Wildgehölze aus der familie Rosaceae als natürliche reservoire von viren des kern- und steinobstes

Abstract

Summary Wild-growing woody plants of species taxonomically related to cultivated pome and stone fruits were surveyed for the presence of fruit tree viruses in order to determine their importance as natural virus sources. Among wild-growing roses ( Rosa canina L., R. corymbifera Borckh. , R. elliptica Tausch , R. rubiginosa L.) no plants investigated were infected by ilarviruses (Prunus necrotic ringspot virus, prune dwarf virus) or nepoviruses (especially Arabis mosaic virus). Wild-growing apple trees ( Malus sylvestris Mill .) proved to be not infected by closteroviruses (apple chlorotic leaf spot virus) or by the apple Spy decline agent. In wild-growing mountain ash ( Sorbus aucuparia L. em. Hedl .) neither closteroviruses (apple chlorotic leaf spot virus, apple stem grooving virus) nor ilarviruses (apple mosaic virus) were detectable, although 7 % of the trees investigated were infested by the mountain ash ringspot disease. Mazzard cherries ( Prunus avium (L.) L. var. avium ) were free from nepoviruses (Arabis mosaic virus, cherry leaf roll virus, raspberry ringspot virus, strawberry latent ringspot virus, tomato black ring virus), but tomato bushy stunt virus was present in this species with 1.2%. Wild-growing European dwarf cherry ( Prunus fruticosa Pall .) proved to be free from ilarviruses (Prunus necrotic ringspot virus, prune dwarf virus), while escaped sour cherry shrubs ( Prunus cerasus L.) were shown to contain Prunus necrotic ringspot virus at a rate of 40%. Wild-growing or escaped rose, apple, mountain ash, mazzard cherry or European dwarf cherry plants therefore seem not to be dangerous virus sources for cultivated apples and cherries, because of lack of virus infestation. The main danger of virus spread seems to originate from cultivated pome and stone fruit trees itself.