Feature Article

Gypsy Moth Program Summary, 2001

taken in part from the MDA Gypsy Moth Report by Kimberly Thielen Cremers

By Susan Burks

Cooperative Program:

The cooperative strategic plan was completed, signed and distributed this year. The plan formalizes the Department's role in the gypsy moth program and outlines a process for outside input that will help address any concerns our clients might raise. It also outlines the transfer of leadership to take place once areas of the state become generally infested. While that will be some time from now, formalizing the agreement is an important step in gaining future support and funding for the job that needs to be done to protect our natural resources.

While finalizing the strategic plan is an accomplishment to be proud of, the real work has just begun. The advisory committee started work this fall to outline annual work plans and long term operational plans in a number of areas. The effort to develop the strategic plan has helped create a cooperative spirit, which has already improved the level of involvement for DNR representatives. That input can only improve the work done within the cooperative program and the public support behind it.

Task forces are working on silvicultural recommendations and work plans for treatment and survey efforts. All are to be completed this year. The scientific subcommittee has been activated and will be meeting soon to outline research issues. An education subcommittee will be activated this winter to address outreach efforts and education needs in the face of national concerns for public safety. The Executive Council made up of the Division Directors (or their equivalent) for each participating agency will be meeting in February to outline the key policy and legislative issues for the up-coming year.

male gypsy moth survey trap locations and catches - map

While the news so far has been good, we have one disappointing note to add, that Steve Seybold, UMN Forest Entomologist will be leaving us. He took a position in CA and will be leaving in April. Steve has been of immense help in ensuring the scientific basis for cooperative decisions and as an ambassador to both state agencies. We will sorely miss both his friendship and his contributions to the cooperative program.

Survey Program:

Under the leadership of MDA, approximately 15,000 pheromone traps were set across the state during 2001. Traps were set at a density of one trap per square mile in the five southeastern most counties of the state, the Twin Cities metropolitan area extending north to the city of St. Cloud, and along the North Shore of northeastern Minnesota, including the city of Duluth. In 2001 the northwest and central part of the state received one trap per four square miles, while towns, cities, and incorporated communities within this area were trapped at 1 trap per square mile.

For the first time, saw mills and pulp mills were added to the detection survey. The United States Department of Agriculture-APHIS, PPQ (USDA) oversaw this trapping due to the regulatory nature of these sites. Using information provided DNR, they focused primarily on mills producing more than 500 MBF. Outreach activities were coupled with an effort to enlist mills that import wood products across state lines in a voluntary compliance agreement. See the discussion below for more details on the effort.

If you take the number of positive moth catches at face value, it appears that after two years of steady decline, Minnesota took a turn for the worse (see map 1). In 1998, Minnesota had a total of 953 moths. In the following two years, numbers dropped to 296 moths and 182 moths respectively. In 2001, the moth totals rose to 429 positive catches. However, over 85% of the moths were found on only 7 sites (332 of the 429 moths). Each of these sites received delimit trapping due to a history of past catches. Standard detection traps had a total of only 62 moths, the lowest number in some time!!

north shore detail: minnesota 2001 gypsy moth survey - map

Gypsy Moth Survey: North Shore detail.
View a larger image of this map.

The North Shore situation improved for a second straight year. In 1999, an unprecedented 96 moths were caught over a three county region. In 2000 that number dropped to 32 and in 2001 the number dropped slightly lower with 29 moths found. The city of Two Harbors in Lake County, which in 1999 had 32 moths, came up empty after two years of heavy delimiting. The northern tip of Cook County faired the worst, for the second year in a row (see map 2). Catches remained high at 26 moths, slightly up from 2000's 22 moth finds. The relatively high number of moths scattered over a wide area with no obvious focal point, may be due to the ever-increasing populations of gypsy moth across the waters of Lake Superior. While conclusions at this time would be premature, the north shore now appears as much at risk of introductions as SE MN. This year, the entire upper peninsula of MI was quarantined and the Bayfield/Apostle Islands area of WI produced very high numbers of moth catches.

survey delimiting sites: areas of concern - map

View a larger image of this map.

In the Twin Cities metro region, four delimiting sites in Hennepin County created some concern. These four sites alone produced 285 of the 429 (66%) total moths found in the state (see map). In early September, an egg mass survey was conducted at a SW Minneapolis delimiting site that yielded a record breaking 170 moths in a trapping grid of 36 traps per square mile. The site had little prior history of catches prior to 2000, but in 2000, a general detection trap yielded 10 moths. No eggmasses were found that year. This year, over 50 staff members from multiple city, county, state and federal agencies were on hand for an extensive search of the area and hundreds if not thousands of egg masses were found in a one-block area. The site was placed under a state quarantine that will be lifted after treatment this coming spring. A treatment area of 425 acres is being proposed. The public meeting is scheduled for December 18, 2001 from 7-9 p.m. at the Armatage Park Neighborhood Recreation Center located at 2500 West 57th Street.

A second egg mass survey was conducted at two delimit sites in Golden Valley which yielded a total of 100 moths combined, 76 at one site and 28 at the other. Both sites were delimited at 16 traps per square mile in 2001. After only one short hour of searching, 30-40 egg masses were found within a heavily wooded parcel of land adjacent to a commercial site within the 76 male moth delimit site. The second site which is composed of a residential neighborhood resulted in no egg masses found. Due to the proximity of the sites and the high number of male moths captured across the two sites, treatment is being considered for the entire block of approximately 2,000 acres. The suggested treatment block straddles Hwy 394 at approximately Theodore Wirth Parkway. The public meeting for this area has not yet been scheduled, but is planned for January.

A third egg mass survey was conducted in Plymouth, just south of Bass Lake. This site has a history of male moth capture dating back to 1997; however the site is approximately one block in size and the number of male moths remains low. In 2001, 15 male moths were found in 9 traps. No egg masses have been found. This site will receive heavy delimit traps in the 2002 trapping season.

Similar results occurred in the SE part of the state when compared to the Twin Cities metro area, with three delimiting sites making up 73% of the total moths found in the area. Two of the three sites received egg mass surveys and no egg masses were found (see map 5). One of the three sites, Crooked Creek in Houston county, is being proposed for a pheromone flake treatment due to the history of male moth capture, topography, cover type and difficulty of trapping the site as well as searching for egg masses. The site overlaps state land where timber sales are under way. SE DNR Forestry staff are working with the logger to inspect material coming off the site and APHIS will be working with the WI buyer to help monitor life stages that may have been moved offsite.

Nursery and Mill sites had a total of six positive moths. All were single catches in 5 different sites. One nursery had two traps with a single moth each. No treatment programs are scheduled.

Eradication Program:

In the spring of 2001, a single 28 acre site on the Winona/Houston county border received three treatments of Dipel DF using a helicopter. Dipel DF was used in order for the farm to maintain its organic certification. Subsequent trapping this year yielded no moths. The site will again be trapped at high density in 2002.

The Minnesota Department of Agriculture along with the USDA-APHIS,PPQ also monitored gypsy moth treatments of a Minnesota wholesale nursery in the spring of 2001. The site had been under compliance since 5 moths were caught in the summer of 2000. The Compliance Agreement was lifted after completion of two applications of Dimilin in May 2001. Follow-up delimit trapping in summer 2001 caught no moths. The MDA/USDA continue to recommend that all nurseries receiving stock from regulated areas should administer appropriately timed, annual treatments to their premises regardless of the previous season's survey results.

Compliance Agreements:

The MDA and USDA?APHIS, PPQ entered into compliance agreements with two major mills, one in Grand Rapids and the second in Cloquet, in the fall of 2001. The purpose of the agreements is to allow the importation and processing of pulpwood from gypsy moth regulated areas of the Upper Peninsula of Michigan.

The major components of the agreements are designed to: track all regulated articles and shippers moving material across state lines; process all regulated articles and destroy any associated waste product on site; disallow movement or storage of any regulated materials during the gypsy moth larval stage; regulate the handling and storage of regulated materials within designated areas on site; require vegetation free zones around designated areas; provide unrestricted mill access for regulatory officials; hold mill operators responsible for any eradication costs that may be incurred.

The MDA/USDA will (at no cost to the company): conduct annual detection surveys; inspect shipments when necessary; monitor compliance; provide training to appropriate mill staff; and provide all updated information necessary to the companies. The required training of mill staff was completed by MDA/USDA personnel in September 2001.

Plans for 2002:

Final treatment decisions based on catches in 2001, will be made after the public meetings this winter. Planned treatments will begin when 80% of the larvae reach the second instar stage of development, usually in early May. Standard NEPA guidelines will be followed and those documents can be made available upon request, later this spring.

Due to budget restrictions, DNR will not participate in the regular detection survey. As in the last two years, DNR Parks will provide MDA trappers with passes to state owed recreation areas. State lands will be trapped by MDA as part of their normal detection grid. Because funding constraints dictate that the MDA grid rotate around the state from county to county on a 3-4 year basis, not all state lands will be trapped in 2002. However, in most cases that trapping frequency is sufficient to detect emergent populations before they have had a chance to spread.

In 2001, state owned recreation sites along the major freeways, outside the normal MDA trapping grid, were trapped through special funding provided by the USDA. That funding, and thus a similar trapping effort, has not yet been confirmed. If possible, those high risk sites outside the normal trapping grid will again be trapped in 2002.

Sites with multiple moth catches, single moth catches over multiple years or single moth catches in close proximity to other moth catches are delimited with an intensive trapping grid. The seven areas of particular concern will be heavily trapped to monitor treatment success and/or population status. DNR staff will be made available to help with special trapping needs in specific areas as needed.

The situation in the Grand Portage area has raised a concern about the effect of cold temperatures on moth flight. If cold temperatures in August and September retard moth flight, our detection methods may be ineffective and the scattered pattern of moth catches may be more indicative of a resident population than of new introductions. To test that theory, a study is being designed that would utilize the release and capture of marked male moths in specific sites. While funding has not yet been secured, DNR Forestry and the USFS will likely take the lead in the project, the scope of which has yet to be determined.

MDA has seen a number of staff changes this last year. Their new staff deserves a round of applause for their cooperative spirit and the already evident expertise they bring to the program. If you have the chance, welcome Anne Selness, Unit Supervisor for the Shade Tree and Invasive Species Unit, Kimberly Thielen-Cremers, Gypsy Moth Program Coordinator, Val Cervenka, Gypsy Moth Trapping Coordinator, Peter Dzuik, Exotic Species Coordinator and Erich Borchardt, the unit's GIS Specialist.