Forest-entomology
Guides
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.
Olesicampe benefactor
Olesicampe benefactor is a European ichneumonid wasp introduced to eastern North America as a biological control agent for the larch sawfly (Pristiphora erichsonii), a forest pest. Small numbers (147–388 individuals) were released in Maine, Nova Scotia, and New Brunswick in 1967. The species successfully established at multiple sites, surviving two to three winters at several locations. It disperses slowly, which may limit its effectiveness over large areas without multiple release points.
Oncideres
Twig Girdling Beetles, Twig Girdlers
Oncideres is a genus of longhorn beetles (Cerambycidae: Lamiinae) containing over 120 species distributed throughout the Nearctic and Neotropics. These beetles are commonly known as twig girdlers due to the distinctive behavior of females chewing around branches to cause them to break and fall. The larvae develop within the girdled, decomposing wood. Several species are economically significant pests of fruit trees, pecans, and forest trees, while others play roles in ecosystem engineering by altering host plant population structure.
Oobius
Oobius is a genus of parasitic non-stinging wasps in the family Encyrtidae (Hymenoptera: Chalcidoidea). Species are specialized egg parasitoids of wood-boring beetles, particularly in the family Buprestidae (jewel beetles) and Cerambycidae (longhorn beetles). The genus has gained significant attention due to the use of O. agrili as a biological control agent against the invasive emerald ash borer (Agrilus planipennis) in North America. Oobius species are small, morphologically cryptic wasps that are often distinguished by subtle differences in antennal structure and tarsomere count. Several species exhibit parthenogenetic reproduction and undergo diapause to synchronize their life cycles with host availability.
Oobius agrili
Oob
Oobius agrili is a tiny, solitary egg parasitoid wasp in the family Encyrtidae, native to Northeast Asia. It is the only egg parasitoid released for biological control of the invasive emerald ash borer (Agrilus planipennis) in North America, where it has been introduced in over 31 US states. The species is parthenogenic, produces multiple generations annually, and achieves partial phenological synchrony with its host's egg-laying period. Individual females can parasitize more than 60 host eggs, with field parasitism rates reaching 60% in optimal conditions.
Orthotomicus
Orthotomicus is a genus of bark beetles in the family Curculionidae, subfamily Scolytinae, containing approximately nine described species. The genus is primarily associated with coniferous trees, particularly pines (Pinus spp.) and cedars (Cedrus spp.). Several species, notably Orthotomicus erosus (Mediterranean pine engraver) and O. laricis, have become significant forest pests through native population outbreaks and invasive range expansions. Species in this genus are known for their associations with ophiostomatoid fungi, which they vector and which contribute to tree decline.
Parasetigena
Parasetigena is a genus of tachinid flies (Diptera: Tachinidae) containing at least two described species: P. silvestris and P. takaoi. Species in this genus are larval parasitoids, with P. silvestris documented as a specialized parasitoid of gypsy moth (Lymantria dispar) larvae. These flies contribute to natural biological control of forest lepidopteran pests. The genus has been recorded from northern Europe (Denmark, Norway, Sweden) and is associated with woodland habitats where host larvae occur.
Phasgonophora
Phasgonophora is a genus of chalcidid wasps in the family Chalcididae, with at least two described species: Phasgonophora sulcata and Phasgonophora rugithorax. Members of this genus are solitary endoparasitoids of woodboring beetle larvae. Phasgonophora sulcata, the better-studied species, is native to North America and has been documented attacking Agrilus planipennis (emerald ash borer) as a novel host, as well as Agrilus bilineatus (twolined chestnut borer). The genus has gained attention for its potential role in biological control of invasive forest pests.
Pineus
Pineus is a genus of adelgids (family Adelgidae) comprising more than 20 described species. These insects are small, sap-feeding hemipterans specialized on conifer hosts, primarily Pinus (pines) and Picea (spruces). Species exhibit complex life cycles with multiple morphological forms, including winged and wingless generations, and some alternate between two host species. Several species are economically significant as pests of forestry and ornamental plantings.
Pineus pinifoliae
Pine Leaf Adelgid, Pine Leaf Aphid, Pine Leaf Chermid
Pineus pinifoliae is a small, phloem-feeding insect in the family Adelgidae, commonly known as the pine leaf adelgid or pine leaf aphid. It has a complex life cycle involving alternation between spruce (Picea) as the primary host, where it forms galls on new shoots, and white pine (Pinus strobus) as the secondary host. The species produces multiple generations annually, with distinct morphological forms including winged migrants that transfer between hosts. Heavy infestations on white pine cause characteristic damage patterns including needle stunting, reduced radial growth, and branch mortality concentrated in the lower and mid-crown.
Pissodes
Pine Weevils
Pissodes is a genus of weevils in the family Curculionidae containing at least 140 described species. These insects are specialized inhabitants of coniferous forests, with their distribution across the Northern Hemisphere closely tracking that of Pinaceae host trees. Several species, including Pissodes strobi, P. nemorensis, and P. terminalis, are recognized as significant forest pests due to the damage they inflict on economically important trees. The genus was first described by Ernst Friedrich Germar in 1817.
Pityogenes
bark beetles
Pityogenes is a genus of bark beetles in the family Curculionidae, comprising over 30 described species distributed across the Northern Hemisphere. Species in this genus are primarily associated with coniferous trees, with P. chalcographus being the most extensively studied due to its economic significance as a pest of Norway spruce. The genus exhibits typical scolytine characteristics including aggregation pheromone communication and specialized host-finding behaviors. Some species demonstrate notable geographic variation in morphology and genetics, suggesting population differentiation across their ranges.
Pityogenes bidentatus
Pityogenes bidentatus is a European bark beetle that colonizes Scots pine (Pinus sylvestris). The species exhibits sophisticated olfactory-mediated behaviors for host location, including attraction to aggregation pheromone components (grandisol and cis-verbenol) and active avoidance of nonhost volatiles. Its behavioral response to monoterpene odors is context-dependent: avoidance occurs during flight but not during walking, likely representing distinct sensory mechanisms for long-range host discrimination versus short-range gallery establishment.
bark-beetleScolytinaePinus-sylvestrisaggregation-pheromoneolfactory-behaviorhost-selectionmonoterpene-avoidancecontext-dependent-plasticitynonhost-avoidancenorthern-Europegrandisolcis-verbenol1-octene-3-olβ-caryophylleneflight-behaviorwalking-behaviorelectroantennographypopulation-genetics-modelnematode-associationBursaphelenchus-pinophilusnematangiaCzech-Republicmixed-forestconifer-forestScots-pineNorway-sprucenonhost-volatileschemical-ecologyinsect-plant-interactionsherbivore-host-rangesensory-ecologybehavioral-plasticitypheromone-ecologyforest-entomologyinvasive-potential-(North-America-records)Pityogenes carinulatus
Pityogenes carinulatus is a small bark beetle in the weevil family Curculionidae, described by Wood & Bright in 1992. It belongs to the subfamily Scolytinae (true bark and ambrosia beetles), a group of economically significant forest pests. The species has been recorded in western North America including British Columbia, Canada, and parts of Middle America. Like other members of the genus Pityogenes, it is associated with coniferous trees.
Pogonocherus
flat-faced longhorn beetles
Pogonocherus is a genus of flat-faced longhorn beetles in the family Cerambycidae, established by Dejean in 1821. Species in this genus are wood-boring cerambycids associated with coniferous hosts, particularly pines. At least one species, P. perroudi, has been identified as a potential vector of pinewood nematode (Bursaphelenchus xylophilus), the causal agent of pine wilt disease. The genus contains approximately 30 described species distributed across the Northern Hemisphere.
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.
Rhyacionia zozana
Ponderosa Pine Tip Moth
Rhyacionia zozana is a tortricid moth commonly known as the ponderosa pine tip moth. The species is a specialist herbivore of ponderosa pine, with larvae feeding on terminal shoots. It serves as host to a diverse community of parasitoids, with documented parasitism rates averaging 47% in California and Oregon populations. Males locate females using pheromone cues, a behavior that has been successfully disrupted using aerially applied synthetic pheromone for population management.
Sasajiscymnus tsugae
hemlock woolly adelgid lady beetle
Sasajiscymnus tsugae is a small black lady beetle native to Japan that was introduced to eastern North America as a biological control agent against the invasive hemlock woolly adelgid (Adelges tsugae). First described in 1997 and released in the United States beginning in 1995, this predator has established populations in forest and urban environments. The species exhibits high host specificity, feeding primarily on three adelgid species. Field studies demonstrated 47–88% reduction in adelgid densities within five months of beetle introduction.
Scymnus coniferarum
conifer lady beetle
Scymnus coniferarum is a small predatory lady beetle native to western North America. It has been studied as a potential biological control agent for the hemlock woolly adelgid (Adelges tsugae), an invasive pest of eastern hemlock in eastern North America. Field studies in Washington State indicate it feeds on multiple adelgid species across different conifer hosts, with higher abundance observed on pine adelgids than on hemlock woolly adelgid.
Semanotus
Semanotus is a genus of longhorn beetles (Cerambycidae) described by Étienne Mulsant in 1839. Species within this genus are primarily wood-boring pests of coniferous trees, with documented associations including juniper, fir, cedar, cryptomeria, and cypress. Several species cause significant economic damage to timber and ornamental plantings. The genus has a broad distribution spanning North America, Europe, Asia, and North Africa, with at least 19 recognized species.
Steremnius
Steremnius is a genus of true weevils (Curculionidae) established by Schoenherr in 1835, containing at least four described species. The genus includes the conifer seedling weevil Steremnius carinatus, a documented reforestation pest in coastal British Columbia. Other described species include S. scrobiculatus, S. shermani, and S. tuberosus. Information on genus-level biology is limited; most ecological and behavioral data derive from studies of S. carinatus.
Thanasimus dubius
dubious checkered beetle, American bark beetle destroyer, checkered beetle predator, Wavering Checkered Beetle
Thanasimus dubius is a predatory checkered beetle (Cleridae) native to North and Central America. It specializes in preying upon bark beetles, particularly species in the genera Ips and Dendroctonus, with the southern pine beetle (Dendroctonus frontalis) being a well-documented prey item. Adults exhibit a stereotyped five-act predatory sequence involving search/ambush, seizure, alignment, consumption, and grooming. The species demonstrates chemotactic responses to bark beetle pheromones and tree volatiles, and shows regional genetic differentiation across its eastern North American range. It has been investigated as a potential biological control agent for forest pest management.
Thecodiplosis
Thecodiplosis is a genus of gall midges (Diptera: Cecidomyiidae) comprising approximately six described species. Species in this genus induce galls on pine needles, with documented hosts including Pinus densiflora, P. thunbergii, P. resinosa, and other Pinus species. The genus has become economically significant as an invasive pest in some regions, particularly Thecodiplosis japonensis, which has established populations in China since 2016.
Tomicus
pine shoot beetles
Tomicus is a genus of bark beetles in the family Curculionidae, described by Pierre André Latreille in 1802. The genus contains at least seven recognized species, including economically significant forest pests such as T. piniperda, T. minor, T. destruens, and T. yunnanensis. These beetles are commonly known as pine shoot beetles due to their distinctive life history involving feeding on pine shoots before trunk colonization. Several species have caused substantial mortality in pine forests across Europe, the Mediterranean region, and southwestern China, with T. yunnanensis described as unusually aggressive in its native range.
Xylotrechus sagittatus sagittatus
Xylotrechus sagittatus sagittatus is a subspecies of longhorn beetle in the family Cerambycidae, tribe Clytini. It is a pine-associated wood-boring beetle found in southeastern North America, with its distribution extending to the northern limits in Arkansas. The species exhibits strong behavioral responses to olfactory cues, particularly ethanol and turpentine in a 5:1 ratio, and visual cues play a secondary role in host-finding behavior. Adults are attracted to stressed or dying pine trees and have been documented responding to elevated traps.
Zeiraphera hesperiana
Douglas-fir Bud Moth
Zeiraphera hesperiana is a North American tortricid moth species described in 1967. It belongs to the bud moth genus Zeiraphera, which includes several economically significant forest pests. The species is associated with coniferous hosts, particularly Douglas-fir.