# MINNESOTA DEPARTMENT OF NATURAL RESOURCES

DIVISION OF ECOLOGICAL RESOURCES

STAFF REPORT 45

Management of Rooted Aquatic Vegetation,

Algae, Leeches, Swimmer’s Itch, 2008

May 2009

## A Summary of Permitted Management Work f or Aquatic Vegetation,

Algae, Leeches, Swimmer’s Itch, 2008

By

Steve Enger

Aquatic Plant Management Program Coordinator

and

Steven Hanson

Aquatic Pesticide Enforcement

Minnesota Department of Natural Resources

Division of Ecological Resources

May 2009Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 1 

### Executive Summary 2008 Aquatic Plant Management Program

In Minnesota the state is the owner of wild rice and other aquatic vegetation growing in public

waters (M.S. 84.091). The Minnesota Department of Natural Resources (DNR) regulates t he

harvest, transplanting

, and destruction of aquatic plants in public waters through a permit

program. The purpose of the Aquatic Plant Management (APM) permit program is to protect the

beneficial functions of aquatic vegetation while allowing riparian p roperty owners to obtain

reasonable access to public waters.

Permits/Properties/Fees

The number of public waters where aquatic plant management is permitted has increased

gradually from 1953 until 2000. However, from 2003 through 2005 the numbers of la kes with

permitted APM activity have remained essentially the same. During this period, there was an

average of 898 public waters with permitted APM activity annually. In 2006 the number of

public waters with permitted APM activity rose to 953 but fell t o 927 in 2007. In 2008 there were

925 public waters with permitted APM activity.

The increase in the numbers of permits issued from 2003

- 2007 averaged approximately 360 per

year. The numbers of permits issued decreased in all regions in 2008. I n 2008 there were 237

fewer permits issued than in 2007

. The Central Region, which includes the seven county

metropolitan area, typically issues more permits for more properties than any other DNR

regional office. However, in 2008 the Central Region issued 49 fewer permits than they issued

in 2007. The largest decreases in the numbers of permits issued were in Region 1 (down 126

permits from 2007) and Region 2 (down 158 permits from 2007).

The numbers of properties involved in the APM program statewide decr eased for the second

consecutive year. There were 712 fewer properties permitted in 2008 than in 2007. The

number of properties with permitted aquatic plant management activities decreased in all

regions with the exception of Region 4 which saw a small i ncrease of 39 properties. The

Central Region saw the largest decrease in the numbers of properties permitted, down 433

properties from 2007.

Permit revenue decreased from about $ 315,000 in 2007 to about $ 300,000 in 2008. The

average fee per property w as up $3.37, from $24.58 in 2007 to $27.95 in 2008.

AUAPCD

The Department first began issuing permits for Automated Untended Aquatic Plant Control

Device’s (AUAPCD’s) in 1997. Now, permits for AUAPCD make up nearly 40% of the active

Aquatic Plant Manag ement permits. The number of single season permits issued in 2008

increased by 11 statewide over 2007 . The number of single year permits issued has increased

annually since 1998. The 2005 total of 1081 is more than double the number of 1

- year permits

is sued in 1998. After a decline in the number of three

- year duration permits issued from 2003

- 2005, the number of 3

- year permits increased in both 2006 and 2007. However, in 2008 there

were 132 fewer three

- year AUAPCD permits issued than in 2007. The thre e

- year permit option

is allowed for persons who limit the size of the area of AUAPCD operation to 50 feet alongshore

or one

- half the ir frontage whichever is less and no more than 2,500 square feet. Persons who

obtained a three

- year permit in 2008 will not have to reapply again until the year 2011 . Some

people ( 177 of those reporting) obtained a permit but did not run their device in 2008 . In 2008,

about 39% of the permits issued allowed the use of automated aquatic plant control devices like

the Crary We edRoller, the Colman Beach Groomer, the Lake Restoration Lake Sweeper and

similar home made devices. The remaining 61% of the aquatic plant management permitsMn DNR, Ecological Resources 2008 APM Annual Report May 2009 2 

### issued in 2008 allowed chemical or other mechanical removal as the method of control. These

per centages were similar in 2007.

Most AUAPCD permits are issued to a single property owner. Although AUAPCD’s make up

39% of the permits issued, they only accounted for about 16% of the total number of properties

permitted in 2008, this was unchanged from 2007

. The other 84% of properties were permitted

to use other mechanical methods or herbicides for aquatic plant control.

Summary of Aquatic Plant Ma nagement permits issued in 2008.

Region Harvest

Chemical *** 200 8

Issued

Channel* <2008

Act ive

Channel** AUAPCD’s

with

chemical

control AUAPCD

All

Active

Permits Issued

Restoration

Permits Issued

2008 Issued

2007 Issued

2006

1 year 3 year 3 year 3 year

Reg 1 481 46

- 64 682 197 248 294 1,902 15

Reg 2A 146 14

- 0 0 7 7 4 16 4 9

Reg 2B 616 9

- 54 199 211 220 227 1,473 4

Reg 3A 801 9

- 8 93 21 18 35 968 15

Reg 3B 468 6

- 18 165 61 102 71 867 15

Reg 4 181 7

- 2 49 23 52 7 312 7

All 2,693 91 711 146 1,188 520 647 638 6,397 65

* Channel permits are of unlimited duration iss ued to the property owner to mechanically maintain a channel to more than 16

shoreline feet wide of vegetation.

** All active permits as of 11/ 23 /200 8 . Total by Region cannot be calculated because Region boundaries were changed in 2003.

All Active Permits = Permits issued in 2007 and all active AUAPCD and channel permits excluding restoration permits.

*** Excludes permits for AUAPCD’s

S ummary of all APM permits issued, fees c ollected, numbers of lakes properties treated and harvested in

200 8

.

Region Permits

Issued in

200 8 * Lakes** Fees*** Properties

Permitted

in 2008 Ave. Fee/

Property All Reporting ****

Harvest

Work Chemical

Treatment Both

Reg 1 1,356 259 $ 51

, 245 .00 1,356 $ 37.79 125 204 32

Reg 2A 153 52 206 10 75 8

Reg 2B 1,02 5 143 1,608 30 458 14

Reg 2 total $ 51,112.00 1,814 $ 28.18

Reg 3A 915 262 4,747 48 500 20

Reg 3B 694 131 2,035 10 347 13

Reg 3 total $ 18 3

, 151 .00 6,782 $ 27.01

Reg 4 253 78 $ 14, 663.00 786 $ 18.66 22 97 5

200 8 TOTAL 4,396 925 $ 3 00

, 1 71.00 10,738 $ 27.95 2 45 1 ,681 92

2007 TOTAL 4,633 927 $ 315,417.74 11 ,450 $ 24.58 277 1,773 115

CHANGE

- 237

- 2 $ 15,246.74

- 712 $ 3.37

- 32

- 92

- 23

* Permits issued for restoration work are excluded.

** Includes all lakes, ponds, ditches and streams listed on APM permits for 200 8

.

*** Fee totals prov ided by Karen Sokola on 12/16/08

.

**** Data tabulated from 2,159 surveys and commercial applicator reports returned as of 2/4/09

.Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 3 

### INTRODUCTION

Value of Aquatic Plants

Aquatic plants are essential compone nts of most freshwater ecosystems. In many lakes, plants

are the base of the aquatic food chain. The habitat aquatic plants provide in the shallow near

shore areas is important to both aquatic and terrestrial animals. They also serve important

function al roles in lakes by stabilizing the lake bottom, cycling nutrients, and preventing

shoreline erosion.

Many of Minnesota’s most sought

- after fish species depend heavily on aquatic vegetation

throughout their life histories. Yellow perch, northern pike, m uskellunge, panfish, and bass all

depend on aquatic vegetation to provide food, spawning habitat, and nursery areas. Juvenile

fish of most species feed on small crustaceans and insects that are abundant in stands of

aquatic vegetation. Even species that may not require vegetation for spawning depend on the

cover and forage found in aquatic vegetation.

Many species of wildlife are dependent on aquatic plants for food and nesting sites. Ducks eat

the seeds and tubers produced by various water plants. Oth er aquatic plants, which are not

eaten directly by waterfowl, support many insects and other aquatic invertebrates that are

important sources of food for migratory birds and their young. Ducks have been known to alter

migration patterns in response to foo d availability. Emergent aquatic vegetation provides

nesting cover for a variety of waterfowl, wading birds, shorebirds and songbirds. The

reproductive success of ducks that nest near lakes is closely tied to available aquatic plants and

the cover it pro vides to hide young birds from predators.

The muskrat, an important furbearer, is almost entirely dependent on aquatic vegetation for food

and shelter. Minnesota’s largest mammal, the moose, also relies heavily on aquatic vegetation

for food.

The distri bution of many amphibians and reptiles is directly linked to the vegetation structure of

aquatic habitats. Species preference of particular habitat types is related to food availability,

types of escape cover

, and specific microclimates. Emergent and sub merged vegetation

support invertebrate populations that are an important food source for amphibians and reptiles.

During the breeding season some species of frogs call from emergent vegetation at the water’s

edge and their egg masses are often attached to aquatic plants. Freshwater turtles often eat

submerged vegetation, which is an important source of calcium.

Beyond providing food and shelter for fish and wildlife, aquatic vegetation is important in

maintaining a stable lake environment. Aquatic veget ation helps maintain water clarity by

limiting the availability of nutrients, and preventing suspension of bottom sediments. Aquatic

plants limit erosion of shorelines by moderating the effects of wave and ice erosion. A healthy

native plant community is also important in preventing the establishment of non

- native invasive

aquatic plants. In short, aquatic plants serve many important functions for lakes, fish

, and

wildlife. Many of the things that we enjoy most about lakes are directly linked to aquatic

vegetation.

The Aquatic Plant Management Program

Riparian property owners (lakeshore property owners) in Minnesota have a legal right to use

and access the lake adjacent to their property. Aquatic vegetation may interfere with a

lakeshore homeowner’s ab ility to exercise that right. The purpose of the DNR’s Aquatic PlantMn DNR, Ecological Resources 2008 APM Annual Report May 2009 4 

### Management Program is to regulate how much aquatic vegetation lakeshore residents can

control while preserving the beneficial functions of aquatic vegetation.

Other aquatic organism s can also interfere with the lakeshore property owner’s enjoyment of the

lake. Swimmer’s itch, caused by the immature life stage of a parasite common in waterfowl, can

cause significant and sometimes severe discomfort in humans depending upon a person’s

sensitivity to the organism. Algae (plankton and filamentous) can also create a nuisance and

occasionally unhealthy conditions when they become overabundant. Relief from these

nuisances may also be sought under an aquatic plant management permit.

Admini strative Regions

In July of 2002 the number of DNR administrative regions was reduced. The previous six

region structure was reduced to four administrative regions. The Brainerd Lakes Region,

previously Region Three, was divided up between the Northeast Region (Region Two) and the

Metro Region (Region Six), now the Central region. The southeastern part of the state, Region

Five, was combined with the South Region or Region Four. Aquatic plant management permits

were issued as they had been in the six

- re gion structure through the remainder of the 2002

open

- water season. In 2003 APM permits were issued according to the new regional

boundaries. The new regional structure makes historical comparisons between regions more

difficult. However, it is still po ssible to identify statewide trends and make comparisons between

years.

DNR Administrative Regions DNR Administrative Regions as of

Pre

- July 2002 October 2006Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 5 

### The number of staff reviewing APM permit applications increased concurrent with the reduction

of DNR regions. The reorganization moved some regional headquarters farther away from the

major centers of APM permit activity (Appendix Table G). The Brainerd DNR Office, now in the

Northeast Region, retained an Aquatic Plant Management s pecialist because the Brainerd

Lakes Area is a center of APM permit activity. The Brainerd (2B) area office is responsible for

application review for Aitkin, Crow Wing, and southern Cass c ounties. Grand Rapids

, (2A) the

location of the Northeast Regional DNR Headquarters

, is responsible for application review for

Carlton, St. Louis, Lake, Cook, Koochiching, and Itasca c ounties. The Central Region added an

APM position to the Little Falls Fisheries o ffice to accommodate the large number of permits

previou sly issued from the Brainerd o ffice. The Little Falls office (3B) is responsible for

application review for Benton, Isanti, Kanabec, Pine, Mille Lacs, Morrison, Sherburne, Stearns,

Todd and Wright c ounties. The Central Region DNR Headquarters in St. Paul (3A) is

responsible for application review for the metropolitan area, Anoka, Carver, Chisago, Dakota,

Hennepin, Ramsey, Scott, and Washington c ounties. In October of 2006 the Central Region

boundaries were expanded to include Goodhue, Wabasha, Olmsted, W inona, Fillmore, and

Houston c ounties along the Mississippi River in Southeastern Minnesota.

The DNR’s Division of Fish and Wildlife is responsible for the administration of the Aquatic Plant

Management Permit Program. Riparian property owners apply fo r a permit to their Regional

Fisheries Manager. The Northwest, Northeast, and Central DNR Regions have Aquatic Plant

Management Specialists who make site inspections and review applications for permit. In 2006,

an Aquatic Plant Management Specialist was hired for the South Region. This person works

out of the New Ulm Regional Fisheries office. Prior to 2006, site inspections and application

review in the South Region were the responsibility of the Area Fisheries Supervisors.

The recommendation for the disposition of the permit application (approval, modification

, or

denial) is determined during the review process. This decision often involves a discussion with

the lakeshore property owner. When applications for APM permits are received for shallow

la kes where waterfowl management is the primary focus, the Aquatic Plant Management

Specialist will seek the advice of the Area Wildlife Manager. When applications are modified or

denied

, the applicant may appeal to the Commissioner’s Office for review. Th e purpose of this

review is to determine if the permit decision was based upon rule standards. Finally, permit

decisions can be appealed to an Administrative Law Judge through the contested case hearing

process.

The coordinator of the Aquatic Plant Man agement Program is in the Division of Ecological

Resources. This position is the department’s contact with commercial mechanical control

businesses, commercial aquatic herbicide applicators, and the Minnesota Department of

Agriculture (MDA). The coordina tor provides technical expertise on aquatic plant control

methods and permitting requirements to lakeshore property owners and Department staff. The

coordinator works to insure consistent interpretation of the APM rules throughout the

Department. This po sition administers exams and issues operating permits to commercial

aquatic plant harvesters. This person also reviews appeals of permit decisions for the

Commissioner. The Program Coordinator maintains current labeling for aquatic plant control

products and provides that information to field personnel. The Program Coordinator also

prepares an annual report on program activities (this document) and coordinates the

development of informational materials and forms provided to riparian property owners

inter ested in aquatic plant management.Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 6 

### The APM program coordinator supervises staff in the Division of Ecological Resources whose

job responsibility includes enforcement of aquatic pesticide rules and pesticide label

requirements. An Aquatic Pesticide Enfo rcement Specialist conducts inspections of herbicide

applications in public waters to monitor compliance with state and federal pesticide law and

respond to reports of pesticide misuse (Appendix Tables E and F). The U.S. Environmental

Protection Agency (E PA) partially funds DNR’s aquatic pesticide enforcement activities through

a grant administered by MDA.

Regulations

Authority for the DNR’s aquatic plant management program is found in Minnesota Statutes M.S.

84.091 Subdivision 1, which designates ownersh ip of wild rice and other aquatic vegetation in

public waters to the State. M.S. 103G.615 authorizes the Commissioner of the DNR to issue

permits to harvest or destroy aquatic plants, establish permit fees, and prescribe standards to

issue or deny permits for aquatic plant control. The standards for the issuance of permits to

control aquatic vegetation and the permit fee structure are found in MN Rules Chapter 6280.

Minnesota Statutes and Rules can be reviewed at the Revisor of Statutes website

http://www.leg.state.mn.us/leg/statutes.asp

.

A permit from the DNR is required to use pesticides in public waters (generally any body of

water 2.5 acres or larger within an incorporated city limit, or 10 acres or larger in rural areas), to

use an automated aquatic plant control device, to control emergent vegetation such as cattails,

wild rice

, or bulrush

, and t o control submerged or floating

- l eaf vegetation above specified limits.

A riparian property owner may, without a permit, physically remove (cut, pull, or harvest)

submerged vegetation along one half the individual’s lake frontage or 50 feet, whichever is less.

The total area where submerged vegetation is removed may not exceed 2,500 square feet. In

addition, a boat channel up to 15 feet wide, and as long as necessary to reach open water, may

also be maintained by mechanical means without a permit. If floating

- leaf vegetation is

interfering with riparian owner ’s access

, a channel, not more than fifteen feet wide, extending to

open water, may be mechanically maintained without a permit. The vegetation that is cut or

pulled must be removed from the lake and the managed area must remain in the same location

each year.

The mechanical control of pur ple loosestrife, a plant on the Minnesota Department of

Agriculture’s noxious weed list, does not require a permit from the DNR. However, herbicide

control of purple loosestrife below the ordinary high water level on public waters does require a

permit. Because of the plant’s status as a noxious weed, these permits are issued free of

charge.

Beyond the permit requirement, any pesticide used in surface waters must be labeled for

aquatic use and registered with the United States Environmental Protection Ag ency. When

using an aquatic herbicide all label instructions and precautions must be followed. The

permittee must post areas treated with herbicides so that anyone entering the area is informed

of the herbicide application. The notification signs contai n the following information: the name

of the applicator, the treatment date, the name of the product used, expiration dates of any

water use restrictions on swimming, fishing, household, and other uses. The DNR provides

these signs to permittees and comm ercial applicators at no cost. A list of herbicides most

commonly used for aquatic plant control and the amount used under permit in Minnesota in

1981

- 2008 is found in Appendix A and B.Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 7 

### Summary of Aquatic Plant Management Program Activities in 2008

The following summary of Aquatic Plant Management (APM) Program activities in 2008 comes

from four sources: permittee survey forms ( Appendix Table C and D ), commercial aquatic

applicator and commercial mechanical control reports, and Aquatic Plant Management (APM)

permits.

Commercial applicators, harvesters, and riparian property owners who do control work in public

waters are required to provide a yearly summary of their APM activity. With this information the

past year’s activities can be summarized, the control of aquatic vegetation in public waters is

monitored, and trends in aquatic plant management are identified.

Survey forms are mailed to permit holders that did their own aquatic plant control work. Prior to

2000, permit holders that hired comme rcial applicators to perform the control work for them

were included in the survey. They were asked to answer only those few questions pertinent to

their situation. This often caused confusion and permittees would either not respond or would

send the for m to the commercial service for completion. In addition, when commercial

applicators do the control work there are usually many customers on a single permit. However,

only one of those custo mers is listed as the permittee. Hen ce , this approach relied on one individual to provide accurate information for up to 100 or more other people. Since commercial

pesticide applicators are required by law to keep detailed records and their reporting is generally

more precise, permit holders who hire a commercial fir m are no longer asked to complete a

survey form.

Survey forms were sent to all permittees that did their own chemical or mechanical control work.

Of the 1,287 surveys mailed 1064 (83%) were returned. A separate survey was sent to 1,708

AUAPCD permit rec ipients, 1,502 (88%) were returned

.

Permit Issuance

In 2008, a total of 4,396 permits were issued statewide for APM activities (this includes 65

shoreline habitat restoration permits), 237 fewer than in 2007 (Appendix Table G provides the

county by county distribution of permits and permitted properties). These permits were issued

for properties on 925 public waters (i.e. lakes, ponds, and streams) in 2008 ( Figures 1, 2, and

3 ). In 2008

, there were 1,708 permits issued for the operation of Automated Unte nded Aquatic

Plant Control Devices (AUAPCD). The remaining 2,688 permits were issued to municipalities

and lakeshore homeowners for pesticide use (includes al gae and swimmer’s itch control),

mechanical control (cutting, pulling, or ha rvesting) of aquatic vegetation

, or shoreline habitat

restoration.

Over the last 15 years, the number of public waters where permits are issued has almost

doubled. Little increase occurred until 1999 when the number of public waters with permitted

APM activity increased shar ply (Figures 2 & 3). The number of public waters with permitted

APM activity in 2008 was 925

, 2 fewer lakes than in 2007

.Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 8 0 200 4 00 600 800 1000 1200 1400 1600

1 2A 2B 3A 3B 4 Permit s and Lakes

Region 

### Figure 1. Permits issued, and the number of lakes with permitted aquatic plant

control, by region, in 2008.

permits issued

lakes with permits issued in 2008Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 9 0 500 1000 1500 2000 2500 3000

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 

### Figure 2. Numbers of permits issued for mechanical and chemical

control (excluding AUAPCD) of aqu atic vegetation, algae, and

swimmer’s itch, and numbers of lakes where permits were issued 1992

-

2008.

protected waters

permits issued (no

AUAPCD's)Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 10 

### Aquatic plant management permit issuan ce increased annually from 1992 until about 1999.

Then in the early 2000’s the numbers of permits issued decreased and there was a

corresponding decrease in the numbers of participating properties. Permit numbers and

properties began to increase again in 2003 through 2006

. In 2008 the total number of

properties declined for a second year in a row and the number of permits also declined. Spring

of 2000 was the beginning of several years in a row that were cooler and wetter than normal in

the Metro area. Cooler temperatures in the early part of the open water season may contribute

to the decline in lakeshore property owners participating in the Aquatic Plant Management

program.

Lakeshore homeowners may apply for an aquatic plant management permit as a g roup. Group

permits are more popular in the Twin Cities metropolitan area than in greater Minnesota (Table

1). Homeowner’s on large group permits can benefit from the $750 cap on permit fees. The

individual permit fee ($35.00 per property) begins to dec rease for groups larger than 21. Some

permits have more than 100 properties listed on a single permit. In 2008 there were 10,738

properties covered by the 4,396 permits issued.

The statewide average number of properties per permit in 2008 was 2.4, sim ilar to 2007

. The

Central Region, which includes the Twin Cities metropolitan area, typically has larger group

permits than other areas of the state. In 2008

, the Central Region averaged 4.2 properties per

permit issued down from 4.4 in 2007 . The Northw est Region averaged one property per permit;

the Northeast Region averaged nearly two properties per permit ( 1.5 ). The average number of

properties per permit in the Southern Region in 2007 was 2.9, but increased to 3.1 properties

per permit in 2008.



### 0 2000 4000 6000 8000 10000 12000 14000

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 Prop erties 

## Figure 3. N umbers 

## of properties permitted for APM statewide,

1997

- 2008.Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 11 Ta ble 1. Permits grouped by the number of properties listed (excluding AUAPCD) by Region, 200 8

.

Region 1 2A 2B 3A 3B 4

Propert ies /permits: >100

51

- 100

21

- 50

11

- 20

2

- 10

1 0

0

0

0

0

481 0

1

0

0

0

145 1

0

8

9

19

579 2

11

50

50

165

523 0

3

19

24

42

380 1

4

2

1

14

159



### The rules regulating aquatic plant removal from public waters require an inspection of the

treatment site the first time an application is received or when there are changes requested to

previously issued permits. Aquatic pla nt management specialists and area fisheries staff visit

these sites to determine if the permit application is consistent with the standards for permit

issuance in APM rules. T his is also an opportunity to determine what kinds of plants and habitat

are pr esent in the treatment area. During these inspections, the size of the area may be

reduced to protect important habitat based on the observations and professional judgment of

the specialist. The number of applications received for shoreline vegetation re moval and the

numbers of permits that are issued as requested is shown in Table 2

.

Table 2. Percent of permits requesting near

- shore control that are issued as requested by region in 200 8

.

Region

1 2A 2B 3A 3B 4 Statewide

number of applicatio ns requesting near

- shore control 1,315 149 988 796 568 2 00 4,016

permits issued as requested 1,099 97 635 613 411 158 3,013

% of permits issued as requested 83.6 65.1 64.3 77.0 72.4 79.0 75.0



### Permit Fees

Permit fees were increa sed during the 2003 legislative session. People applying for APM

permits after August 1, 2003 were required to pay the higher fee. The new fee increased many

types of APM permit s from $20.00 per property to $35.00 per property. The cap on large group

pe rmits to control submersed vegetation was increased from $200 to $750.

Permit fee r evenues in 2008 were $300,171 about $15,246 less than 2007 . The average permit

fee per property owner in 2007 was $24.58 . I n 2008 the average fee per property was $27.9 5

. There is still an economy of scale for large group permits, hence the statewide average cost per

property was a little above $27.00 in 2006

, and $8.00 less than the cost of an individual permit

under the new fee structure. The increase in the average permit fee in 2007 is likely due to a

reduction in numbers and properties on multi

- property permits and an increase in individual

property permits.Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 12 

### Timing of Treatment

Permits are issued for the open water season, generally from May through September 1.

However, aquatic plant control can begin as early as January and extend through November. In

2008 about 87% of the permitted work, reported statewide, was completed in June, July, and

August ( Figure 4 ). Because most aquatic plant control in Minnesota is recreationally motivated

this pattern has been consistent over time.Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 13 

### Acres of aquatic plant control permitted

The number of acres permitted for chemical control of s ubmer s ed aquatic plant s fluctuates

annually and has increased sharply in recent ye ars ( Figure 5 ). This may mean that aquatic

plant control is highly variable depending on the season. One contributing factor is the offshore

control of aquatic vegetation focused primarily on non

- native invasive species. A few large

Eurasian watermilfoi l and curly

- leaf pondweed treatments can have a significant influence on

the total number of acres permitted for treatment. This was evident in 2004 and 2005 . In 2004,

several lake

- wide treatments of curly

- leaf pondweed in the Central Region were respons ible for

the increase in treated acres. These lakes in addition to Lake Benton, a 3000

- acre lake in

Lincoln County, (South Region), were treated again in 2006, 2007

, and 2008 with an aquatic

herbicide to manage curly

- leaf pondweed. As the interest in man aging invasive species

increases this trend is likely to continue.

Aquatic plant control methods

Again, in 2008 , about 39% of all permits issued for aquatic plant control permitted the use of

plant removal with AUAPCD’s. Aquatic plant control using herbicides, plant harvesting, and

plant removal by hand, and aquatic plant restoration accounted for the remaining 61% of the

permits issued for aquatic plant management ( Figure 6 ). It is important to remember that a

limited am ount of mechanical control of submerged and floating leaf vegetation can be done

without a permit and a permit is always required when herbicides or automated devices are

used for aquatic plant control. The total area permitted statewide for the various m ethods of

near shore aquatic plant removal and the average area permitted per property in 2008 are found

in Table 3

. Permit holders were asked if the y performed the control over the entire area allowed

in their permit. Nearly 24% of those responding indi cated that control work don e was less than

the area permitted

.

0 1000 2000 3000 4000 5000 6000 7000 8000

2001 2002 2003 2004 2005 2006 2007 2008 Acres

Year 

### Figure 5. Permitted off shore chemical control acreage of aquatic

vegetation statewide from 2001

- 2008.

-

-Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 14 Table 3. Total near

- shore area permitted, in acres, by region, for control of submerged vegetation,

swimmer’s itch and AUAPCD use in 200 8

.

Control Region Total number

of acres Props Ave.

Acres/Prop. 1 2A 2B 3A 3B 4

Herbicide control

excluding off shore

treatment 40.9 7.9 74.8 683.7 239.1 140.2 1,186.6 6,183 0.192

Mechanical control

excluding off shore

removal 19.2 1.2 19.6 28.0 0.9 7.3 74.2 406 0.183

Swi mmer’s itch

control * 31.7 7.1 102.0 865.3 191.8 75.4 1,273.3 5,587 0.228

AU APCD 2008

issued 69.8 0.3 31.1 9.5 15.0 4.3 130.0 1,703 0.076

* includes all permits with swimmers itch controlMn DNR, Ecological Resources 2008 APM Annual Report May 2009 15 

### Percent of Aquatic Plant Removal Permits Us ed

Each year some permits issued for aquatic plant management activities are not used ( Figure 7 ).

Statewide, 8 5 % of permits issued were reported used by the permittees or commercial

applicators/operators doing the work, this is down slightly from 2007

. Permittees indicating that

their permit was not used were asked to indicate why by responding to one or more choices

provided on the survey. The results are summarized in Table 4 , below. In 2008

, the reason

most frequently given ( 4 6 %) for not using an AP M permit was that the property owner was

unable to do the permitted work; 4% reported not doing the work because of getting their permit

too late, down from 20% in 2007.

Table 4. Response by permit holders to choices indicating that their APM permit was not used,

expressed as a percent by region in 200 8

.

Region 1 2A 2B 3A 3B 4 Statewide

nuisance condition did not devel.

got permit too late

unable to do the work

other

total 20

4

48

28

100 4

22

44

30

100 18

2

49

31

100 39

0

57

4

100 25

19

36

19

100 33

22

28

17

100 21

8

46

25

100

2A = Grand Rapids, NE Region; 2B = Brainerd, NE Region; 3A = St. Paul, Central Region; 3B = Little Falls, Central Region

353

92 505 567 50

370

124

2011

85

28 97 54

24 338

0 500 1000 1500 2000 2500

1 2A 2B 3A 3B 4 statewide Permit s

Region 

### Figure 7. Total reported number of per m its used and not used by region

(excluding AUAPCD permit holders), 2008

not used

usedMn DNR, Ecological Resources 2008 APM Annual Report May 2009 16 

### Who does control

Lakeshore homeowners perform about 40% of the permitted mechanical and herbicide plant

control . Commercial applicators and mechanical control companies performed a bout 60% of

the control work statewide in 2008

. Th is represents a slight increase over the percent of the

work done by commercial applicator and aquatic plant harvesting companies in 2007 . Permit

holders in the Central Region hire commercial services more frequently than any other region

( Figure 8 ). Commercial aquatic plant control companies perform abo ut 74% of the control in the

Central Region. In 2008

, 60% of the control in the Northeast Region was performed by

commercial service. However, most of the commercial treatment was done in the Brainerd

Lakes Area (2B), most permitted control in the Grand Rapids area (2A) is still done by the

homeowner. Permit holders perform about 78% of the control in the Northwest Region and 50%

in the South Region. Figure 8a shows the trend in the percent of permitted aquatic plant control

performed by commercial serv ice over the last eight years.

Satisfaction

Permittees who personally undertook aquatic plant control activities were asked to indicate their

satisfaction with the results of the aquatic plant control. Generally, permit holders were satisfied

with the results of the control. About 72% of the respondents were satisfied with the results of

the herbicide control. About 68% of those responding were satisfied with the results of

treatments to control swimmer’s itch and 51% of respondents were satisfied wit h results of

mechanical control. It is important to remember that permit holders hiring commercial services

were not included in the survey.

Reapply for permit

Permit holders, excluding AUAPCD permittees, were asked if they would apply for a permit in

20 08 . Of the 1002 responses, 779 (78%) said they would reapply next year

, a 6% increase

from 2007. Approximately 19% (190) of the permit holders responding indicated that they were

unsure if they would reapply for permit in 2008. The number of permittees reporting that they

would not apply ( 33 or 3.3%) was slightly higher than in 2007

. Regardless of their response, all

2008 permit holders, whose permits expire, will receive permit application materials prior to the

start of the 2009 open water season.Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 17 0 10 20 30 40 50 60 70 80 90 100

1 2A 2B 3A 3B 4 overall % 

### Figure 8. Percent of reported permitted APM work done by permittee and by

commercial serv ice for each region in 2008.

commercial

service

permittee

0 10 20 30 40 50 60 70 80 90 100

2000 2001 2002 2003 2004 2005 2006 2007 2008 

### Figure 8a. Percent of reported permitted APM work done by permittee and

by commercial service s tatewide from 2000

- 2008.

-

commercial

service

permitteeMn DNR, Ecological Resources 2008 APM Annual Report May 2009 18 

### Automated Untended Aquatic Plant Control Devices (AUAPCD)

Before 1997 the operation of an automated mechanical aquatic plant control device did not

automatically require an APM permit, and few AUAP CD permits were issued. The Aquatic Plant

Management Rules were revised in 1997 to require a permit for the operation of these devices

because of their potential to excavate bottom sediments, and impact spawning habitat. In 2008

there were 1,708 permits issued for these devices statewide. Of those permits 1,188 were

issued for a one

- year term and 520 were issued for a three

- year permit term. Permits are

issued for three years if the applicant agrees to a reduced area of operation and qualifies for a

thr ee

- year permit based on the vegetation types present. More than 76 percent of the AUAPCD

permits were issued in the Northwest and Northeast Regions; this is one percent higher than

2007

. In addition to the permits issued in 2008 , there are active three

- y ear permits issued in

2006 and 2007 (638 and 647 respectively ). Of the 1,701 surveys mailed 1,610 (88%) of the

AUAPCD permit holders statewide responded to the questionnaire. Three

- year AUAPCD

permit holders issued permits in 2006 and 2007 were not surve yed.

There are at least three different companies producing AUAPCD’s that are used in Minnesota,

the Crary Company WeedRoller , the Colman Beach Groomer and the Lake Restoration

Lake Maid

. Thirteen permit holders that responded reported they used homem ade devices in

2008

. Based on survey results, two

- thirds of AUAPCD owners in Minnesota have owned their

device for more than three years. In contrast, 22% have owned their device from 1 to 3 years

and 12% have responded that they have owned their device for less than one year.

Most of the people responding to our questionnaire ( 83%) were the sole owner of an AUAPCD.

Nine permit holders stated that they rented their device in 2008

. This was a small decrease from

those reporting renting in 2007

. Some h omeowners opt to purchase the device cooperatively

a nd share it during the summer months. Approximately 17% of the people who used an

AUAPCD in 2008 either, rented, borrowed, owned and shared, or jointly owned their AUAPCD,

a 6% decrease from 2007

.

Lakes hore homeowners have two AUAPCD permit options, provided the location is suitable for

the operation of these devices. The annual renewal option is used when the lakeshore

homeowner operates in an area greater than 2,500 square feet or more th an 50 feet

al ongshore. The one

- year permit option showed a moderate increase in 2008 (Figure 9).

Applicants choosing the three

- year permit option decreased significantly from 2007 ( Figure 9 ).

The manufacturer of the WeedRoller has stated that with time people wil l need to use the

WeedRoller less frequently to achieve acceptable control. The company explained that once

the plants were gone there would be little need to use the machine. We have asked the

question, how often do you operate your AUAPCD? and sorted the responses by the length of

time people had indicated they had owned the machine. Recent AUAPCD owners are more

likely to operate the device longer than those people who have owned the device for several

years ( Figure 10 ). About 1 80 persons permitted to operate an AUAPCD stated that, for various

reasons, they did not operate the device in 2008

, similar to 2007

.

The AUAPCD had higher satisfaction ratings than other methods of aquatic plant control. When

asked, were you satisfied with your AUAPCD, 96% of those responding indicated that they were

satisfied with these devices. This percentage is 2% lower than 2007

.Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 19 0 200 400 600 800 1000 1200 1400 1600 1800 2000

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 permits issued

year 

### Figure 9. Numbers of permits issued allow ing the use of AUAPCD's in

Minnesota public waters

1 yr. Issued current yr.

3 yr. Issued current yr.

Total 1 and 3 years issued current year

Lakes with active AUAPCD'sMn DNR, Ecological Resources 2008 APM Annual Report May 2009 20 

### The DNR sends AUAPCD permit holders a sticker that must be displayed on or n ear the unit to

help Conservation Officers and APM staff identify permitted units. Beginning in 2000 use of the

sticker became a mandatory condition of the permit. For the last 5 years about 98% of the

permit holders responding to this question had no di fficulties displaying the sticker. For this

reason 2008 permit holders were not asked if they had any difficulties displaying the sticker.

Filamentous algae control

The aquatic plant management rules allow the control of filamentous algae with copper sul fate.

Filamentous algae can become a nuisance by interfering with swimming and wading. Permit

issuance for filamentous algae control has increased at about the same rate as permits for

submerged vegetation control (Figure 11). Filamentous algae control is commonly requested

on applications for control performed by commercial services.

Chara control

The aquatic plant management rules allow the control of chara with copper sulfate. Chara is a

macro

- algae that can interfere with recreation in some lakes. Since 1997 there have been

approximately 300 hundred lakes each year where permits have been issued for chara control

(Figure 12).

0 5 10 15 20 25 30 35 40

>0

- 20 >20

- 50 >50

- 144 Continuous Percent of AU APCD permittees reporting

Estimated Weekly Hours of Operation 

### Figure 10. AUAPCD use from May through August, 2008 catagorized by length of

ownership expressed as a percent of all AUAPCD permittees reporting.

AUAPCD owned less

than 1 ye ar

AUAPCD owned 1

- 3

years

AUAPCD owned more

than 3 yearsMn DNR, Ecological Resources 2008 APM Annual Report May 2009 21 0 200 400 600 800 1000 1200 1400

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 

### Figure 11. Numbers of permits issued for filamentous algae control,

and numbe rs of lakes w h ere permits were issued 1997

- 2008.

permits

protected waters

0 100 200 300 400 500 600 700 800 900

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 

### Figure 12. Numbers of permits issued for chara control, and numbers of lakes

where permits were issued 1997

- 2008.

permits

protected watersMn DNR, Ecological Resources 2008 APM Annual Report May 2009 22 

### Plankton algae control

The aquatic plant management ru les allow the control of plankton algae when there is an

“excessive algae bloom.” The characteristics of an “excessive algae bloom” as defined by the

rules are: an algae population dominated by blue green algae, a S ecchi disc reading typically 2

feet or less, floating mats or scums of algae have accumulated on the downwind shore, or

decomposition of accumulated algae has occurred releasing a blue

- green pigment and causing

on offensive odor.

The numbers of lakes treated with algaecides to control plankt on algae has been decreasing

over the last ten years (Figure 13). Copper sulfate treatments can cause an increase in water

clarity when the turbidity is due to algae, but the increased water clarity is usually temporary and

the treatment may need to be re peated. Due to the temporary nature of control, the possibility

of a fish kill caused by a dissolved oxygen sag from decomposing algae, the buildup of copper

in lake sediments, and the potential for algae to become resistant to copper, lake

- wide plankton

algae treatments are discouraged.

S wimmer’s itch control in Minnesota lakes

A condition known as S wimmer’s i tch (a.k.a. lake itch, wader’s itch) has garnered complaints

from swimmers in Minnesota lakes since at least the 1 800's and has likely been around for

much longer. The cause of this irritating skin condition was discovered by W.W. Cort in 1928 at

the University of Michigan B iological Station (Blankespoor and Reimink, 1991). Cort discovered

that swimmer’s itch ( cerca rial schistosome dermatitis ) is caused by the immature life stage of

common non

- human schistosome trematodes called the cercaria

. 0 10 20 30 40 50 60 70 80 90 100

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 

### Figure 13. Numbers of permits issued for lake

- wide plan kton algae control,

and numbers of lakes treated 1997

- 2008.

permits

protected watersMn DNR, Ecological Resources 2008 APM Annual Report May 2009 23 

### These parasites have a complex life history. The adult fluke lives in the blood vessels lining the

intestine of its definit ive host where it reproduces and releases eggs. The eggs enter the gut

and leave the animal in the feces. The eggs hatch when they enter the water becoming a

larvae called a miracidia. The miracidia then infects a snail where it develops into a life st age

called the cercaria. The cercaria, upon release from the snail, seeks its definitive host, usually

some sort of waterfowl. The c ercaria does not feed and will only live for about 24 hours unless

they find a proper host. When a proper host is locat ed the cercaria penetrates the skin, finds its

way to the blood vessels lining the gut, and becomes an adult completing its life history.

The problem for humans occurs when the cercaria mistakes us for its proper host. When a

cercaria penetrates a human’ s skin it is attacked and killed by the person’s immune system.

Although the organism cannot complete its life history in humans, individuals sensitive to the

infection can suffer from an allergic reaction. The symptoms will appear on areas of the body

s ubmersed in the lake and are typified by areas of redness and swelling, similar to a mosquito

bite, and are accompanied by a severe itching sensation. These symptoms can last up to two

weeks.

Not everyone is bothered by swimmer’s itch; about 30 to 40% of the population is sensitive to

swimmer’s itch infection. This explains why some people swimming in a lake at the same time

and place as a person severely affected experience no symptoms. Like other allergic reactions

, a person’s degree of sensitivity inc reases with each exposure.

The numbers of permits issued for swimmer’s itch has increased steadily since 1997. The

Brainerd Lakes Region, has had more lakes per year with permitted swimmer’s itch control than

any other area. In 2008 there were nearl y 3 70 lakes statewide with requests for permit to

control swimmer’s itch (Figure 14 , Appendix Table H ). About 70% of those responding were

satisfied with the results of treatments to control swimmer’s itch

.

0 200 400 600 800 1000 1200 1400

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 

### Figure 14. Numbers of permits issued for swimmer's itc h control, and

numbers of lakes where permits were issued 1997

- 2008.

permits

protected watersMn DNR, Ecological Resources 2008 APM Annual Report May 2009 24 

### Lakeshore prope rty owners may get a permit from the DNR that allows the application of copper

sulfate to the lake for the control of swimmer’s itch. The intent of the copper sulfate application

is to kill snails that harbor the immature life stage of the fluke that caus es swimmer’s itch.

Individuals receiving a permit to control swimmer’s itch with copper sulfate are generally allowed

to treat the permitted area 3 times per summer.

Invasive species control

In addition to oversight (permitting) responsibilities for aq uatic plant management efforts

conducted by individuals to improve access or recreational use, the DNR has statewide control

programs for three, non

- native invasive aquatic plants: curly

- leaf pondweed, purple loosestrife,

and Eurasian watermilfoil. The D NR has recently initiated a pilot project to learn if ecological

benefits can be attained from lake

- wide control of curly

- leaf pondweed or Eurasian watermilfoil

or both.

Curly

- leaf pondweed

Curly

- leaf pondweed ( Potamogeton crispus ) is a non

- native invas ive, submersed aquatic plant

species introduced to Minnesota at the turn of the 20 th 

### Century. Curly

- leaf pondweed is known

to occur in 752 Minnesota lakes in 70 of the 87 counties in Minnesota. In many lakes this plant

causes severe recreational nuisance s.

Curly

- leaf pondweed’s life cycle is considerably different than native aquatic plants. When

native aquatic plants are just beginning to grow (mid to late May) curly

- leaf pondweed is forming

dense mats on the lakes surface that can interfere with rec reation and the growth of native

aquatic plants. By mid

- summer, (early to mid July) curly

- leaf plants begin to die back, which

results in rafts of dying plants piling up on shorelines. But before the plants die they form

vegetative propagules called turi ons (hardened stem tips). New plants sprout from turions in the

fall (Catling and Dobson, 1985). The die back is often followed by an increase in phosphorus

(Bolduan et al., 1994) and undesirable algal blooms. These algae blooms interfere with light

pen etration and can also reduce native plant abundance.

Standard control methods provide relief to lakeshore property owners from the recreational

nuisances caused by surface mats of curly

- leaf pondweed, but ha ve no long

- term effect on the

abundance of the plant. Recent research conducted by the U.S. Army Corps of Engineers

(ACE) has revealed promising control strategies that may help to reduce the abundance of this

plant. The key to the new strategies for the control of curly

- leaf pondweed is treating th e plant

early in the season (when water temperatures are between 50 and 60 degrees F). If this early

season treatment strategy is repeated in successive years the turion bank should become

depleted, resulting in the reduction of overall abundance of the p lant, the severity of algae

blooms, and give native vegetation a competitive advantage.

Figure 15 shows how interest, reflected by the numbers of permits issued, in curly

- leaf

pondweed control has increased since the completion of the Army Corp of Engin eers research

on early season cold

- water control.

The Department of Natural Resources is conducting early season curly

- leaf pondweed

treatments in cooperation with several lake associations on a trial basis to determine the

effectiveness of this strategy . In 2008

, one lake w as treated with the aquatic herbicide fluridone

and 13 others were treated with Aquathol K. These lakes will be treated and monitored for at

least three successive years to determine if it is possible to produce ecological benefits s uch as:Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 25 

### 1. Reduce peaks in concentrations of phosphorous and associated algal blooms.

2. Reduce the abundance of curly

- leaf pondweed for long periods of time.

3. Increase the abundance of native, submersed aquatic plants.

4. Reduce the interferenc e with use of the lake caused by curly

- leaf pondweed.

Figure 16 shows how the development of the pilot project program has influenced the numbers

of acres of curly

- leaf pondweed and Eurasian watermilfoil treated since the programs beginning

in 2005.

See the 2008 Invasive Species Program Annual report for more detailed information on this

project (http://files.dnr.state.mn.us/ecological_services/invasives/annualreport.pdf).

0 10 20 30 40 50 60 70 80 90 100

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 

### Figure 15. Nu mbers of permits issued for curly

- leaf pondweed and

Eurasian watermilfoil control 1998

- 2008.

CLP

EWMMn DNR, Ecological Resources 2008 APM Annual Report May 2009 26 

### Purple Loosestr ife

Purple loosestrife, a non

- native invasive plant that can out compete native wetland vegetation,

was introduced to North America from Europe in the 1800’s and until 1987 was a common

ornamental sold by nurseries and landscape companies. Natural resourc e managers became

aware of the plant’s invasive nature and disruptive effects on native wetland vegetation in the

early 1980’s. The DNR, concerned about the plants impact on native species and wildlife

habitat, conducted preliminary surveys to determine t he status of the plant in Minnesota. The

survey revealed that 77 of Minnesota’s 87 counties had populations of purple loosestrife in

wetlands, lakeshore, stream banks and ditches. In 1987 Minnesota became one of the first

states in the nation to develop a program to control this invasive plant. Minnesota has

designated purple loosestrife as a noxious weed, which makes it illegal to import, buy, sell,

propagate and transport.

The main components of the purple loosestrife program are:

An inventory of pu rple loosestrife sites is maintained and used to prioritize control efforts.

To c arry out management activities including chemical and biological control.

To s upport research to evaluate and expand control efforts.

To m onitor and evaluate the success of bi ological control and other management efforts.

Public education/awareness efforts to involve the public in the management of this plant. 0 1000 2000 3000 4000 5000 6000 7000

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 Figure 16. Acres of off

- shore curly

- leaf pondweed and Eurasian

watermilfo il control 1998

- 2008.

CLP

EWMMn DNR, Ecological Resources 2008 APM Annual Report May 2009 27 

### Large stands of purple loosestrife are extremely difficult to control because of their enormous

seed bank; therefore , it is necessary to prioritize purple loosestrife control efforts. The h ighest

priority stands for herbicide treatment are small

, recently established stands

, located near the

top of the watershed

. Because of their small size these newly established sit es are poor

candidates for biocontrol. Rodeo, a broad

- spectrum glyphosate herbicide, is used to spot treat

high priority purple loosestrife sites with a backpack sprayer.

Minnesota’s herbicide control effort has been reduced dramatically since the introd uction of bio

control agents began in 1992. In 2008

, DNR staff treated a total of 47 purple loosestrife sites

with 0.2 gallons of Rodeo herbicide. Most of these sites were very small with the majority

having fewer than 100 plants. For more detailed info rmation on Minnesota’s purple loosestrife

program, see the 2008 Invasive Species Annual Program report.

( http://files.dnr.state.mn.us/ecological_services/invasives/ annualreport.pdf )

Eurasian Watermilfoil

Eurasian watermilfoil, hereafter called milfoil, is an exotic aquatic plant introduced to North

America in the mid

- 1900’s. It was first identified in Minnesota in 1987 in Lake Minnetonka.

Milfoil is a submerged a quatic plant that can displace native vegetation. The plant reproduces

by fragmentation, establishes itself readily in disturbed areas, and has the potential to become a

nuisance in Minnesota lakes. The main strategies of the Eurasian watermilfoil progra m are:

Slow the spread of the plant through public education and awareness activities.

Support management by lake associations and local units of government of problems

caused by milfoil.

Maintain an accurate inventory of populations.

Investigate new contr ol methods and the biology of the plant.

Eurasian watermilfoil was discovered in 1 2 additional water bodies in 200 8 . There are now 2 15

Minnesota lakes known to have populations of this invasive submersed aquatic plant.

The most commonly used herbicide for control of milfoil is a granular 2,4

- D ester product

labeled for aquatic use. In 2001, a liquid dimethylamine salt 2,4

- D product was registered for

aquatic use and has been applied to milfoil in Minnesota. Late in 2002, a liquid trimethylamine

salt, triclopyr product, was registered for aquatic use and is available for control of milfoil in

Minnesota. These systematic herbicides are preferred because they are the most selective

products available.

The total reported 2,4

- D use in 2008 for milfoil wa s 56,000 pounds. The total reported annual

use of 2,4

- D ester products since 1987 is provided in Figure 17 . For more detailed information

on the management of invasive species see the 2008 Invasive Species Program Annual Report.

The report may be reviewe d on line at

http://www.dnr.state.mn.us/ecological_services/invasives/index.html

.

In 2008, the DNR provided $1 05 ,000 in state funds to cooperators on 2 2 lakes for managem ent

of milfoil. The DNR spent an additional $1 7 ,000 on control work at public water accesses to

control Eurasian watermilfoil to help minimize its spread between lakes.Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 28 

### References Cited

Blankespoor, H.D., and R.L. Reimink . 1991. The Control of Swimmer’s Itch in Michigan: Past,

Present, and Future. Michigan Academician XXIV , 7

- 23.

Bolduan, B.R., G.C. Van Eeckhout, H.W. Quade, and J.E. Gannon. 1994. Potamogeton

crispus

- the other invader. Lake and Reservoir Managemen t 10(2):113

- 125.

Catling, P.M. and I. Dobson. 1985. The biology of Canadian weeds. 69. Potamogeton crispus

L. Canadian Journal of Plant Science 65:655

- 668. 0 20000 40000 60000 80000 100000 120000

1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 

### Figure 17. Permitted 2,4

- D Ester (lbs. ) use in Minnesota after identification of

Eurasian watermilfoil in Minnesota, 1987

- 2008Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 29 

# APPENDIX

Table: Page_

A A list of commonly used herbicides registered by the EPA fo r 30

aquatic use and approved by the MN DNR.

B Reported various aquatic he rbicide use statewide, 1981

- 2008

. 31

C Aquatic Plant Management Report Survey, Chemical

- Mechanical, 32

200 8

.

D Aquatic Plant Management Report Survey, AUAPCD, 2008. 33

E Aquatic Pesticide Enforcement Citizen Complaint Investigation, 34

20 08.

F Aquatic Pesticide Enfor cement Use Inspections, 2008. 34

G Statewide numbers of permits and properties by county , 2008. 36

H Lakes with nine or more total perm its i ssued for swimmer’s itch 38

from 1997 through 200 8

.Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 30 

### Table A. A list of commonly used herbicides registered by the EPA for aquatic use and

approved by the MN DNR.

Product Name Selective Broad

Spectrum Active Ingredient (Formulation)

Part 1. Aquati cally labeled systemic herbicides

.

Aquacide (Pellet)

Navigate (Granular)

Riverdaletm (Granular)

SEE 2,4

- D (Liquid)

Weedtrine II (Granular)

Sonar (Liquid or Granular)

Rodeo (Liquid)

Pondm aster (Liquid)

Garlon

- 3A X

X

X

X

X

X

X

X

X 2,4 Dichlo rophenoxyacetic Acid (Sodium Salt)

2,4 Dichlorophenoxyacetic (Butoxyethyl Ester)

2,4 Dichlorophenoxyacetic ( Isooctyl Ester )

2,4 Dichlorophenoxyacetic (Isooctyl Ester)

2,4 Dichlorophenoxyacetic (Isooctyl Ester)

Fluridone

Isopropylamine salt of Glyphosate

I sopropylamine salt of Glyphosate

Triclopyr (Experimental use permit, full aquatic

label pending)

Part 2. Contact Herbicides

.

Aquathol (Liquid or Granular)

Hydrothol 191 (Liquid or Granular)

Reward (Liquid) X

X

X Dipotassium salt of endothall

Mon o

- amine salt of endothall

( liquid by licensed applicator only)

Diquat dibromide

(licensed applicator only)

Part 3. Copper Compounds (Algaecides and Herbicides)

.

Cutrine Plus (Liquid or Granular)

Komeen (Liquid)

K

- Tea X (A)

X (H)

X (A) Copper

- Ethon alamine complex

Copper

- Ethylenediamine complex

Copper

- Triethanolamine complex

Part 4. Other

.

Copper sulfate

Aquashade (Liquid) X (A) X CuSO4 ( wide variety of registered brands)

Acid Blue 9 / Acid Yellow 23

(Filters light in wavelengths require d for plant

growth)Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 31 

### Table B. Reported aquatic herbicide use under DNR permit, 1981

- 200 8

.

Year 2,4

- D

ester

lbs. 2,4

- D

salt

lbs. 2,4

- D

amine/acid

gal. Aquathol

lbs. Aquathol

gal. Diquat

(Reward)

gal. Hydrothol

191

lbs. Hydrothol

191

gal. Cop per

sulfate

lbs.

1981 150 370 0 1,900 1,300 730 3,200 390 *

1982 120 320 0 1,700 1,500 550 4,200 44 *

1983

- 350 0 1,400 1,500 560 11,900 31 *

1984 110 130 0 730 980 780 7,300 80 *

1985 25 270 0 740 1,200 870 14,000 100 *

1986 25 370 0 1,100 1,400 1, 200 6,900 170 *

1987 100 1,400 0 1,100 1,400 1,400 13,000 62 *

1988 3.700 600 0 950 1,300 1,300 11,000 100 *

1989 13,000 470 0 910 1,300 1,700 12,000 200 *

1990 23,000 290 0 680 1,100 1,500 9,500 130 *

1991 48,000 1,300 0 1,400 850 1,400 9,600 210 55, 400

1992 81,000 320 0 870 1,600 1,700 9,000 67 64,000

1993 96,000 40 0 830 1,000 1,600 5,000 240 34,600

1994 45,000 70 0 710 940 1,800 10,000 510 59,800

1995 80,000 87 0 930 700 2,300 8,300 420 55,000

1996 39,000 400 0 1,000 730 1,900 8,900 830 32,500

1997 46,000 290 0 1,200 700 2,400 7,800 820 39,700

1998 47,000 440 0 790 1,280 2,580 4,460 670 50,800

1999 39,800 650 0 1,050 740 2,280 4,190 740 31,600

2000 41,500 700 0 1,380 1,850 2,970 5,820 530 41,900

2001 49,300 1,000 0 700 2,600 2,700 3,900 95 0 58,200

2002 49,400 700 20 540 2,660 2,530 4,220 760 42,200

2003 71,100 634 336 339 2,515 2,370 7,610 429 47,100

2004 64,100 1,068 216 366 5,200 2,856 8,040 643 53,700

2005 48,800 1,154 533 1,077 7,054 2,773 6,744 715 63,500

2006 53,400 805 215 1,530 8,757 2,953 11,653 126 47,000

2007 57,700 971 85 1,320 9,838 3,685 10,105 782 46,000

2008 56,000 655 7.4 2,462 13,208 2,643 10,693 550 32,290

* Data not availableMn DNR, Ecological Resources 2008 APM Annual Report May 2009 32Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 33Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 34 

### Table E. Aquatic Pesticide Enforcement Citizen Complaint Investigations, 200 8

.

Date Complaint Lake Name County Observation Action Result

June 10 Fish die off. Prior Lake Scott Not observed Small sunfish

crappie die off

reported several

days after the

fact. Fish

decomposition

too far

advanced for

analysis.

Jun e 8 No posting

following

herbicide

treatment. Jennings Bay,

Mtka. Hennepin Inspected

6/9/2008. One

sign posted near

access to marina.

Posting was

inadequate. Referred to area

APM Specialist. Pending

July 9 Unauthorized

herbicide

treatment. Fore st Lake Washington Aquatic Pesticide

Enforcement staff. Observation

reported to

conversation

Jason Jenson. Jason Jenson

was unable to

determine the

person’s

involved.

August 20 Unauthorized

herbicide

treatment. Blue Lake Isanti Aquatic Pesticide

Enforcement staff. Referred to area

APM Specialist. Over treatment

of a permitted

area. Referred

to area CO.



### Table F. Aquatic Pesticide Enforcement Use Inspections, 200 8

.

Treatment

Date County Lake Applicator Number of

Treatments

Inspected

23

- Apr Ramsey Kohlman Lake Restoration 1

5

- May Ramsey Bald Eagle Lake Restoration 1

8

- May Crow Wing Lower Mission Professional Lake Management 1

8

- May Isanti Long Lake Restoration 2

13

- May Chisago Green Green Lake Association 2

14

- May Hennepin Sarah Lake Restoration 2

14

- May Sherburne Rush Lake Management 1

15

- May Morrison Crookneck Professional Lake Management 1

16

- May Ramsey Silver (nsp) Aquatic Engineering, Inc. 2

19

- May Douglas Smith Professional Lake Management 1

19

- May Stearns Grand Lake M anagement 1

21

- May Cass Margaret Professional Lake Management 1

22

- May Morrison Long Professional Lake Management 1

23

- May Stearns Kings Professional Lake Management 1

28

- May Cass Norway Professional Lake Management 1

28

- May Crow Wing Sibley Professio nal Lake Management 1

30

- May Hennepin Bass Lake Management 2Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 35 

### Table F. Continued

Treatment

Date County Lake Applicator Number of

Treatments

Inspected

2

- Jun Chisago Rush (west) Lake Restoration 2

4

- Jun Washington White Bear Professional Lake M anagement 1

10

- Jun Ramsey Gervais Lake Improvement Consulting 2

16

- Jun Todd Little Birch Professional Lake Management 2

17

- Jun Wright Clearwater Clearwater Lake Property Owners 2

18

- Jun Hennepin Mtka Priest Lake Management 2

19

- Jun Wright Augusta Lake Augusta Property Owners 2

20

- Jun Morrison Alexander Professional Lake Management 1

23

- Jun Sherburne Long Professional Lake Management 2

24

- Jun Todd Mound Minnesota Shoreline Restoration 2

26

- Jun Carver Mound Midwest Aquacare 2

9

- Jul Washington Forest Lake Management 2

10

- Jul Dakota Crystal Lake Restoration 2

17

- Jul Anoka Coon Lake Restoration 2

21

- Jul Hennepin Mtka Gideons Lake Management 2

23

- Jul Carver Lotus Midwest Aquacare 2

30

- Jul Crow Wing Upper Mission Professional Lake Management 1

31

- Ju l Mille Lacs Mille Lacs Midwest Aquacare 1Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 36 

### Table G. Statewide numbers of permits and properties by county, 2008.

County Properties Permits

Aitkin 197 156

Anoka 156 56

Becker 255 255

Beltrami 23 23

Benton 24 4

Big Stone 1 1

Blue Earth 3 3

Carlt on 52 52

Carver 329 80

Cass 368 261

Chisago 380 86

Clay 8 8

Clearwater 3 3

Cottonwood 2 2

Crow Wing 1,086 678

Dakota 329 59

Douglas 228 228

Faribault 55 2

Freeborn 6 6

Grant 11 11

Hennepin 1,860 375

Hubbard 55 55

Isanti 134 40

Itasca 47 47

Jackson 6 6

Kanabec 34 8

Kandiyohi 100 86

Koochiching 1 1

Lake of the Woods 1 1

LeSueur 197 42

Lincoln 2 2

McLeod 40 4

Mahnomen 5 5

Martin 8 8

Meeker 159 29

Mille Lacs 60 21Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 37 

### Table G. (Continued)

County Properties Permits

Morrison 209 101

Murray 2 2

Nicollet 1 1

Nobles 1 1

Olmsted 2 2

Ottert ail 571 571

Pennington 1 1

Pine 214 54

Pipestone 1 1

Polk 8 8

Pope 59 59

Ramsey 807 78

Rice 156 24

Rock 2 2

St. Louis 106 53

Scott 400 65

Sherburne 210 52

Stearns 254 120

Steele 2 2

Tod d 175 131

Wadena 10 10

Waseca 13 6

Washington 485 115

Watonwan 1 1

Wright 826 235Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 38 

### Table H. Lakes with nine or more total permits issued for swimm er’s itch from 1997 through

2008

.

Region County Lake Total permits issued

1 Becker Detroit 22

1 Beck er Height of Land 11

1 Becker Sallie 10

1 Beltrami Julia 10

1 Clay Blue Eagle 12

1 Douglas Carlos 20

1 Douglas Darling 24

1 Douglas Geneva 13

1 Douglas Ida 44

1 Douglas Irene 69

1 Douglas Le Homme Dieu 50

1 Douglas Miltona 43

1 Grant Pelican 15

1 Grant Pomme De Terre 11

1 Hubbard Alice 10

1 Hubbard Big Sand 21

1 Hubbard Fishhook 11

1 Otter Tail East Battle 19

1 Otter Tail Rush 20

1 Otter Tail Stalker 10

1 Otter Tail Wall 24

1 Pope Amelia 24

1 Pope Linka 46

1 Pope Minnewaska 22

1 Pope Scandinavian 12

2a Carlton Eagle 39

2a Carlton Tamarack 11

2a Itasca Bowstring 10

2a Itasca Jessie 12

2a Itasca Sand 14

2a Itasca Swan 91

2a St. Louis Big Sturgeon 13

2a St. Louis Long 16

2b Aitkin Big Sandy 27

2b Aitkin Cedar 11

2b Aitkin Farm Island 94

2b Aitkin Gun 35

2b Aitkin Hanging Kettle 10

2b Aitkin Minnewawa 27Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 39 

### Table H. Continued.

Region County Lake Total permits issued

2b Aitkin Pine 15

2b Aitkin Pine 18

2b Aitkin Round 20

2b Aitkin Spirit 22

2b Cass Birch 13

2b Cass Gull 280

2b Cass Margaret 12

2b Cass Roosevelt 50

2b Crow Wing Clark 13

2b Crow Wing Crooked 15

2b Crow Wing Cross 76

2b Crow Wing Crow Wing 67

2b Crow Wing Daggett 46

2b Crow Wing Edward 14

2b Crow Wing Gilbert 71

2b Crow Wing Gladstone 15

2b Crow W ing Hubert 19

2b Crow Wing Island 17

2b Crow Wing Little Hubert 19

2b Crow Wing Little Pine 35

2b Crow Wing Love 18

2b Crow Wing Lower Cullen 35

2b Crow Wing Lower Hay 26

2b Crow Wing Lower Mission 28

2b Crow Wing Middle Cullen 11

2b Crow Wing Nis swa 27

2b Crow Wing North Long 92

2b Crow Wing O’Brien 39

2b Crow Wing Ossawinnamakee 34

2b Crow Wing Pelican 36

2b Crow Wing Perch 49

2b Crow Wing Pig 17

2b Crow Wing Pine 19

2b Crow Wing Portage 16

2b Crow Wing Red Sand 18

2b Crow Wing Rice 27

2b Crow Wing Round 129

2b Crow Wing Roy 52

2b Crow Wing Rush 68Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 40 

### Table H. Continued.

Region County Lake Total permits issued

2b Crow Wing Serpent 104

2b Crow Wing Sibley 18

2b Crow Wing South Long 89

2b Crow Wing Upper Cullen 14

2b Crow Wing Up per Hay 65

2b Crow Wing Upper Mission 25

2b Crow Wing Upper South Long 51

2b Crow Wing West Fox 15

2b Crow Wing White Sand 41

2b Crow Wing Whitefish 130

2b Mille Lacs Mille Lacs 32

3a Anoka Centerville 11

3a Anoka Coon 66

3a Carver Minnewashta 73

3a Carver Pierson 47

3a Carver Riley 38

3a Carver Virginia 30

3a Carver Waconia 31

3a Carver Wassermann 10

3a Carver Zumbra 15

3a Chisago Chisago 35

3a Chisago Fish 18

3a Chisago Goose 16

3a Chisago Green 64

3a Chisago Horseshoe 10

3a Chisago K roon 16

3a Chisago Little Comfort 12

3a Chisago North Lindstrom 12

3a Chisago Rush 64

3a Chisago South Center 75

3a Chisago South Lindstrom 33

3a Dakota Marion 28

3a Dakota Orchard 23

3a Dakota Salem 13

3a Hennepin Bass 11

3a Hennepin Bryant 31

3a Hennepin Bush 12

3a Hennepin Castle Ridge 11

3a Hennepin Christmas 29Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 41 

### Table H. Continued.

Region County Lake Total permits issued

3a Hennepin Duck 21

3a Hennepin Dutch 14

3a Hennepin Eagle 47

3a Hennepin Fish 36

3a Hennepin Forest 20

3a Henn epin Gleason 28

3a Hennepin Greentree Pond 11

3a Hennepin Hadley 13

3a Hennepin Independence 52

3a Hennepin Long 17

3a Hennepin Lower Twin 14

3a Hennepin Medicine 68

3a Hennepin Melody 12

3a Hennepin Minnetonka Cooks 65

3a Hennepin Mtka Jennings 4 3

3a Hennepin Mtka Lafayette 69

3a Hennepin Mtka Lower Lake N 27

3a Hennepin Mtka Lower Lake S 44

3a Hennepin Mtka Maxwell 46

3a Hennepin Mtka North Arm 68

3a Hennepin Mtka Phelps 59

3a Hennepin Mtka Priests 55

3a Hennepin Mtka Robinsons 26

3a Hen nepin Mtka Upper Lake 56

3a Hennepin Mtka Seton 17

3a Hennepin Mtka Smiths 14

3a Hennepin Mtka Smithtown 48

3a Hennepin Mtka Spring Park 35

3a Hennepin Mtka St. Albans 59

3a Hennepin Mtka St. Louis 19

3a Hennepin Mtka Stubbs 28

3a Hennepin Mtka Way zata 44

3a Hennepin Mtka West Arm 44

3a Hennepin Parkers 27

3a Hennepin Rebecca 12

3a Hennepin Red Rock 45

3a Hennepin Round 10

3a Hennepin Sarah 62

3a Hennepin Schmidt (Smith) 18Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 42 

### Table H. Continued.

Region County Lake Total permits issued

3a Hennepin Shady Oak 11

3a Hennepin Weaver 22

3a Hennepin Wrestling (Unnamed) 12

3a Ramsey Bald Eagle 58

3a Ramsey Gervais 29

3a Ramsey Gilfillan 19

3a Ramsey Island 12

3a Ramsey Johanna 25

3a Ramsey Josephine 28

3a Ramsey Keller 11

3a Ramsey Kerr y Pond 12

3a Scott Fish 16

3a Scott O’Dowd 31

3a Scott Prior 128

3a Scott Spring 29

3a Scott Thole 28

3a Scott Upper Prior 65

3a Washington Big Carnelian 51

3a Washington Big Marine 34

3a Washington Demontreville 12

3a Washington Forest 161

3a W ashington Jane 17

3a Washington Lily 12

3a Washington Mary 11

3a Washington Olson 12

3a Washington Pine Tree 10

3a Washington Tanners 17

3a Washington White Bear 94

3b Isanti Blue 30

3b Isanti Fannie 25

3b Isanti Long 16

3b Isanti Paul 21

3b Isa nti Spectacle 13

3b Kanabec Fish 22

3b Kanabec Mud 14

3b LeSueur Tetonka 24

3b LeSueur Washington 45

3b Morrison Alexander 64

3b Morrison Crookneck 51Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 43 

### Table H. Continued.

Region County Lake Total permits issued

3b Morrison Fish Trap 33

3b Morr ison Platte 122

3b Morrison Shamineau 17

3b Morrison Sullivan 17

3b Pine Cross 34

3b Pine Sand 10

3b Pine Upper Pine 13

3b Pine/Aitkin Big Pine 49

3b Sherburne Big 34

3b Sherburne Briggs 15

3b Sherburne Fremont 18

3b Sherburne Julia 14

3b Wright Charlotte 25

3b Wright Clearwater 114

3b Wright Crawford 11

3b Wright Deer 16

3b Wright French 24

3b Wright Maple 45

3b Wright Mink 10

3b Wright North Center 48

3b Wright Pleasant 35

3b Wright Pulaski 39

3b Wright Rock 19

3b Wright Somers 12

3 b Wright Sugar 71

3b Wright Sylvia 49

3b Wright Waverly 31

4 Benton Little Rock 12

4 Faribault Bass 15

4 Kandiyohi Elkhorn 11

4 LeSueur Tetonka 24

4 LeSueur Washington 45

4 Rice Mazaska 11

4 Rice Roberds 16

4 Stearns Big Fish 15

4 Stearns Big Sp unk 23

4 Stearns Grand 22

4 Stearns Koronis 19

4 Stearns North Browns 14Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 44 

### Table H. Continued.

Region County Lake Total permits issued

4 Stearns Pearl 24

4 Stearns Pelican 30

4 Stearns Rice 37

4 Waseca Clear 14Mn DNR, Ecological Resources 2008 APM Annual Report May 2009 45 

### Mention of trademarks or propri etary products does not constitute a warranty of the products by

the Minnesota Department of Natural Resources and does not imply its approval to the

exclusion of other products that may also be suitable.

Cop yright MnDNR 2001. All rights reserved.