Draeculacephala minerva Ball 1927c: 36Membracoidea : Cicadellidae
|Diseases Transmitted||Pathogen Type|
|Crops Affected by Draeculacephala minerva Ball 1927c: 36|
This species is a vector of Pierce’s disease virus of grape in California. It was first suspected as a vector by Weimer in 1937 (854), when he tested a number of leafhoppers species and other insects for transmission of alfalfa dwarf virus. Although transmission of the virus was effected in this instance, Hewitt et al. in 1949 and1942 (359, 361) were successful in transmitting the virus to grape by minerva. In 1942 Houston et al. (379) confirmed transmission to alfalfa. Further confirmation was reported by Hewitt et al. in 1946 (362) when a high percentage of transmission occurred from diseased alfalfa and grape to healthy alfalfa and grape. The species was also naturally infective. The incubation period in the vector was less than 4 days. In 1947, Houston et al. (378) in studies of vector feeding found that 88 percent of the total feeding punctures made by minerva ended in the xylem tissue.
Further studies on the transmission of Pierce’s disease virus were reported by Severin in 1949 (706), Freitag 1951 (282), and Freitag and Frazier in 1955 (288). Severin found that the minimum latent period of the virus in the vector was 7 hours and the maximum was 24 hours. He also reported that single leafhoppers were capable of transmitting the virus effectively from diseased grape to healthy grape but not from diseased alfalfa to healthy alfalfa. In 1951, Freitag (282) reported that 75 species of plants in 23 families were experimentally infected with Pierce’s disease virus. Most of the infections were made by minerva. He also found that virus was not passed through the egg of minerva. In 1954 Freitag and Frazier (286) showed that percentage of natural infectivity of nymphs varied from 8 to 13 and of adults from 9 to 40. The insects were infective during most of the year.
This species is one of the most important vectors of Pierce’s disease virus of grape in California and is responsible for much of the natural spread of the virus in alfalfa and grape.
Medium size, slender species. Length of male 5.30—5M0 mm., female 6.40—6.70 mm.
General color green. Crown and pronotum light green; elytra dark green with apex weakly reticulated, veins yellowish green.
Pygofer in lateral aspect about 11/4 times as long as wide, caudodorsal margin narrowed to distinct, fingerlike lobe; aedeagus in lateral aspect curved laterally, somewhat narrowed apically with distinct median broad tooth on dorsal margin, shaft somewhat pear shape in ventral aspect; paraphyses symmetrical with two pairs of processes, terminal pair about twice as long as basal pair; style in dorsal aspect simple, sharply attenuated apically; female seventh sternum in ventral aspect with short spatulate process on caudal margin.
This species is closely related to
from which it is very difficult to separate on the basis of the male genitalia.
Colored illustrations of the adults were published by Hewitt et al. (1949) and DeLong and Severin (1949)
illustrated the male genitalia.
|Nielson, M. W. 1968b. The leafhopper vectors of phytopathogenic viruses (Homoptera, Cicadellidae). Taxonomy, biology and virus transmission. United States Department of Agriculture Technical Bulletin . 1382 386 pp.|