Sign up for email updates on our 2018 gypsy moth treatment proposals:
Lowry Hill, Minneapolis
Split Rock, Beaver Bay
White Iron Lake, Lake County
Use our interactive map to see if your address is located within one of the Proposed Gypsy Moth Treatment areas.
Please select a heading to learn more:
The Minnesota Department of Agriculture (MDA), in collaboration with federal, state, and local partners, has proposed to slow the spread of gypsy moth populations in Hennepin, Lake, and St. Louis counties. Surveys in 2017 revealed five distinct areas where monitoring traps caught a high numbers of moths. These results, combined with the trap records of previous years and follow-up site surveys, prompted the MDA and the Minnesota Gypsy Moth Program Advisory Committee to develop a proposed treatment project for 2018.
Public involvement and participation is encouraged. Citizens are invited to submit comments about the gypsy moth treatment proposal in writing to the MDA. All comments will be reviewed and a response will be given. Comments received by March 15 will be most useful for identifying issues and alternatives for the required environmental assessment. Site specific environmental assessments will be prepared to identify and consider local issues before the project is authorized by the federal government and implemented by the state. A final environmental assessment is expected to be released in April. It will be posted on this website and on participating agency websites.
Comments can be submitted in writing to the MDA at 625 Robert St. N, St. Paul, MN 55155, or by emailing email@example.com.
For the most up-to date information on treatments call 888-545-MOTH (6684).
Public open houses will be held near the proposed treatment block to provide outreach to citizens. The open house information is listed below:
The Lowry Hill treatment block is irregularly shaped and approximately runs from Interstate 394 on the north to West 22nd street on the south, and Penn Avenue on the west to Lyndale and Hennepin avenues on the east. See map below
The Lowry Hill treatment is located entirely within Minneapolis Ward 7. The majority of the treatment block is located in the Lowry Hill neighborhood (approximately 240 acres). The eastern portion is located in the Kenwood neighborhood (approximately 70 acres), and the extreme northwestern corner is located in the Bryn-Mawr neighborhood (less than an acre). There are no state, federal, or tribal lands located within the block.
The Two Harbors treatment block is roughly centered on the intersection of Shoreview Rd and 7th Av. See map below.
The majority of the Two Harbors treatment block (approximately 510 acres) is located within the unorganized territory of Two Harbors and the remaining area (approximately 16 acres, along the eastern boundary) is located within the City of Two Harbors. There are no known state, federal, or tribal lands within the Two Harbors treatment block.
The southeastern corner of the White Iron Lake treatment block intersects with Sunset road approximately 2 miles southwest from the intersection of Kawishiwi Trail, southeast of Silver Rapids, MN. A 0.2 mile section of Sunset road is located within this treatment block.
All 77 acres of the White Iron Lake treatment block are located in the Fall Lake Township in Lake County. The White Iron Lake treatment block is located within the proclamation boundary of Superior National Forest. Bear Island State Forest owns approximately 11 acres in the southeast corner of the treatment block.
The Lakeside, Duluth treatment block is a square that begins approximately at Oneida Street on the South and North 52nd Avenue East on the east and extends northwest past Skyline Drive. See map below.
The Lakeside treatment block is located entirely within the city of Duluth in St. Louis County. There are no state, federal, or tribal lands within the Lakeside treatment block.
The southwest corner of the treatment block is located approximately 0.4 miles northeast from the terminus of Nester Grade. The Western boundary extends north for approximately 11 miles. The northern boundary is a series of three 90°turns: the first turn continues for 1.7 miles, then the boundary turns north and extends for approximately 4 miles, the boundary then turns east and extends for 3.4 miles, turns north and extends for 1.8 miles, and finally turns east and extends for 3.2 miles. The northeastern corner is located approximately 2.3 miles (as the crow flies) from the intersection of Heffelfinger Rd and Beaver River Road. The eastern boundary is approximately 14 miles long and extends to the shore of Lake Superior. The southern boundary approximately follows the shore of Lake Superior.
The Split Rock Beaver Bay treatment area is located in Lake County with 15,313 acres in the township of Beaver Bay and 58,126 acres in the township of Silver Creek. In the northern section of the treatment block, 25,294 acres intersect the proclamation boundary of Superior National Forest (SNF), with SNF owning 11,784 of these acres. There are several aquatic management areas (AMA) located within the block including: Mink Creek AMA, East Beaver River AMA, Bud Creek AMA, Split Rock River AMA, Skunk Creek AMA, and Stony Creek AMA. Additional public lands include Iona’s Beach Scientific and Natural Area, Finland State Forest, and Split Rock Lighthouse State Park.
Treatments for gypsy moth in Minnesota can have two different goals. An eradication treatment, in the pre-infested area, is designed to completely eliminate a population of gypsy moths. A Slow-the-Spread (STS) treatment, is designed to reduce the gypsy moth population by two-thirds.
To reach these goals, several products are available to target gypsy moths. Btk and mating disruption are useful for most projects.
Btk, short for Bacillus thuringiensis var. kurstaki, is a common soil bacterium that has been isolated and mass produced for maximum effectiveness against gypsy moth. It is organic certified and has a proven safety record. Visit the Minnesota Department of Health's webpage for human health risk information about Bacillus thuringiensis.
Mating disruptants take advantage of the natural pheromone attractant of the female gypsy moth. Flooding the treatment area with the pheromone confuses the male gypsy moth's search for a mate and, if mating success is limited, fewer eggs are laid and fewer caterpillars are expected to hatch the following year.
The MDA's annual trapping program is the first step in determining where a treatment may take place. Our small cardboard traps are baited with a scent that lures in the male gypsy moths, where they become trapped in the sticky coating on the trap's interior. If multiple catches in a single trap are found, more traps in and near that location are set the following year. This helps to outline a possible infestation.
Once trapping survey data are analyzed, an alternate life stage survey is conducted in areas with high numbers of male moths. If a gypsy moth egg mass is found, this confirms that a reproducing population exists. Finding even one egg mass often leads to proposing the site for treatment, since there are undoubtedly more egg masses – gypsy moths hide their egg masses very well. Moreover, each egg mass contains 500-1,000 eggs, which allows for moth numbers to increase rapidly.
The next step is to examine egg mass survey results, past history, and survey data from the current year. Habitat suitability for gypsy moth is also taken into consideration. Urban environments with an abundance of oak and other trees, relatively few predators, and lots of sheltered spots for laying egg masses provide ideal gypsy moth habitat. Based on this information, recommended treatment sites are proposed.
At this point the local involvement process begins. Before treatments begin, local officials and the public are notified of our proposal, and public meeting are conducted in the treatment areas as part of an environmental assessment process. These public meetings not only allow us to explain what is proposed and why, but allows citizens to have their comments included in the assessment. We emphasize that this is a proposal. The final treatment decision comes at the end of this process, when the environmental assessment is signed by representatives from the U.S. Forest Service, the U.S. Animal & Plant Health Inspection Service, and other cooperating agencies.
U.S. Postal carrier routes are used to identify residents within the proposed treatment area, and the MDA attempts to notify everyone in the area by mail. Because treatments are weather dependent, exact spray dates are estimated. Exact dates and times will be announced as soon as possible through local media, the MDA's toll-free telephone line and on this website. Local law enforcement, health departments, schools, and hospitals will also be notified.
Because of its ability to defoliate trees year after year, the gypsy moth is a significant environmental, economic, and quality-of-life issue. Therefore, infestations and the treatments are taken very seriously. This insect pest is not native to North America and has no natural enemies to keep its population in check. Urban neighborhoods in the northeastern United States, much of the Atlantic Seaboard and Lower Michigan have been devastated by repeated defoliation by the gypsy moth.
If sites are left untreated in Minnesota, here is what residents can expect within 5 to 10 years: In May/June, caterpillar numbers in any single backyard will reach into the thousands or even millions. Oak trees and other host trees and shrubs will be bare by the beginning of summer. Trees may grow a second set of leaves if they are healthy, but they will be weakened. If the tree is already stressed, as many urban trees are, they may die. If trees are defoliated for a second year in a row, they could die, falling victim to other pests because of their weakened state.
As thousands of caterpillars feed, there is an audible sound of caterpillar droppings falling to the ground. Like any other excess nutrient, droppings get into runoff water and into the local watershed. Each caterpillar sheds its bristly skin four or five times as it grows, and the skins pile up. The bristles may become airborne and irritate human eyes, skin and respiratory systems. In fact, many people develop a rash if they come into contact with the bristles. It becomes extremely unpleasant to work or play outdoors; the caterpillars will also crawl on houses and may get inside.
Caterpillars pupate in July, offering some respite to humans. The adult moths emerge shortly afterwards, and thousands of male moths begin fluttering around during the day, searching for females to mate with (female gypsy moths don't fly). Females lay eggs, resulting in thousands of unsightly egg masses, visible and hidden, reachable and out of reach, waiting through the winter to start the cycle over. Eventually the moth population will crash, but will re-establish over several years and repeat the devastation.
Treatment at high infestation levels is more costly than the current low level of infestation and is typically funded in part or completely at the local level – often by individual property owners. Homeowners may have the option of not having their property treated once gypsy moth becomes established, but they will be unable to prevent neighbors from participating in local spray programs or using far more toxic pesticides than a public program might use. There is also considerable cost in removing dead trees and a decline in property value because of the loss of mature trees.
These are the effects of individuals living in a gypsy moth-infested area, but what about the broader implications? When gypsy moth becomes generally established, counties go into quarantine status, meaning that no outdoor household articles may be moved to non-quarantines areas without proof they have been inspected and found free of gypsy moths. Individuals moving to new places, loggers transporting pulp wood, and nursery growers shipping their stock are all covered by the quarantine. Quarantines increase regulations, increasing costs to consumers. Minnesota has a responsibility to neighboring states to slow the spread of this pest. Not treating does not mean that we are letting nature take its course; the gypsy moth is not a part of Minnesota's natural ecosystem, and is a serious threat to our environment.
Spray aircraft normally arrive at urban sites at sunrise or shortly after. On average, a 640-acre block (one square mile) takes about a half-hour to spray with a plane or two hours by helicopter. The aircraft flies over the treatment block, making sequential passes. It will be very low (about 50 feet above the treetops), and loud.
The MDA offers the following tips to residents in and around the treatment area:
For the moth treatment to work, it must begin early in the morning. Residents may be awakened on that day by the noise of the low-flying airplane. MDA apologizes for any inconvenience;
The airplane noise may spook pets, so residents may wish to keep them indoors during the treatment;
The treatment product has no known health effects for humans, but to avoid it residents may wish to stay indoors during the treatment and keep windows closed for a half hour after application; and
The residue will not damage a vehicle's finish, but residents may wish to park vehicles indoors to avoid having to wash them after the application. Soapy water will remove any residue on outdoor items.
Treatment products are determined based on the results of annual survey trapping, alternate life survey results, and size of the treatment area. Depending on the product, treatments are conducted to target either very young caterpillars or adult moths. In areas that have many male moths captured and where egg masses are found during the alternate life stage survey, Btk is used due to the evidence of a reproducing population. In areas with lower male moth captures over a more extensive area and where no egg masses are found during the alternate life stage survey, mating disruption is used.
Btk is used against small caterpillars and is applied in May-June. Since insect development is temperature dependent, an unusually cool or warm spring affects this timing. Treatments occur twice, about a week apart, to catch late-hatching caterpillars. Spraying normally takes place early in the day when low winds and high humidity allow the spray droplets to land on tree tops where they will be the most effective, and also because fewer people are active outside. A site will typically be finished before children are walking to school or people are heading to work. Learn more health risk information about Bacillus thuringiensis from the Minnesota Department of Health and see frequently asked questions.
Treatments targeting adult moths will take place in July, just before the male moths emerge from their pupal cases. Aircraft will fly very low (about 50 feet above the treetops) and be loud. There will only be one application over each treatment area. Spray planes will start very early in the morning but are able to fly for most of the day if weather is favorable. People on the ground may or may not detect any product coming out of the airplane, but be assured that it is being distributed in a swath beneath the aircraft.
Gypsy Moth Brochure
What You Need to Know When Visiting a Gypsy Moth Quarantined Area
Gypsy Moth Poster
Gypsy Moth in Minnesota - Background
Gypsy Moth in Minnesota - Treatment: Mating Disruption
Gypsy Moth in Minnesota - Treatments: Btk
Identificación de las etapas de vida de la “Gypsy Moth” (Mariposa Gitana) Lymantria dispar
Gypsy Moth Program
Biology, Life Cycle, & Identification
Gypsy Moth Quarantine
Questions and Answers about Gypsy Moth and Btk
Tree Care Registry
Arrest the Pest