Fungus behind Rapid Ohia Death found in Kauai forest reserve

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RAPID OHIA DEATH ON KAUAI COURTESY DLNR

A fungus behind the death of native trees on Hawaii island has now been confirmed on Kauai.

Experts say at least five ohia trees in the remote Moloaa Forest Reserve on the northeast side of the island were infected with the fungus known as Ceratocystis huliohia, one of two pathogens behind Rapid Ohia Death (ROD) on Hawaii island.

“I think that it’s very serious that we’ve detected a pathogen that can kill ohia on an island where we didn’t know it existed before,” said Rob Hauff, State Protection Forester for the Department of Land and Natural Resources Division of Forestry and Wildlife.

Prior to this discovery, scientists thought ROD was contained to the Big Island.

Researchers say there’s no evidence that Ceratocystis huliohia recently spread directly from Hawaii island, and it’s possible the fungus could have gone undetected on Kauai for a long time.

It could mean ROD is also on the other Hawaiian islands, and it just hasn’t been detected yet.

“It’s definitely a possibility,” Hauff said. “We’ve been running aerial surveys across all of the ohia forests in the state twice a year trying to get those. Sometimes you see a dead tree in a really remote area and it’s hard to get in and sample and verify what killed the tree. So that’s always a struggle because you do need that on-the-ground confirmation of what the tree died from.”

Scientists say there is one upside. This particular fungus is not the same as the one behind the widespread death of hundreds of thousands of native ohia trees on Hawaii island, known as Ceratocystis lukuohia.

“It’s fortunate that we are only dealing with the less aggressive species of this disease. We hope everyone on Kauai will be vigilant in practicing the sanitation protocols developed on Hawaii island to keep both species from getting a stronger foothold on the Garden Island,” said Melissa SP Fisher, director of The Nature Conservancy’s Kauai Forest Program.

Ambyr Mokiao-Lee, the state’s ROD outreach coordinator, explained how the fungus kills the trees.

“Once there’s a wound, this fungal disease is carried on the wind from another infected tree and it will land in this wound and it will begin to colonize,” Mokiao-Lee said. “What happens is it grows within the water transport system of the tree. Essentially it prevents the water and nutrients from flowing up to the top or the crown of the tree and it pretty much starves it to death.”

A rapid response team of experts from state and federal agencies and non-government organizations will continue to investigate and test for the potential spread of the disease on the island.

Since the identification of ROD on Hawaii Island more than four years ago, officials say the disease has affected more than 135,000 acres of ohia forest there, killing millions of trees.

The disease is so widespread that the state has banned the transport of ohia trees and soil from ROD-infested areas from Hawaii island.

Mokiao-Lee says there are 14 different varieties of ohia tree, and all of them are being impacted by ROD.  Losing the ohia tree would be devastating.

“Our watershed is very dependent on these trees. These trees soak up the water. They take the mist, and they pump it down to our underground aquifers for us to use in our water supply,” Mokiao-Lee said.

“Ohia is our foundation tree for our watershed,” said Bob Masuda, DLNR first deputy. “It’s 80 percent of the trees that cover a million acres of watershed. We are so blessed in Hawaii to have wonderful water and that’s our goal, that’s our mission. We need to conserve, protect our natural resources.”

Not only is ohia an integral part of our ecosystem, it plays a key role in Hawaiian culture. 

“It’s an integral part of the culture,” Mokiao-Lee said. “It was used in various forms of hula or dance. It was used in oli, which are chants, mele, which are songs, and mo’olelo, which are stories.”

Hawaiians used almost every part of the plant in some way. Its wood would be used to make tools. The leaves were used in medicinal teas, and the flower was used in lei and as offerings to Hawaiian gods. 

Scientists said there is no treatment for Rapid Ohia Death yet. They said the best thing to do is to prevent the spread of the fungus.

Officials urge the public to scrub their shoes with 70-percent isopropyl alcohol after any forest activity, and thoroughly wash any equipment and vehicles that enter or are used in the forest.

“This should become a best practice statewide for all forest users, since we still don’t fully understand how these fungi move from place to place,” said Hauff.

Keep your eyes open, experts say, and if you see ROD symptoms, take a photo and contact the Rapid Ohia Death Outreach Team at (808) 969-8268.

Click here for more information on Rapid Ohia Death.

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