Since the U.S. Congress has funded the National Slow The Spread Program (STS) in the year 2000, eleven states located along the leading edge of the main gypsy moth population have implemented a region-wide strategy with the USDA Forest Service to minimize the rate at which gypsy moth spreads into uninfested areas.

The National Slow The Spread Program uses education, detection, and control strategies to slow the spread of the pest across a 1,200 mile long gypsy moth frontier from Minnesota to North Carolina.

Northeast Iowa and southeast Minnesota are now considered to be in the 100 mile wide "transition zone" between generally infested gypsy moth areas and unifested areas. Gypsy moth is moving forward by natural spread into new areas in this zone.

It is not economical, or environmentally feasible to completely stop the spread of gypsy moths; however, slowing their spread is economically and environmentally palatable. Focusing on newer and smaller gypsy moth infestations is more efficient than trying to contain a larger, more heavily infested area. If you are an Iowa resident and suspect gypsy moth as a new introduction to your area, we would be interested in taking a closer look. Please let us know by visiting our Contact us page.

The management area, also known as the transition zone, is located ahead of the advancing front of the main gypsy moth population. The program focuses on early detection of low level gypsy moth populations, and then disrupts the normal build-up and spread of gypsy moth in those locations.

Link: Gypsy Moth: Potential Impact on Iowa (.pdf)

• As a direct result of this program, the spread of gypsy moth has been dramatically reduced by more than 70% from the historic level of 13 miles a year to 3 miles per year.
• STS protects the extensive urban and woodland hardwood forest in the south and upper Midwest.
• STS protects the environment through the use of gypsy moth specific treatment tactics.
• STS unifies partners and promotes a well coordinated, region-wide action based on biological need.
• STS yields a benefit to cost ratio of more than 4 to 1, by delaying the impacts that occur as gypsy moth invades new areas.

The management area, also known as the transition zone, is located ahead of the advancing front of the main gypsy moth population. The program focuses on early detection of low level gypsy moth populations, and then disrupts the normal build-up and spread of gypsy moth in those locations.

• Gypsy moth detection traps are first placed throughout the management area, using a precise topographical grid.
• A computer algorithm analyses annual male moth catch data, and provides recommendations for project boundaries, delimitation, and treatment.
• A trap catch above a certain threshold of male moths, triggers a more intensive trapping the following year to find the extent of the localized infestation.
• Some measure of control may be taken in the third year to "slow the spread" in those locations if data suggests that action is necessary.
• As the gypsy moth population builds in a new location, the strategy gradually moves from slowing the spread of the pest, to one where suppression of large outbreaks is the main focus.

Mating disruption is a non-insecticidal treatment that is one of the key elements in the STS program. Pheromone flake treatments have been applied in northeast Iowa during June 2011, 2013, and 2016. A similar treatment using a non-toxic pheromone paste is scheduled for the spring of 2019. This paste-like product was also used as part of the treatment program in 2011. Please visit IowaGypsyMoth.com for more details on the treatments used and listed locations.

Link: Questions and Answers - Gypsy Moth Mating Disruption (.pdf)

Pheromone applications are a non-toxic method for managing low level gypsy moth populations by preventing male moths from finding mates. This is accomplished with tree canopy applications of the female gypsy moth pheromone, the powerful scent produced by flightless female moths, that is used to attract a mate.

Airplane applied treatments are very economical and most often used. These products are designed to stick to tree foliage and can be used in urban areas as well as woodland areas. About 1/2 cup of flakes or liquid paste is used for 1 acre of land.