VIEW ARTICLE

A Comparison of Two Strains of Apple Chlorotic Leaf Spot Virus. R. Chairez, Postdoctoral Assistant, Department of Botany and Plant Pathology, Purdue University, W. Lafayette, Indiana 47907; R. M. Lister, Professor, Department of Botany and Plant Pathology, Purdue University, W. Lafayette, Indiana 47907. Phytopathology 63:1458-1464. Accepted for publication 14 May 1973. DOI: 10.1094/Phyto-63-1458.

On the basis of biological and serological properties, two apple chlorotic leaf spot virus (CLSV) isolates, CLSV-A (from apple), and CLSV-P (from peach), were differentiated as strains. They differed in symptoms on woody indicator hosts and in the severity of symptoms caused on Chenopodium quinoa. In serological ring precipitin tests, CLSV-A antiserum had a homologous titer of 1/128 to 1/256 and a heterologous titer of 1/32. CLSV-P antiserum had homologous and heterologous titers of 1/128 and 1/64, respectively. In serological gel diffusion tests, partial identity of the two strains was indicated by spur formation when the two strains were reacted with either antiserum. Differences in physical properties were minor. The yield of CLSV-P was increased by including 1% polyethylene glycol (MW=6,000) in the extraction buffer.