Researchers identify aggressive fungus killing ‘ohia trees

Researchers identify aggressive fungus killing ‘ohia trees
Updated: Feb. 23, 2015 at 10:04 PM HST
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HONOLULU (HawaiiNewsNow) - For the past five years, 'ohia trees on Hawai'i Island have been under attack -- dying mysteriously and rapidly from an unknown disease, but researchers are now one step closer to figuring out how to prevent mass devastation now that they've figure out what's killing the native species.

Ceratocystis Fimbriata is an aggressive and deadly fungus so powerful, the disease has been named Rapid 'Ohia Death -- because of how quickly a once-healthy tree deteriorates once it's been infected.

"It basically plugs up the sap wood so that the tree basically is strangled to death by the fungus and that's why we see the leaves turning brown so quickly. The fungus is plugging up the trees ability to transport water," said Dr. Flint Hughes, an Ecosystem Ecologist with the Institute of Pacific Islands Forestry.

The disease spreads so quickly, officials say once the leaves start turning brown the entire tree dies within about a month. It's not the first time experts have encountered the fungus in Hawai'i, but they've never seen it attack 'ohia before.

"It usually is pretty host dependent so while it has been seen on sweet potato here for quite a few decades, i's not necessarily the same pathogen that's causing the problem on 'ohia. It might possibly be a new introduction or an exotic isolate," explained Dr. Lisa Keith, a Research Plant Pathologist with thePacific Basin Agricultural Research Center.

Officials don't have a plan to eradicate it just yet, because traditional treatments like fungicide are impractical when the problem is forest-wide.

"We've seen the acreage grow from about a thousand acres in 2012 to roughly 6,000 acres," said Hughes.

Experts say the diseases is especially bad in the Puna district, but for now, appears to be contained to Hawai'i Island and they're hoping to keep it that way.

They say the fungus isn't spread by seedlings or picking the lehua blossoms, but is transferred through the bark.

"It's very important not to take diseased or fallen wood into other locations and really try to limit the spread of any kind of firewood or wood posts. It could be managed with sanitation," described Keith.

Officials say right now the focus is preventing the fungus from spreading to another island. They say there have been reports of some trees exhibiting symptoms of disease on Maui, but there have not been any confirmed 'ohia deaths.

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