The leafhoppers Orosius argentatus(Evans),Austroagallia torrida(Evans) and Batracomorphus angustatus(Osborn) were used in transmission tests to determine their vector status for the phytoplasma associated with Australian lucerne yellows (ALuY). Caged, seed-grown lucerne plants were monitored for foliar symptom expression after feeding by leafhoppers transferred from ALuY symptomatic lucerne plants. Twelve of 25 plants developed phytoplasma disease-like symptoms including stunting and yellowing. The most pronounced foliar symptoms were displayed by five plants that had been fed on byO. argentatus and four plants that had been fed on byA. torrida.One plant, fed on byO. argentatus, showed the distinctive root symptoms of ALuY.A phytoplasma was identified by electron microscopy in two plants fed on byO. argentatusand one byA. torrida. For each group of plants that had been fed on by a single leafhopper species, one plant was phytoplasma positive as determined by the polymerase chain reaction (PCR) using universal primers. The phytoplasma detected by PCR in the plant fed on byA. torridawas identified by restriction fragment length polymorphism (RFLP) analysis as the tomato big bud (TBB) phytoplasma. The PCR product from two plants fed on byB. angustatusandO. argentatus were too faint for RFLP analysis. PCR assays were conducted on DNA extracted from the head and thorax of each leafhopper species from transmission tests and from field-collected insects, but no phytoplasma DNA was detected. These findings suggestO. argentatusis a vector of the ALuY pathogen andA. torridais a vector of the TBB phytoplasma.