Scleroracus flavopictus (Ishihara 1953a: 197 )

Description & Identification

Small, slender species. Length of male 3.60—4.00 mm., female 4.00—4.30 mm. (Nielson, 1968)General color dark brown to black. Crown, and pronotum deep tan, heavily marked with black; elytra dark brown to black, veins tan.(Nielson, 1968)This species similar to vaccinii in genital characteristics can be separated by the aedeagus with a pair of long, tubular processes and a lateral spine on each side of the middle of each process. In 1953, Ishihara (385) originally described this species in the genus Omaniella, and then in 1954 he (387) transferred the species to Ophiola and synonymized Omaniella. Later he transferred it from Ophiola to Scleroracus.’ Most American and European authors consider Ophiola as a generic synonym of Scleroracus and I have elected to follow their works. Consequently, I have transferred flavopictus to Scleroracus.(Nielson 1968)

Biology & Ecology

The biology of this species is not well known. Fukushi et al. in 1955 (301) found abundant populations of nymphs and adults on red clover and reared the species in captivity on red clover and potato. (Nielson, 1968)

Worldwide Distribution

This species is known only from Japan. (Nielson, 1968)

Vector Status

Economic Crops

This species is a vector of potato witches’ broom virus and Japanese aster yellows virus. In 1955, Fukushi et al. (301) were first to report transmission of witches’ broom virus in Japan. Leafhoppers were fed on diseased potato and red clover plants for 4 to 15 days, then transferred to healthy potato seedlings to feed from 2 to 48 days. Six of 23 potato plants were infected using diseased potato as the virus source, and 3 of 10 potato plants were likewise infected using diseased clover plants as the virus source. Natural transmission was also effected to Vicia unijuga A. Br., potato, red clover, alsike clover, and China-aster. The incubation period in the insect was not determined, but in plants it was long, ranging from 39—49 days to 98—102 days.The transmission of Japanese aster yellows virus by this species was first reported by Fukushi and Nemoto in 1953 (298). In 1959, Yoshii (873) reported evidence that both viruses were distinct and listed additional host plants of witches’ broom virus.(Nielson 1968)This species is considered an important vector in the natural spread of these viruses in Japan.(Nielson 1968)

Plant Diseases

Phytoplasmas

* Citations of Phytoplasma occurrance in Scleroracus flavopictus (Ishihara 1953a: 197 ) 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).