Groups contemplate national weed risk assessment

The U.S. government’s approach to invasive plant screening is less effective than systems set up in Australia and New Zealand, according to a study released in February by the Nature Conservancy and University of Florida. Researchers looked at the regulatory weed risk assessment (WRA) system in Australia and New Zealand.

“The WRA system can be used to test all new plants proposed for import and determine whether or not a plant should be allowed entry into a country in under 24 hours,” said Doria Gordon, associate director of science for the Nature Conservancy’s Florida chapter and lead author of the research paper. “Under the current U.S. law, few species are tested and the process can take up to eight weeks.”

Fewer than 100 non-parasitic plants are blocked from entering the United States. Other new plants are allowed immediate entry into the country. In 2005, more than 2.6 billion individual plants were imported into the U.S.

Each year the United States spends $120 billion to control invasive species. Invasive plants represent $34 billion of that expense, and the number continues to increase, the Nature Conservancy reported.

The University of Hawaii and the USDA Forest Service have been conducting a WRA for Hawaii and the Pacific Islands.

“The Hawaii-Pacific Weed Risk Assessment (HP-WRA) score does not measure actual invasiveness or economic or ecological harm in the field,” according to Curt Daehler, botany professor at the University of Hawaii. “Rather, a designation of H(HP-WRA) is a prediction that a species will become invasive.”

The ratings have no regulatory authority.

However, one nurseryman views the WRA as a stepping stone to a white list.

“This would be a serious blow to our industry and prevent new valuable material from coming into botanical gardens and private enterprises,” said David Fell, owner of Hawaiian Sunshine Nursery in Hilo. “How would an unknown species or genus be treated with the WRA?”

For more: The Nature Conservancy, (701) 841-5300; www.nature.org. Curt Daehler, University of Hawaii, (808)-956-3929; www.botany.hawaii.edu/faculty/daehler/WRA/default2.htm; daehler@hawaii.edu.

Hawaiian Sunshine Nursery, (808) 959-4088; www.hawaiinursery.com.

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May 2008