Cuerna occidentalis Oman & Beamer 1944a: 119

Occidental sharpshooter

Published in: Oman, P.W. & Beamer, R.H. (1944a) Some new species of Cuerna (Homoptera-Cicadellidae). Journal of the Kansas Entomological Society, 17(3), 119–120.

Description & Identification

Medium size, slender species.male 5.80—6.60 mm., female 6.60—7.40 mm. (Nielson, 1968)General colour yellowish gray to black with prominent yellow or ivory band running laterally from anterior margin of head to eighth tergum; head, pronotum, scutellum, and elytra with numerous fine yellow and black markings.(Nielson, 1968) Pygofer in lateral aspect about 1½ times as long as wide, can-dab margin convex; aedeagus in lateral aspect excluding atrial processes about 1½ times longer than wide, shaft very short, curved posterodorsad with prominent tooth on each side of middle in caudal aspect; lateral atrial processes bong, about 1½ times longer than caudal atrial processes, basal two-thirds straight, apical one-third curved posterodorsad, projecting dorsad beyond apex of aedeagal shaft, broad basally, attenuated apically; caudal atrial processes short, narrower than lateral atrial processes, nearby straight, projecting dorsad to but not extending beyond apex of aedeagal shaft, curved slightly laterad in caudal aspect; female eighth sternum in dorsal aspect with two weakly sclerotized, elongate, oval-shaped, symmetrical plates about half as long as seventh tergum and broadly separated from each other; each plate projecting posterolaterad, sometimes nearly laterad, lateral sides nearly parallel, apex convex. (Nielson, 1968)This species, similar to yuccae in general habitus, can be distinguished by the aedeagus with lateral and caudal atrial processes straight and projecting dorsad in lateral aspect.(Nielson 1968)

Biology & Ecology

The biology is unknown. The principal host of this vector is not known, but it has been recorded by Nielson in 1965 (563) from Aretosta.phylos pungen.s IIBK, Symphoricarpos sp., Artemisia sp., Lotus sp., Lupinus sp., and grass. In 1952, Freitag et al. (287) reported good survival on grape and alfalfa during virus transmission experiments, and Freitag and Frazier later in 1954 (286) collected it from unidentified range weeds. (Nielson, 1968)


Oman & Beamer 1944a: 119

Common Names (full list)

Occidental sharpshooter
Source: Catalogue of Life Checklist

Additional Images

Images provided by GBIF data providers. We cannot verify that identifications are correct.

Worldwide Distribution

United States: California (Nielson 1965a)It is known only from the southern half of California. In 1965, Nielson (563) examined specimens from Alpine, Bbythe, Campo, Cbaremont, Cucamonga, Davis Creek, Green Valley, He-met, Idyllwild, Jacumba, Laguna Mountains, Mill Valley, Mint Canyon, Pasadena, Pine Hills, Pine Meadows, Riverside, San Diego, San Jacinto Mountains, and Santa Maria. (Nielson, 1968)

North America

Distribution point data provided by GBIF.

Vector Status

Economic Crops


This species is a vector of Pierce’s disease virus of grape in California. Frazier (273) first reported this species as a vector of this virus in 1944. Later, in 1952 Freitag et al. (287) confirmed these results and showed that the species was an efficient vector by infecting 63 percent of plants tested. The virus was transmitted from diseased grape to healthy grape and alfalfa, and from diseased alfalfa to healthy grape and alfalfa. The high percentage of transmission was attributed to long survival of the vector on test plants. Natural infectivity was demonstrated by testing field-collected specimens (Freitag and Frazier 1954) [286]. Twenty-eight percent of seven individuals tested were infective.(Nielson 1968)This species is considered of some importance in the natural spread of Pierce’s disease virus of grape.(Nielson 1968)

Plant Diseases


Nielson, M. W. 1968b. The leafhopper vectors of phytopathogenic viruses (Homoptera, Cicadellidae). Taxonomy, biology and virus transmission.

Redak et. al., 2004.

The Biology of Xylem Fluid-Feeding Insect Vectors Of Xylella fastidiosa and Their Relation to Disease Epidemiology

EFSA, 2019.

Pest categorisation of non-EU Cicadomorpha vectors of Xylella spp.


Redak et. al., 2004.

The Biology of Xylem Fluid-Feeding Insect Vectors Of Xylella fastidiosa and Their Relation to Disease Epidemiology


Cicadellidae Cicadellinae Cuerna Grape Membracoidea North America Other Proconiini Alfalfa dwarf disease (AD) Pierce's disease Xylella fastidiosa

Cuerna occidentalis Oman & Beamer 1944a: 119: Wilson M. R. & Turner J. A. 2021. Insect Vectors of Plant Disease. Amgueddfa Cymru - National Museum Wales. Available online at [ Accessed:  17/06/2024 ].
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