Long-Horned Beetle Could Pose Threat to Native Hardwoods

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The recent discovery of two Asian Longhorned Beetles (ALB) in packing material for a slate shipment illustrates how vulnerable Hawai`i is to the effects of travel and trade. If the bullet-shaped beetle were to ever become established here, Hawai`i’s native hardwoods and burgeoning forestry industries could be devastated.

Experts believe that the likelihood of establishment increases with the number of times a pest is introduced to a place. So as international trade increases, so does the threat that alien species will become established in Hawai`i.

“In 1997, China’s total exports of agricultural and nonagricultural products to the United States were valued at $72.8 billion (including $10.3 billion for Hong Kong), an 8.4-percent share of total U.S. imports,” a USDA report on ALB states.

“In the last 13 years, trade with China has increased tremendously, to $62 billion a year up from $5 billion in 1985. As a result, the volume of pallets and crates passing through ports of entry has grown exponentially as goods are generally shipped in wood packaging materials, which can conceal a broad spectrum of pests,” it continues.

Increased trade around the world has caused establishment of alien species to bloom here in the United States.

“At least 4,500 species have established free-living populations in the United States. About 15 percent of these cause significant harm. One estimate places losses caused by exotic species between 1906 and 1991 at nearly $100 billion. An increased rate of exotic introductions could mean as much as $134 billion in future losses — or more. Despite this threat, the pact of introductions has not slowed. In the U.S. about 205 new exotic species have been detected since 1980, and 59 of these — or 1 in every 3 or 4 — are expected to cause economic or environmental harm,” states “Exotics in the Chesapeake: An Introduction,” a report published last year by the Maryland Grant College and the Smithsonian Environmental Research Center.

The shiny, black and white ALB (Anoplophora glabripennis) is originally from China, where it is a pest of hardwood tress and has few natural enemies. Through trade, hidden within wooden packing crates from China, the ALB has become established in New York and Illinois, and has been found in a few dozen warehouses throughout the United States.

The insects bore into and lay eggs in tree trunks of hardwoods including various maples, elm, mulberry, and willows. They bore deep, rendering insecticides practically ineffective. Once inside, the bugs will kill a tree within a few years.

So far, the bugs can’t be trapped, and cutting of infected trees has been the only remedy. More than four thousand infected trees have been cut in New York since 1996, and more than 1,300 have been cut in Illinios since 1998.

In 1998, the U.S. Department of Agriculture established an interim rule requiring all shipments containing solid wood packing material that depart from China must be accompanied by “a certificate signed by an official with the Chinese government stating hat the solid wood packing material was treated with preservatives, heat treated, or fumigated before leaving China,” an October 1998 press release states. In addition, U.S. regulations state the solid wood packing material must be free of bark and appear free of live pests.

Regulations, however, accomplish nothing if they are not followed. The crate in which the two ALB were found here in Hawai`i had a certificate stating that it had been treated. While this may have been the result of ineffective treatment, a USDA report suggests that some exporters are trying to skirt around the rules: “Some evidence suggests that certain exporters may be intentionally hiding bark and covering up insect hole damage in wooden crates,” it states.

The volume of that enters Hawai`i is too great for the USDA and state Department of Agriculture inspectors to visually inspect everything. The state has about 30 inspectors for all cargo entering the state. One species of a longhorn beetle from Asia has already slipped by and become established, says Neil Rerimer, a DOA entomologist with the Plant Quarantine Division. The beetle attacks plumeria and other trees that are under stress, such as mango and hibiscus. The beetles bore into the trees and kill its branches, he says. He adds that the longhorn beetle, would pose a greater threat, to local hardwoods like koa, mamane, and ohi`a, since the ALB has a wide variety of hosts.

— Teresa Dawson

Volume 10, Number 12 June 2000

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