Studies on virus infection of diseased Quercus robur (L) from forest stands in northern Germany

Abstract

Virus-like symptoms such as distinct chlorotic lesions, ringspots and chlorotic mottle were observed on leaves of oak trees and seedlings growing at several forest stands and nurseries in north Germany. The same symptoms were induced on young oak seedlings after grafting. The causing agent was not transmissible by mechanical inoculation of plant sap to indicator plants. Studies with leaf fissue confirm the detection of double-stranded RNA (dsRNA) indicated at 1.5 to 2.0 kbp in oak with and without symptoms, which leads to the hypothesis that the particles belong to the cryptic virus group.