Abstract: | A lot of 105 specimens from 25 families including weeds or wild plants which had grown naturally in the severely infested hop garden were tested for detecting reservoir plants for hop stunt viroid (HSV). HSV was detected in hop plants only. Susceptibility tests with various cultivated plants including 14 families indicated that hop and Humulus japonicus developed visible symptoms, while tomato was symptomless. When infected hop plant residues, leaves and cones, were left to be weather-beaten, infectivity of HSV was completely lost within 3 months. No transmission through the pollen or the ovule was demonstrated. HSV could survice in root systems of hop plants during the winter months. Based on these results, the route of HSV survival in the hop garden was discussed. |