Gypsy Moth in Toronto, 2007 World distribution of gypsy moth Gypsy Moth Distribution in Canada: CFIA Quarantine Zones 2005 Gypsy Moth in Canada Gypsy Moth in Ontario: 1981-2006 (Moderate-to-Severe defoliation) 400,000 350,000 300,000 Hectares 250,000 200,000 150,000 100,000 50,000 0 81 83 85 87 89 91 93 95 97 99 01 03 05 19 19 19 19 19 19 19 19 19 19 20 20 20 Year Adults (July/Aug.) The female is creamy white and does not fly but emits a pheromone to attract the males. A single male can mate with many females Egg masses (July – April) Egg masses contain between 50 and 1000 eggs. The egg masses are covered with hairs from the female’s abdomen and can survive temperatures as low as -30oC. New and Old Egg Masses New: Firm to touch Eggs pop when squeezed Dark beige colour Old May be soft to touch Exit holes present Ragged bleached appearance Small Larvae (May) This stage lasts 7-10 days after eggs hatch in May. They linger around the egg mass for several days if weather is cool or rainy, then climb trees where they can drop on silken threads and disperse in the wind. Mature larva (May/June) Large larvae feed at night for 4 to 6 weeks and generally rest during the day or wander when populations are high. GM Larval feeding During the caterpillar stage, each gypsy moth eats about one square meter of foliage Pupa (June/July) Larvae are changing to moths, generally late July to early August. After about 10 days the adults emerge from the pupal case. Natural Control Favoured host trees All oaks All aspen and poplar White birch All willow White pine Beech Basswood All apple Impacts: Environment Reduced tree vigor; Tree crown dieback and mortality; Damage to other trees (bark); +ve and –ve impacts on wildlife; Reduced shade, dry soils; Increased stream temperatures and reduced water quality; Increased water fluctuations. Impacts: Human Health Allergic reactions to hairs, wing scales; Rashes and skin irritations; Respiratory tract irritations; Eye irritations; Psychological reactions; Slippery sidewalks and roadways; Hazard trees – dead branches and trees. Impacts: Economic Costs to homeowners: Pesticide treatments; Cleanup of insect body parts; Egg mass removal; Pruning dead branches; Dead tree removal and replacement Liability for damage to property and personal injury. Impacts: Economic Costs to the Municipality: Tree removal and replacement; Reduced use of damaged parklands and recreational facilities; Increased tree inspections; Tree pruning and maintenance; Liability for damage to property and personal injury; Tourism: First impressions. Good decisions are based on good information! Delineate the outbreak Assess egg mass densities Assess egg mass size Assess egg mass distribution New/old egg mass ratio Pathogen status Management options Management constraints Available resources Action Thresholds 100 90 80 Defoliation % 70 60 50 40 30 20 10 0 25 125 250 1250 2500 5000 12000 18500 25000 Egg masses per ha Nuisance abatement Foliage protection Prevention of tree mortality Urban vs. natural forest Management Options: IPM Do nothing Maintain or enhance tree health (PHC) Destroy Egg masses Barrier bands Burlap skirts Homeowner sprays Property maintenance Ground/Aerial spraying The Insecticide: Foray 48B BioForest recommends the biological insecticide Bacillus thuringiensis var. kurstaki (Btk): Naturally occurring bacteria Harmless to fish, birds, mammals and most non-target insects Approved by PMRA, EPA, WHO, OPAC Biodegradable Must be ingested – delayed mortality What's in Bt? Mostly water (about 75%) About 3% Bt Inerts are added to maintain product quality and microbial purity: All are food grade materials (EPA List 4) E.g. Alfalfa, acetic acid, beer, bread crumbs, decanol, glycerin, lactose… Rachel Carson described Btk in Silent Spring as an “… important answer to the problems of such forest insects as the budworms and the gypsy moth.” Has Bt been sprayed over inhabited areas before? Gypsy moth programs in USA and Canada Victoria B.C. 1999 Ministry of Environment 1999 Auckland N.Z. 1998 (up to 32 appl.) Ministry of Ag and Forestry 2001 Waskesiu, Prince Albert National Park, 2003-2005 Village of Candle Lake, Saskatchewan – 2003 + 2004 U.S. gypsy moth programs Mississauga, 2006 Factors influencing spray effectiveness: Pest population density Insecticide, dose and applications Aircraft and navigation Weather (oC, RH, wind) Block size Insect and host development What can you expect for results? Greener trees Fewer caterpillars Fewer egg masses Some gypsy moth will survive Some defoliation will occur Some trees will die. Treated vs. Untreated Potential Constraints Technical: Aircraft availability Financial: Cost share arrangement Operational: Pearson & major highways Time: Delays in acquiring permits Legal: Transport Canada exemption and actions initiated by opponents Political:?
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