Cynosurus mottle virus, a virus affecting grasses in New Zealand

Abstract Cynosurus mottle virus (CyMV) was detected in four species of grasses from New Zealand pastures. CyMV from New Zealand was serologically related to, but not identical with, CyMV from the U.K. The virus had a dilution end point of 10-7 and a thermal inactivation temperature of 75°c; the isometric virus particles were 28 nm in diameter. The virus was transmitted mechanically from grasses to oats, and from oats to oats by the aphid Rhopalosiphum padi L. Thirteen species of Gramineae, mainly Festucoids, were susceptible to the virus after mechanical inoculation while 12 other species were not susceptible. During a survey carried out in the spring of 1976, CyMV was found to be widespread in New Zealand pastures and was detected in 7 out of 22 areas sampled. The incidence of virus symptoms ranged from 1% to 19%. Infected pastures ranged in age from 6 months to more than 20 years.