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Surveys find no Rapid Ohia Death along East Maui

Drone, helicopter surveys follow first detection on island

HAIKU — Drone and helicopter surveys in East Maui conducted in mid-July did not find evidence of Rapid Ohia Death, but residents and visitors still should remain vigilant, officials from the state Department of Land and Natural Resources and the Maui Invasive Species Committee said Friday night.

“On the bright side for our island in particular is that most ohia is on protected lands and in high elevations,” DLNR communications and outreach specialist Jeff Bagshaw said Friday night at the Haiku Community Center. “But it’s still a big concern. . . . We’re in a big push to get this information out to everybody.”

An ohia infected with the fungus that kills the tree critical to native forest ecosystems was found for the first time on Maui in early July on private property near a loi patch in the Hana area. All remnants of the tree were burned July 5 after it tested positive for the Rapid Ohia Death fungus Ceratocystis huliohia by the U.S. Department of Agriculture Agricultural Research Service lab in Hilo.

“That was the quickest turnaround; from the time it was reported to the time it was disposed of was two weeks,” said Lissa Strohecker, public relations and education specialist for MISC. “We didn’t see any other trees in that immediate area that were suspect, but I wouldn’t say that we’re confident that we’re in the clear. We’ll definitely continue to do surveys in that area.”

Rapid Ohia Death was first detected on Hawaii island in 2014 and was later found on Kauai, Maui and earlier this month on Oahu.

“It’s very distinctive in the way it dies,” Bagshaw said of the ohia. “Fungus is only found in woody tissue, not in the leaves or flowers or the seeds.”

Although the particular East Maui tree was infected with the less aggressive of the two Ceratocystis species associated with Rapid Ohia Death, it is still deadly to the ohia.

Ohia grow on about 80,000 acres in the West Maui Mountains and across Haleakala, “which is a lot more than people know or assume,” Bagshaw said. There are 14 different varieties of ohia, Strohecker added.

Ohia serves as a keystone species, providing watershed cover for recharging the island’s aquifer, as habitat for endangered plant and bird species and as a tree with cultural and spiritual importance.

A partnership of state, federal, university and nongovernment organizations have been coordinating quarterly helicopter and ground surveys to monitor for Rapid Ohia Death since 2016.

Both strains — the most aggressive Ceratocystis lukuohia and the less aggressive Ceratocystis huliohia — have been detected on Hawaii island and on Kauai, according to Bagshaw. Only the less aggressive strain was found on Maui and Oahu.

Genetic testing could help reveal where the less aggressive strain found on Maui originated from. However, researchers are still trying to understand the source of both pathogens, Bagshaw said.

“We don’t know if we can find a resistant sub-species in our forests,” he said. “The more ohia out there, the better.”

Another method for detecting potential Rapid Ohia Death are spore collectors, large sticky traps that are placed in areas near an infected tree.

MISC partners with Haleakala National Park in placing two spore collectors in suspect areas, usually during Kona storms, or in areas “closer to Big Island,” such as East Maui.

“Nothing was found,” Strohecker said. “Even though it’s not a huge indicator, it’s still another method of detecting Rapid Ohia Death and showing that there was no ROD.”

During the meeting, Bagshaw told the four attendees how they can help protect the remaining ohia forests:

• Avoid injuring ohia. Open wounds are an entry point for the disease spores, allowing it to spread from tree to tree. Wounds can easily be caused by goats, cows and pigs.

• Don’t transport ohia between islands.

• Don’t move ohia wood, posts or plants, especially from areas known to have Rapid Ohia Death.

• Clean hiking boots, gear and tools. Scrub off all dirt and spray boot soles and tools with 70 percent rubbing alcohol and wash clothes in hot water. Use a dryer to ensure the disease is not spread on boots and clothing.

• Wash vehicle if driving near ohia forests. The disease can remain alive and infectious in soil.

Bagshaw and Strohecker also encourage everyone to plant ohia and buy them locally. Locations include Hoolawa Farms, Home Depot, Kihana Nursery, Kula Hardware & Nursery, Lowe’s Home Improvement and Maui Nui Botanical Gardens.

Reports of trees suspected with Rapid Ohia Death can be made to the Maui Invasive Species Committee at 573-MISC (6472) and the Division of Forestry and Wildlife Maui office at 984-8100.

* Dakota Grossman can be reached at dgrossman@mauinews.com.