Mechanical Transmission of Soil‐borne Barley Yellow Mosaic Virus

Leaves of winter barley (Hordeum vulgare L.) cv. Gerbel were mechanically sap‐inoculated with Barley Yellow Mosaic Virus (BaYMV). Different additives to the inoculation fluid were tested. Whereas the dilution of plant sap by water alone resulted in an infection rate of 43%, the addition of sodium sulphite (80 %) and potassium phosphate‐buffer (89%) increased the proportion of infected plants substantially. Infectivity was further increased by repeated inoculation, when sodium sulphite yielded 96 % and potassium phosphate 100% of infection. The usefulness of the technique in further research and application is discussed.