Studies on the sensitivity of a latex agglutination test for the serological detection of potato virus S and potato virus X in Wisconsin

Abstract

A latex agglutination test using capillary pipettes as reaction vessels was a sensitive serodiagnostic procedure for detecting potato virus S (PVS) and potato virus X (PVX). In purified preparations, PVS could be detected at 0.5 μg/ml and PVX could be detected at 0.1 μg/ml. PVS and PVX were detected in composite samples simulating one infected plant in 10 or fewer plants at all stages of growth. Detection, however, was most effective when leaflets were collected from the middle of the haulm at midseason (prebloom to bloom). Then, depending on the cultivar, PVS could be detected in composite samples of leaflets from 10–20 plants and PVX could be detected in composite samples of leaflets from 20–25 plants. Tuber sprouts were as suitable as leaflets for virus indexing.