Wilt disease leads to ban of ohia shipments

Ohia trees and products may no longer be shipped off the Big Island in a new state effort to keep a deadly fungus from spreading into forests on other islands.

Faced with the rapidly spreading ohia wilt in East Hawaii forests, the state Board of Agriculture has approved an emergency quarantine of ohia plants, leaves, seeds, untreated wood, mulch and other products for a period of one year. The rule takes effect in 12 days.

Beginning in January 2016, the movement of soil off the island will also be restricted. Although the spore of ohia wilt has been found in the soil, the delay in implementing the soil ban will allow time to research whether the disease can be spread that way and to test treatment options, according to the BOA.

The disease causes a yellowing and browning of foliage followed by sudden die-off of more than 50 percent of the trees it infects. The fungus has spread to 15,000 acres of forest in Puna as far west as Volcano and up to the 3,500 foot level on Saddle Road. The infestation has grown from 6,000 acres in 2014, leaving researchers scrambling to better understand where the disease came from and how it is spread.

“We don’t have all the answers about how the disease is transmitted,” said BOA Chairman Scott Enright. “However, the urgency to stop its spread is very clear. Ohia makes up 50 percent of our native forests and watershed — resources that we just cannot risk losing.”

The fungus causing rapid ohia wilt can be spread by the movement of infested wood, insects, the sawdust produced by wood-boring insects, and by soil, said Lisa Keith, a research plant pathologist with the USDA Agricultural Research Service in Hilo. The disease kills by colonizing and impeding the tree’s water transport system.

The fungus has not been confirmed on the west side of the island, but it may only be a matter of waiting for the lab results on samples from both Kona districts.

“We do have at least three suspicious samples from the Kona side,” said James Friday, an extension forester with the College of Tropical Agriculture and Human Resources in Hilo.

Friday will be on the Kona side this week training state agriculture inspectors to identify signs of the disease in ohia wood products. Those products may still be shipped off island with a permit, under the new rules.

Larry Blatt, manager of Aloha Woods in Kailua-Kona, said the permitting system will probably allow the ohia to be shipped off island once inspectors set up a system for recognizing contaminated wood and giving the green light to products that are free of the fungus. The requirement that products be kiln-dried to a certain temperature could be part of the new shipping parameters that will have to be hashed out, he said.

The company offers ohia flooring, boards and poles among a wide offering of tropical hardwoods.

“We can’t really make any deals until we figure out the permitting,” Blatt said. “We’re just going to have to tell people we’re on hold for awhile.”

Susan Hamilton, co-owner of Plant It Hawaii nursery in Kustistown, said her business does not export ohia off-island, but the prohibition on soil shipments could affect her in the future.

“There is an educational component for people,” Hamilton said. “If you’re in an area of ohia that is dying, don’t take any, even within your own island. They don’t know how it spreads yet.”

Friday likened the disease to the spread of the coqui frog.

“Those of us who spend time in the forest are saying, ‘My God, look at this thing,’” Friday said.

Friday said there are at least four sizable operations on the Big Island exporting ohia posts and flooring. These and the affected nurseries that he has spoken to are on board with the rules, Friday said.

“They very much want not to ship diseases,” Friday said. “They want to know what the treatment is so they can ship a clean product.”

Ohia wilt on the web: www.ohiawilt.org