Virus-vector
Guides
Planococcus
mealybugs
Planococcus is a genus of mealybugs in the family Pseudococcidae, comprising economically significant agricultural pests. The genus includes species such as Planococcus citri (citrus mealybug), Planococcus ficus (vine mealybug), and Planococcus minor, which infest a wide range of host plants including citrus, grapevines, and numerous horticultural crops. These insects cause direct damage through phloem feeding and indirect damage via honeydew secretion that promotes sooty mold growth; several species are also known vectors of plant viruses. The genus is characterized by small, soft-bodied insects covered in white, powdery wax secretions, with complex taxonomic histories involving multiple synonymies and cryptic species complexes.
Planococcus citri
citrus mealybug
Planococcus citri, the citrus mealybug, is a highly polyphagous pest native to Asia that has established populations worldwide through human-mediated transport. Adult females are approximately 3 mm long, wingless, and covered in white wax with marginal filaments; males are slightly larger with functional wings. The species reproduces sexually with multiple generations per year, producing ovisacs containing up to 20 eggs. It feeds on phloem sap from over 200 host plant species across 82 families, causing direct damage through sap removal and indirect damage via honeydew secretion and sooty mold growth. It is also a known vector of Cacao swollen shoot virus. The species is difficult to distinguish morphologically from the vine mealybug (Planococcus ficus), requiring microscopic examination of pore and duct arrangements or molecular methods for accurate identification.
Pseudococcus longispinus
long-tailed mealybug, longtailed mealybug
Pseudococcus longispinus is a cosmopolitan mealybug pest in the family Pseudococcidae. It is distinguished by two long, waxy filaments extending from the posterior abdomen of adult females. The species is a significant agricultural and horticultural pest, particularly damaging to grapevines, citrus, orchids, and tropical fruits. It is a known vector of Grapevine leafroll-associated virus 3 (GLRaV-3), transmitting the virus only during the first instar crawler stage. The species has been observed to develop three generations annually in temperate regions, with complex dispersal patterns shifting from exposed foliage in early instars to protected bark and fruit clusters for reproduction.
Pseudococcus maritimus
grape mealybug, vine mealybug
Pseudococcus maritimus, commonly known as the grape mealybug or vine mealybug, is a scale insect in the family Pseudococcidae that primarily infests grapevines (Vitis vinifera). It has been documented as a vector of Grapevine leafroll-associated virus 3 and, more recently, was confirmed to transmit Little cherry virus 2 to sweet cherry, making it an economically significant pest in tree fruit and vineyard systems. The species is part of a species complex that includes morphologically similar taxa such as Pseudococcus meridionalis. Research indicates limited natural dispersal capacity, with first instars rarely walking between plants and wind dispersal declining sharply with distance from source plants.
Rhopalosiphum
Cherry-Grass Aphids
Rhopalosiphum is a genus of aphids in the family Aphididae comprising approximately 16-17 species worldwide. Species within this genus are significant agricultural pests, feeding on phloem of host plants and causing direct damage to crops. Several species, notably Rhopalosiphum padi (bird cherry-oat aphid) and Rhopalosiphum maidis (corn leaf aphid), are important vectors of plant viruses including barley yellow dwarf virus and maize dwarf mosaic virus. The genus exhibits typical aphid characteristics including polymorphism with both winged and wingless forms, and parthenogenetic reproduction in favorable conditions.
Rhopalosiphum maidis
Corn Leaf Aphid, Corn Aphid
Rhopalosiphum maidis is a globally distributed aphid species and the most economically damaging aphid pest of maize (Zea mays), particularly in tropical and warmer temperate regions. It feeds on phloem sap and causes direct damage through photoassimilate removal. Dense populations can deposit large amounts of honeydew on maize tassels, preventing pollen shed and reducing yield by up to 90%. The species transmits several destructive plant viruses including Maize yellow dwarf virus, Barley yellow dwarf virus, Sugarcane mosaic virus, and Cucumber mosaic virus. Most populations reproduce parthenogenetically (anholocyclic), though sexual reproduction has been reported in Pakistan and Korea with Prunus species as primary hosts.
Rhopalosiphum padi
bird cherry-oat aphid, oat-bird cherry aphid, apple-grain aphid
Rhopalosiphum padi is a globally distributed aphid species and major pest of temperate cereal crops. It exhibits a complex life cycle involving host alternation between a woody primary host (Prunus padus, bird cherry) and herbaceous secondary hosts including barley, oats, wheat, and other grasses. The species is the principal vector of barley yellow dwarf virus (BYDV) and several other economically important plant viruses. Unlike some cereal aphids, it does not inject toxins while feeding, so direct damage from feeding is generally less severe than virus transmission losses.
Rhopalosiphum rufiabdominale
rice root aphid, red rice root aphid
Rhopalosiphum rufiabdominale is a globally distributed root-feeding aphid pest with a remarkably broad host range spanning 22 plant families. Native to East Asia, it has established populations across every continent except Antarctica. The species exhibits a heteroecious holocyclic life cycle in its native range, alternating between Prunus species (primary hosts) and herbaceous plant roots (secondary hosts), though asexual reproduction dominates in temperate regions and protected cultivation. Its subterranean habit makes detection difficult and management challenging. The aphid vectors several economically important plant viruses including barley yellow dwarf virus and sugarcane yellow leaf virus, and has emerged as a significant pest of indoor-grown cannabis in North America.
Scirtothrips dorsalis
chilli thrips, yellow tea thrips, castor thrips, Assam thrips, strawberry thrips
Scirtothrips dorsalis is a highly invasive thrips species native to South or Southeast Asia that has achieved global distribution over the past two decades. It is a significant agricultural pest with an exceptionally broad host range spanning vegetables, ornamentals, and fruit crops. The species is characterized by rapid population growth, with development from egg to adult completed in approximately two weeks under optimal conditions. Its feeding causes distinctive damage including leaf curling, brown scarring along leaf veins, and bronzing to blackening of fruits and flowers. The species has been implicated in transmission of tospoviruses, though its efficiency as a vector remains debated. Genetic evidence indicates S. dorsalis represents a species complex of morphologically similar but genetically distinct lineages.
Sipha
yellow sugarcane aphid (for S. flava), hedgehog grain aphid (for S. maydis)
Sipha is a genus of aphids (Aphididae) in the tribe Siphini, with nearly cosmopolitan distribution. The genus includes notable agricultural pests, particularly Sipha flava (yellow sugarcane aphid) and Sipha maydis (hedgehog grain aphid). Species in this genus feed on grasses and cereal crops, with some capable of transmitting plant viruses such as barley yellow dwarf virus. Several species have expanded their ranges rapidly in recent decades, becoming significant pests of sorghum, sugarcane, wheat, and barley.
Sitobion
Sitobion is a genus of aphids in the family Aphididae, comprising more than 80 described species. Species within this genus are primarily associated with grasses and cereal crops, with Sitobion avenae (English grain aphid) being the most extensively studied. These aphids are phloem-feeding insects that can cause direct damage to host plants and vector plant viruses. The genus has a cosmopolitan distribution, with species found across Europe, Asia, Africa, North America, South America, and Oceania.
Sogatella
white-backed planthopper (for S. furcifera)
Sogatella is a genus of delphacid planthoppers in the family Delphacidae, comprising more than 20 described species. The genus was established by Fennah in 1956. The best-studied species, Sogatella furcifera (white-backed planthopper), is a major agricultural pest of rice across Asia. Members of this genus are characterized by their association with rice and grass hosts, with S. furcifera serving as a vector for plant viruses including southern rice black-streaked dwarf virus.
Sogatella kolophon
Sogatella kolophon is a delphacid planthopper species with a broad pantropical and subtropical distribution spanning Africa, Australia, the Caribbean, Central America, North America, Oceania, South America, and Southern Asia. It is a documented vector of at least two significant plant viruses: Digitaria striate virus (a rhabdovirus) and pangola stunt virus (a fijivirus), both affecting pasture grasses in the genus Digitaria and related grasses. The species has three recognized subspecies: S. k. atlantica, S. k. kolophon, and S. k. meridiana. Immature stages have been described, though detailed biological information remains limited in accessible literature.
Spissistilus
Three-cornered alfalfa hopper (for S. festinus)
Spissistilus is a genus of treehoppers (family Membracidae) native to North and Central America and the West Indies. The genus was erected by John S. Caldwell in 1949, with Membracis festina (now Spissistilus festinus) as the type species. The genus contains eight recognized species, with S. festinus being the most economically significant due to its status as a major agricultural pest.
Spissistilus festinus
threecornered alfalfa hopper, three-cornered alfalfa hopper
Spissistilus festinus is a treehopper species in the family Membracidae, commonly known as the threecornered alfalfa hopper. It is a significant agricultural pest of leguminous crops, particularly alfalfa, soybeans, and peanuts, causing damage through stem girdling. The species has gained additional economic importance as the confirmed vector of Grapevine red blotch virus (GRBV), a pathogen threatening North American viticulture. Two distinct genetic lineages exist in the United States—Southeastern and Californian—with documented differences in viral transmission efficiency. The species exhibits a hemimetabolous life cycle with temperature-dependent development rates and uses substrate-borne vibrational signals in mating communication.
Tagosodes
sogata
Tagosodes is a genus of delphacid planthoppers native to the Americas. The genus contains at least three described species, including Tagosodes orizicolus, a major agricultural pest of rice in Latin America. This species transmits rice hoja blanca virus (RHBV) and causes direct feeding damage to rice plants. The genus was established by Asche & Wilson in 1990.
Tarophagus
taro planthoppers
Tarophagus is a genus of delphacid planthoppers that feed on taro (Colocasia esculenta) and related aroid plants. The genus contains three recognized species: T. colocasiae, T. persephone, and T. proserpina, which are distinguished by male and female genitalia characters and have non-overlapping geographic distributions across Asia and the Pacific. These insects have been used as circumstantial evidence in biogeographic studies of taro domestication and origins. The genus was first described by Zimmerman in 1948.
Therioaphis
Therioaphis is a genus of aphids in the family Aphididae comprising more than 20 described species. The genus includes significant agricultural pests, notably the spotted alfalfa aphid (Therioaphis maculata, also treated as T. trifolii forma maculata) and the yellow clover aphid (Therioaphis trifolii), which infest alfalfa, clovers, and related legumes. These species have been extensively studied for biological control, host plant resistance, and their role as vectors of plant pathogens including alfalfa mosaic virus.
Thripidae
Common Thrips
Thripidae is the most species-rich family of thrips, comprising over 290 genera and approximately 2,000 species. Members are characterized by derived morphological traits including a downward-curving saw-like ovipositor, narrow wings with two longitudinal veins, and antennae bearing six to ten antennomeres with stiletto-like forked sense cones on segments III and IV. The family is divided into four subfamilies: Thripinae (227 genera), Panchaetothripinae (38 genera), Dendrothripinae (16 genera), and Sericothripinae (11 genera). Many species are economically significant agricultural pests, with some exhibiting invasive characteristics.
Thripinae
Thripinae is a subfamily of thrips (order Thysanoptera, family Thripidae) comprising approximately 1,400 species across 150 genera. The subfamily contains the majority of economically significant pest thrips, including species that damage crops through direct feeding and virus transmission. A 2012 molecular phylogeny found Thripinae to be paraphyletic, indicating that taxonomic revisions are needed to clarify relationships within the group. Members are distributed worldwide, with particularly high diversity in tropical and subtropical regions.
Thrips tabaci
onion thrips, potato thrips, tobacco thrips, cotton seedling thrips, tomato thrips
Thrips tabaci is a minute agricultural pest thrips species known by multiple common names reflecting its broad host range. Adults measure 1–1.3 mm and exhibit highly female-biased sex ratios in many populations, with reproduction primarily by parthenogenesis. The species causes direct damage through rasping-sucking feeding and serves as a vector for multiple plant viruses including tomato spotted wilt virus and iris yellow spot virus. It is considered the most serious insect pest of onion crops in tropical regions and has achieved global distribution.
Trialeurodes abutiloneus
bandedwinged whitefly, banded-wing whitefly
Trialeurodes abutiloneus is a small whitefly species in the family Aleyrodidae, first described by Haldeman in 1850. Adults measure approximately 1 mm in length and are distinguished by transverse zig-zag bands on the forewings. The species is a phloem-feeding plant pest and a known vector for Abutilon yellows virus and Sweet potato chlorotic stunt virus. It is primarily associated with malvaceous crops including cotton and hibiscus, as well as sweet potato and soybean.