STEIN, A., Virus Laboratory, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel
LEVY, S., Virus Laboratory, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel
LOEBENSTEIN, G., Virus Laboratory, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel

Detection of prunus necrotic ringspot virus (PNRSV) by enzyme‐linked immunosorbent assay (ELISA) in rose, peach and almond was improved by absorbing the enzyme‐conjugated γ‐globulin with healthy leaf extracts. Non‐specific reactions were reduced markedly, thereby increasing the infected/healthy A405 ratio several‐fold. Absorbing the conjugate with peach leaf extract was most effective in lowering the non‐specific reaction in peach and rose, especially during the summer. Consequently, absorption of the enzyme conjugate with peach extract is now used in routine indexing for PNRSV in rose and peach. Copyright © 1987, Wiley Blackwell. All rights reserved