Quarantine: A first in Minnesota's fight vs. spread of gypsy moths

  • Article by: TOM MEERSMAN , Star Tribune
  • Updated: January 23, 2014 - 10:49 PM

A proposed quarantine in northeastern Minnesota would help keep the invasive species from infecting woods statewide.


In spring gypsy moths hatch into caterpillars, which eat voraciously for five to six weeks.

Photo: Minnesota Department of Agriculture,

CameraStar Tribune photo galleries

Cameraview larger

State agriculture officials are proposing a first-ever quarantine in northeastern Minnesota to control the spread of invasive gypsy moths to other parts of the state. The destructive tree pest was found in record numbers along the North Shore in 2013.

The quarantine, which would affect Lake and Cook counties, would impose restrictions on anyone moving wood out of those areas to lessen the chances that the moth will be transported to uninfested places.

Among other things, it will increase paperwork for loggers and require agreements or inspections for those selling nursery stock, Christmas trees, firewood or other outdoor products.

Lucia Hunt, gypsy moth program supervisor for the Minnesota Department of Agriculture, said that quarantines exist for other pests in Minnesota, but this is the first one for gypsy moths.

“We knew the day would come when a quarantine would be needed,” she said. “It will protect uninfested forests to the south and to the west.”

The pest is no stranger to Minnesota. State officials have been tracking it since 1973, and populations have popped up from time to time in several areas, including the Twin Cities. In some communities, helicopter crews buzzing at treetop level have sprayed biological insecticides to eradicate local concentrations of the bug.

Those efforts have been successful in slowing down the invasion, but not in stopping it, said Chuck Dryke, assistant director of the Agriculture Department’s plant protection division.

The state captured a record number of gypsy moths in traps last year, he said, and 90 percent of them were located in Lake and Cook counties. The traps are an indicator of population strength, he said.

Westward invasion

Agricultural officials have spent much of the past year discussing the need for a possible quarantine, Dryke said, and consulted with timber and nursery industries, and with local, tribal and federal authorities.

“We feel this is the right decision to protect our forest and recreational industries and all the people tied to them,” he said.

The moth escaped by accident from a Massachusetts lab in 1869, and has been slowly but steadily spreading across the United States from Maine to Virginia and northwest through Ohio, Michigan and into Wisconsin.

Minnesota will be the 21st state to be partly or completely quarantined because of the moth, Dryke said.

The moths have no natural enemies, and consume vegetation from more than 300 species of shrubs and trees.

“Their very favorite species are anything oak, but they also do quite well on aspens, birches, willows and basswoods,” Hunt said.

The females lay egg masses that hatch into hundreds of hungry larvae that eat voraciously for five or six weeks, defoliating natural and urban forests. Trees attacked year after year can be so weakened that they eventually die.

Quarantine details

Hunt said that the quarantine will affect both businesses and individuals.

  • related content

  • A male gypsy moth, a pest that will feed on foliage of more than 300 trees and shrub species.

  • Gypsy moth (in white) laying egg mass (yellow mass).

  • get related content delivered to your inbox

  • manage my email subscriptions


Connect with twitterConnect with facebookConnect with Google+Connect with PinterestConnect with PinterestConnect with RssfeedConnect with email newsletters