Read the Spring Newsletter

Eyes on the Lake

This feature will help us all with learning what plants are native and healthy for our lakes vs. the invasive plants. We hope you find this information helpful. Thanks for helping to keep our waters clean.

Slowing the Spread

Our AIS Efforts are Working

In 2014 Minnesota started allocating funds to Counties for efforts to control Aquatic Invasive Species (AIS). That funding has made a major contribution to reducing the spread of AIS across Minnesota. Since the County AIS funding came online the rate of new infestations in Minnesota has declined by almost 50%.

Looking at AIS of all types the peak of new infestations was 2012 through 2014 with an average of 93 lakes being listed as infested in each of those years. In the most recent three years of 2021 through 2023 we saw an average of only 56 lakes listed as newly infested in each of those years. There has been a trend of fewer infestations each year for the past five years and in 2023 only 42 lakes were listed down from the peak of 118 new infestations in 2012.

Looking specifically at zebra mussels the story is even better. The peak of zebra mussel infestations in Minnesota was 2014 with 67 lakes listed that year as newly infested. Since then the rate of new zebra mussel infestations has dramatically dropped with only 28 lakes being listed in 2023. In Cass County only 13 lakes with public accesses have been listed as zebra mussel infested out of the 103 lakes with public accesses. Only 12.6% of publicly accessible lakes in Cass County are infested with zebra mussels.

Through the efforts of local groups and individual water users we have made a dramatic change in the spread of AIS across Minnesota. We have shown that by working together to implement AIS inspections, education, and outreach we can reduce the spread of AIS across Minnesota. The rate of AIS spread across Minnesota is a function of the behavior of each of us individually. Let’s all commit to continue reducing the spread of AIS and redouble our efforts to preserve Minnesota’s lakes for future generations.

Steve Henry

AIS Lake Technician

PO Box 3000/303 Minnesota Ave W, Walker, MN 56484

steve.henry@casscountymn.gov

(218)-536-0584

AIS Explorer

How 10,000+ Lakes Are Protected with Limited Resources

After five years of development, researchers at the Minnesota Aquatic Invasive Species Research Center (MAISRC) released an online dashboard in 2021 that predicts the introduction risk of aquatic invasive species (AIS) and identifies the optimal placement of watercraft inspection locations for waterbodies across Minnesota – AIS Explorer. Based out of the University of Minnesota, an extensive network was created that explains how Minnesota boaters travel between waterbodies. This tool helps Minnesota’s resource managers prioritize their AIS prevention efforts, and maximize efforts with limited resources.

The prioritization for watercraft inspections is run at the county-level and considers the movement of boats into, within, and out of an individual county paired with “risky” boats—the predicted number of boats moving from an infested waterbody to an uninfected waterbody.

AIS Explorer is utilized by the Cass County AIS Program to assist with determining the number of AIS watercraft inspector hours to be scheduled for the various lakes. This tool helps to rank the lakes within the county that should be prioritized for watercraft inspections, as well as visualizes the point of diminishing returns from added inspections and provides a figure that displays the optimal balance of inspections to maximize the number of intercepted risky boats.

The AIS Explorer is easy to use and available for all. Users can focus on any lake in Minnesota. Not only will you see the overall risk score for potential future infestation, but it’s also possible to see the incoming and outgoing network of boater activity.

Summary data from our lakes: (Overall risk score: 1.0 indicates lake is infested)

Little Boy Wabedo

Risk Score: Overall: 0.3865 Risk Score: Overall: 0.3535

Boater Network: Boater Network:

Incoming infested: 25.5% Incoming infested: 27.4%

Incoming non-infested: 74.5% Incoming non-infested: 72.6%

Outgoing Infested: 13.1% Outgoing infested: 13.6%

Outgoing non-infested: 86.9% Outgoing non-infested: 86.4%

The AIS Explorer dashboard is free and open to the public at www.aisexplorer.umn.edu. Funding for AIS Explorer was provided by the Minnesota Environment and Natural Resources Trust Fund as recommended by the Minnesota Aquatic Invasive Species Research Center (MAISRC) and the Legislative-Citizen Commission on Minnesota Resources (LCCMR).

For more information: www.maisrc.umn.edu/aisexplorer

Is It Curly-leaf Pondweed or Clasping-leaf Pondweed?

Curly-leaf (non-native/invasive)

Keys to identify the 2 types of pondweed:

Thin, submerged leaves with distinct “teeth”/wavy edges.
Leaves don’t clasp around stem where they connect.
Generally, first pondweed to come up in the spring.
In waters up to 15 feet deep.
Dies back in the summer.
Turions look like small, greenish-brown pinecones.

Clasping-leaf (native)

Leaves are wide and wavy without "teeth"
Leaves clasp around stem
Leaves alternate along the stem
In waters up to 12 feet deep.

Curly-leaf pondweed impacts:

In spring, curly-leaf pondweed can interfere with recreational and other uses of lakes and rivers by producing dense mats at the water’s surface.
Matted curly-leaf pondweed can displace native aquatic plants.
When curly-leaf pondweed dies back in the summer, the dense mats decay and release nutrients into the water column which contribute to algal blooms. The decomposing plant material can also deplete oxygen levels in the water, causing anoxic conditions leading to possible fish kills.

Curly-leaf pondweed is native to Eurasia, Africa, and Australia. It was likely introduced when common carp were intentionally introduced into Midwest waters as a game fish in the 1880’s. The species was likely spread through the movement of watercraft and water-related equipment. It was first noted in Minnesota around 1910. It is known to be present in more than 750 lakes in 70 of the 87 counties in Minnesota.

Curly-leaf pondweed is classified as prohibited invasive species in Minnesota. It is illegal to possess, buy, sell, transport, and introduce a prohibited invasive species.

Neither Little Boy nor Wabedo lakes are known to have curly-leaf pondweed, however we do have the native clasping-leaf pondweed. Broad-leaf pondweeds, e.g., clasping-leaf pondweed, provide excellent habitat for panfish, largemouth bass, muskellunge, and northern pike; bluegills nest near these plants and eat insects and other small animals found on the leaves; walleyes use these pondweeds for cover.

Credits:

Aquatic Invasive Species Identification Guide for Minnesota, www.maisrcumn.edu.

MN DNR website

Siberian Pea shrub

Siberian Pea shrub has been identified growing along the shore of Wabedo Lake. Ideally, these shrubs should be removed, or at minimum, not allowed to spread. If you suspect you have Siberian pea shrub on your property, contact us at wlbcrlakes@gmail.com or Cass County or the Minnesota Department of Natural Resources for assistance in identification and management. Siberian Pea shrub is listed as a Restricted Noxious Weed – propagation, importation, transport and sale of the plant are prohibited in Minnesota.

Keys to identify:

Small or large shrub (woody stems) up to 18 feet tall
Alternate, compound leaves with an even number of leaflets, usually 8-12
Yellow flowers in May and June
Long seed pods that are green in summer, then turn brown, curl, open and release seed in the fall

Impacts:

Outcompetes native vegetation
As a legume, the plant fixes nitrogen in the soil, altering soil chemistry and making the soil less hospitable to native plants

Looks similar to:

Honey locust (native) – Honey locust is a tree with leaves that look similar to Siberian peashrub leaves. Honey locust leaves can be once or twice compound and have 18-28 leaflets per leaf on once compound leaves and up to 150 leaflets on twice compound leaves. Siberian peashrub has 8-12 leaflets per leaf. Honey locust flowers are white and Siberian peashrub flowers are yellow.
Bristly locust (invasive) – Bristly locust has pink flowers and has stems covered in red bristles.
Forsythia (non-native) – Forsythia have yellow flowers with four petals and simple, oval-shaped leaves, not compound leaves with multiple leaflets as Siberian peashrub has.

How to eradicate:

Pull up or dig up small or medium shrubs getting as many roots as possible
Cut down large shrubs, then paint the stump with herbicide

Plant these natives instead:

Red osier dogwood (Cornus sericea) or gray dogwood (Cornus racemosa)
Chokecherry (Prunus virginiana)
Bush honeysuckle (Diervilla lonicera)
Nannyberry (Viburnum lentago)
American hazelnut (Corylus americana)

Credits and for more information on eradication and control:

Photographs: Minnesota Department of Agriculture, MinnesotaWildflowers.info

http://extension.umn.edu/identify-invasive-species/siberian-peshrub

http://www.dnr.state.mn.us/invasives/terrestrialplants/woody/siberianpeashrub.html

http://extension.umn.edu/planting-and-growing-guides/woody-vegetation-control

Rusty Crayfish and Chinese Mystery Snail

Chinese mystery snails and rusty crawfish are both present in Little Boy and Wabedo. Although they are considered to be invasive species, a lake isn’t identified as “infested” when these species are present. According to the MN DNR they are regulated invasives.

What does it mean if it is a regulated invasive species? In Minnesota, it means it is legal to possess, sell, buy, and transport, but it may not be introduced into a free-living state, such as being released or planted in public waters.

Rusty Crayfish

Rusty crawfish were likely introduced and spread through the improper use and disposal of live bait. The species is also commonly imported and sold by the aquarium trade, and to schools by biological supply houses, leading to the potential for illegal release into the wild. The first established population in Minnesota was in Lake Superior in the late 1990s.
Rusty crayfish are omnivores, consuming many food sources such as plants, animals, organic material, sediment, etc.
There is no known population control for rusty crayfish in natural water bodies at this time. Trapping may reduce numbers but would likely not have a significant impact on the population. Increasing fish predator numbers, either through regulation and/or stocking, has shown potential for reducing crayfish populations.

Keys to Identify:

All crayfish resemble miniature lobsters with long antennae, a pair of claws, and 8 legs.
Light to dark brown body.
Red spots on the sides of carapace.
Has larger, more robust claws than native crayfish species.
Claws have dark black bands on the tips.
Can grow up to 5” long.

Impacts:

Destruction of aquatic plant beds.
Aggressive displacement of native crayfish species.
Breeds with native crayfish, replacing native crayfish populations with hybrids.
Competes with fish for prey and consumes fish eggs.

Credits: AIS Identification Guide: A Minnesota Handbook, www.maisrcumn.edu.

MN DNR website: https://www.dnr.state.mn.us/invasives/index.html

Chinese Mystery Snail

Chinese Mystery Snails:

The Chinese mystery snail grazes on lake and river bottom material. They are called “mystery” snails because females give birth to young, fully developed snails that suddenly and “mysteriously” appear.
They are spread primarily through movement of water-related equipment and illegal release of aquarium pets. It is illegal to release or dispose of unwanted aquatic plants or animals in or near public waters.
There is no known effective population control for Chinese mystery snails in natural water bodies at this time.

Keys to Identify:

Large, smooth, tan to brown shell that can grow 2-3” long.
Shell lacks banding and can have 6–7 whorls.
Snails have an operculum (structure that functions much like a lid or “trapdoor”) with distinct growth rings.
An operculum is not likely to be present in dead specimens.

Impacts:

Can die-off in large numbers, fouling beaches and shoreland.

Looks similar to:

Zebra mussels and quagga mussels
Native snails and mussels

Credits: AIS Identification Guide: A Minnesota Handbook, www.maisrcumn.edu.

MN DNR website: https://www.dnr.state.mn.us/invasives/index.html

Purple Loosestrife (Lythrum salicaria)

What Is It?:

A prohibited invasive aquatic plant/terrestrial.
Is on the control noxious weed list meaning you must prevent the spread of this plant, and that it should be reported.

Where is it Found?

It can invade many wetland types including wet meadows, stream banks, pond or lake edges and ditches.

Keys to Identify:

Flowers are purple-pink bloom in tall spikes.
Blooms from early July through September, and then goes to seed.
Flowers typically have 6 petals. Multiple rings of flowers boom at once from the bottom of the spike to the top.
Can grow 3-7 feet tall with multiple stems growing from a single rootstock. Bushy appearance.
Stem is stiff, typically square shaped.
Leaves are opposite or whorled with smooth edges.
Roots are a large, woody taproot with rapidly extending fibrous rhizomes.

Impact of Purple Loosestrife and Why Does It Matter:

It is exceedingly aggressive and can overtake native plants very quickly.
Creates dense growth along shoreline areas making it difficult to access open water.

How It Grows and Spreads:

Spreads primarily by seeds which are tiny. Up to 300,000 seeds produced per stem each year and are viable for up to 20 years.
Through the movement of water-related equipment and uninformed release of garden plants.
Seeds can be hidden in mud and debris, and can stick to boots, waders, and other fishing and hunting gear. Roadside maintenance equipment can also spread this plant and its seeds.

How to Prevent:

Follow the “Play, Clean, Go” best management practices:
- Remove plants, animals, and mud from your boots, gear, boat, and trailer
- Clean your gear before entering and leaving a recreation site
- Drain bilge, ballast, wells and buckets before leaving the area
- Dry equipment before launching into another body of water
- Dispose of unwanted bait in a sealed container
- Use certified or local firewood and hay
Management can include chemical, mechanical, mowing/hand-cutting and biocontrol treatments.
Report new occurrences of purple loosestrife to the DNR immediately by contacting our regional DNR Invasive Species Specialist: Nicole Kovar, Park Rapids DNR, 218-616-8102, nicole.kovar@state.mn.us.

Look-alike Native Plants:

Blue Vervain

Fireweed

Credits:

MN DNR website: https://www.dnr.state.mn.us/invasives/aquaticplants/purpleloosestrife/index.html

University of Minnesota Extension: www.extension.umn.edu

Photo Credit:

Minnesota Wildflowers: www.minnesotawildflowers.org

For more information:

Restore Your Shore – MN DNR: https://www.dnr.state.mn.us/rys/index.html

Score Your Shore – MN DNR: https://www.dnr.state.mn.us/scoreyourshore/index.html

Play-Clean-Go: https://www.playcleango.org/help-stop-invasive-species-with-playcleango

Spiny Waterflea (Invasive)

What Is It?:

Microscopic freshwater zooplankton that can decimate populations of other native zooplankton resulting in a decreased food source for native fish and an increase in algal blooms.

Keys to Identify:

Range in size from 1/4 to 5/8 of an inch.
Have a single long tail with 1-4 barbs, which helps them avoid predation.
Opaque in color.
Have distinctive black eyespots.
Most abundant during late summer & autumn.

Where to Look:

Most often found on fishing line.
When they are grouped together, as ensnared on fishing lines and cables, they collect and form gelatinous globs with a texture of wet cotton.

Nearby Lakes with Spiny Waterfleas:

First found in Lake Superior in 1987; and first discovered in inland Minnesota lakes in Island Lake Reservoir north of Duluth in 1990.
Lake Vermillion, Lake Milles Lacs, Lake of the Woods
MN DNR infested waters website for more info: https://www.dnr.state.mn.us/invasives/ais/infested.html

How to prevent Spiny Waterflea:

Because recreational boaters and anglers can inadvertently move them or their eggs on fishing line, bait buckets, live wells, or fishing nets, it’s so important to follow MN AIS laws:

o Clean watercraft of all aquatic plants and prohibited invasive species.

o Drain all water, including livewells and bait water. Remove boat drain plugs; keep them out during transport.

o Dispose of unwanted bait in the trash.

o Dry docks, lifts, swim rafts and other equipment for at least 21 days before placing equipment into another water body.

Credits:

MN AIS Research Center (MAISRC): https://www.maisrc.umn.edu/about-spinywaterflea

AIS Identification Guide: A Minnesota Handbook, www.maisrcumn.edu

MN DNR website: https://www.dnr.state.mn.us/invasives/aquaticanimals/spinywaterflea/index.html

For More Information:

MAISRC spiny waterflea research: https://www.maisrc.umn.edu/spinywaterflea-research

Zebra Mussels

Keys to identify:

Stripes are generally in zigzag patterns
Pattern is variable; some may lack striping altogether and can be solid tan or brown
Have a flat edge and won’t topple over when set on its edge
Shells form straight light when closed
Range from 1/8 of an inch to 2 inches; adults are typically fingernail sized.

Looks similar to:

Other invasive invertebrates: Quagga mussels, Asian clams & Chinese mystery snails.
Native invertebrates: native snails and native mussels.

Where to look:

Often found attached to submerged objects (such as boats and docks, as well as plants and rocks)
Newly settled mussels are usually in shallow areas; adults are common in depths of 10-20 feet.

Zebra Mussel Impact:

Encrusts equipment, such as boat motors and hulls, which reduces performance and efficiency, and is costly to clean and repair
Swimmers and pets can cut their feet on zebra mussels attached to rocks, docks, swim rafts and ladders
Creates a costly problem for power plants, cities and residents when they clog water intakes.
Filters tiny food particles out of the water, which can reduce available food for larval fish and other animals, and can increase aquatic plant growth as a result of increased water clarity.
Attaches to and kill native mussels.

What we should know:

A single zebra mussel can filter one quart of water per day while feeding primarily on algae.
A female can produce 100,000 to 500,000 eggs per year. Fertilized eggs develop into microscopic, free-living larvae, called "veligers," that form shells. After two to three weeks, the veligers settle and attach to a firm surface using tiny fibers called byssal threads. Beds of zebra mussels can reach tens-of-thousands within a single square yard.
Microscopic larvae (veligers) can survive in water contained in bait buckets, live wells, bilge areas, ballast tanks, motors and other water containing devices.
Zebra mussels are unintentionally spread through the movement of water-related equipment, attaching to boats, docks, swim rafts and boat lifts, as well as aquatic plants.
Adult mussels can survive out of water – less than 5 days in dry conditions, but up to 21 days in very wet conditions (such as, inside dock/lift pipes).
It is a prohibited invasive species and it is unlawful (a misdemeanor) to possess, import, purchase, transport, or introduce this species except under a permit for disposal, control, research, or education.

How to prevent zebra mussels:

Clean watercraft of all aquatic plants and prohibited invasive species.

Drain all water, including live wells and bait water. Remove boat drain plugs; keep them out during transport.

Dispose of unwanted bait in the trash.

Dry docks, lifts, swim rafts and other equipment for at least 21 days before placing equipment into another water body.

Credits:

AIS Identification Guide: A Minnesota Handbook, www.maisrcumn.edu

MN DNR website: https://www.dnr.state.mn.us/invasives/aquaticanimals/zebramussel/index.html

Eurasian Milfoil

Is It Eurasian Milfoil or Northern Milfoil?

Eurasian watermilfoil looks similar to many native, beneficial watermilfoils found in Minnesota lakes and rivers. Its common native look-alike is northern watermilfoil. It’s spread primarily through the movement of water-related equipment. Plant fragments can get tangled on boats, trailers, motors, anchors and other water-related equipment. All it takes is a single plant fragment to start a new population. It is a prohibited invasive species in Minnesota, which means it is unlawful (a misdemeanor) to possess, import, purchase, transport or introduce these species except under a permit for disposal, control, research or education.

Eurasian watermilfoil impacts:

Dense mats at the water’s surface inhibit water recreationists.
Overtakes habitat and outcompetes native aquatic plants, potentially lowering diversity.
Provides unsuitable shelter, food, and nesting habitat for native animals.

Keys to Identifying the 2 Types of Milfoil

EURASIAN NORTHERN

Featherly looking with 4 leaves per whorl
Leaves have central axis with 12-20 leaflet pairs
Can grow up to 10 feet long
Produces pink & white flowers on spike above surface
Flowers 2x/year; usually mid-June & late-July
Leaves become limp when taken out of water
Grows best in 3-15 feet

4 leaves per whorl
Leaves have central axis
Each leaf has 4-11 leaflet pairs
Forms winter bud in late fall and winter
Leaves are rigid when taken out of water
Grows underwater in depths of up to 20 feet

Credits:

AIS Identification Guide: A Minnesota Handbook, www.maisrcumn.edu

MN DNR website: https://www.dnr.state.mn.us/invasives/aquaticplants/milfoil/index.html

Starry Stonewort

Keys to Identify:

Bushy, bright green macro-algae. It produces a characteristic star-shaped bulbil.
Small, white star-shaped bulbils form on clear threads at base of plant (asexual reproductive structure). May be found above or below the sediment surface – bulbils are the size of a grain of rice.
Small, orange spheres may be visible near the tips of the structure (male reproductive structures called antheridia).
Long, smooth branchlets are attached in whorls of 5-8 and branch asymmetrically at tips.
Stems are smooth.
Branchlets typically form several inches long – longer than Chara or Nitella (native aquatic grasses).
Can fill water column and form surface mats.

Looks similar to the follow native species:

Other native stoneworts and muskgrasses that are beneficial grass-like algae, and are found in Minnesota lakes and rivers.
Look-alike natives: Chara; Nitella; Sago pondweed; Water stargrass.

Where to look:

In shallow, still water and near accesses.

Starry Stonewort Impacts:

Dense mats at the water’s surface inhibit waterways and clog boat propellers, as well as water recreation.
Overtakes habitat and out-competes native aquatic plants, potentially lowering diversity.
Provides unsuitable shelter, food, and nesting habitat for native fish and wildlife.
No known herbicides will kill it. Mechanical harvesting is used to remove it and stop it from spreading.

What we should know:

Believed to be spread from one body of water to another by the unintentional transfer of bulbils, the star-like structures produced by the plant. These fragments are most likely attached to trailered boats, personal watercraft, docks, boat lifts, anchors or any other water-related equipment that was not properly cleaned.
First discovered in Minnesota in August 2015 on Lake Koronis near Paynesville in Stearns County.
13 Minnesota counties have infested lakes, including Cass and Itasca (Lake WInnibigoshish, 2016) and Beltrami County (Lake Beltrami, 2019; Wolf, 2018; Upper Red Lake, 2016; Cass, 2016)

How to prevent starry stonewort:

Clean watercraft of all aquatic plants and prohibited invasive species.
Drain all water, including livewells and bait water. Remove boat drain plugs; keep them out during transport.
Dispose of unwanted bait in the trash.
Dry docks, lifts, swim rafts and other equipment for at least 21 days before placing equipment into another water body.

Credits:

AIS Identification Guide: A Minnesota Handbook, www.maisrcumn.edu.

MN DNR website: https://www.dnr.state.mn.us/invasives/aquaticanimals/zebramussel/index.html.

MN DNR infested waters: https://www.dnr.state.mn.us/invasives/ais/infested.html.

Common tansy (Tanacetum vulgare)

Common tansy is everywhere—a good example of how a non-native plant escapes the garden and runs amok. In this case, tansy escaped gardens long ago—before 1900—giving it plenty of time to spread and choke out native plants. The flowers are yellow and button-like, arranged in flat-topped clusters at the stem tips, and the leaves are lacy and fern-like. Flowering occurs mid-July to September, and the dried seed heads persist all winter.

Tansy is highly invasive and on the “control” noxious weed list, so do make every attempt to eradicate it on your property. Be careful though! Tansy can be toxic to humans and livestock if eaten. Wear gloves when handling to prevent skin irritation.

Warning: Eating common tansy can be toxic to humans and livestock. Wear gloves when handling common tansy.

What Is It?

Common tansy is a perennial plant with distinctive yellow button-like flowers. It can form dense cover and degrade pastures, impede reforestation efforts, and outcompete native plants. It is an invasive species and is on the control noxious weed list meaning you must prevent the spread of this plant.

Where is it Found?

It is commonly found along roads, streambanks, and in pastures and abandoned fields.

How to Identify?

Flowers are yellow and button-like, arranged in flat-topped clusters at the stem tips. Flowering occurs mid-July to September.
A perennial plant with multiple stems that grow from a clump, giving the plant a shrub-like appearance.
Emits a strong odor when plant parts are crushed.
Grows 3-4 feet tall; can reach 6 feet tall.
Stems are reddish-brown and support the distinctive alternate leaves that are finely divided with a fern-like appearance.
Brown seed heads persist until spring.
Reproduces by both seeds and rhizomes, forming dense stands.
Leaves are finely divided with a fernlike appearance.

Impact of Common Tansy and Why It Matters:

It is highly invasive and therefore can severely reduce pasture capacity and desirable forage. In some instances it can be toxic to livestock if consumed. Common tansy can also degrade wildlife habitat, hinder reforestation and landscape restoration efforts.

How It Grows and Spreads:

Spreads primarily by rhizomes and seeds. Seeds are lightweight and easily moved by wind, water, wildlife, equipment, etc.

How to Manage and Prevent:

Persistent hand-pulling and digging may be practical on small patches. Removal of rhizomes is crucial to prevent re-sprouting.
Mowing before flowering will prevent seed production. Repeated mowing throughout the season is required to keep the plants from re-sprouting and producing seeds. Mowing can be beneficial when used several weeks prior to herbicide applications.
Various herbicides have been used successfully for which expert advice is recommended. Contact University of MN Extension for more information.

Resource & Photo Credits:

MN Dept. of Agriculture: https://www.mda.state.mn.us/plants/pestmanagement/weedcontrol/noxiouslist/commontansy

Minnesota Wildflowers

For More Information:

University of Minnesota Extension: www.extension.umn.edu

Minnesota Wildflowers: https://www.minnesotawildflowers.info/flower/common-tansy

Emerald Ash Borer

What Is It?

Emerald Ash Borer (EAB). EAB was recently found in Remer and in Hackensack – both just about 15 miles from Longville. EAB attacks and kills ash trees by eating the tissues under the bark. It arrived in the eastern US from northeastern Asia, probably via wooden shipping crates. It has been slowly moving west since around 2002 by short distance natural flight of adult insects and movement of infested firewood by humans.

How to Identify:

The adults are small, iridescent green beetles that lay their eggs on the outside of ash trees. The larvae hatch, then burrow under the bark, where they feed and pupate to emerge the next spring as adults. In the process of feeding under the bark, the larvae destroy the channels by which the tree takes up nutrients, basically starving the tree.

Often, the first hint that trees are infected with EAB is flying bark chips from woodpeckers drilling for the larvae. Woodpeckers will chip off great quantities of bark, leaving obvious white patches on the tree. At this point, the tree has been infected for 2-3 years. Within another 2-3 years, the tree will die from the canopy down. Dead ash trees quickly become very brittle, dropping branches and subject to wind, ice and snow.

Impact of EAB and Why It Matters:

All species of ash are attacked by EAB. Minnesota has one of the largest population of ash trees in the country, with close to one billion ash trees in cities and forests. Black ash is a very common tree in Cass County and across northern Minnesota. It is important to native wildlife, and regulates soil moisture in wet forests. Losing Black ash trees will have extreme ecological consequences on the northern forest ecosystems. Chances are you have at least one, and maybe dozens or even hundreds of black ash trees on your lake property. Some may shade your cabin or lakeshore.

How it Grows and Spreads:

On its own, EAB spreads about one mile per year. Unfortunately, likely movement of infected wood has caused jumps in infestation along tourist routes – from St. Cloud to Brainerd to Hackensack and from Elk River to Milaca to Remer. It may already be in the Longville area, as yet undetected. Let’s hope not! And let’s do our part to slow it down!

Our portion of Cass County is now under quarantine. Access the quarantine area map here: www.mda.state.mn.us/plants-insects/emerald-ash-borer-quarantine.

How to Manage and Prevent:

It is illegal to move ash firewood or any ash wood products out of quarantined areas unless it is Minnesota Department of Agriculture (MDA) certified firewood. Importantly, the quarantine does not limit movement within the quarantine area – you may move ash firewood from Hackensack or Remer to Longville, for instance, but doing so might move the borer that much more quickly to our lakeshore.

Healthy, high-value trees can be treated with insecticide to protect them from EAB. When EAB is within 10 miles is good time to start applying insecticide. DIY soil treatments are available for smaller trees and must be applied every year. For large trees, licensed professionals may apply an injected insecticide that lasts for 2-3 years. Consider planning ahead to remove untreated ash trees near structures before they die, as the dead, brittle trees are dangerous to cut down. Otherwise, trees can be left to die and fall apart.

As with AIS, taking steps to slow the spread of EAB may buy time for science to catch up; more is being learned about EAB weaknesses, and tests using a wasp that is its natural predator in Asia shows promise. Your choices today could save the boreal forest tomorrow.

Resources:

The Lifecycle of the Emerald Ash Borer – a short animated video www.youtube.com/watch?v=9G-0eG632OI
EAB Informational Meeting for Cass, Isanti, and Kanabec Counties – an hour long webinar www.youtube.com/watch?v=7V1NI-h1b5U
Information for homeowners—Department of Agriculture www.mda.state.mn.us/eab-info-homeowners

Who can I contact for more information?

Steve Bartz, DNR Forester, 218-203-4423, steve.bartz@state.mn.us

How do I report an infestation?

www.mda.state.mn.us/reportapest or reportapest@state.mn.us or 888-545-6684

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