular system.

The primary host for this fungus is the ohia tree (Metrosideros polymorpha), a critical species for the ecosystem of the Hawaiian Islands. While not as rapidly fatal as the related species C. lukuohia, this pathogen still causes significant long-term decline and eventual mortality of mature forest stands.

Symptoms of an infection include a gradual yellowing and browning of leaves, accompanied by a slow decline in crown density. Often, the wood within the stem develops discolored areas or streaks, and the tree may show external signs of stress such as bark lesions or canopy thinning that can persist for several months.

Environmental conditions that favor the spread of the pathogen include high humidity and the presence of open wounds on the trunk. Spores are primarily dispersed by wind, water, or soil movement, and they can be inadvertently transported across long distances on contaminated tools, equipment, or footwear by humans.

Management practices prioritize strict biosecurity measures. This includes the sterilization of equipment using 70% isopropyl alcohol, restricting the movement of wood products from infected zones, and avoiding any unnecessary injury to healthy trees. Currently, there is no known cure for infected trees, making early detection and prevention the most important management tools available.