VIEW ARTICLE

Isolation and Differentiation of Five Strains of Curly Top Virus. Peter E. Thomas, Plant Pathologist, Crops Research Division, ARS, USDA, Irrigated Agriculture Research and Extension Center, Prosser, Washington 99350. Phytopathology 60:844-848. Accepted for publication 15 December 1969. DOI: 10.1094/Phyto-60-844.

Differences in host range, mortality rate, degree of stunting, and severity of foliage distortion on selected hosts were used to differentiate five distinct strains (12A, 13B, 16C, 31A, and 35B) of curly top virus. The procedure used to isolate the individual strains from natural mixtures of strains is described. Strain 31A was distinguished from the other strains on Nicotiana glutinosa, V. R. Moscow tomato, and highly susceptible, moderately resistant, and highly resistant sugarbeet varieties. Strain 12A was distinguished on N. glutinosa, highly susceptible, and moderately resistant sugarbeets. Strain 13B was distinguished on N. glutinosa and moderately resistant sugarbeets. Distinction between strains 16C and 35B occurred only on N. glutinosa, but the distinction was clear. There was no correlation between the relative severity of symptoms caused by the strains on different hosts.