Christmas-tree-pest
Guides
Adelges piceae
Balsam Woolly Adelgid, Balsam Woolly Aphid
Adelges piceae is a small, wingless, sap-sucking insect native to Europe that has become a destructive invasive pest of fir trees (Abies spp.) in North America. Introduced to the United States around 1900, it has killed millions of trees across the continent. The species produces distinctive white, woolly wax secretions that protect adults and eggs. It is particularly damaging to balsam fir and Fraser fir, causing gouting, reduced growth, and tree mortality.
Chionaspis
pine needle scale
Chionaspis is a genus of armored scale insects (family Diaspididae) that feed primarily on conifers, especially pines. The genus contains multiple species, including at least 10 cryptic species in the pine-feeding complex previously treated as two species (C. pinifoliae and C. heterophyllae). Species in this genus are economically significant pests of pine trees and Christmas tree plantations. Adult females are sedentary, covered by a hard waxy shield, and lack wings; males develop wings as adults.
Cinara costata
Mealy Spruce Aphid
Cinara costata is a large aphid species in the family Aphididae, commonly known as the Mealy Spruce Aphid. It feeds on conifers, particularly spruce (Picea spp.), and is native to Europe where it has been documented in Great Britain, Denmark, Belgium, and France. Like other Cinara species, it produces honeydew that attracts ants and wasps. The species was first described by Zetterstedt in 1828 from specimens collected in Scandinavia.
Cinara obscura
Dark Spruce Stem Aphid
Cinara obscura is a species of large aphid in the family Aphididae, commonly known as the Dark Spruce Stem Aphid. It is a conifer-feeding aphid that infests spruce trees (Picea species). Like other members of the genus Cinara, it possesses a long piercing-sucking beak adapted for tapping into phloem tissues. The species overwinters as eggs on host needles. It produces honeydew, which attracts ants and wasps and supports sooty mold growth.
Colaspis pini
Pine Colaspis
Colaspis pini, commonly known as the pine colaspis, is a leaf beetle in the family Chrysomelidae. First described by American entomologist Herbert Spencer Barber in 1937, this species is known to feed on pines in the southern United States. It has been documented as an occasional pest of Christmas trees. The species is externally almost identical to Colaspis flavocostata but can be distinguished by the shape of the male aedeagus. Two subspecies are recognized: C. p. pini and C. p. schotti.
Fiorinia
Fiorinia is a genus of armored scale insects (family Diaspididae) comprising approximately 70 species. The genus is characterized by pupillarial development, where the adult female remains enclosed within the second-instar exuviae. Species are predominantly distributed in tropical and subtropical Asia and the Pacific Islands, though several have become invasive pests globally through trade in ornamental plants. Notable invasive species include F. externa (elongate hemlock scale), F. fioriniae (palm fiorinia scale), F. phantasma (phantasma scale), and F. theae (tea scale).
Fiorinia externa
elongate hemlock scale
Fiorinia externa, the elongate hemlock scale, is an invasive armored scale insect native to Japan and southern China. Accidentally introduced to North America around 1908, it has become established throughout the northeastern United States and threatens hemlock (Tsuga) and related conifers. The species is a pupillarial scale, with adult females remaining within their second-instar exuviae. Heavy infestations cause yellowing, premature needle drop, branch dieback, and occasional tree death. It poses particular economic concern for Fraser fir Christmas tree production in the southeastern United States, where it can persist on harvested trees for up to 13 weeks post-harvest.
Hylobius pales
Pales Weevil
Hylobius pales, commonly known as the pales weevil, is a significant forest pest in North America that primarily attacks coniferous trees, especially species of Pinus. Adults are dark red-brown with yellowish or gray hair tufts on the elytra and thorax, and possess a robust, cylindrical, gently curved rostrum nearly as long as the thorax. The species is particularly damaging to young pine seedlings in cut-over areas and Christmas tree plantations, with mortality rates reaching 30-70% in unprotected plantings. Larvae develop in stumps and roots of host trees, while adults feed on bark.
Mindarus
balsam twig aphid
Mindarus is a genus of conifer-feeding aphids in the family Mindaridae, commonly known as balsam twig aphids. Species in this genus are specialized phloem feeders on fir trees (Abies spp.), where they cause needle discoloration, shoot deformation, and reduced aesthetic quality. Several species are significant economic pests in Christmas tree plantations, particularly M. abietinus on balsam fir and M. pinicola on Fraser fir. The genus exhibits a holocyclic life cycle with overwintering eggs, spring fundatrices, and summer parthenogenetic generations.
Paradiplosis
balsam gall midge (for P. tumifex)
Paradiplosis is a genus of gall midges (Cecidomyiidae) containing at least four described species. The genus is best known for P. tumifex, the balsam gall midge, which induces characteristic needle galls on balsam fir and is a significant pest in Christmas tree plantations. Other species include P. abietispectinatae, P. manii, and P. obesa. Species in this genus are associated with coniferous hosts and exhibit specialized gall-inducing behaviors.
Pleocoma dubitabilis
rain beetle
Pleocoma dubitabilis is a rain beetle species in the family Pleocomidae. It is known from North America and comprises two recognized subspecies: P. d. dubitabilis and P. d. leachi. The nominate subspecies has been documented as a pest of commercially grown Christmas trees, specifically feeding on Abies species.
Pleocomidae
Rain Beetles
Pleocomidae, known as rain beetles, is a family of scarabaeoid beetles found in western North America. The family contains a single extant genus, Pleocoma, with two extinct genera known from the fossil record. Adults emerge in response to rain or snow events, giving the group its common name. The family is considered the sister group to all remaining families of Scarabaeoidea. At least one species, Pleocoma dubitabilis dubitabilis, has been documented as a pest of Christmas trees.