Asian Defoliators

Sharpening Your Observation Skills

Objectives

• To learn how to recognize key characteristics of Dendrolimus (lappet moths) and Lymantria (gypsy moths)

• To learn how to recognize similar, native, look-alike species and distinguish them from the potential invaders

Introduction

• Defoliation = the removal of all or part of the foliage of a plant

• Herbivore = an animal which eats only plants

• Insect defoliators damage plants by eating leaves or needles

Photo: tent and defoliation on aspen © William M. Ciesla, Forest Health Management International, Bugwood.org

Introduction

Classification based on

• Insect order

• Pattern

• Feeding structure

• Time of year

• Host specificity

Photos: katydid feeding on leaves (top) © Herbert Pase III, Bugwood.org and skeletonizing on European linden (bottom) © Steven Katovich, USDA-FS, Bugwood.org

Defoliation clue: insect order

Most common insect orders which defoliate plants

• Lepidoptera—moths, butterflies

• Hymenoptera—sawflies, wasps

• Coleoptera—beetles

• Orthoptera—katydids, grasshoppers, etc.

• Diptera—flies Photos: pine sawfly (top) © USDA-FS Region 8 - Southern Archive, Bugwood.org and

(bottom) viburnum leaf beetle adults © D.D. O’Brien, Cornell University, Bugwood.org

Defoliation clue: pattern

Defoliation by pattern

• Complete leaf eaten

• Individual holes

• Mining

• Skeletonizing

Photo: complete defoliation on pine caused by spiny caterpillar © William M. Ciesla, Forest Health Management International, Bugwood.org

Defoliation clue: pattern

Complete defoliation Individual holes

Skeletonizing Mining damage

Photos: clockwise from top left © H. Ovidiu, University of Oradea; P. Weston, Cornell University; M. Zubrik, FRI – Slovakia; J. Solomon, US-FS. All images Bugwood.org.

Defoliation clue: feeding structures

Feeding structures

• Tents

• Rolled leaves

• Casebearers

• Free feeders

Photos: eastern tent caterpillars (top) © David Cappaert, Michigan State Univ., Bugwood.org and orangestriped oakworms © Ryan St. Laurent, Cornell University

Defoliation clue: feeding structure

Tents Rolled leaves

Free feeders Casebearers

Photos: clockwise from top left © P. Sloderbeck, Kansas State University; DPIW, Tasmania Archive; W. Upham, KSU; B. McNee, WI-DNR. All images Bugwood.org

Defoliation clue: time of year

Insects cause damage at specific times of the year

• Spring defoliators

• Spring/summer

• Summer

Photo: fall webworm nests © Dawn Dailey O’Brien, Cornell University

LYMANTRIA SPP. & DENDROLIMUS SPP.

Asian defoliators featuring

Asian defoliators (AD) vs native defoliators

• Native defoliators and the established European gypsy moth (Lymantria dispar) frequently defoliate broadleaved trees

• The AD belonging to the genus Lymantria may defoliate broadleaved or coniferous trees

• The ADs in the genus Dendrolimus are conifer feeders

• Total defoliation of conifers is uncommon to rare in the Eastern US―and should alert you that it could likely be an AD introduction

AD vs native defoliators

Native defoliating lappet moths (Lasiocampidae)

– Same family as Dendrolimus

– Forest tent caterpillar is common on oaks

– Eastern tent caterpillar is common on black cherry

Photos: forest tent caterpillar (top) © Franclemont larval slide collection, CUIC and eastern tent caterpillar (bottom) D. D. O’Brien, Cornell University

AD vs native defoliators

• Native defoliators feed primarily on broadleaved trees

• Conifer defoliation is uncommon in the Eastern US

– Pine sawflies (order: Hymenoptera)

• In parts of the western US native Lepidoptera conifer defoliators include the pine silkmoths & Douglas fir tussock moth

AD vs native defoliators

• Defoliation of conifers in the Eastern US should be an instant red flag – Dendrolimus sibiricus, D. punctatus, and D. pini

are obligate conifer feeders

– Gypsy moths native to Asia (Lymantria spp.) will also feed on conifers

• In the event of defoliation of coniferous trees, any Lepidoptera larvae should be collected and identified

© John H. Ghent, USDA Forest Service, Bugwood.org

Conifer defoliation facts

• Coniferous trees are less tolerant of defoliation than deciduous trees.

• Defoliation makes trees more vulnerable to secondary organisms.

• Late season defoliation is less stressful than early season defoliation.

Recognizing AD larvae

• The larvae of the three Dendrolimus spp. are all similar to each other, but very recognizable when compared to native conifer feeders

• Most AD Lymantria spp. larvae are very similar to each other and cannot always be readily differentiated from the already established European gypsy moth

Larvae: Siberian silk moth (Dendrolimus sibiricus)

Photo: © John Ghent, US-FS, Bugwood.org

Larvae: Dendrolimus

Pine-tree lappet moth (Dendrolimus pini)

Masson pine caterpillar (Dendrolimus punctatus)

Photos: © William M. Ciesla, Forest Health Management International, Bugwood.org

Larvae: European gypsy moth (Lymantria dispar dispar)

Photos: © Franclemont larval slide collection, CUIC, Cornell University

SOME NATIVE LYMANTRIA LARVAL LOOK-ALIKES

Sharpening Your Observation skills

Lymantria look-alike: Panthea furcilla (Noctuidae: Pantheinae)

Photos: © Franclemont larval slide collection, CUIC, Cornell University

Lymantria look-alike: Panthea spp.

Lymantria look-alike: Orgyia spp. (Lymantriinae)

Lymantria look-alike: Dasychira spp. (Lymantriinae)

SOME NATIVE DENDROLIMUS LARVAL LOOK-ALIKES

Sharpening Your Observation Skills

Dendrolimus larval look-alike: Tolype sp. (Lasiocampidae)

Tolype velleda

Tolype laricis

Photos: © David Cappaert, Michigan State University, Bugwood.org and Connecticut Agricultural Experiment Station Archive, Connecticut Agricultural Experiment Station, Bugwood.org

Dendrolimus larval look-alike: Artace sp. (Lasiocampidae)

Dot-lined white Artace cribrarius larva Artace colaria female

Photos: Artace cribrarius larva, courtesy of Sean McCann, Bugguide.com and Artace colaria female © CUIC, Cornell University

Dendrolimus larval look-alike: American lappet moth

(Phyllodesma americana: Lasiocampidae)

Photo courtesy of Andrée Reno Sanborn of Barton, Vermont

Dendrolimus larval look-alike: Gloveria (Lasiocampidae)

Gloveria gargamelle larvae

Photos: Gloveria gargamelle courtesy of Valerie Bugh

Dendrolimus larval look-alike: Olceclostera angelica (Apatelodidae)

Photo courtesy of Colin Gillette

ADULT IDENTIFICATION

Dendrolimus spp.

Siberian silk moth (Dendrolimus sibiricus)

Males and females are similar but females are larger, with broader wings.

Wingspan

• male: 40–60 mm

• female: 60–80 mm

Key features

• three dark, notched stripes on the wings

• white spot usually present near center of forewing

© Kent Loeffler, Plant Pathology and Plant-Microbe Biology, Cornell University

Siberian silk moth (Dendrolimus sibiricus)

♀

Photo: Pest and Diseases Image Library, Bugwood.org

Males and females are similar but females are larger, with broader wings. Wingspan • male: 40–60 mm • female: 60–80 mm Key features • three dark, notched

stripes on the wings • white spot usually

present near center of forewing

Pine-tree lappet moth (Dendrolimus pini)

Males and females are similar but females are larger, with broader wings. Wingspan • male: 50–70 mm • female: 70–90 mm Key features • prominent brown bands

located at the base of the forewing

• white spot usually present near center of forewing

Pine-tree lappet moth: brown form

Masson pine caterpillar (Dendrolimus punctatus)

Males and females are similar but females are larger, with broader wings. Wingspan • male: 50–80 mm • female: larger Key features • wings mostly uniform brown • line nearest edge of wing

unconnected • line discontinuous rather

than mostly continuous as in D. sibiricus and D. pini

ADULT LOOK-ALIKES

Dendrolimus spp.

Large look-alike, Southwestern lappet moths (Lasiocampidae)

Caloecia juvenalis

Caloecia entima

Large look-alike, Southwestern lappet moths (Lasiocampidae)

Dicogaster coronada

Quadrina diazoma

Large look-alike, Southwestern lappet moths (Lasiocampidae)

Gloveria arizonensis Gloveria medusa Gloveria gargamelle

Large native non-Lasiocampidae pine feeders

Pine devil (Citheronia sepulcralis) Northern pine sphinx (Lapara bombycoides)

Pandora pine moth (Coloradia pandora)

ADULT IDENTIFICATION

Lymantria spp.

Lymantria (the similar species)

• L. dispar asiatica

• L. dispar japonica

• L. umbrosa

• L. albescens

• L. postalba

The key feature to recognize: arc and dot

dot

arc

Lymantria (the similar species)

Lymantria dispar dispar (EGM) L. d. asiatica L. d. japonica

Lymantria (the similar species)

Lymantria umbrosa L. albescens

L. postalba

Lymantria (the unique, easily identifiable species)

• L. mathura — Rosy gypsy moth

• L. monacha* — Nun moth

• L. xylina

Rosy gypsy moth (Lymantria mathura)

Wingspan

• male FW length: 21–24 mm

• female ~38 mm

Key features

• males yellow hindwings

• females whitish with pink

– immediately recognizable from other AD Lymantria spp.

– no native look-alike species

Lymantria xylina

Wingspan

• male FW length: 25–28 mm

• female: ~35 mm

Key features

• off-white coloration

• single transverse, wavy band on forewing

– No native look-alike species

Nun moth (Lymantria monacha)

Wingspan • male FW length: 18–20

mm • female: 27–29 mm Key features • white forewings with ziz-

zagging lines • arc/dot not as

pronounced • heavy maculation • hindwings are greyish

Nun moth look-alikes

Furcula scolopendrina

Lichnoptera decora

Black zigzag moth (Panthea acronyctoides)

Native tussock moths (Erebidae: Lymantriinae)

Orgyia spp. Key diagnostic features

• white patch in lower corner of forewings, about a quarter of the way from edge (in most species)

• dorsal abdominal tufts of scales

• females are wingless

Dasychira spp. Key diagnostic features

• Dorsal abdominal tufts of scales

Native tussock moths: Orgyia

Orgyia spp.

Key diagnostic feature

• patch of white scales on the bottom edge of the forewing

Lymantria dispar dispar

Key diagnostic feature

• no white patch

• arc dot feature

Native tussock moths: Orgyia

Orgyia leucostigma

Orgyia definita

Orgyia pseudotsugata

Orgyia falcata Orgyia antiqua

Native tussock moths: Dasychira

Dasychira spp. Key diagnostic features • dorsal tufts of scales • stockier than Orgyia spp. • females are winged

Lymantria dispar dispar Key diagnostic features • no dorsal tufts • arc dot feature

Native tussock moths: Dasychira

Dasychira tephra Dasychira obliquata

Dasychira vagans Dasychira plagiata

Dasychira grisefacta

Supporting materials

Visit www.FirstDetector.org for materials to supplement this presentation including posters, diagnostic photo guides and promotional materials.

Authors

Ryan St. Laurent ‘16, Department of Entomology, Cornell University

Rachel McCarthy, NPDN Training and Education Coordinator, Department of Plant Pathology and Plant-Microbe Biology, Cornell University

Reviewed by

John H. Ghent, USDA Forest Service Entomologist, Ashville, North Carolina

References

• https://caps.ceris.purdue.edu/survey/asian-defoliator/reference/2013 • Ferguson D.C. (1978) Noctuoidea, Lymantriidae. In: Hodges RW et al. (Eds) The

moths of North America, fascicle 22.2. Wedge Entomological Research Foundation, Washington, DC.

• Franclemont, J.G. (1973). The Moths of America North of Mexico. 20.1. Mimallonoidea and Bombycoidea, Apatelodidae, Bombycidae, Lasiocampidae. London, E.W. Classey & R.B.D.

• Pogue, M. G. and P. W. Schaefer. (2007) A review of selected species of Lymantria Hübner [1819] including three new species (Lepidoptera: Noctuidae: Lymantriinae) from subtropical and temperate regions of Asia, some potentially invasive to North America. Forest Health Technology Enterprise TeamTechnology Transfer. FHTET-2006-07.

• Wagner, D. L. (2005) Caterpillars of Eastern North America: A Guide to Identification and Natural History. Princeton University Press.

• Wagner, D. L., D. F. Schweitzer, J. B. Sullivan, and R. C. Reardon. (2011) Owlet Caterpillars of Eastern North America (Lepidoptera: Noctuidae). Princeton University Press.

Acknowledgements

Funding for the Sharpening Your Observations Skills project was provided by the USDA 10201 Farm Bill, cooperative agreement 13-8236-0984-CA.