Some luteovirus diseases in Tasmania caused by beet western yellows and subterranean clover red leaf viruses

Abstract

A range of crop plants, pasture legumes and weeds, mostly with yellows symptoms similar to those caused by luteoviruses, were collected from the field around Tasmania and checked for infection with beet western yellows virus (BWYV) and subterranean clover red leaf virus (SCRLV) using aphids and indicator plants. BWYV was recovered from 216 of 897 plants tested, representing 30 different species and including 16 not previously recorded as natural hosts. SCRLV was recovered from 163 of 637 plants, representing twelve species including four not previously recorded as natural hosts. BWYV was isolated most often from composites and crucifers, while SCRLV was recovered most frequently from legumes. Eight plants were found infected with both viruses together. In host range studies, Tasmanian isolates of BWYV caused symptoms in lettuce, subterranean clover and sugar beet like those seen on these plants in the field from which the virus was isolated, and were thus similar to isolates of BWYV from North America. The Tasmanian isolates of BWYV were also closely related serologically to Californian isolates of BWYV; these were serologically quite distinct from isolates of SCRLV, and both these groups were serologically distinct from legume yellows virus and from potato leaf roll virus.