Public campaign takes aim at Hawaii’s ohia wilt disease

State and federal officials have pulled together videos, maps and brochures about ohia wilt disease, hoping broad dissemination of information will make its way to members of hula groups and others who often collect ohia blossoms and leaves from forests for lei making.

The state is fighting to stop the spread of a disease that has killed hundreds of thousands of ohia trees on Hawaii island — threatening the health of Hawaii’s native watershed.

State Department of Agriculture quarantine rules prohibit interisland transport of any ohia plant, or even part of a plant, without an inspection and permit.

At a news conference Wednesday, officials with various state and federal agencies issued a reminder about quarantine rules, and asked the public to take measures to help stop the spread of ohia wilt, about which they have developed videos, maps, and brochures.

They hope the information will be widely used for events such as the Merrie Monarch Festival, where some participants collect ohia blossoms and leaves from forests to use in leis.

“We would encourage people to avoid the areas where the dead trees are,” state Land Department spokesman Rob Huff said.

If contact is made with infected plants, ohia wilt fungus can spread in a number of ways, including from hiking boots, vehicle tires and tools.

The ohia wilt disease, also known as rapid ohia death, was estimated to infest 6,000 acres from Kalapana to Hilo in 2014. Flint Hughes, a research ecologist with the U.S. Forest Service, estimated the infestation now covers roughly about 100,000 acres.

Hawaii island has more than 617,000 acres of forest, which is the main source of water, according to federal agriculture officials.

“We anticipate if we lose our ohia forest there’s going to be negative and cascading effects on native species that depend on ohia,” said Hughes.

Hughes, who works at the Institute of Pacific Islands Forestry, said the infestation has spread to new areas, including South Kona, Kau and the upper level of ohia forest on the windward side of the island.

The fungus known as Ceratocystis fimbriata invades the vascular tissue to the ohia, restricting the flow of water and causing death.

U.S. Department of Agriculture plant pathologist Lisa Keith said researchers suspect the fungus came from outside of Hawaii but don’t know its origin and haven’t found any similar infestation of ohia elsewhere.

“We think it’s unique to here and to ohia,” she said.

State information, including maps about the location of ohia wilt, are located at rapid ohiadeath.org; a video brochure can be found at vimeo.com/149782586.