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Wrap-up of 2000April 27, 2001

Cooperative gypsy moth program

(taken in part from the MDA Annual Report 2000, written by Peter Dzuik)


In response to expanding populations within Wisconsin, the Cooperative Minnesota Gypsy Moth Program was initiated and development of a strategic plan was begun. Participating agencies include the MN Dept. of Agriculture (MDA), Dept. of Natural Resources (MNDNR), USDA Forest Service, USDA Animal and Plant Health Inspection Service and the University of Minnesota. The Strategic Plan, to be finalized in 2001, represents a comprehensive guideline for the management of the gypsy moth within the state. Copies will be made available at all DNR and MDA field offices.

The gypsy moth program, as outlined in the plan, involves three levels or phases of gypsy moth infestation:

pre-infestation (no established populations are known to exist in the state),

transition (high male moth catches indicate low-level populations are likely to exist in some portions of the state, while other portions remain uninfested), and,

general infestation (permanent populations of gypsy moths exist in all or portions of the state).

MDA, recognized as the lead regulatory agency, will be the lead agency during the pre-infestation and transition phases of gypsy moth management. MNDNR will be the lead agency over gypsy moth population management activities under generally infested conditions.


Representatives from each organization assessed the status of gypsy moths within the state, outlined survey and treatment needs and carried out various activities to meet those needs. Cooperating partners included MDA, MNDNR, USDA APHIS, FS & F&WS, BIA and several county agencies. Overall, more than 16,700 traps were set up across the state. MDA placed by far the largest majority of the trap total. They trapped the eastern half of the state at varying grid densities based on the risk of introduction, the presence of favorable habitat and the history of past catches. The western portion of the state was not trapped on a grid system (see map). Instead, high risk sites, such as parks, campgrounds and rest-stops were trapped by local DNR personnel. In general, the south-eastern portion of the state was trapped at 1 trap/sq. mile, while the north eastern portion of the state was trapped at 1 trap/ 4 sq. miles. Other agencies contributed by trapping lands under their own management.

We try never to let the term "Minnesota Nice" apply to gypsy moths attempting to introduce themselves to our state and it's resources. For the second year in a row, moth catches dropped dramatically from the previous season. At the same time trapping intensity remained constant or was substantially increased in areas of high concern. From a high of 953 moths in 1998, only 286 moths were caught in 1999. In 2000, the total number of moths caught slipped even further to 182 (see map).

Numbers of trapped moths fell significantly or remained steady in all counties surveyed except Hennepin County. Of 54 moths caught in Hennepin County, three sites (Plymouth, south Minneapolis and north Minnetonka) account for more than 60% of the catches. Last year, the Plymouth site had one trap with three moths in it. This year, the site produced two traps with 4 moths each and another two traps had one a piece. The site is of some concern because it consists of prime gypsy moth habitat in a wooded area along a rail road track. The south Minneapolis site produced no moths in 1999, but 16 moths in seven traps (one trap had ten moths)in 2000. Six moths were caught in two traps within an existing delimit area in northern Minnetonka along another rail road track and two other traps just outside the delimit area caught two moths each. In 1999, one trap at the site caught three moths. Gypsy Moth Catches 2000 map While repeated catches at these sites are of concern, no alternate life stages (egg masses or pupae) have been found. Delimit trapping, at 36 traps/sq. mile, is expected to determine the need for further action.

In Houston Co., a site in Brownsville Twp. produced nine of 23 moths caught and Money Creek Twp. accounted for another seven moths. The Money Creek site is associated with 21 moths caught just across the border in Winona Co. The site, an area situated on steep, heavily wooded hills surrounding a farm in Wiscoy Twp., had a three-year history of low moths catches that grew to 28 moths this last summer.

In October, an egg mass survey was conducted in Winona Co. Twenty eight-staff members from multiple county, state and federal agencies were present. Searchers combed the area for three hours before the sharp eyes of an MCC crew member spotted an egg mass on an oak branch situated nearly ten feet overhead. An intensified search around this initial egg mass produced two more egg masses and several spent female pupal cases.

The North Shore situation also looks greatly improved last year. In 1999, the area created quite a stir when moth catches rocketed to an unprecedented 96 moths over three counties. In response, all three NE counties were trapped at 1 trap/4 sq. miles in the interior and 1 trap/sq. mile in 2000 along the tourist route from Duluth to Grand Portage. All 1999 multiple and clustered-single moth catch sites were delimited at 16 traps/sq. mile. In addition, from Duluth north, the trapping schedule was extended from four to six weeks longer to take into account the colder seasonal temperatures.

In St. Louis County, moth catches dropped from 26 a year ago to four, just one of which was caught in a delimiting site. Moving up the shore into Lake Co., the overall number declined from 37 to six. Last year, 32 moths were caught in the city of Two Harbors. This year, in spite of heavy delimiting throughout the township, only five moths were caught. While the results do not eliminate the need for extensive follow-up trapping next year, the picture looks much less grim than previously thought.

Cook, the northeastern most county faired the worst. Catches remained regionally high at 22, down only eleven from previous year's 33. However, a single trap catch of nine moths accounted for nearly half the moths caught. The site is an isolated residence on the Grand Portage Reservation. Since there is no prior history of moth catches, the site is so far north and there is minimal traffic into or out of the area, the site is considered to be at relatively low risk for an established infestation. This was a standard detection trap not associated with any of last year's finds. Using the GMHPEN model for gypsy moth phenology based on seasonal high and low temperatures, adult moth emergence in Cook progressed slowly into October. Strategic delimiting traps were left out through October 15th. The timing of moth development suggests the catch was a recent introduction rather than from a resident population.

Any conclusions for the North Shore of Lake Superior would be premature. Tourism is still likely a major factor in moths showing up where they do, although imported logs are being assessed as another pathway for the introduction of gypsy moth life stages. Future trapping should give us a better understanding of gypsy moth in that region.

There was also good news in the nursery monitoring portion of the survey. Overall numbers declined from 44 moths at six sites in 1999 to eight moths at three sites. One site was placed under a Compliance Agreement (CA), however, there is no indication of any major quarantine breach having taken place. In addition, the three sites under CA in 1999 were successfully treated last spring and all regulatory actions have been lifted.

Because of MDA's considerable regulatory authority over Minnesota nurseries and their aggressive monitoring program, the relationship between regulatory personnel and the nursery industry is well established. But there has been relatively little contact in past years with the logging mills. In 2000, efforts were initiated to develop ties between regulatory officials and the logging industry. Trapping efforts were used as an opportunity to contact mill owners, map mill sites and build a network for future communication. Those contacted were made aware of the risks associated with imported wood products and precautions that help prevent accidental introductions. Educational efforts planned for the future will build on the contacts made last year.

Overall the entry pressure into Minnesota appears to be steady despite moth populations in eastern Wisconsin which remain steady or continue to increase. This means that when a warm dry spring does come along (and it will), we can expect a sudden and dramatic increase in trap catches through the eastern half of Minnesota. The cooperative program plans to be ready when the next wave arrives.

The results of this survey are good news for the people and resources of Minnesota. It is another year of reprieve against the oncoming threat of gypsy moth invasion. Similar to 1999, it appears that cool wet weather in May and June of 2000 probably had a negative impact on any small moth populations present. This is also the conclusion of Wisconsin's GM program for their western counties.


Due to budget restrictions, the level of participation for DNR staff will be greatly reduced during the 2001 trapping season. DNR personnel will set traps only for the delimit area in Rock Co. All other trapping will be done by MDA and APHIS. The MDA trapping grid will shift westward away from the Arrowhead counties (see map). SE Minnesota and the strip along the North Shore of Lake Superior will be trapped at 1 trap/sq. mile. The northwestern counties will be trapped at 1 trap/ 4 sq. miles. As in 2000, multiple and clustered-single moth catch sites will be trapped at 16 traps/sq. mile and the trapping schedule from Duluth northward will be extended.

State Parks will be trapped by MDA staff. Those Parks inside the MDA trapping grid will be trapped according to the grid pattern. Parks outside the MDA grid will now also be trapped because the state received monies from the federal Slow-The-Spread Program.

MDA Trapping area for 2001 map

At the Houston County site, 26 acres will be treated with three applications of Dipel® DF (a Bt product). This is the product of choice for use on organic farming sites because it does not contain the acid salts and spreader/stickers found in the other formulations. Treatments will begin in early May when the gypsy moth phenology models (found on the national STS web site) indicate gypsy moth larvae are in the 2nd instar stage of development. Because federal funds will not be used in the treatment program, NEPA (National Environmental Protection Act) requirements do not apply. This eliminates the need for an EIS statement and a public meeting, although adjacent landowners are being notified of the project. Because of the size of the treatment area, contained within private land, these procedures were deemed unnecessary. Intensive trapping, later in the season, will help determine treatment success.

Multicolored Asian lady beetle

asian ladybug

Since last fall, the multicolored Asian lady beetle, Harmonia axyridis, has become a nuisance pest in many Minnesota homes. Unlike most other lady beetles, this species is attracted to the sunny south and west sides of light colored buildings. Their movements involve crawling through spaces and gaps between siding and windows, into vents and chimneys, around doors, and other entry points. Once they find a suitable site for overwintering, they can congregate within walls of buildings as well as in open rooms. Many individuals eventually starve and die, but some survive and become a nuisance all winter and early spring. They do not reproduce in houses, nor do they bite, although they may pinch the skin when handled

Almost all of the 400 species of lady beetles in the U.S. are predaceous on aphids, scale insects, mites and many other destructive insect adults, larvae and eggs. Both adult beetles and their larvae are predators. A single adult beetle may consume 300 aphids or other prey before it reaches adulthood. Its alligator-like, blackish and spiny larva also eats many insects and mites. Like other lady beetles, the adult Asian multicolored lady beetle is distinctively oval to nearly hemispherical. The adult grows to about 1/3 inch long, is often pale orange in color, and can have 0 to 19 black spots on its wing covers. It is called multicolored because it occurs in other colors, ranging from black (with 2 red spots), to yellow or red. A distinct M-shaped black mark is found on its whitish pronotum (top segment between its head and wing covers).

The Asian multicolored lady beetle is one of many exotic lady beetles that has been purposely released in the U.S. since l9l6 as a biological control of selected insect pests. Many entomologists, however, believe that the Asian multicolored beetles plaguing homeowners today descended from beetles that hitched a ride on an Asian freighter and jumped ship near the port of New Orleans. After being discovered in Louisiana in l988 the beetles colonized Mississippi and Georgia by l992, then moved south to Florida and north to Virginia, Delaware, and Pennsylvania by l993. They were extremely abundant in Minnesota in 2000. They travel fast

The beneficial feeding activities of lady beetles were recognized in the Middle Ages. They were then known as Beetles of the Blessed Lady, which today has been shortened to lady beetles, or ladybird beetles. In Sweden the beetles are called Virgin Mary's Golden Hens, and in parts of France they are known as Cows of the Lord.

As these beetles appear in houses from their overwintering sites, they can be vacuumed or hand collected and removed. Loosely insert a fine mesh cloth between vacuum hose sections to provide an easy collection method. Smashed beetles leave permanent stains and a foul odor. Their fecal material can also leave stain spots on cloth objects.

To prevent their re-entry this fall, seal obvious spaces, holes, or gaps where they can enter your house. And, as you notice them congregating this fall, spray a labeled insecticide on the outside walls, especially on the south and west sides.

Notes from the aerial survey - 2000

Again, hats off to the aerial survey crew from Resource Assessment for a job well done! Twenty-two types of causal agents were detected this year on 2,348,000 acres. See table and maps for selected damage and agents. Thanks also to our Seasonal Plant Health Specialists who did the ground truthing.

Aerial survey results, 2000
Agent  Damage  Area  Covertype 
Forest tent caterpillar Defoliation 2,039,900 ac Aspen
Large aspen tortrix Defoliation 63,900 Aspen
Spruce budworm Defoliation and topkill 28,500 Balsam fir,

white spruce

Oak decline Topkill and mortality 5600 Oak
Flooding Mortality 30,800 All, esp. lowland
Frost Defoliation 7500 Oaks
Blowdown Mortality & breakage 1700 All

aspen defoliation map

spruce budworm defoliation and topkill map

Ticks and diseases

Lyme disease continues to be an increasing problem in Minnesota. There were a total number of 1328 reportable cases from 1993 through 1998 (approximately 221 per year). In 1999 there were 283 reportable cases and in 2000 the number jumped to 465. See map. Yet this could be just the tip of the iceberg. The very strict definition of a "reportable" case means that the actual number of cases may be many times the number of reportable cases.

There are two other less common diseases that deer ticks can also transmit to humans, granulocytic ehrlichiosis (HGE) (79 reported cases in 2000) and babesiosis (two reported cases in 2000). The signs and symptoms of these three diseases are very similar and include fever, chills, headache and muscle and joint pain. Babesiosis is most often seen in people who have had their spleen removed or have had their immune systems suppressed in some other way. Ehrlichiosis is treated with antibiotics and babesiosis (a protozoan infection) is treated with antimicrobial drugs.

If you spend time in an outdoor area where Lyme disease is indicated, you should check yourself for ticks each, day, especially during mid-May to mid-July when the tiny tick nymphs are prevalent.

It is also important to take precautions to reduce your chances of getting a tick-borne disease. These precaution are described in an illustrated brochure that is free of charge and available from the Mn. Dept. of Health, telephone 612-676-5414 and from many DNR offices. The brochure is titled "Lyme Disease-Signs and Symptoms, Diagnosis and Treatment, Other Tick-borne Diseases, the Deer Tick, Prevention, and Exposure". Prevention centers on wearing light-colored clothes so ticks are visible, using a tick repellent, promptly inspecting your body after spending time in the woods or grassy areas where ticks might be present, removing embedded ticks with tweezers by grasping ticks close to their mouths rather than squeezing their bodies, applying an antiseptic to the bites, and watching for signs and symptoms of the diseases. It is also recommended that the tick be preserved in alcohol and saved for identification during consultation with medical personnel.

map of lyme disease occurrences

Lyme Disease in Minnesota

Number of cases by county of exposure, 2000

Minnesota (n=289)
Wisconsin (n=93)
Other State/Country (n=6)
Unknown (n=77)
Total cases (n=465)