Quick-killing ohia fungus detected on Kauai for first time

Kauai forestry experts have been operating at elevated levels on Kauai since a more virulent form of rapid ohia death was found on the island for the first time last week.

“Here we thought it was going to be a quiet week” before the holidays, said Kim Rogers, spokeswoman for the Kauai Rapid Ohia Death Working Group, a collective of public and nongovernment agencies working to stop the spread of the disease. “It’s pretty devastating news.”

Three diseased trees, whose leaves had all turned brown, were spotted during a botanical survey, according to the Department of Land and Natural Resources’ Division of Forestry and Wildlife. All three are in a remote area on Department of Hawaiian Home Lands property behind Kalalea Mountain on the east side of Kauai at about 550 feet above sea level.

Since the presence of Ceratocystis lukuohia was confirmed in the three diseased trees Dec. 17, experts have been conducting helicopter and drone surveys to locate other possibly infected trees nearby and hiking into the forest to take additional samples and collect more data.

C. lukuohia can kill a tree within weeks and is responsible for wiping out 90 percent of the hundreds of thousands of trees destroyed by rapid ohia death on the Big Island, where it was first detected more than four years ago. The other pathogen that causes rapid ohia death, Ceratocystis huliohia, can take months to years to kill a tree and was identified on Kauai in three locations this past year.

There is no known cure for either fungus.

The latest discovery brings the number of trees on Kauai infected by either form of rapid ohia death to 20. The trees were found in four distinct locations — two spots on the east side of the island, one on the north side and one on the south side, Rogers said. All were growing in mixed forests in remote locations between 550 to 1,600 feet in elevation away from any maintained trails.

Rogers said 21 possible locations of the disease have been identified, but scientists have been able to obtain samples from only about half of those areas. Because data is still being collected, the scope of rapid ohia death on Kauai “could totally change on its head in a couple months,” she said. “We have to wait and see.”

Both fungal species, C. lukuohia and C. huliohia, were previously unknown to scientists, who are still trying to figure out how they first appeared in Hawaii and how they got to Kauai.

After further research, experts will determine what action should be taken. Rogers said one concern is that if the diseased trees are cut down, the disturbance to the surrounding area could cause the fungus to spread because the fungus enters trees through broken twigs or a scuffed exposed root.

The loss of ohia trees can remake the forests because the ohia could be replaced by more aggressive invasive species, Rogers said. Ohia trees also provide nectar for native birds and homes for native insects, and are critical to the watershed.

Rogers offered tips on how the public can help protect “the sacred tree of Hawaii” from the deadly disease:

>> Decontaminate outdoor gear, including shoes, clothes and tools, before and after entering forests. After hosing down the gear, spray with 70 percent rubbing alcohol to kill any remaining spores. Clothes should be washed in hot water and soap.

>> If taken off-road, vehicles, mountain bikes and motorcycles should be washed with a high-pressure hose and the tires and undercarriage thoroughly cleaned of soil.

>> Ohia wood or tree parts, including adjacent soil, should not be moved.

>> Hikers who observe ohia trees with browning limbs or crowns should take a photo and contact the Kauai Invasive Species Committee at saveohia@ hawaii.edu or 821-1490.