• facebook
  • twitter
  • YouTube
  • RSS feed
  • 651-201-6000
  • 800-967-2474
  • 711 TTY
  • PARKING

NodeFire Save Document
Home > News, Media & Government Relations > News Releases > Gypsy moth numbers rise throughout Minnesota

News Release


Printable Version (PDF: 153 KB / 1 page)

FOR IMMEDIATE RELEASE:  Tuesday, December 1, 2015

Gypsy moth numbers rise throughout Minnesota

Cold limits population growth, but experts caution a normal winter could bring numbers back quickly

ST. PAUL, Minn. – Numbers are on the rise again for an invasive insect feeding on Minnesota’s trees. The Minnesota Department of Agriculture (MDA) captured approximately 1,049 gypsy moths this year in traps around the state. That’s up from last year’s 523 moths, but still a major shift from a 2013 count of over 71,000 moths. The survey results give scientist an indication of insect population size within a targeted area.

Researchers say the 2014 population drop reflected a severe winter, especially in northern Minnesota. However, predictions of a warmer than average winter this coming season bring concerns that gypsy moth numbers could once again surge.

“We cannot let our guard down over this invasive insect,” said Kimberly Thielen Cremers, MDA’s Gypsy Moth Program Supervisor. “One surviving female gypsy moth can lay an egg mass that will produce more than 500 hungry caterpillars the next year.”

Fluctuating insect populations are not uncommon. Since 2002, MDA trapping data shows gypsy moth numbers have swung up and down across the state.

“Populations often take some time to rebound after drastic crashes such as the one caused by the winter of 2013-14,” said Dr. Brian Aukema of the forest insect laboratory at the University of Minnesota. “But while moth populations may be knocked down, they are not knocked out. They have doubled in the past year, for example, and a normal winter will provide the egg masses the chilling requirement they need to hatch in the spring without killing them."

State and federal officials implemented a quarantine of gypsy moth in 2014 for Lake and Cook counties after data showed a reproducing population had established itself in the area. The quarantine helps ensure gypsy moths aren’t being transported by human activity. Outdoor items in the quarantined counties, like logs and firewood, camping equipment and patio furniture, that could be infested with gypsy moth must be inspected and certified as gypsy moth-free before moving to a non-quarantined area.

“A quarantine is one of few tools we have to combat the human-assisted spread of gypsy moth. We will continue our conversations with the timber and logging industry and local, state, federal and tribal partners as we further study the gypsy moth population in the state,” said Thielen Cremers.

Gypsy moth caterpillars, which are not native to North America, eat the leaves of many trees and shrubs. Severe, repeated infestations can kill trees, especially when the trees are already stressed by drought or other factors.

For more information on gypsy moth, go to www.mda.state.mn.us/gypsymoth.  

CONTACT:  Allen Sommerfeld / MDA Communications
651-497-5768 / allen.sommerfeld@state.mn.us

- 30 -