State officials said Friday that about half the container shipments of mainland Christmas trees had been held up because they are "widely infested" with non-native pests including banana slugs, which can carry the rat lungworm parasite.
Shipments of Christmas trees from the Pacific Northwest are being held for treatment by the Plant Quarantine Branch of the state Department of Agriculture, officials said.
Of 150 containers holding tens of thousands of trees from Oregon and Washington, 74 have been blocked from distribution to retailers since the beginning of the month.
"We’ve never had to hold this many before," said Janelle Saneishi, spokeswoman for the Hawaii Department of Agriculture. "It’s half the load."
Forty-nine containers are stuck on Sand Island for treatment before being authorized for release. Fifteen others were released with low-risk pests or pests already found in the islands. An additional six have already been treated and released, and four were sent back to shippers.
State plant quarantine inspectors found invasive species of slugs, wasps and other pests in trees, which may pose a threat to Hawaii’s environment, agriculture and public health and safety.
Officials don’t know why there’s such a large infestation this year, but wet weather in the Pacific Northwest might be the cause.
"Every year, the weather’s different, the pests are different and the conditions are just different," Saneishi said.
Inspectors were sent to Oregon and Washington earlier this year to look at the trees, Saneishi said, but pests still had ample opportunity to make the trees their homes.
Glenn Sakamoto, a plant quarantine inspector for 27 years, added that the state is trying to work out a requirement that all containers arrive in the islands with paperwork stating the trees have all been mechanically shaken.
"It’s something we’re working on," he said. "It’s getting to the point where containers do come with the paperwork, but it’s more like a protocol. Actual compliance isn’t required yet."
So far, two containers arrived in the islands and have been held for paperwork confirming that trees had been shaken.
Before being released to Hawaii importers, pest-infested trees must undergo either a manual shaking or hot water treatment, depending on the types and concentration of pests found, or may be sent back to the mainland.
"I think because companies do want customers to get their trees, they usually decide to go with the shaking or water treatments," Sakamoto said.
Manual shaking was the primary treatment for many years, Sakamoto said, but this is the third year the hot-water treatment is being used.
Trees, usually those with slugs and high concentrations of pests, are showered in 118-degree water for eight minutes to kill the pests.
Arnold Hara, who helped develop the hot-water treatment process, said, "Surprisingly, there’s no negative effect, and though we haven’t done a scientific study, there seems to be a positive effect. Trees look greener and more vibrant when we pull them out."
Hara is an entomologist and extension specialist at the University of Hawaii-Manoa College of Tropical Agriculture and Human Resources research center on Hilo.
Both the shaking and hot-water treatments are applied at the importers’ expense. Sakamoto said he believes treating the trees is cheaper than shipping them back to the mainland. The state covers the overtime costs for the inspectors.
Currently, four to six containers are being treated a day, though a second hot-water treatment chamber, which can process an additional container a day, is expected to be ready for use by Monday. In the future, Sakamoto said, mechanized shaking might take the place of manual shaking.
About 100 more Christmas tree containers are expected to arrive in the islands in the coming weeks, Saneishi said, including Matson’s traditional after-Thanksgiving shipment on the MV Manoa, dubbed the "Christmas Tree Ship."
That shipment, coming from the Port of Oakland in California, was delayed a day due to union picketing Tuesday.
A total of 120,000 to 140,000 trees will be shipped to the islands this year.
