European Gypsy Moth ( Lymantria dispar)

First Detectors

European Gypsy Moth(Lymantria dispar)

First Detectors

Why be Concerned about Gypsy Moth?

Tree defoliator

Attacks over 300 species of woody plants

Increases host susceptibility to secondary pests and pathogens

Native range and established areas: appears as an outbreak pest Greatest damage occurs at first introduction Over 1 million acres defoliated in the U.S. in 2010

First Detectors

Jul

y !

Local Impacts

Leaves are stripped

Trees are stressed, leaving them

susceptible to other pests and diseases

Each caterpillar consumes 9 square feet

of foliage!

Photo courtesy of Garrett (MD) County extension Office

First Detectors Landscape Impacts

Photo courtesy of Garrett (MD) County Extension Office

First Detectors Human Nuisance

First Detectors Where is Gypsy Moth Established?

Europe and north Africa (native) U.S. and Canada (invasive)

First Detectors Identifying Gypsy Moth

Egg Masses Caterpillars Pupae Adults (males vs. females)

First Detectors Gypsy Moth Life Cycle

First Detectors

Emergence

Each female lays one mass

containing 500-1000 eggs

Overwinter in a protected spot

Egg Masses(laid in late summer, hatch in late spring)

First Detectors

Spot the Egg

Mass

First Detectors

6 pair of red spots

5 pair of blue spots

Caterpillar (late spring through early summer)

First instar larvae

Larger caterpillars rest by day, eat at night

First Detectors

Gypsy moth, fg = 2”

Fall webworm, fg = 1”

Whitemarked tussock moth

fg = 1 1/3”

Yellownecked caterpillar

fg = 1 3/4”

Eastern tent caterpillar

fg = 1 3/4”

Forest tent caterpillar

fg = 1 3/4”

Spiny elm caterpillar

fg = 2”

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Caterpillar Lookalikes

First Detectors Feeding Damage

Entire leaf to midrib Can cover acres of woody habitat

First Detectors Host Preference

Preferredeaten by all stages of larvae

Oak, aspen, willow, white and river birch, basswood, larch, mountain-ash, alder and apple

Hawthorn, hazelnut, hophornbeam, hornbeam, serviceberry, witch-hazel

Less-preferredeaten only by older larvae

Yellow birch, boxelder, butternut, black walnut, cherry, eastern cottonwood, elm, hackberry, hickory, red and sugar maple, pine, and spruce

Blueberries, pin cherry, chokecherry, sweet fern

Avoidedrarely fed upon

ash, cedar, fir, silver maple, catalpa, mulberry and many urban species

Dogwood, elderberry, grape, greenbrier, juniper, raspberry, viburnum, and buckthorn!!

First Detectors

Pupa (Cocoon)(summer months)

Males smaller than females Sparse silken threads Found in protected spots

Bark crevices Duff layer

2 weeks

First Detectors

Adult(mid-summer to early fall)

Female(does not fly)

Male (daytime flier)

Distinct “commas”

on both top and

underside of wings

Feathered antennae

First Detectors Mating Behavior

Females do not fly Pheromone attracts males Females lay one egg mass Adults die, eggs overwinter

First Detectors

“Ballooning of larvae”

Populations expand 1¼ miles per year due to larval dispersal

Natural ArtificialTourism

Nursery stock

Household moves

How Do Gypsy Moths Spread?

Life stages are transported by humans 13-16 miles per year

First Detectors Predators and Pathogens

Entomophaga maimaiga NPV (nucleopolyhedrosis virus)

Mammals Birds Amphibians Invertebrates NPV

E. maimaiga

First Detectors

Factors That Influence Spread Rates

Early season temperatures & larval survival

Wind events & larval dispersal

Habitat & host abundance

Spring rains & disease incidence

Predator habitat & predation rates

PEOPLE through artificial introductions

First Detectors

Population Stage

Management Strategy

Management Goal

General infestation

Suppression To protect high value resources by reducing outbreak populations

Building Slow the Spread To reduce the population peaks beginning to coalesce along the “front”

Pre-Infestation Eradication To eliminate isolated outlier populations

National Gypsy Moth Management

First Detectors Management Options

Bacillus thuringiensis var. kurstaki (Btk) Common soil bacterium toxic to GM caterpillars Halts feeding

Disparlure (mating disruption) Targets adults Reduces mating success

Diflubenzuron Interferes with molting Often used in nursery settings

Treatments in Minnesota have kept gypsy moth in check since 1980!

First Detectors Treatments 2013

Slow the Spread area only

No eradications necessary

Mating disruption Covers

St. Louis County Bear Head Lake SP Superior National Forest Cloquet State Forest

First Detectors Which is Gypsy Moth Damage?

0%

0%

0%

A B C

A. Leaf A

B. Leaf B

C. Leaf C

First Detectors Which is Gypsy Moth?

0%

0%

0% A. Tree A

B. Tree B

C. Tree C

C

BA

First Detectors

In What Life Stage of Gypsy Moth Would You Expect to Find Here

20%

20%

20%

40% A. Egg masses

B. Caterpillars

C. Pupae

D. Adults