Unaspis

Unaspis species are armored scales distinguished by their hard, protective test (covering) formed from exuviae and wax secretions. The genus can be differentiated from related armored scale genera by morphological features of the adult female test and body structure; a key to all 19 Unaspis species has been published. Specific identification requires examination of microscopic characters including pygidial margin structures and duct arrangements. U. citri produces a conspicuous white, elongated test on citrus bark, while U. euonymi shows sexual dimorphism with females producing a brown, oyster-shaped test and males producing a narrower white covering.

Species occur in agricultural, horticultural, and urban environments where their host plants grow. U. citri and U. yanonensis inhabit citrus groves and orchards. U. euonymi occurs in urban landscapes, gardens, and nurseries on ornamental shrubs. U. mabilis and U. lansivora infest lanzones (Lansium domesticum) trees in the Philippines.

The genus has a broad global distribution corresponding to host plant ranges. U. citri occurs in citrus-growing regions worldwide including North, Central, and South America, Europe (Azores), Africa, Asia (China, Southeast Asia), Australasia (Australia, New Zealand, Pacific Islands). U. euonymi is established in Europe, Asia, North Africa, and North and South America. U. yanonensis is distributed in East Asia (China, Japan, Korea) and has been reported in France. U. mabilis and U. lansivora are known from the Philippines.

Phytophagous; species feed on plant sap from host tissues. U. citri and U. yanonensis feed on Citrus species. U. euonymi feeds on Euonymus species, Prunus, Hibiscus, and other ornamentals. U. mabilis and U. lansivora feed on Lansium domesticum (lanzones).

• Citrus - primary hostU. citri, U. yanonensis
• Lansium domesticum - primary hostU. mabilis, U. lansivora
• Euonymus - primary hostU. euonymi
• Prunus - hostU. euonymi
• Hibiscus - hostU. euonymi

As phytophagous pests, heavy infestations cause premature leaf senescence, defoliation, reduced fruit production, and tree mortality. U. lansivora has been documented causing tree death in lanzones plantations. The genus serves as prey for introduced and native biological control agents including predatory beetles (Chilocorus kuwanae, Cybocephalus nipponicus) and parasitoid wasps (Aphytis yanonensis, Coccobius fulvus, Aspidiotiphagus spp., Encarsia spp.).

Several species are economically significant agricultural pests. U. citri (citrus snow scale) and U. yanonensis (arrowhead scale) threaten citrus production globally. U. euonymi is a major pest of ornamental Euonymus in urban landscapes. U. lansivora has emerged as a damaging pest of lanzones in the Philippines with potential plant quarantine significance. Management relies on biological control, monitoring, and chemical interventions.

• AulacaspisBoth are armored scale genera in Diaspididae with similar morphology; molecular data shows U. mabilis has 87.4% COI sequence similarity to Aulacaspis tubercularis, but phylogenetic analysis places Unaspis as a distinct monophyletic clade.
• LepidosaphesU. lansivora was initially misidentified as Lepidosaphes ulmi before being recognized as a distinct Unaspis species; both genera produce elongated scale coverings but differ in pygidial and duct morphology.
• ChionaspisU. euonymi was previously classified as Chionaspis euonymi; the genus Unaspis was erected based on distinct morphological features separating it from Chionaspis.

• armored scale
• Diaspididae
• agricultural pest
• horticultural pest
• citrus pest
• biological control
• invasive species
• Asia
• global distribution

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Unaspis euonymi . [Distribution map].
• Unaspis yanonensis . [Distribution map].
• Unaspis citri . [Distribution map].
• Unaspis lansivora sp. n. (Hemiptera: Diaspididae), a new pest of Lansium domesticum (Meliaceae), and a key to Unaspis species
• Distribution of Natural Enemies of Euonymus Scale, Unaspis euonymi (Comstock), in Virginia
• Release of Aphytis yanonensis DeBach et Rosen and Coccobius fulvus Compere et Anneke, parasitoids of Unaspis yanonensis Kuwana introduced to Nagasaki prefecture. Effect on the control of Unaspis yanonensis Kuwana.
• Host selection in arrowhead scaleUnaspis yanonensis: Can arrowhead scale infest KawanonatsudaidaiCitrus natsudaidai?
• Citrus Snow Scale Unaspis citri (Comstock) (Insecta: Hemiptera: Coccoidea: Diaspididae)
• DNA barcode of the Lanzones scale insect, Unaspis mabilis Lit & Barbecho (Hemiptera: Diaspididae)
• Biology of the Euonymus scale Unaspis euonymi (Hemiptera: Diaspididae) in Urban Areas of Ankara, Turkey
• Distribution Patterns of the Number of Unaspis yanonensis Individuals between Trees and within a Tree
• EUONYMUS SCALE, UNASPIS EUONYMI (COMSTOCK) (HOMOPTERA: DIASPIDIDAE): EFFECTS OF HOST CULTIVAR AGE, AND LOCATION ON INFESTATION LEVELS1
• Use of Host Plant Resources by the Euonymus Scale, Unaspis euonymi (Homoptera: Diaspididae)