OCCURRENCE OF STONE FRUIT VIRUSES IN PLUM ORCHARDS IN LATVIA

To evaluate the occurrence of nine viruses infecting prunus a large-scale survey and sampling inlatvian plum orchards was carried out. occurrence of apple mosaic virus (apmv), prune dwarfvirus (pdv), prunus necrotic ringspot virus (pnrsv), apple chlorotic leaf spot virus (aclsv), andplum pox virus (ppv) was investigated by rt-pcr and das elisa detection methods. the detectionrates of both methods were compared. screening of occurrence of strawberry latentringspot virus (slrsv), arabis mosaic virus (armv), tomato ringspot virus (torsv) and petuniaasteroid mosaic virus (peamv) was performed by das-elisa. in total, 38% of the tested trees byrt-pcr were infected at least with one of the analysed viruses. among those 30.7% were infectedwith pnrsv and 16.4% with pdv, while apmv, aclsv and ppv were detected in fewsamples. the most widespread mixed infection was the combination of pdv+pnrsv. observedsymptoms characteristic for ppv were confirmed with rt-pcr and d strain was detected. comparativeanalyses showed that detection rates by rt-pcr and das elisa in plums depended onthe particular virus tested. the results obtained in this study revealed that commonly grown plumcultivars in latvia are infected with economically important stone fruit viruses and highlight theneed to implement a programme to produce and propagate virus-free planting material.