Aceratagallia obscura Oman

Description & Identification

Small, robust species. Length of male 3.25—3.50 mm., female 3.35—3.50 mm. (Nielson, 1968)General color tan to brown. Vertex with two distinct dark spots; pronotum tan; elytra with brown markings on commissure and claval veins giving banded appearance to body.(Nielson, 1968)Pygofer in lateral aspect about 1% times longer than wide, caudal margin strongly produced posteriorly at about middle to large broadly angled lobe; 10th segment with pair of long straight spines directed posteroventrad along inside of caudal submargin of pygofer; aedeagus in lateral aspect simple, basal third of shaft tubelike, slightly curved laterally and narrowed at apex; gonopore terminal; style in dorsal aspect with margins of distal third parallel, inner margin coarsely serrate, sharp spine on apex of outer margin, bluntly pointed spine on apex of inner margin, small subapical spine on ventral surface; female 7th sternum in ventral aspect with caudal margin deeply notched at middle with small notch on each side of middle. (Nielson, 1968)From eurvata, to which it is closely allied, obscura can be separated by the distal part of the style, of which the lateral margins are parallel.(Nielson 1968)

Biology & Ecology

Little is known on the biology of this species. DeLong and Davidson in 1931 [186] reported it from 22 crops in California under the name of 'Agallia lyrata.” Common crops attacked were alfalfa, potato, beans, carrots, turnips, and sugarbeets, which supported the heaviest populations. Oman in 1933 [576] also reported it from sugarbeets in California. (Nielson, 1968)

Worldwide Distribution

It is restricted to the Western United States in the coastal States of California and Oregon (Oman 1933). (Nielson, 1968)

Vector Status

Economic Crops

This species is a vector of the New York strain of potato yellow dwarf virus. Black (81) was first to report this species as a vector of this virus in 1944. Transmission was accomplished from diseased crimson clover to healthy crimson clover plants. Details of the transmission tests were not given. Specimens used in the tests were sent to New Jersey from California. Although obscura transmitted potato yellow dwarf virus experimentally in New Jersey, it has not been incriminated as a vector of other viruses nor have other workers confirmed Black’s work.(Nielson 1968)This species is considered a potentially important vector of potato yellow dwarf virus in the Western United States.(Nielson 1968)

Plant Diseases