[Virus infestation of garden radish (Raphanus sativus L. var. sativus) (author's transl)].

Abstract

In July 1974 a mosaic disease was stated in seed plants of garden radish near Aschersleben which spread more and more within some weeks and eventually infected over 40 per cent of the stand. Investigations in comparison with healthy seed plants demonstrated the following average losses induced by the disease: number of pods 51 per cent, seed weight 67 per cent, number of seeds per plant 53 per cent, weight of 1,000 seeds 33 per cent. Nearly unaffected were: number of seeds per pod, percentage of seed germination, and percentage of emerged seedlings. However, the seedlings were smaller when they derived from diseased mother plants. From diseased seed plants cauliflower mosaic virus was isolated. Seed transmission of this virus could not be stated with several hundreds of seedlings deriving from diseased garden radish. Back transmissions were successful with sap and with aphids. Only one strain which was cultivated in greenhouse for a long time gave no positive results. Three isolates of cabbage black ring virus from different plant species and the four beetle-transmissible viruses, namely turnip yellow mosaic, turnip crinkle, turnip rosette, and radish mosaic viruses induced no symptoms on garden radish seedlings. However, Erysimum latent virus, also belonging to the beetle-transmissible viruses, sometimes caused symptoms in garden radish. For the first time the investigations demonstrated in Europe, but probably also for the other continents, a spontaneous virus infection of Raphanus sativus var. sativus.