SUGI (CRYPTOMERIA-JAPONICA D. DON) BARK, A POTENTIAL GROWTH SUBSTRATEFOR SOILLESS CULTURE WITH BIOACTIVITY AGAINST SOME SOILBORNE DISEASES

There were no significant differences in the growth of tomato plants g rown on rockwool or on sugi bark fibre slab. However, sugi bark greatl y reduced the incidence of fusarium crown and root rot (Fusarium oxysp orum f, sp. radicis-lycopersici), fusarium wilt (Fusarium oxysporum f. sp. lycopersici), and bacterial wilt (Pseudomonas solanacearum). Old bark was less suppressive than young bark. The population of Fusarium was significantly lower in sugi bark than in rockwool, and ethanol ext racts of the bark greatly inhibited Fusarium and Pseudomonas with the extracts from fresh bark having higher activity than aged bark. The in hibition was caused mainly by volatile oils, phenolics and acidic subs tances in the bark. Isophyllodecene and ferruginol were the main const ituents of the oil. Injecting volatile oil from sugi leaves into rockw ool also suppressed the incidence of bacterial wilt.