Abstract
Inoculation tests were made of violet root rot fungus, Helicobasidium mompa Tanaka, using commercially sold horticultural soils as well as field soils. The mycelial growth of H. mompa on sterilized horticultural soils were superior to that on sterilized field soils, when tested in test tubes. There was little difference in mycelial growth on various sterilized horticultural soils used but was much difference among the isolates used. Isolates with fast growth in sterilized horticultural soils also showed fast growth in non-sterilized horticultural soils (Kanumatuchi and Kanumatuchi: Fuyoudo mixture (1:1, w/w)). Furthermore, mycelial growth in non-sterilized Kanumatuchi: Fuyoudo mixture (1:1, w/w) was superior to that in non-sterilized Kanumatuchi only. In inoculation tests using Kanumatuchi and Fuyoudo mixture, the isolate 475 was highly pathogenic to carrot toproots and roots of apple young trees and the isolate 827 highly pathogenic to carrot toproots, asparagus roots and roots of apple young trees. The inoculation method using horticultural soils is effective to reproduce the disease in potted plants.
