Abstract
A rapid method of detection and evaluation of potato virus X (PVX) infection in potato leaves is described. The method is based on: 1) discarding of major part of cytoplasmic proteins from leaf homogenate by precipitation with polyethylene glycol in final concentration of 2%, 2) precipitation of virus containing fraction by increasing the concentration of polyethylene glycol to 3.5% and electrophoretic identification of virus coat protein extracted from this fraction. The procedure allows early detection of PVX in plants inoculated with virus as well as grown from infected tubers.