Orosius argentatus Distant 1918b: 85
Description & Identification
Small, linear species. Length of male 2.90—3.00 mm., female 3.00mm. (Nielson, 1968)
General color light brown to dark brown. Crown grey to light brown, disk with brown or black spots and reticulate markings; pronotum light brown with small dark-brown reticulations; elytra light grey with numerous brown or black markings bordering cells and numerous reticulations among cells.(Nielson, 1968)
This species is one of two in the genus Orosius that is a vector of a plant virus, and it can be separated from albicinctus by the aedeagus with shafts nearly parallel in ventral aspect. No résumés or illustrations of albicinctus are presented here owing to lack of authentically determined material.In 1960, Linnavouri (462) transferred Orosius argentatus to the genus Nesophrosyne on the basis that the former genus was congeneric ith the latter. Later in 1960, he (463) suppressed argentatus as a synonym of N. lotophagorum (Kirkaldy) without access to type material. According to Ghauri (personal communication), who had finished a revision of Orosius at the time of this writing, argentatus is distinct from lotophagorum and belongs in the genus Orosius.
(Nielson 1968)
Biology & Ecology
The biology of this species is well known. Many host plants have been recorded. The insect’s appearance in tobacco fields in large numbers was the result of migrations initiated by drying up of winter and spring host plants (Hill 1941 [366]). In 1942, Helson (347) collected specimens from a wide range of host plants, but only nymphs were found on a few plants. The insect completed its life cycle continuously on Malva patviflora L., Modiola caroliniana (L.) G. Don, and Beta vulgaris L. Eight species were recorded as autumn and spring hosts and an additional eight species supported summer populations. Many other plants, including tobacco and tomato, were poor hosts as evidenced by failure of nymphs or adults to survive on these plants.The life history studied in the laboratory by Helson in 1942 (347) on M. parviflora showed that oviposition began 3 to 7 days after the insect reached the adult stage. Eggs were laid singly in the stem, petiole, or leaf rib and hatched in 7 to 22 days. There were five instars, each requiring about 5 days to complete development. Females laid an average of six eggs per day for several months. The maximum longevity for a male was 125 days and for a female 240 days. Insects overwintered as adults in cold regions and as adults and nymphs in warm regions. Three generations a year were found. Females were fertilized in the autumn and laid eggs until the end of August, producing the first generation of adults in October. The peak of the second generation occurred in late February, and adults of the third and overwintering generation appeared in late March. The insect was carried through a succession of host plants alternating between dry-hot and cool-wet seasons.In 1951, Helson (348) studied the seasonal abundance in lucerne fields in the Australian Capital Territory and found highest populations of adults in November and December. Swarming occurred in January and populations gradually disappeared from lucerne fields by June. The insect did not prefer lucerne, but evidently survived on other plants growing in the field. Aster was found to be an excellent breeding host. -In 1956, Bergman (68) studied the biology in West Java on groundnuts and found that the eggs were laid in the petioles and stems. The egg stage varied from 9 to 10 days and the nymphal stage from 14 to 16 days. Females laid an average of 5 eggs per day, and the highest number laid by a single female was 200. The nymphs and adults fed on the underside of the leaves and on the stems and petioles. Populations were never very high on groundnuts and did not fluctuate during the season.In 1951, Day and McKinnon (162) studied the ingestion of radioactive plant sap and found that the insect excreted 65 percent of ingested material within 30 minutes after feeding. No conclusion was drawn to account for the insect’s variability in transmitting plant viruses. Feeding tracks of argentatus terminated about equally in the phloem as in the parenchyma tissue (Day et al. 1952 [161]). (Nielson, 1968)
Classification
Synonymy
Thamnotettix argentea (Evans, 1938)
Common Names (full list)
Source: Catalogue of Life
Additional Images
Images provided by GBIF data providers. We cannot verify that identifications are correct.
Worldwide Distribution
It is known from Australia, Fiji, New Britain, and Java (Ghauri, personal communication). Hill and Helson (1949)and Helson in (1951) reported it from all regions in Australia from the moist tropics in the north to the dry temperate areas in the south and west. Bergman (1956) recorded it from Indonesia. Owing to the confusion in the literature between argentatus and lotophagorum, records of distribution outside of those given above are probably not applicable to argentatus
Distribution point data provided by GBIF.
Vector Status
Economic Crops
This species is a vector of tobacco yellow dwarf virus, tomato big bud virus, lucerne witches’ broom virus, potato purple top wilt virus, legume little leaf virus in Australia, mosaic I virus, and witches’ broom virus of groundnuts in Java. Tomato big bud, lucerne witches’ broom, and potato purple top wilt diseases are believed to be caused by the same virus or different strains of the same virus. The others are a complex of different but closely related viruses.In 1941, Hill (366) was first to report transmission of yellow dwarf of tobacco virus by this species under the name of 'Thamnotettix argentata.” A total of 121 of 262 plants were infected with the virus using populations collected from diseased tobacco fields and other sources. Both nymphs and adults transmitted the virus.Transmission of tomato big bud virus was first reported by Hill in 1943 (367). Twenty-three species of plants in 13 families were infected with the virus by means of the leafhopper. The virus occurred naturally in numerous other plants, a few of which were used as sources of inoculum in transmission tests. Lucerne witches’ broom virus and its transmission were first reported by Helson in 1951 (348). Naturally infective leafhoppers transmitted the virus to Datura stramonium L. Helson subsequently transmitted the virus to seven species of plants after nonviruliferous leafhoppers were caged on diseased lucerne from 3 to 20 days and transferred to test plants for 14 to 96 days.Hutton and Grylls (382) were first to report the transmission of legume little leaf virus in 1956. Laboratory-reared leafhoppers from Canberra failed to transmit the virus whereas those collected from legume plots at other stations did. The virus was transmitted to 48 of 68 plants in 10 species. Numerous other species of plants were found as natural hosts of the virus. The authors stated that potato purple top wilt virus was related to legume little leaf virus.In 1956, Bergman (68, 69) transmitted witches’ broom of peanuts to peanuts and was first to report transmission of a new virus, mosaic I, of peanuts. The insects remained infective up to 77 days and the latent period of the virus in the insect was at least 8 days. Thung and Hadiwidjaja in 1957 (787) confirmed transmission of witches’ broom virus to groundnut by feeding nymphs for 10 days on diseased plants and 10 days on one series of healthy plants and another 10 days on a second series of healthy plants. Of 84 plants tested, 24 were infected. Most of the infections were obtained in the second series of plants tested.(Nielson 1968)This species is considered an important vector of a complex of several viruses in Australia and West Java. The relationship among these viruses is not fully understood as evidenced by the lack of information on virus-vector and virus-plant relationships.(Nielson 1968)
Plant Diseases
Nielson, M. W. 1968b. The leafhopper vectors of phytopathogenic viruses (Homoptera, Cicadellidae). Taxonomy, biology and virus transmission.
Nielson, M. W. 1968b. The leafhopper vectors of phytopathogenic viruses (Homoptera, Cicadellidae). Taxonomy, biology and virus transmission.
Phytoplasmas
Grylls, N.E. 1979. Leafhopper vectors and the plant disease agents they transmit in Australia. In: "Leafhopper Vectors and Plant Disease Agents", eds K. Maramorosch and K.F. Harris, Academic Press, New York, pp. 179- 214
Helson, G.A.H. 1951. The Transmission of Witches' Broom Virus Disease of Lucerne by the Common Brown Leafhopper, Orosius argentatus (Evans). Australian Journal of Biological Sciences, 4(2): 115 - 124
Grylls, N.E. 1979. Leafhopper vectors and the plant disease agents they transmit in Australia. In: "Leafhopper Vectors and Plant Disease Agents", eds K. Maramorosch and K.F. Harris, Academic Press, New York, pp. 179- 214
Grylls, N.E. 1979. Leafhopper vectors and the plant disease agents they transmit in Australia. In: "Leafhopper Vectors and Plant Disease Agents", eds K. Maramorosch and K.F. Harris, Academic Press, New York, pp. 179- 214
Glenn, D. 2000. National program for the management of phytoplasmas in australian grapevines. In: Final report CRCV 95/2 for grape and wine research and development corporation
Pilkington, L.J., Gurr, G.M., Fletcher, M.J., Nikandrow, A., Elliott, E. 2004. Vector status of three leafhopper species for Australian lucerne yellows phytoplasma. Australian Journal of Entomology, 43: 366-373
* Citations of Phytoplasma occurrance in Orosius argentatus Distant 1918b: 85 have been exctracted from the database of Hemiptera-Phytoplasma-Plant (HPP) biological interactions worldwide (Valeria Trivellone. (2019). Hemiptera-Phytoplasma-Plant dataset (v1.2) [Data set]. Zenodo. https://doi.org/10.5281/zenodo.2532738).