Gall-former
Guides
Meunieriella on-smilax
Meunieriella on-smilax is a species of gall midge in the family Cecidomyiidae. This species is known for inducing galls on Smilax species (greenbriers), with the specific epithet reflecting this host association. Gall midges in this genus are specialized herbivores that manipulate plant tissue to form protective structures for their developing larvae.
Mompha sturnipennella
Kentish Cosmet
Mompha sturnipennella is a small gelechioid moth in the family Momphidae, with a wingspan of 13–18 mm. It exhibits a bivoltine adult flight pattern, with one generation active in July–August and a second generation emerging in September, overwintering, and flying until May. The species is widely distributed across the Holarctic, occurring throughout most of Europe (excluding the Mediterranean south), Siberia, the Russian Far East, and Canada.
Mordwilkoja vagabunda
Poplar Vagabond Aphid
A gall-forming aphid that induces distinctive galls on Populus deltoides (eastern cottonwood). Nymphs exhibit anti-predator behaviors including synchronized rhythmic movements and active defense against pyralid moth larvae using legs and rostrums. Unlike some related aphids, defensive nymphs include alatoid forms rather than specialized first-instar soldiers. The species has a complex life cycle with alternation between primary and secondary hosts.
Neolasioptera allioniae
Neolasioptera allioniae is a gall midge in the family Cecidomyiidae. The species induces galls on plants in the genus Allionia (Nyctaginaceae). It has been recorded from Colorado to Texas, with its range potentially extending more widely based on the distribution of its host plants. The species was described by Felt in 1911.
Neolasioptera boehmeriae
Boehmeria stem gall midge
Neolasioptera boehmeriae is a gall midge in the family Cecidomyiidae, commonly known as the Boehmeria stem gall midge. The species induces galls on false nettles (Boehmeria spp.), with which it has a specialized host relationship. It occurs in the northeastern United States and southern Canada. The species was first described by Beutenmüller in 1908.
Neolasioptera clematidis
Neolasioptera clematidis is a gall midge species in the family Cecidomyiidae, first described by Felt in 1907. The specific epithet 'clematidis' suggests an association with plants in the genus Clematis. As with other gall midges, this species likely induces gall formation on host plants.
Neolasioptera desmodii
Neolasioptera desmodii is a species of gall midge in the family Cecidomyiidae, first described by Felt in 1907. As a member of the genus Neolasioptera, it is associated with inducing galls on host plants. The specific epithet "desmodii" indicates a relationship with plants in the genus Desmodium.
Neolasioptera impatientifolia
Neolasioptera impatientifolia is a gall midge in the family Cecidomyiidae, first described by Felt in 1907. The species forms galls on jewelweed (Impatiens species), with the specific epithet reflecting this host association. It is one of numerous Neolasioptera species specialized on particular host plants. The species has been documented in the northeastern United States.
Neolasioptera perfoliata
Boneset Stem Midge
Neolasioptera perfoliata is a gall midge in the family Cecidomyiidae. The common name "Boneset Stem Midge" indicates its association with boneset plants (Eupatorium species). As a gall midge, it induces gall formation on host plants during its larval development. The species was described by Felt in 1907.
Neolasioptera rudbeckiae
Neolasioptera rudbeckiae is a species of gall midge in the family Cecidomyiidae. The specific epithet 'rudbeckiae' indicates an association with Rudbeckia (coneflowers), suggesting this species forms galls on these plants. As a member of the genus Neolasioptera, it belongs to a group of gall midges known for inducing stem and leaf galls on Asteraceae. The species was described by E.P. Felt in 1908.
Neolasioptera vernoniae
Neolasioptera vernoniae is a gall midge in the family Cecidomyiidae. As a member of the genus Neolasioptera, it induces galls on host plants. The species was originally described by Beutenmüller in 1907 under the basionym Cecidomyia vernoniae.
Olliffiella cristicola
Gall Kermes
Olliffiella cristicola, commonly known as the gall kermes, is a species of scale insect in the family Kermesidae. The species forms gall-like structures on host plants, a distinctive trait among kermes scales. It was described by Theodore Dru Alison Cockerell in 1896 and is known from the United States.
Pachypappa sacculi
Aspen leaf-pocket aphid
Pachypappa sacculi, commonly known as the aspen leaf-pocket aphid, is a gall-forming aphid species in the family Aphididae. It induces distinctive pocket-like galls on leaves of aspen and related poplar species. The species belongs to the subfamily Pemphiginae, which includes many aphids that form complex plant galls. Observations on iNaturalist indicate it is documented across multiple regions where host trees occur.
Pachypsylla
hackberry gall psyllids, hackberry psyllids
Pachypsylla is a genus of North American psyllids (jumping plant lice) in the family Aphalaridae. All known species are specialized gall-formers on hackberry trees (Celtis spp.), with each species producing a distinct gall type on leaves or petioles. The genus is notable for its intimate association with the bacterial endosymbiont Carsonella ruddii, which has the smallest known cellular genome of any bacterium. Adults are tiny (3.5–4.5 mm), resembling miniature cicadas, and overwinter in concealed locations before emerging to lay eggs on new hackberry growth in spring.
Pachypsylla celtidisgemma
Hackberry Gemma Psyllid
Pachypsylla celtidisgemma is a hackberry psyllid species that induces distinct galls on hackberry trees (Celtis spp.). Adults are small, cicada-like insects measuring 3.5–4.5 mm, with piercing-sucking mouthparts. The species produces "gemma galls"—irregular, wart-like growths on hackberry leaves that house developing nymphs. Like other hackberry psyllids, it has a single generation per year and overwinters as adults in concealed locations.
Pachypsylla celtidisinteneris
Hackberry Blister Gall Psyllid
A tiny psyllid species that induces blister galls on hackberry leaves. Adults overwinter in concealed locations and emerge in fall, sometimes becoming nuisance pests when they congregate on building exteriors. The species is one of approximately seven hackberry psyllid species in North America, each producing distinct gall morphologies.
Pachypsylla celtidismamma
hackberry nipplegall maker, hackberry psylla
A plant-parasitic hemipteran that induces distinctive nipple-shaped galls on hackberry (Celtis) leaves. Adults are 3.5–4.5 mm long, resembling tiny cicadas. The species overwinters as adults in concealed locations and emerges in fall to seek hibernation sites, sometimes becoming a nuisance pest on building exteriors. Nymphs develop within galls, progressing through five instars before emerging as adults.
Pachypsylla celtidisumbilicus
Hackberry Disc Gall Psyllid
Pachypsylla celtidisumbilicus is a species of hackberry psyllid that produces distinctive disc-shaped galls on hackberry leaves (Celtis spp.). Adults emerge in fall and seek shelter to overwinter, often becoming household nuisances when they congregate on building exteriors. The species is one of at least seven Pachypsylla species associated with hackberry in North America, each producing a characteristic gall morphology.
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Hairy Bud Gall Psyllid
Pachypsylla pallida is a hackberry psyllid species in the family Aphalaridae, known for inducing distinctive galls on hackberry trees (Celtis spp.). It is one of at least seven species in the genus Pachypsylla that specialize on hackberry hosts. The species produces hairy bud galls, distinguishing it from congeners that create nipple galls or other gall morphologies. Like other psyllids, it has piercing-sucking mouthparts and undergoes incomplete metamorphosis with five nymphal instars developing within the protective gall structure.
Pachypsylla venusta
Hackberry Petiole Gall Psyllid
Pachypsylla venusta is a hackberry-associated psyllid that forms distinctive woody galls on hackberry leaf petioles. Adults are small (3.5-4.5 mm), resembling tiny cicadas with piercing-sucking mouthparts. The species maintains an obligate mutualism with Carsonella ruddii, a γ-Proteobacterium with the smallest known cellular genome (160 kb), housed within specialized 16-ploid bacteriocytes. While galls are visually conspicuous, they cause minimal harm to host trees.
Pachypsyllinae
Pachypsyllinae is a subfamily of jumping plant lice (psyllids) in the family Aphalaridae. It comprises three genera: Celtisaspis, Pachypsylla, and Tetragonocephala. Members of this subfamily are associated with hackberry trees (Celtis species) as their host plants. The group was previously classified in the family Carsidaridae, but recent revisions have placed it in Aphalaridae. The genus Pachypsylla includes species that form distinctive plant galls on hackberry leaves and stems.
Papaipema maritima
maritime sunflower borer moth, giant sunflower borer moth
Papaipema maritima is a noctuid moth species native to North America, first described by Henry Bird in 1909. The larvae are specialized stem borers that tunnel into the stems of giant sunflower (Helianthus giganteus), creating distinctive stem galls. The species has experienced significant population decline and is classified as a species of special concern in Connecticut, where it is believed to be extirpated. Its specialized host relationship and habitat loss contribute to its vulnerable conservation status.
Patchiella kolokasia
Patchiella kolokasia is a gall-forming aphid in the subfamily Pemphiginae. It forms distinctive leaf nests on Tilia species and exhibits host alternation, with Araceae serving as secondary hosts. The species was described from China in 1999 and has since been recorded from Japan and, more recently, South Korea. This represents the first documentation of the genus Patchiella on the Korean Peninsula.
Pemphigus
Poplar Leaf-stem Gall Aphids
Pemphigus is a genus of gall-forming aphids in the family Aphididae, commonly known as poplar leaf-stem gall aphids. Species in this genus are specialized herbivores that induce distinctive galls on poplar (Populus) and related host plants. The genus is notable for its complex life cycles involving alternation between primary woody hosts and secondary herbaceous hosts, with some species remaining entirely on roots of secondary hosts. Pemphigus species are frequently confused with other root-feeding aphids in agricultural and horticultural contexts.
Pemphigus bursarius
lettuce root aphid, poplar gall aphid
Pemphigus bursarius is a host-alternating aphid with a heteroecious life cycle involving Populus species as primary hosts and Asteraceae (particularly lettuce) as secondary hosts. On poplars, it forms flask-shaped leaf-stalk galls in spring; on secondary hosts, it lives subterraneanly feeding on roots. The species exhibits unusual flexibility in its life cycle, with some populations capable of asexual overwintering in soil without returning to the primary host. It is an economically significant pest of lettuce crops and shows genetically distinct host-associated populations.
Pemphigus populicaulis
Poplar Leaf-base Gall
Pemphigus populicaulis is a gall-forming aphid species that induces distinct galls at the leaf bases of poplar trees. As a member of the genus Pemphigus, it exhibits the typical life cycle of root-gall aphids, alternating between primary hosts (Populus species) and secondary hosts (often roots of herbaceous plants). The species was described by Fitch in 1859 and is widely distributed across North America. It is frequently referenced in historical literature on gall aphids but has been subject to taxonomic confusion with related Pemphigus species.
Periploca ceanothiella
Ceanothus stem gall moth
A small gall-forming moth in the family Cosmopterigidae that induces stem galls on Ceanothus species. The species has been recorded across much of North America, with adults active primarily from March to August. Larvae bore into host stems, causing distinctive gall formations, and overwinter within these structures.
Phylloxera
phylloxeras
Phylloxera is a genus of tiny, soft-bodied, sap-sucking insects in the family Phylloxeridae, closely related to aphids. The genus includes economically significant agricultural pests, most notably the grape phylloxera (Daktulosphaira vitifoliae), which devastated European vineyards in the late 19th century and remains a major threat to viticulture worldwide. Phylloxera species induce characteristic galls on host plants through chemical secretions that manipulate plant tissue development. The genus exhibits complex life cycles involving multiple morphological forms, including winged and wingless parthenogenetic generations and a brief sexual generation.
Phylloxera auburnensis
Phylloxera auburnensis is a gall-forming insect in the family Phylloxeridae, closely related to aphids. Like other phylloxerans, it induces abnormal plant growths (galls) on its host through chemical secretions that manipulate plant tissue development. The species is part of a genus containing several economically significant pests, including grape phylloxera (Daktulosphaira vitifoliae, formerly Phylloxera vitifoliae) and pecan phylloxera species. Specific details about P. auburnensis hosts and distribution remain limited in available literature.
Phylloxera bispinae
Phylloxera bispinae is a gall-forming insect in the family Phylloxeridae, closely related to aphids. Like other phylloxerans, it induces abnormal plant growths (galls) on host plants through chemical secretions that manipulate plant tissue development. The species overwinters as eggs and has a complex life cycle involving multiple generations and winged dispersal forms. Specific host associations and detailed biology for this species remain poorly documented compared to economically important relatives such as the grape phylloxera (Daktulosphaira vitifoliae) and pecan phylloxera species.
Phylloxera caryaeavellana
hickory phylloxeran, hickory phylloxera
Phylloxera caryaeavellana is a small, gall-forming insect in the family Phylloxeridae that infests hickory trees (Carya species). The species causes distinctive swollen, globular galls to form on leaves, petioles, and leaf veins during spring growth. It is closely related to aphids and shares their piercing-sucking mouthpart morphology. The insect has a complex life cycle involving multiple generations and winged dispersal forms. Unlike the economically devastating grape phylloxera (Daktulosphaira vitifoliae), this species is primarily a curiosity rather than a significant agricultural pest, causing minimal lasting damage to healthy host trees.
Phylloxera caryaefoliae
pecan leaf phylloxera
Phylloxera caryaefoliae is a tiny, soft-bodied, gall-forming insect closely related to aphids that infests pecan trees. It produces conspicuous galls exclusively on leaf tissue, distinguishing it from the more damaging pecan phylloxera (P. devastatrix) which attacks shoots and nuts. While extensive infestations may cause some defoliation, this species is generally less economically significant than shoot-attacking phylloxerans. The insect has a complex life cycle involving multiple generations and both winged and wingless forms.
Phylloxera caryaeglobuli
hickory phylloxeran, hickory phylloxera
Phylloxera caryaeglobuli is a small, soft-bodied, gall-forming insect closely related to aphids. It induces distinctive globular galls on hickory leaves and petioles, particularly on mockernut hickory. The species has a complex life cycle involving parthenogenetic reproduction within galls and winged dispersal stages. It overwinters as eggs deposited on bark or near old galls.
Phylloxera caryaegummosa
pecan phylloxera
Phylloxera caryaegummosa is a tiny, soft-bodied insect in the family Phylloxeridae, closely related to aphids. It is a significant pest of pecan (Carya illinoinensis), causing galls to form on shoots and nuts. This species is considered more damaging than pecan leaf phylloxera (Phylloxera notabilis), which affects only leaves. Heavy infestations can reduce yield, impair tree vitality, and curtail subsequent production. The insect has a complex life cycle involving multiple generations and forms, with winter survival as eggs protected within the bodies of dead females.
Phylloxera caryaemagna
pecan phylloxera
Phylloxera caryaemagna, commonly known as the pecan phylloxera, is a tiny, soft-bodied insect closely related to aphids and a significant pest of pecan trees (Carya illinoinensis). This species is considered the most damaging of the two primary phylloxera species attacking pecans, as it attacks shoots and developing nuts rather than just leaves. The insect induces the formation of galls on new growth through chemical secretions that stimulate abnormal plant tissue development. Widespread infestations can reduce current-year yield, impair tree vitality, and curtail subsequent production. Management requires precisely timed insecticide applications targeting the vulnerable nymph stage before gall formation encloses and protects the insects.
Phylloxera caryaeren
pecan phylloxera, pecan stem phylloxera
Phylloxera caryaeren is a small, soft-bodied, gall-forming insect closely related to aphids that attacks pecan trees (Carya illinoinensis). It is considered the most damaging phylloxera species on pecans because it attacks shoots and developing nuts, unlike the pecan leaf phylloxera which only affects foliage. Heavy infestations can reduce current-year yield, impair tree vitality, and reduce production in subsequent years. The insect is sedentary and cannot fly long distances, so infestations spread slowly from tree to tree.
Phylloxera caryaescissa
pecan leaf phylloxera, hickory phylloxeran
Phylloxera caryaescissa is a tiny, soft-bodied insect closely related to aphids that forms galls on hickory and pecan leaves. The species survives winter as eggs in bark crevices, with nymphs emerging during spring bud break to feed on new growth. Unlike the more destructive pecan phylloxera (Phylloxera devastatrix), this species attacks leaf tissue only and does not damage shoots or nuts. Extensive infestations may cause some defoliation but typically do not significantly reduce yield.
Phylloxera caryaesemen
pecan phylloxera, pecan nut phylloxera
Phylloxera caryaesemen is a small, soft-bodied, gall-forming insect closely related to aphids that attacks pecan trees (Carya illinoinensis). It is considered the most damaging phylloxera species on pecans because it attacks shoots and developing nuts, unlike the related pecan leaf phylloxera which feeds only on leaves. Heavy infestations can reduce current-year yield, impair tree vitality, and diminish subsequent production. The insect induces abnormal plant growths (galls) by secreting substances that stimulate tissue development, with nymphs completing development inside these protective structures.
Phylloxera caryaesepta
pecan leaf phylloxera, pecan phylloxera
Phylloxera caryaesepta is a tiny, soft-bodied insect in the family Phylloxeridae, closely related to aphids. It is a significant pest of pecan trees (Carya illinoinensis), forming conspicuous galls on leaves, twigs, and nuts. The species survives winter as eggs in bark crevices, with nymphs emerging during spring bud break to feed on new growth. Unlike the related pecan leaf phylloxera (Phylloxera notabilis) which attacks only leaves, P. caryaesepta damages shoots and nuts, making it more economically destructive. Heavy infestations can reduce yield, impair tree vitality, and curtail subsequent production.
Phylloxera castaneae
Phylloxera castaneae is a gall-forming insect in the family Phylloxeridae, closely related to aphids. The species induces abnormal plant growths (galls) on its host plants through chemical secretions that manipulate plant tissue development. Like other phylloxerans, it has a complex life cycle involving multiple generations and both parthenogenetic and sexual reproduction. The species name indicates an association with Castanea (chestnut) hosts, though specific details about its biology remain poorly documented in available literature.
Phylloxera chippokesiensis
Phylloxera chippokesiensis is a gall-forming insect in the family Phylloxeridae, closely related to aphids. Like other phylloxerans, it induces abnormal plant growths (galls) on host tissues through chemical secretions that redirect plant development. The species is named for Chippokes Plantation in Virginia, indicating an association with specific geographic or host plant contexts. As with congeners, it likely has a complex life cycle involving parthenogenetic reproduction within galls and seasonal transitions between winged and wingless forms.
Phylloxera conica
hickory phylloxeran, hickory phylloxera
Phylloxera conica is a gall-forming insect closely related to aphids that induces distinctive globular galls on hickory leaves and petioles. The insect overwinters as eggs on bark or near old galls, with nymphs emerging during bud break to feed on new growth. Their feeding stimulates abnormal plant cell development, creating hollow galls that provide shelter and food. The species has a complex life cycle involving multiple generations, with winged forms eventually dispersing to lay overwintering eggs. Heavy infestations can reduce tree vigor and nut production in hickory trees.
Phylloxera crypta
Phylloxera crypta is a gall-forming insect closely related to aphids, known to induce distinctive galls on hickory trees (Carya species). Like other phylloxerans, this species manipulates plant tissue development through chemical secretions during feeding, creating protective structures that house developing nymphs. The species exhibits a complex life cycle involving multiple generations and both sexual and parthenogenetic reproduction phases.
Phylloxera devastatrix
pecan phylloxera
Phylloxera devastatrix, commonly known as the pecan phylloxera, is a gall-forming insect closely related to aphids that infests pecan trees (Carya illinoinensis). It is considered the most damaging phylloxera species attacking pecans because it attacks shoots and nuts, whereas the related pecan leaf phylloxera (Phylloxera notabilis) forms galls only on leaves. Heavy infestations reduce yield, impair tree vitality, and curtail subsequent production. The insect's galls also serve as an alternate host for hickory shuckworm (Cydia caryana) larvae.
Phylloxera echinus
Phylloxera echinus is a species of gall-forming insect in the family Phylloxeridae, closely related to aphids. Like other phylloxerans, this species induces abnormal plant growths (galls) on host plants through chemical secretions that manipulate plant tissue development. The specific host associations and gall morphology of P. echinus have not been well documented in available literature. The genus Phylloxera contains several economically important species, most notably the grape phylloxera (Daktulosphaira vitifoliae), though P. echinus itself appears to be poorly studied.
Phylloxera flavoconica
Phylloxera flavoconica is a species of phylloxeran, a tiny sap-sucking insect in the family Phylloxeridae. Phylloxerans are closely related to aphids and are known for inducing gall formation on host plants. The genus Phylloxera includes species that are significant agricultural pests, most notably the grape phylloxera (Daktulosphaira vitifoliae), though the specific impacts of P. flavoconica are not well documented in available sources.
Phylloxera glabra
Phylloxera glabra is a species of phylloxeran, a group of small, soft-bodied insects closely related to aphids within the family Phylloxeridae. Like other phylloxerans, this species induces gall formation on host plants through chemical secretions that manipulate plant tissue development. The species was described by von Heyden in 1837 and has been recorded from parts of Europe including Belgium, Denmark, and Norway. Phylloxerans exhibit complex life cycles involving multiple generations and both sexual and parthenogenetic reproduction.
Phylloxera intermedia
Phylloxera intermedia is a species of phylloxeran, a group of tiny, soft-bodied insects closely related to aphids. Like other phylloxerans, it induces gall formation on host plants through chemical secretions that manipulate plant tissue development. The species was described by Pergande in 1904. Specific details about its host associations and biology are limited in available literature, though phylloxerans generally have complex life cycles involving both sexual and parthenogenetic generations.
Phylloxera killianae
Phylloxera killianae is a gall-forming insect in the family Phylloxeridae, closely related to aphids. Like other phylloxerans, it induces abnormal plant growths (galls) on host tissues through chemical secretions during feeding. The species overwinters as eggs in bark crevices, with nymphs emerging in spring to feed on new growth and stimulate gall formation. Specific host associations and detailed biology of P. killianae remain poorly documented compared to economically significant relatives such as the grape phylloxera (Daktulosphaira vitifoliae) and pecan phylloxera species.
Phylloxera myristica
Phylloxera myristica is a gall-forming insect in the family Phylloxeridae, closely related to aphids. Like other phylloxerans, this species induces abnormal plant growths (galls) on host plants through chemical secretions that manipulate plant development. The insect develops within these protective structures, which provide both shelter and nutrition. Specific host associations and detailed biology for this species remain poorly documented in available literature.