Wisconsin may ease up on emerald ash borer invasive ranking

The Wisconsin DNR wants to downgrade the tree-eating beetle's status from prohibited to restricted, acknowledging the pest has become too widespread to eradicate. The beetle has been found in 28 of the state's 72 counties, according to the DNR. University of Illinois entomology Professor James Appleby

MADISON, Wis. -- The state Department of Natural Resources' board could add scores of organisms to Wisconsin's invasive species list next month in the first revisions to the catalog since it was created five years ago.

The DNR has proposed classifying 49 more species as prohibited, which means people can't sell, possess or transport them and must destroy them if they find them on their property. The agency also wants to list 32 other species as restricted, meaning people can't sell or move them but can possess them.

Another notable change involves the notorious emerald ash borer. The DNR wants to downgrade the tree-eating beetle's status from prohibited to restricted, acknowledging the pest has become too widespread to eradicate. The beetle has been found in 28 of the state's 72 counties, according to the DNR.

"Having it listed as prohibited is completely ridiculous at this stage," said Andrea Diss-Torrance, the DNR's invasive insects program coordinator. "We can't really be expecting people to act upon every population they find because there's a lot of places in Wisconsin where that's pretty common."

The state's invasive species list currently contains about 100 organisms, including the ash borer, zebra mussels, Asian carp and garlic mustard. Each one is cataloged as prohibited or restricted.

DNR officials say they always intended to update the list established in 2009. The agency has been working on revisions with the Wisconsin Invasive Species Council, the nursery industry and species assessment groups since 2012.

New prohibited species would include killer algae, a species of seaweed native to the Indian Ocean; water lettuce, a floating plant some experts believe originated in Africa; the walnut twig beetle, a creature native to the southwestern United States and Mexico that spreads a fungus that kills black walnut trees; and killer shrimp, an eastern European crustacean.

Most newly restricted organisms would be plants. Some of the species, such as various offshoots of Japanese barberry, are popular in home and commercial landscaping, sparking concern among the nursery industry that growers would lose some of their most profitable species.

The DNR responded by giving growers five years to sell down their inventories of restricted trees and shrubs and three years to sell out their restricted woody vines and herbaceous plants, or plants that lack a permanent stem. The phaseout provisions convinced the Wisconsin Green Industry Federation, an umbrella organization that represents nursery growers, landscape contractor, sod producers and Christmas tree farmers, to support the package.

The DNR's board is scheduled to vote on the changes Dec. 18 in Madison.