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European Gypsy Moth ( Lymantria dispar). Why be Concerned about Gypsy Moth?. Tree defoliator Attacks over 300 species of woody plants Increases susceptibility to secondary pests and pathogens Native range and established areas: appears as an outbreak pest
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Why be Concerned about Gypsy Moth? • Tree defoliator • Attacks over 300 species of woody plants • Increases susceptibility to secondary pests and pathogens • Native range and established areas: appears as an outbreak pest • Greatest damage occurs at first introduction • 425,000 acres were defoliated in the U.S. in 2009
Impacts • Gypsy moth is a tree defoliator • Trees are stressed, leaving them susceptible to other pests and diseases July Widespread defoliation in Wisconsin caused by gypsy moth • Each caterpillar consumes 3 square feet of foliage!
Where is Gypsy Moth Established? • Europe and north Africa (native) • U.S. and Canada (invasive)
Identifying Gypsy Moth • Egg Masses • Caterpillars • Pupae • Adults (males vs. females)
Egg Masses(laid in late summer, hatch in late spring) Each female lays one mass containing 500-1000 eggs Overwinter in a protected spot Emergence
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
Spiny elm caterpillar Eastern tent caterpillar Whitemarked tussock moth fg = 2” fg = 1 3/4” fg = 1 1/3” Yellownecked caterpillar fg = 1 3/4” Forest tent caterpillar Fall webworm, fg = 1” fg = 1 3/4” Caterpillar Lookalikes Gypsy moth, fg = 2” MN Dept of Ag. Whitney Cranshaw
Feeding Damage • Entire leaf to midrib • Can cover acres of woody habitat
Pupa (Cocoon)(summer months) • Males smaller than females • Sparse silken threads • Found in protected spots • Bark crevices • Duff layer • 2 weeks
Feathered antennae Distinct “commas” on both top and underside of wings Adult(mid-summer to early fall) Female (does not fly) Male (daytime flier)
Mating Behavior • Females do not fly • Pheromone attracts males • Females lay one egg mass • Adults die, eggs overwinter
Early Detection • Pheromone Lure Traps • Male moths are caught as they try to find a mate • Sticky interior
2006-2011 Trap Catch Trends 2008 2006 2007 2009 2010 2011
Gypsy Moth in Minnesota • Counts increase as main population nears • Population growth increasing • Meteorological explanation?
How Do Gypsy Moths Spread? Natural Artificial Tourism “Ballooning of larvae” Nursery stock Household moves Life stages are transported by humans 13-16 miles per year Populations expand 1¼ miles per year due to larval dispersal
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
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!
Treatments 2012 • Slow the Spread area only • No eradications necessary • Mating disruption • Covers • Jay Cooke SP • Fond du Lac Reservation • Superior National Forest • Cloquet State Forest
Which is Gypsy Moth? B A C
What Life Stage of Gypsy Moth Would You Look For? • Egg Mass • Caterpillar • Pupa • Adult John Kyhl, USFS
How would you control this outbreak? A. Btk B.Diflubenzuron C. Mating Disruption D. It depends on the location
Summary • Gypsy moth is a destructive forest pest • Confidence in early detection systems • Minnesota has prime habitat for defoliation • Management takes advantage of behavior • Larval feeding • Mating • People are the main source of long-distance transportation and spread of gypsy moth • Call 888-545-MOTH or visit www.mda.state.mn.us/gypsymoth for more information about trapping and treatment