Defoliator
Guides
Macremphytus
Dogwood Sawflies
Macremphytus is a genus of common sawflies in the family Tenthredinidae, comprising at least four described species. The best-known member is Macremphytus tarsatus, commonly called the dogwood sawfly, which is a significant defoliator of dogwood trees in North America. Sawflies in this genus are herbivorous, with larvae feeding on leaves of woody plants. The genus exhibits distinctive larval traits including waxy secretions and overwintering behaviors in wood.
Macrophya
Macrophya is a genus of sawflies in the family Tenthredinidae. The genus contains numerous species distributed across Europe, Asia, and North America, with particularly high diversity in China. Several species have been documented as pests of woody plants, including Macrophya satoi, which damages Japanese ash (Fraxinus japonica). The larvae of many species feed on foliage of trees and shrubs. Some species have had their genomes sequenced, including M. alboannulata and M. annulata.
Macrophya nigra
Macrophya nigra is a sawfly in the family Tenthredinidae whose larvae are specialized herbivores of turtlehead plants (Chelone spp.). Larval activity peaks in midsummer, with feeding damage capable of reducing host plant reproductive output. The species has been documented in Canada and is known to interact competitively with other herbivores sharing the same host plants.
Malacosoma
Tent Caterpillar Moths
Malacosoma is a genus of tent caterpillar moths in the family Lasiocampidae, first described by Jacob Hübner in 1820. Larvae are commonly known as tent caterpillars and are recognized for their communal nesting behavior in silken tents. The genus includes both oligophagous species with restricted host ranges and polyphagous species with broader diets. Several species are significant forestry pests capable of causing large-scale defoliation across North America and Eurasia.
Malacosoma californica
Western Tent Caterpillar Moth, Western Tent Caterpillar
Malacosoma californica, the western tent caterpillar, is a moth species in the family Lasiocampidae found in western North America. The larvae are social caterpillars that construct conspicuous silken tents in host trees and shrubs. They undergo cyclical population outbreaks and are significant defoliators of various woody plants. The species overwinters as eggs and completes one generation per year.
Malacosoma constricta
Pacific tent caterpillar
Malacosoma constricta, the Pacific tent caterpillar, is a moth species endemic to western North America, recorded from California, Oregon, and Washington. The species is specialized on oaks (Quercus spp.) as larval hosts. Two subspecies are recognized in California: M. c. austrinum occurs from Santa Barbara County southward, while M. c. constrictum occurs from Los Angeles County northward. The larvae construct small silken tents for group living and thermoregulation, feeding gregariously on oak foliage.
Malacosoma disstria
Forest Tent Caterpillar Moth
The forest tent caterpillar moth (Malacosoma disstria) is a native North American lasiocampid moth known for its periodic outbreak populations. Unlike its congener the eastern tent caterpillar, it does not construct true silken tents; instead, larvae form silk mats on which they rest between feeding bouts. The species is highly polyphagous on deciduous trees and exhibits gregarious behavior in early instars, becoming more solitary in later stages. Population cycles are regulated by natural enemies including parasitoid wasps, flies, and pathogens.
Malacosoma incurva
Southwestern Tent Caterpillar Moth
Malacosoma incurva is a tent caterpillar moth native to the southwestern United States. Adults have a wingspan of approximately 27 mm. The larvae construct silken tents and feed on specific host plants including Fremont cottonwood, willows, and Prunus species. The species was first described by Henry Edwards in 1882 and is distinguished from related eastern and western tent caterpillars by its restricted geographic range.
Malacosoma tigris
Sonoran Tent Caterpillar
Malacosoma tigris, the Sonoran tent caterpillar, is a tent caterpillar species in the moth family Lasiocampidae. It is one of several North American Malacosoma species that construct silken tents on host plants. The species is distinguished by its distribution in the southwestern United States and Mexico. Like related tent caterpillars, it exhibits social larval behavior and undergoes complete metamorphosis with egg, larva, pupa, and adult stages.
Melanchroia chephise
white-tipped black, snowbush spanworm
Melanchroia chephise is a moth in the family Geometridae, commonly known as the white-tipped black or snowbush spanworm. It ranges from the southern United States through Central America to Paraguay. The adult exhibits striking black wings with white apical patches, while the gregarious larvae feed on foliage of plants in the Phyllanthaceae family, particularly Breynia and Phyllanthus species. Despite occasional outbreaks that defoliate ornamental plantings, the species typically causes no lasting harm to hosts and poses no risk to humans.
Monema
slug moths, cup moths
Monema is a genus of medium-sized yellowish moths in the family Limacodidae, commonly known as slug moths or cup moths. The genus comprises at least four described species distributed across East and Southeast Asia. Members are notable for their larval morphology: caterpillars are flattened, legless in appearance, and move using suckers and liquefied silk lubricant in a wave-like motion resembling slugs. The genus includes significant forestry pests, particularly Monema flavescens, which has been introduced to North America.
Monema flavescens
Oriental moth
Monema flavescens is a medium-sized moth in the family Limacodidae (slug moths or cup moths), native to East Asia. Adults exhibit yellowish coloration typical of the genus, with males having a wingspan of 30–32 mm and females 35–39 mm. The larvae are polyphagous defoliators of broadleaf trees, bearing urticating spines that can affect human health. The species has one to two generations per year depending on region, with adults active from late June to August. It has been introduced to Massachusetts, USA, and is considered a potential quarantine pest for Europe.
Monophadnoides rubi
raspberry sawfly, Dark Bramble-cutter
Monophadnoides rubi, commonly known as the raspberry sawfly or Dark Bramble-cutter, is a species of common sawfly in the family Tenthredinidae. It is a defoliating pest of Rubus species, particularly raspberry and blackberry. The species is native to North America and has been documented across Canada and the United States.
Neoalbertia constans
Grape Leaf Skeletonizer
Neoalbertia constans is a zygaenid moth species commonly known as the Grape Leaf Skeletonizer. The species was originally described as Lycomorpha constans by Edwards in 1881 and later transferred to the genus Neoalbertia. It is recognized as a defoliating pest of grapevines in North America. The common name reflects the distinctive feeding damage caused by larvae, which consume leaf tissue between veins while leaving the vascular framework intact.
Neodiprion
Neodiprion is a genus of conifer sawflies in the family Diprionidae, containing approximately 25 species native to North America. Larvae are specialized folivores of pine needles, with most species exhibiting strong host associations with particular Pinus species. Several species, including N. lecontei and N. sertifer, are significant forest pests capable of causing extensive defoliation during outbreak years. The genus is distinguished from related sawflies by morphological and ecological traits associated with conifer specialization.
Neodiprion abbotii
Neodiprion abbotii is a conifer sawfly species in the family Diprionidae. As a member of the Diprioninae subfamily, it belongs to a group of primitive Hymenoptera that are among the few folivores capable of feeding on conifer needles. Adults are small, stingless wasps with a saw-like ovipositor used to insert eggs into conifer foliage. Larvae are caterpillar-like but possess more pairs of prolegs than Lepidoptera larvae and lack crochets.
Neodiprion abietis
balsam fir sawfly
Neodiprion abietis, the balsam fir sawfly, is a conifer-feeding sawfly native to North America. Larvae are gregarious defoliators that feed preferentially on balsam fir (Abies balsamea) needles, with outbreaks capable of causing significant tree mortality in eastern Canadian forests. The species exhibits sexual dimorphism in development, with females typically undergoing six instars over 35 days and males five instars over 30 days. Population dynamics are strongly regulated by a host-specific nucleopolyhedrovirus (NeabNPV), which has been developed as a registered biological insecticide (Abietiv™) for outbreak management.
Neodiprion compar
redheaded pine sawfly
Neodiprion compar is a conifer sawfly in the family Diprionidae, commonly known as the redheaded pine sawfly. The species is native to eastern North America and feeds primarily on pine needles. Larvae are gregarious and can cause significant defoliation during outbreaks, though populations are typically moderated by natural enemies. The species is one of approximately 25 conifer sawfly species found in eastern U.S. forests.
Neodiprion edulicolus
Pinyon Sawfly, Pinyon Pine Sawfly
Neodiprion edulicolus, the pinyon pine sawfly, is a conifer-feeding sawfly endemic to the Intermountain Region of western North America. The species periodically undergoes population outbreaks causing extensive defoliation of singleleaf pinyon pine (Pinus monophylla), with over 100,000 acres affected during documented events in 1965-1966 in eastern Nevada. Unlike bark beetles and fungi that typically dominate conifer health concerns, this folivore can render host trees commercially unfit for Christmas tree sales. Outbreaks have historically been short-lived, with populations declining due to climatic factors and parasitoid pressure.
Neodiprion excitans
Black-headed Pine Sawfly
Neodiprion excitans, commonly known as the Black-headed Pine Sawfly, is a conifer-feeding sawfly in the family Diprionidae. It is native to eastern North America, with documented populations in North Carolina and surrounding regions. Like other members of its genus, it is a folivore that feeds on pine needles and can cause significant defoliation during outbreak conditions. The species has been studied for its population dynamics and ecological interactions in pine forest ecosystems.
Neodiprion fabricii
Fabricius's Sawfly
Neodiprion fabricii is a conifer sawfly species in the family Diprionidae, native to eastern North America. The larvae are folivores that feed on pine needles, with young larvae consuming partial needles and older larvae eating entire needles. This species is one of approximately 25 conifer sawfly species found in eastern U.S. forests and occasionally contributes to localized defoliation events. Adults are stingless wasps with a saw-like ovipositor used to insert eggs into conifer foliage.
Neodiprion hetricki
Neodiprion hetricki is a species of conifer sawfly in the family Diprionidae, described by Ross in 1955. Like other members of the genus Neodiprion, it is a folivore specialized on conifer needles. The species is part of a diverse sawfly fauna in eastern North America that includes at least 25 conifer-feeding species. Specific biological details for N. hetricki remain poorly documented compared to better-studied congeners such as N. lecontei.
Neodiprion lecontei
red-headed pine sawfly, Leconte's sawfly
Neodiprion lecontei is a pine-feeding sawfly native to eastern North America, commonly known as the red-headed pine sawfly. Adults are small (5–8.5 mm), sexually dimorphic, and active in spring and summer. Larvae are gregarious defoliators of pine needles, capable of stripping entire branches and causing significant damage to young trees and plantations. The species exhibits complex population dynamics with one to three generations per year depending on latitude, and has been extensively studied as a model for host-associated differentiation, gene expression decoupling across life stages, and baculovirus pathology.
Neodiprion nanulus
Red Pine Sawfly
Neodiprion nanulus, commonly known as the Red Pine Sawfly, is a conifer-feeding sawfly in the family Diprionidae. It is a specialist herbivore associated with red pine (Pinus resinosa). The species has been documented in the Maritime Provinces of Canada, with an isolated infestation studied near Fredericton, New Brunswick. Like other members of the genus, it likely undergoes larval development in gregarious groups and overwinters in cocoons in the duff beneath host trees.
Neodiprion pinetum
White Pine Sawfly
Neodiprion pinetum is a conifer-feeding sawfly native to eastern North America. Adults are broad-bodied, stingless wasps with females bearing a saw-like ovipositor used to insert eggs into pine needles. Larvae are creamy-yellow with black heads and four longitudinal rows of black spots, resembling caterpillars but possessing more prolegs. The species is frequently monophagous on eastern white pine (Pinus strobus), though larvae have been documented on several other pine species. Localized outbreaks occur regularly and can kill small stands of host trees, though natural enemies including egg and larval parasitoids typically provide substantial biological control.
Neodiprion pratti
Virginia pine sawfly, jack pine sawfly
Neodiprion pratti is a conifer sawfly native to North America with documented populations in Canada and the eastern United States. The species exhibits complex host-associated population structure, with distinct populations adapted to specific pine hosts including Virginia pine (Pinus virginiana), jack pine (Pinus banksiana), sand pine (Pinus clausa), slash pine (Pinus elliottii), and longleaf pine (Pinus palustris). Populations show significant variation in life history, with northern forms typically univoltine and a distinctive West Florida population exhibiting winter-active phenology with adults emerging in October-November.
Neodiprion virginianus
Neodiprion virginianus is a conifer sawfly (Hymenoptera: Diprionidae) that feeds on jack pine (Pinus banksiana). It is part of a species complex with variable taxonomy. The species has been documented causing localized defoliation outbreaks in northeastern North America, with populations capable of sudden collapse. Larvae are gregarious folivores that consume pine needles.
Nepytia
false hemlock loopers, false pine loopers
Nepytia is a genus of geometrid moths (loopers) in the family Geometridae, established by George Duryea Hulst in 1896. The genus includes at least 13 described species distributed in North America. Several species, notably N. janetae and N. freemani, have been documented as forest defoliators capable of outbreak population dynamics that cause significant damage to coniferous trees. The genus exhibits considerable variation in life history traits, with some species being summer feeders and others, uniquely among studied Nepytia, feeding during autumn and winter at high elevations.
Nepytia canosaria
False Hemlock Looper Moth, false hemlock looper
Nepytia canosaria is a North American geometrid moth commonly known as the false hemlock looper. The species occurs across a broad transcontinental range from northeastern Alberta to the Atlantic provinces, extending south through New England. Adults are active in late summer, with flight records from August through September. The larval stage feeds primarily on conifers including balsam fir, eastern hemlock, and various spruce species.
Nepytia janetae
Nepytia janetae is a geometrid moth species that has transitioned from an innocuous, poorly studied insect to a significant forest pest in the southwestern United States. Since 1996, four major outbreaks have caused extensive defoliation and mortality of conifer trees across tens of thousands of acres in Arizona and New Mexico mountain ranges. The species exhibits an unusual life history as a univoltine, autumn- and winter-feeding looper at high elevations where temperatures regularly approach or fall below 0°F. Outbreaks appear associated with reduced snowpack, though the precise climatic mechanisms remain unclear.
Nepytia janetae
Janeta's looper moth
Nepytia janetae is a geometrid moth in the family Geometridae native to southwestern United States mountain ranges. Prior to 1996, it was an inconspicuous species with little ecological impact. Since 1996, four major outbreaks have caused extensive defoliation of conifer forests across Arizona and New Mexico, killing tens of thousands of acres of trees. The species exhibits an unusual winter-feeding larval stage, active when minimum temperatures approach or drop below 0°F. Outbreak termination occurs primarily through parasitism, viral infection, larval starvation, and occasionally heavy rain during egg deposition.
Nepytia pellucidaria
false pine looper, Boreal Pine Looper Moth
Nepytia pellucidaria is a geometrid moth commonly known as the false pine looper. The species was first described by Alpheus Spring Packard in 1873. It occurs in northeastern North America, where its larvae feed on hard pines including pitch pine and red pine. The species has a wingspan of approximately 34–39 mm.
Nepytia phantasmaria
phantom hemlock looper
Nepytia phantasmaria is a geometrid moth native to North America, described by Herman Strecker in 1899. It is commonly known as the phantom hemlock looper. The species is part of the looper moth group, with larvae that are defoliators of conifer foliage. Its activity patterns have been studied in relation to environmental conditions, showing associations with sunset and sunrise periods.
Noctuidae
owlet moths, cutworms, armyworms
Noctuidae is a large family of moths in the superfamily Noctuoidea, currently comprising approximately 1,089 genera and 11,772 species. The family is taxonomically unstable, having recently lost several subfamilies (Lymantriinae, Catocalinae, Calpinae) to the family Erebidae, making it now the second-largest family in Noctuoidea rather than the largest in Lepidoptera. Adults are predominantly nocturnal with cryptic brown, grey, or black coloration, though some tropical subfamilies exhibit bright coloration. Larvae are commonly known as cutworms or armyworms, with many species being significant agricultural pests.
Numia terebintharia
A Neotropical geometrid moth in the subfamily Ennominae, first recorded in Brazil from the Caatinga region in 2021. Adults are small green moths with approximately 2.5 cm wingspan; females possess an apical spot on the forewings. The species was previously known from the Caribbean, Florida (USA), Haiti, and Costa Rica. Caterpillars are external leaf-feeders that can cause extensive defoliation of host plants.
Odontopus calceatus
Yellow Poplar Weevil, Sassafras Mining Weevil, Tuliptree Leafminer, Tulip Tree Weevil, Magnolia Leaf Miner
A small weevil in the family Curculionidae, known for feeding on and mining the leaves of tulip tree (Liriodendron tulipifera), sassafras (Sassafras albidum), and magnolia species. Adults are most visible in spring when they emerge to feed on host foliage, causing distinctive notching damage along leaf edges. The species is widespread in eastern North America and occasionally reaches outbreak densities that cause noticeable defoliation.
Operophtera
winter moths
Operophtera is a genus of geometrid moths comprising approximately four recognized species, including the economically significant winter moth (O. brumata) and Bruce spanworm (O. bruceata). The genus is notable for its unusual winter-active adult phenology, with adults emerging and mating during cold months when most other Lepidoptera are dormant. Several species have been introduced outside their native ranges, with O. brumata established as an invasive defoliator in North America. The genus has become a model system for studying hybrid zone dynamics, as O. brumata and O. bruceata form a documented clinal hybrid zone in the northeastern United States.
Operophtera bruceata
Bruce spanworm, Bruce Spanworm Moth, native winter moth, hunter's moth
Operophtera bruceata is a native North American geometrid moth commonly known as the Bruce spanworm. Females are wingless and flightless, while males have fully developed wings with a 25–30 mm wingspan. The species is notable for forming a documented clinal hybrid zone with the invasive congener winter moth (O. brumata) in the northeastern United States. Population outbreaks have caused significant defoliation of deciduous forests, with one outbreak in Alberta peaking in 1958 at approximately 50,000 square miles of moderate to heavy infestation.
Orgyia
tussock moths, vapourer moths
Orgyia is a genus of tussock moths in the family Erebidae, characterized by pronounced sexual dimorphism: males are fully winged and diurnal, while females are wingless with reduced, scale-like wings and remain flightless. The genus was established by Ochsenheimer in 1810 and contains cosmopolitan species distributed across most global regions except the Neotropics. Several species are significant forest and agricultural pests, notably Orgyia pseudotsugata (Douglas-fir Tussock Moth), which undergoes periodic outbreaks in western North America.
Orgyia leucostigma
White-marked Tussock Moth
A tussock moth species native to North America, distinguished by sexually dimorphic adults: females are flightless with reduced wings, while males are winged and active. The caterpillar is conspicuously colored with defensive hair tufts and can cause allergic reactions in humans. Multiple generations occur annually in eastern North America, with outbreaks occasionally reported on urban trees.
Orgyia vetusta
Western Tussock Moth
Orgyia vetusta, the Western Tussock Moth, is a species of tussock moth in the family Erebidae. It is native to western North America, ranging from British Columbia through the Pacific States to New Mexico, with an isolated population in Idaho. The species is known to undergo periodic outbreaks, and females are wingless while males possess functional wings. Larvae are notable for their distinctive hair tufts and tussocks.
Oxydia
Oxydia is a genus of geometrid moths in the family Geometridae, first described by Achille Guenée in 1857. Species in this genus are distributed across the Americas, with several species recognized as forest pests of economic importance. The genus includes defoliator species that attack conifers, eucalyptus, and other woody plants. Larvae are commonly known as loopers or measuring worms due to their characteristic looping gait.
Oxydia vesulia
spurge spanworm moth
Oxydia vesulia is a geometrid moth with broad distribution across the Americas. In Brazil, it is a secondary pest of eucalyptus plantations, causing economic damage during population outbreaks. The species has been evaluated as a potential biological control agent for Brazilian peppertree but was rejected due to its wide host range spanning multiple plant families. It serves as host for the parasitoid Tetrastichus howardi, which has been investigated for integrated pest management.
Paectes abrostoloides
Large Paectes Moth, Sweetgum Defoliator
Paectes abrostoloides is a small moth in the family Euteliidae, first described by Achille Guenée in 1852. Adults have a wingspan of 27–32 mm and are active from April to October across eastern and central North America. The species is notable for its larval association with sweetgum trees (Liquidambar styraciflua), earning it the common name 'Sweetgum Defoliator.'
Paleacrita vernata
Spring Cankerworm, Spring Cankerworm Moth
Paleacrita vernata is a geometrid moth known as the spring cankerworm. Males have functional wings and fly from February to late May, while females are wingless and climb tree trunks to lay eggs. The larvae are defoliators of deciduous trees and shrubs, with documented feeding on Acer, Ulmus, Betula, Prunus, and Quercus species. The species has been observed using flax as a secondary host, indicating broader host flexibility than previously recognized.
Panthea
Panthea is a genus of owlet moths in the family Noctuidae, subfamily Pantheinae. The genus name derives from Greek and Persian, meaning 'of all gods.' Species within Panthea are primarily distributed in North America, with some Neotropical representatives including recently described species from Honduras and the Dominican Republic. The genus includes notable species such as Panthea furcilla (eastern panthea or tufted white pine caterpillar) and Panthea acronyctoides (black zigzag or tufted spruce caterpillar), whose larvae feed on conifer hosts.
Paropsis atomaria
Dotted Paropsine Leaf Beetle
Paropsis atomaria is a leaf beetle in the subfamily Chrysomelinae, native to eastern Australia. The species name 'atomaria' refers to its speckled or freckled appearance. It has become an economically significant pest of Eucalyptus plantations in Queensland and New South Wales, and has been introduced to the west coast of North America. Females produce up to 600 eggs, deposited at leaf or twig tips. The species typically completes two generations per summer across most of its range.
Phigalia
Phigalia is a genus of geometer moths in the family Geometridae, established by Duponchel in 1829. Species in this genus are primarily North American and European, with several exhibiting distinctive life history traits including winter-emerging adults and, in some species, wingless females. The genus includes notable species such as the Spring Cankerworm (P. titea) and the Small Phigalia (P. strigataria), both of which are early-season defoliators of deciduous trees.
Phigalia titea
Half-wing Moth, Spiny Looper
Phigalia titea, commonly known as the Half-wing Moth or Spiny Looper, is a geometrid moth native to eastern North America. Adult males have fully developed wings with an average wingspan of approximately 34 mm, while females are wingless (apterous). The species is notable for its exceptionally early adult activity period in late winter and early spring, making it one of the first moths to appear each year. Larvae are polyphagous loopers (inchworms) that feed on a wide variety of deciduous hardwood trees and can cause significant defoliation during outbreak years.
Phratora
Phratora is a genus of leaf beetles (Chrysomelidae) distributed across the Northern Hemisphere in cool, moist regions where their host plants occur. The genus is synonymous with Phyllodecta. Species in this genus feed primarily on willows (Salix), poplars (Populus), or birch (Betula), with host plant associations showing evolutionary conservation—closely related beetle species tend to feed on closely related plant species. European species are difficult to distinguish by external morphology alone and require examination of female genitalia for reliable identification. Several species, particularly Phratora vulgatissima, are economically significant pests of short-rotation coppice willow plantations.