Forest-pest
Guides
Phyllobius
Phyllobius is a genus of broad-nosed weevils (Curculionidae: Entiminae) containing at least 60 described species, with many distributed across Europe. Adults are primarily folivorous, feeding on leaves of broadleaved trees and occasionally causing defoliation damage in young woodlands. Larvae develop in soil, feeding on grass roots. Some species have been introduced outside their native ranges and established as nonindigenous populations in northern hardwood forests.
Pinyonia
Pinyon Spindle Gall Midge
Pinyonia is a genus of gall midges in the family Cecidomyiidae. The genus contains at least one described species, P. edulicola, which forms spindle-shaped galls on pinyon pine needles. These insects are small flies that induce abnormal plant growth through larval feeding activity.
Pissodes approximatus
northern pine weevil
Pissodes approximatus is a true weevil in the family Curculionidae, historically considered a junior synonym of P. nemorensis but now recognized as part of a single widespread species showing geographic variation in life history traits. The species is closely related to P. strobi, with which it can produce fertile laboratory hybrids, but maintains reproductive isolation in nature through breeding site specificity. Populations previously designated as P. approximatus (northern) and P. nemorensis (southern) differ in seasonal activity patterns and critical photoperiods for reproductive maturation.
Pissodes nemorensis
Deodar weevil, Eastern pine weevil
Pissodes nemorensis is a univoltine true weevil in the family Curculionidae, commonly known as the deodar weevil or eastern pine weevil. It is a significant forest pest in North America, particularly in the southeastern United States, where adults and larvae feed on phloem of coniferous trees. The species acts as a vector for pitch canker fungus (Fusarium moniliforme var. subglutinans) and is associated with blue stain fungi including Leptographium procerum and Ophiostoma piceae. Seasonal activity varies geographically: southern populations are primarily active in autumn and winter, while northern populations are active in spring.
Pityogenes hopkinsi
chestnut-brown bark beetle
Pityogenes hopkinsi is a small bark beetle in the family Curculionidae, commonly known as the chestnut-brown bark beetle. It colonizes eastern white pine (Pinus strobus) and uses a three-component aggregation pheromone to coordinate mass attacks on host trees. The pheromone system involves sex-specific synergistic responses and male-produced inhibitory compounds that regulate attraction.
Pityokteines
fir engraver beetles
Pityokteines is a genus of bark beetles (Scolytinae) known as fir engraver beetles. Species in this genus are significant pests of fir trees (Abies) and other conifers in the subfamily Abietoideae. Males initiate gallery construction and produce aggregation pheromones that regulate mass attack on host trees. The genus exhibits species-specific pheromone communication systems involving ipsenol and ipsdienol, which contribute to reproductive isolation among sympatric species.
Pityokteines ornatus
Pityokteines ornatus is a species of bark beetle in the family Curculionidae, subfamily Scolytinae. It was described by Wood in 1966. This species belongs to a genus of conifer-associated bark beetles that are significant forest pests in North America. The genus Pityokteines contains species that primarily infest fir trees (Abies spp.), with adults typically boring into the bark to create galleries where they lay eggs. The larvae develop within the phloem and cambium layers, potentially causing significant damage to host trees.
Pityophthorus
Pityophthorus is a large genus of bark beetles in the family Curculionidae, containing more than 540 described species. The genus is characterized by its association with coniferous and hardwood host trees, with species distributed across North America, Europe, and other regions. Some species, such as P. juglandis (the walnut twig beetle), are significant forest pests that vector pathogenic fungi causing tree diseases.
Pityophthorus juglandis
Walnut Twig Beetle
Pityophthorus juglandis is an invasive bark beetle native to the southwestern United States and Mexico that vectors the fungal pathogen Geosmithia morbida, causing thousand cankers disease in walnut trees. The beetle measures approximately 1.5 mm in length and is among the few Pityophthorus species associated with hardwoods. Research has focused extensively on its chemical ecology, including the male-produced aggregation pheromone 3-methyl-2-buten-1-ol and potential semiochemical repellents for management. The species exhibits strong host discrimination during flight, preferentially landing on Juglans species while avoiding most non-host hardwoods.
Podosesia syringae
Lilac Borer, Ash Borer, Lilac Borer Moth
Podosesia syringae, commonly known as the lilac borer or ash borer, is a clearwing moth in the family Sesiidae found throughout Canada and the United States. The adult moth mimics the appearance of a paper wasp, with transparent wings lacking scales and a wasp-like body form. Larvae tunnel beneath the bark of ash and lilac trees, feeding on the nutritious tissue and potentially causing significant damage over time. The species is a pest of concern for arborists and forest managers, with emergence timing predictable through phenological models based on heat accumulation.
Polydrusus
Polydrusus is a genus of weevils in the family Curculionidae, subfamily Entiminae, containing dozens of species distributed across Europe, North America, and parts of Asia. Several species have been introduced to North America and have become established in northern hardwood forests, where some function as polyphagous herbivores with documented impacts on tree crops. The genus is taxonomically complex, with multiple subgenera recognized including Conocetus and Orodrusus, and has been subject to recent revisionary work clarifying species boundaries and synonymies. Polydrusus species are frequently confused with the genus Phyllobius due to superficial morphological similarities, though they are not closely related.
Polygraphus
four-eyed fir bark beetles, polygraphus bark beetles
Polygraphus is a genus of bark beetles (Coleoptera: Curculionidae: Scolytinae) in the tribe Polygraphini. Species in this genus are phloephagous, feeding on the inner bark of coniferous trees, particularly fir (Abies) and spruce (Picea). The genus includes both native and invasive species, with Polygraphus proximus being the most economically significant due to its invasive spread across Russia and mass mortality impacts on fir forests. Members exhibit monogynous mating systems and produce species-specific stridulatory signals.
Polygraphus rufipennis
Four-eyed Spruce Bark Beetle
Polygraphus rufipennis is a phloeophagous bark beetle restricted to Abietineae hosts in northern and mountainous areas of North America. It completes one generation annually with spring and summer broods, developing from egg to adult in approximately two months. Males produce a highly volatile aggregation pheromone (3-methyl-3-buten-1-ol) that attracts both sexes, with females generally exhibiting stronger responses. The species colonizes both felled and standing trees, with attack densities varying by tree condition and bark characteristics.
Pristiphora erichsonii
Larch Sawfly
Pristiphora erichsonii, commonly known as the larch sawfly, is a species of sawfly native to Europe that was introduced to North America in the mid-to-late 19th century. It is a significant defoliator of larch trees (Larix spp.), particularly tamarack (Larix laricina) in North America. The species undergoes population outbreaks that can cause severe defoliation, though trees typically recover from single-year damage. Severe defoliation over multiple years can weaken trees and reduce winter survival. The species has been the subject of extensive ecological and population dynamics research due to its economic importance in forestry.
Procryphalus
Procryphalus is a genus of bark beetles in the family Curculionidae, established by Hopkins in 1915. The genus comprises seven described species distributed in North America. Species in this genus are associated with woody host plants including maple, ash, poplar, and willow.
Profenusa
oak mining sawflies, birch leafmining sawflies
Profenusa is a genus of leaf-mining sawflies in the family Tenthredinidae. Species in this genus are primarily associated with trees in the genera Quercus (oaks) and Betula (birches), though at least one species, P. japonica, has been documented on Rosa multiflora. Larvae are internal leaf miners that feed on mesophyll tissue, creating blotch mines. Several species are economically significant as forest and urban pests, including the invasive P. pygmaea in Kazakhstan and P. thomsoni in North America.
Profenusa alumna
red oak leaf-mining sawfly
Profenusa alumna is a leaf-mining sawfly in the family Tenthredinidae. It is univoltine, completing one generation per year. Larvae feed as leaf miners within red oak leaves, creating blotch mines. The species is closely associated with red oak (Quercus rubra) in forested habitats. Pupation occurs in soil.
Pseudexentera
oak olethreutid leafroller, aspen leafroller, apple leafroller
Pseudexentera is a genus of tortricid moths in the subfamily Olethreutinae. Species in this genus are early-season fliers whose larvae function as defoliators of economically important trees. Three species are of particular economic significance: P. spoliana (oak olethreutid leafroller) on oaks, P. oregonana (aspen leafroller) on aspens, and P. mali on apples. Female sex pheromones have been identified for these species and are species-specific, with no cross-attraction occurring between species.
Pseudohylesinus grandis
Pseudohylesinus grandis is a bark beetle (Curculionidae, formerly Scolytidae) associated with western hemlock forests of coastal North America. It completes one generation annually with two broods and four larval instars, overwintering as a teneral adult. The species exhibits distinct breeding habitat preferences, utilizing fresh slash in thinned stands rather than stumps. Adult females engage in pre-oviposition feeding on the inner bark of standing live host trees before constructing egg galleries in slash material.
Pseudohylesinus tsugae
Pseudohylesinus tsugae is a crenulate bark beetle in the family Curculionidae, native to western North America. It has a univoltine life cycle with two broods and four larval instars, overwintering as a fourth-instar larva. The species is closely associated with western hemlock (Tsuga heterophylla), where adult females feed on the inner bark of living trees before breeding in fresh stumps. It is distinguished from the sympatric P. grandis by its preference for stumps over slash as breeding substrate.
Pseudopityophthorus
oak bark beetles
A genus of bark and ambrosia beetles in the family Curculionidae, comprising more than 30 described species distributed primarily in North and Central America. Species in this genus are strongly associated with oak trees (Quercus spp.) and have been investigated as potential vectors of forest pathogens, including the oak wilt fungus Ceratocystis fagacearum and the canker-causing fungus Geosmithia pallida. Some species exhibit phoretic behavior and form associations with other organisms including mites and nematodes.
Pseudopityophthorus minutissimus
oak bark beetle
Pseudopityophthorus minutissimus, commonly known as the oak bark beetle, is a small bark beetle in the family Curculionidae. It is native to North America and breeds in oak species (Quercus). The species has been investigated as a potential vector of the oak wilt fungus Ceratocystis fagacearum, though evidence suggests it plays a minor role in long-distance pathogen transmission compared to other insects.
Pseudosciaphila duplex
Poplar Leafroller Moth, Aspen Leaftier, Spotted Aspen Leafroller
Pseudosciaphila duplex is a tortricid moth native to North America, commonly known as the poplar leafroller moth or aspen leaftier. Adults are active during summer months and possess a wingspan of 20–25 mm. The species is notable for its larval association with deciduous trees in the genera Populus, Betula, and Salix, where larvae feed on leaves.
Pterocomma
Willow Bark Aphids
Pterocomma is a genus of aphids in the family Aphididae, commonly known as willow bark aphids. Species in this genus are phloem-feeding insects primarily associated with woody host plants in the genus Salix (willows) and Populus (poplars). The genus exhibits a specialized ecological relationship with ants, which frequently tend colonies and mediate dispersal between host plants. Pterocomma species harbor the obligate bacterial endosymbiont Buchnera aphidicola, which provides essential amino acids necessary for survival on their nutrient-poor phloem sap diet.
Recurvaria
Recurvaria is a genus of small moths in the family Gelechiidae, established by Haworth in 1828. The genus contains approximately 40 described species distributed across the Holarctic region. Several species are economically significant as pests of coniferous trees and pistachio, with larvae that mine needles or feed internally within fruits. The genus exhibits diverse life history strategies, including univoltine and bivoltine cycles, with some species requiring two years to complete development.
Rhyacionia buoliana
pine shoot moth, European Pine Shoot Moth
Rhyacionia buoliana is a tortricid moth known as the pine shoot moth. Native to North Africa, North Asia, and Europe, it has become invasive in North and South America. The species is a significant pest of pine trees, with larvae feeding on shoots of Pinus species. Adults are active during summer months in temperate regions.
Rhyacionia granti
Jack Pine Shoot Borer
Rhyacionia granti is a species of tortricid moth in the family Tortricidae, described by Miller in 1985. It belongs to the genus Rhyacionia, a group commonly known as shoot borers or tip moths that are associated with coniferous trees. The species is known by the common name Jack Pine Shoot Borer, indicating its association with jack pine (Pinus banksiana). As a member of the Olethreutinae subfamily and Eucosmini tribe, it shares characteristics with other conifer-feeding tortricids in the genus.
Sabulodes
Sabulodes is a genus of geometrid moths (Geometridae: Ennominae) first described by Achille Guenée in 1857. The genus contains approximately 50 described species distributed primarily in the Americas, with some species occurring in the Neotropics. Several species have been documented as forest defoliators, including Sabulodes glaucularia, which has been reported as a pest of Pinus patula, Cupressus lusitanica, and Eucalyptus in Colombian forests. The genus is taxonomically well-established but individual species-level biology remains incompletely documented.
Saperda imitans
Oblique-banded Longhorn Beetle
Saperda imitans is a univoltine longhorned beetle in the family Cerambycidae, described by Felt and Joutel in 1904. It is a specialist on black cherry (Prunus serotina), particularly infesting wind-damaged trees in Allegheny hardwood stands. The species overwinters in sapwood and outer heartwood, causing damage that impacts commercial timber value. It is not attracted to ethanol baits and shows specific preferences for host condition, targeting dying trees with moist phloem rather than completely dead or healthy specimens.
Saperda inornata
Poplar-gall Saperda
Saperda inornata is a longhorned beetle (Cerambycidae) native to North America, closely associated with trembling aspen (Populus tremuloides) throughout its life cycle. Larvae develop within living aspen trees, tunneling through wood and inner bark, while adults feed on bark and other tree tissues. The species was described by Thomas Say in 1824 and occurs across Canada and the United States. It has been observed in Manitoba, New Brunswick, Nova Scotia, and Ontario in Canada, as well as the northern United States.
Saperda populnea
small poplar borer
Saperda populnea is a longhorn beetle (Cerambycidae) that forms distinctive woody galls on twigs of poplars and willows. The species was described by Linnaeus in 1758 and has a broad distribution across the Northern Hemisphere. Females create characteristic horseshoe-shaped cuts on host twigs where eggs are deposited, leading to gall formation. The beetle is of economic concern in hybrid aspen plantations due to damage to young trees.
Sarcophaga aldrichi
Friendly Fly, Large Flesh Fly
Sarcophaga aldrichi is a parasitoid flesh fly commonly known as the friendly fly or large flesh fly. It is a specialized parasitoid of the forest tent caterpillar (Malacosoma disstria), depositing live larvae into host cocoons where they consume the pupating caterpillars. The species exhibits distinctive delayed population dynamics, with outbreaks occurring one year after peak host caterpillar abundance. Adults are frequently encountered in large numbers during outbreak years, sometimes becoming a nuisance to humans despite being harmless.
Schizomyia
Schizomyia is a genus of gall midges (Diptera: Cecidomyiidae) with cosmopolitan distribution. Species in this genus induce various types of galls on diverse host plants, including rosette bud galls, inflorescence galls, and stem galls. The genus belongs to the tribe Asphondyliini and contains at least 51 described species. Some species have significant ecological and economic impacts, including outbreaks that reduce seed production in forest trees and potential use as biological control agents.
Scolytinae
Bark and Ambrosia Beetles, Bark Beetles
Scolytinae is a subfamily of weevils (Curculionidae) comprising approximately 220 genera and 6,000 species commonly known as bark and ambrosia beetles. Members are characterized by their specialized association with woody plants, where they excavate galleries beneath bark for reproduction and larval development. The subfamily includes some of the most economically significant forest pests globally, such as the southern pine beetle (Dendroctonus frontalis) and mountain pine beetle (Dendroctonus ponderosae), which cause billions of dollars in timber losses. Species exhibit diverse feeding strategies: phloem-feeding bark beetles consume living or dying tree tissues, while ambrosia beetles cultivate symbiotic fungi in galleries as a food source.
Scolytus
bark beetles, elm bark beetles
Scolytus is a genus of bark beetles in the subfamily Scolytinae, family Curculionidae. Multiple species within this genus are significant forest pests, particularly as vectors of Dutch elm disease. The genus includes both European and North American species with documented roles in tree mortality. Some species exhibit chemically-mediated aggregation behaviors involving pheromone communication.
Scolytus multistriatus
European elm bark beetle, smaller European elm bark beetle
Scolytus multistriatus is a small bark beetle in the subfamily Scolytinae that infests elm trees (Ulmus spp.). It is a known vector of Dutch elm disease caused by the fungus Ophiostoma ulmi, though it is less effective than the related Scolytus scolytus. The species uses chemical cues including vanillin and syringaldehyde to locate host trees during oviposition. It has been introduced to North America and other regions beyond its native European range, where it contributes to elm decline through disease transmission and direct tree damage.
Scolytus muticus
hackberry engraver, hackberry beetle
Scolytus muticus is a bark beetle species in the family Curculionidae, commonly known as the hackberry engraver or hackberry beetle. The species is found in North America and is associated with hackberry trees (Celtis species). Like other members of the genus Scolytus, this species exhibits the typical bark beetle habit of excavating galleries in the phloem of host trees.
Scolytus quadrispinosus
Hickory Bark Beetle
Scolytus quadrispinosus, commonly known as the hickory bark beetle, is a bark beetle species in the family Curculionidae. It is native to North America and has been documented in Canada (Ontario, Québec) and the United States. The species is associated with hickory and related host trees. Its dispersal flight behavior has been studied in relation to host specificity, with individuals attracted to host material during flight.
Scolytus schevyrewi
Banded Elm Bark Beetle
Scolytus schevyrewi is a small bark beetle native to Asia that has become invasive in North America. It is a documented vector of Dutch elm disease pathogens (Ophiostoma ulmi and O. novo-ulmi). The species exhibits strong attraction to stressed or weakened host trees, particularly Ulmus pumila, and has been observed displacing both native elm bark beetles and the earlier-introduced smaller European elm bark beetle (S. multistriatus) in North America. In its native range, it also causes significant damage to fruit trees including apricot.
Scolytus unispinosus
Douglas-fir engraver
Scolytus unispinosus, the Douglas-fir engraver, is a bark beetle native to western North America. It acts primarily as a secondary insect, colonizing the tops, limbs, and branches of Douglas-fir trees that have been killed or weakened by other factors. While it occasionally kills young trees, it is generally of minor economic importance and commonly attacks logging slash. In British Columbia's interior, it frequently occurs in association with the Douglas-fir beetle (Dendroctonus pseudotsugae).
Semanotus japonicus
sugi bark borer, Cryptomeria bark borer
Semanotus japonicus is a cerambycid beetle native to Japan that attacks living Japanese cedar (Cryptomeria japonica). Larvae feed primarily within the inner bark of trunks, where they are vulnerable to drowning by resin flow. The species exhibits a transitional ecological state between primary and secondary bark borer, requiring adequate host nutrition but lacking defenses against host resin defenses. Adults are relatively sedentary, with limited between-tree movement and nocturnal mating activity concentrated from sunset to sunrise.
Semanotus litigiosus
Firtree Borer
Semanotus litigiosus is a longhorn beetle (Cerambycidae) known as the firtree borer, found in the coniferous forest belt of North America. The species is a wood-boring pest of white fir (Abies concolor), with larvae causing significant damage to windthrown timber by excavating galleries in the phloem and boring deep into the sapwood to construct pupal chambers. Adults emerge in spring and lay eggs in bark crevices, with a life cycle spanning approximately one year.
Sinophorus
Sinophorus is a genus of ichneumonid parasitoid wasps established by Förster in 1869. Species are distributed across Europe, Asia, and North America. Members are larval endoparasitoids of Lepidoptera and possibly other insects. The genus includes at least nine described species, with some species such as Sinophorus megalodontis and S. xanthostomus studied for their biological control potential.
Sirex
horntail, wood wasp
Sirex is a genus of horntail woodwasps in the family Siricidae. These insects are characterized by an obligate mutualistic relationship with wood-decaying fungi, which they carry in specialized abdominal organs called mycangia and introduce into host trees during oviposition. The fungus digests wood cellulose, providing nutrition for the developing larvae. The genus includes significant forest pests, notably Sirex noctilio, which has become invasive in multiple continents outside its native range.
Sirex cyaneus
blue horntail
Sirex cyaneus, commonly known as the blue horntail, is a species of woodwasp in the family Siricidae. Native to forests in Alberta, Canada, adults reach approximately 2 cm in length. The species serves as a host for parasitoid wasps including Rhyssa persuasoria and Ibalia leucospoides, which have been studied for potential biological control applications.
Siricidae
horntails, wood wasps
Siricidae is a family of approximately 150 species of non-social wasps commonly known as horntails or woodwasps. These insects are characterized by their cylindrical, cigar-shaped bodies and the prominent spine or "cornus" at the tip of the abdomen that gives the family its common name. Females possess a long, drill-like ovipositor used to bore into wood and deposit eggs. Siricidae are xylophagous, with larvae developing inside dead, dying, or weakened trees, where they feed on wood colonized by symbiotic fungi that females introduce during oviposition. The family is economically significant: most native species are not pests and target already-compromised trees, but introduced species such as Sirex noctilio have become major forest pests in pine plantations worldwide.
Siricinae
horntails, wood wasps
Siricinae is a subfamily of wood-boring wasps within Siricidae, commonly known as horntails. Members possess a distinctive elongated, cylindrical body and a prominent spine-like ovipositor at the tip of the abdomen. Females bore into wood to lay eggs, and larvae develop within timber, feeding on fungal symbionts. The subfamily includes the genus *Sirix*, among others.
Spathius
Spathius is a genus of doryctine wasps in the family Braconidae. Species within this genus are larval parasitoids of wood-boring beetles, with several species introduced to North America as biological control agents for the invasive emerald ash borer (Agrilus planipennis). The genus includes both native and introduced species that exhibit host-specific relationships with their beetle hosts.
Sphinx
sphinx moth, hawk moth, hummingbird moth
Sphinx is a genus of moths in the family Sphingidae, first described by Linnaeus in 1758. These moths are commonly known as sphinx moths, hawk moths, or hummingbird moths due to their rapid, hovering flight and large size. The genus includes several ash-specialist species that have become conservation concerns due to decline of their host trees from emerald ash borer infestation. The name derives from the caterpillar's defensive posture when disturbed—rearing up with head retracted, resembling the Egyptian sphinx.
Sterictiphora serotina
Sterictiphora serotina is a sawfly species in the family Argidae. Larvae feed on Prunus species, including black cherry (Prunus serotina), and produce distinctive zigzag feeding damage on leaf margins. The species is native to North America and has been documented in association with deciduous forest habitats.