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May 3, 2011

MADISON—Some Wisconsin residents will see and hear loud, low-flying planes around sunrise beginning in mid-May. The planes will be spraying gypsy moth caterpillars, an invasive and destructive pest that feeds on the leaves of many species of trees and shrubs.

Spray dates and times are weather dependent, but officials expect spraying to begin in southern Wisconsin in mid-May and end in northern Wisconsin in June.

People can view maps of the specific areas scheduled for treatment on the Wisconsin gypsy moth website []., where they can also sign up for daily email updates to stay informed about spray plans. People can also request to have spray maps mailed to them by calling the toll-free Gypsy Moth Information Line 1-800-642-6684. Press menu option 1 for daily spray schedule updates.

Spraying will be conducted by two programs

The Slow the Spread Program focuses on efforts slowing the westward spread of gypsy moth in areas of Wisconsin where gypsy moth populations are low and emerging. It is conducted by the Department of Agriculture, Trade and Consumer Protection, and this year spray treatments include the following counties: Ashland, Bayfield, Burnett, Chippewa, Clark, Douglas, Dunn, Eau Claire, Grant, Green, Iowa, Jackson, La Crosse, Lafayette, Monroe, Polk, Price, Richland, Rusk, Sawyer, Trempealeau, Vernon, and Washburn. This spraying includes portions of New Glarus state park and the Black River and Brule River state forests.

The Suppression Program focuses on eastern Wisconsin, where counties are quarantined for gypsy moth and the pest is well established. These areas are treated to prevent damage from very high populations and to reduce populations to more sustainable levels. This is a voluntary program that works with landowners and local governments. It is conducted by the Department of Natural resources and this year will treat portions of the following counties: Dane, Brown, Marinette, Menominee, Milwaukee, Rock, Sauk and Shawano. Spraying is planned within portions of Devil's Lake and Governor Thompson state parks and for the Milwaukee Zoo.

Know what to expect

Planes will start treatment at around 5 a.m. and could spray on weekends as well as during the week. The planes fly very low and loud over treatment sites and surrounding areas.

Planes will remain in the area until the completion of the day's spray plans and as long as weather conditions remain favorable. Spraying may last into the late morning or afternoon.

Most sites will be sprayed with Foray, which contains Bacillus thuringiensis var. kurstaki (Btk). Btk is a naturally occurring soil bacteria that kills gypsy moth caterpillars when they ingest it.

Btk is not toxic to people, bees, pets or other wild animals. However, some people with severe allergies may wish to stay indoors during spray application or avoid areas to be sprayed on the day that spraying occurs.

The formulation of this bacterial insecticide used by the state's cooperative gypsy moth program is listed with the Organic Materials Review Institute as acceptable for use in certified organic food production.

DNR Suppression sites receive one application of Btk, while some DATCP Slow the Spread sites in western Wisconsin will receive two applications of Btk, five to 10 days apart.

In areas with endangered species of butterflies and moths, a gypsy moth specific product called Gypchek will be used instead of Btk.

The Slow the Spread program also will apply pheromone compound to disrupt gypsy moth mating at sites in western Wisconsin from mid-June to as late as early August. The compound interferes with the ability of male moths to find female moths in low, isolated populations, preventing reproduction.

More information about the programs or gypsy moths is available in a gypsy moth media kit available on the DNR website, on the Wisconsin gypsy moth website [] or by calling the toll-free Gypsy Moth Line at 1-800-642-MOTH (1-800-642-6684) to hear a recording of the programs' most up-to-date spray plans or talk to staff.

FOR MORE INFORMATION CONTACT: DNR - Colleen Robinson Klug, 608-266-2172,; DATCP Contact: Nkauj (pronounced 'gow') Vang, 608-224-4591,

Last Revised: Tuesday, May 03, 2011

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