March 19, 2008

LANSING - The Michigan departments of Agriculture (MDA) and Natural Resources (MDNR), along with the U.S. Department of Agriculture (USDA), today announced the confirmation of Sirex Woodwasp in Sanilac County. This is the first detection of this exotic pest in Michigan since its initial discovery in Macomb County on July 6, 2007.

Sirex Woodwasp is a wood-boring insect native to Europe, western Asia, and northern Africa and is a potentially serious pest of commercially produced pine trees. It was first detected in North America in Oswego, N.Y. in 2004, and has since been found throughout central New York, northern Pennsylvania, and southern Ontario, and a single site in northern Vermont.

The larvae tunnels within pine tree trunks, interrupting the transport of water and nutrients, but a fungus and mucus introduced into the tree by the adult female are primarily responsible for tree decline and mortality. Sirex Woodwasp primarily attacks two- and three-needled pine trees, including: Austrian, jack, red, and Scotch pines. At least seven native woodwasps are found in Michigan, but they are seldom more than minor pests to forest or landscape trees.

“Sirex Woodwasp appears to be established at low densities in parts of southeastern Michigan. We don't anticipate this pest to have a major economic impact on the state's nursery, landscape and Christmas tree industries,” said MDA Director Don Koivisto. “We will vigorously monitor this exotic pest and its potential to impact our forest systems.”

This, and last year’s, findings occurred at only two of the more than 250 trapping locations established statewide through a cooperative effort including USDA, MDA, MDNR, Michigan Technological University, and Michigan State University as part of an international effort to delimit the extent of the infestation in North America.

“Since the Sirex find in New York we have been monitoring Michigan's pine resource,” said MDNR Director Rebecca A. Humphries. “The network of traps and trap trees established across Michigan will provide excellent data. This information will be used by the workgroup to assess and develop a pro-active response.”

For more information on this pest, please visit www.aphis.usda.gov, and in particular the USDA's Pest Alert on the Sirex Woodwasp.

(Editor’s note: Photos are available at www.forestryimages.org/images/768x512/5314009.jpg or www.invasive.org.)