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GYPSY MOTH UPDATESPRING 2017
Gail K Reynolds
Middlesex County Extension Center
1066 Saybrook Road, PO. Box 70HADDAM, CT 06438-0070PHONE 860.345.4511mastergardener.uconn.edu
GYPSY MOTH HISTORICAL SYNOPSIS
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• Gypsy Moth (Lymantria dispar) introduced to Massachusetts in 1869 as a “get-rich-quick-scheme” to create silk from webs.
• The gypsy moth does not produce much silk, larvae escaped in 1882, and defoliations in the 1880s were soon noted.
• First defoliations in CT were observed in 1905 and increased with the worst outbreak in 1981 with 1.5 million acres defoliated. This was about half the state.
Graph courtesy of CAES
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Pupae on Parthenocissuscinquefolia, June 2016
Early Instar Caterpillar on Rosa rugosa, June 2015
Photos by Gail Reynolds
• The gypsy moth caterpillar has 5 or 6 instars• Male has 5 instars• Female has 6 instars
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Female gypsy moth laying eggs on bag strap, June 2016
The adult moths exist to reproduce
Photos by Gail Reynolds
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Female gypsy moths laying eggs on tree, Higganum, CT July 2016
Photo by Gail Reynolds
RECENT DAMAGE2015-2016
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• Drought conditions in 2015-2016• Gypsy moth outbreaks substantial in certain parts of CT
Map courtesy of USDA Map courtesy of CAES
PHYSICAL CONTROLS
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• Scrape egg masses and drown in 50% oil/50% water mixture• Insecticidal soap; canola, mineral, soybean oils per CAES
• Burlap barrier• Dispose of caterpillars in oil/water or soapy water mixture
• Sticky band, which should be in conjunction with a barrier• Dispose of caterpillars in oil/water or soapy water mixture
BIOLOGICAL CONTROLS
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• Entomophaga maimaiga fungus• Requires moist spring for fungal spores to propagate
• Nucleopolyhedrosis virus (NPV)• Characterized by V-shaped dead caterpillars• GYPCHECK product; not on CAES list
• Parasitoid wasps• Ten insect parasitoids from Europe and Asia released many years ago• Not all eggs in egg mass are parasitized
• Bacillus thuringiensis var. karastaki (BtK)• Must be ingested by the caterpillar to have an effect• Kills all caterpillars • Must be applied when the caterpillars have just emerged
Parasitized egg mass January 2017Photo by Gail Reynolds
CHEMICAL CONTROLS
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• Spinosad, azadirachtin, and pyrethrins* labelled for gypsy moth at larval stage• Not specific to gypsy moth
• Several restricted use products available to licensed pesticide applicators
• Neo-nicotinoid pesticide use restricted
*See Table 1 in Stafford, Kirby, The Gypsy Moth, Connecticut Agricultural Experiment Station, updated March 2017.
MYTHS
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• Gypsy moth caterpillars bite• The caterpillar hairs contain histamine, which may cause a skin
reaction
• Gypsy moth caterpillars have a nest• Gypsy moths are being confused with eastern tent caterpillars, which
emerge at the same time
• The fungus won’t work until the following year• The spores of E. maimaiga are extremely hardy and last in the soil for
up to 10 years and will active as long as sufficient moisture exists
WHAT KIND OF YEAR WILL 2017 BE?
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Egg mass showing signs of emergent caterpillars on a pin oak at the Middlesex County Extension Center, May 4, 2017Photo by Gail Reynolds
WHAT KIND OF YEAR WILL 2017 BE?
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• Many, many egg cases so some defoliation appears inevitable• Windy weather when caterpillars first emerged promoted skin irritations and
notice of the caterpillars• Moist spring will promote fungal growth!
Photo licensed by Creative Commons.Picture by Raindanceby s forever
FUNNIEST GYPSY MOTH STORY
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Waterlogged gypsy moth caterpillar poop received in a jar of pool water at the Middlesex County Extension Center Master Gardener Office in 2016Photo by Gail Reynolds
ADDITIONAL INFORMATION
Connecticut Agricultural Experiment Stationhttp://www.ct.gov/caes/lib/caes/documents/publications/fact_sheets/entomology/gypsy_moth_fact_sheet.pdfhttp://www.ct.gov/caes/lib/caes/documents/publications/press_releases/2016/caes_press_release_gypsy_moth_2016_outbreak.pdfwww.ct.gov/caes/gypsymoth
UConn Home and Garden Centerhttp://www.ladybug.uconn.edu/FactSheets/gypsy-moth.php
DEEPwww.ct.gov/deep/gypsymoths
Alsohttp://www.nbcconnecticut.com/news/local/Health-Department-Releases-Information-on-Gypsy-Moths--421386314.html?_osource=SocialFlowFB_CTBrandwww.nytimes.com/1982/05/27/garden/gypsy-moth-larva-can-cause-a-rash.html
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