Sugi (<i>Cryptomeria japonica</i>D. Don) bark, a potential growth substrate for soilless culture with bioactivity against some soilborne diseases

Abstract

SummaryThere were no significant differences in the growth of tomato plants grown on rockwool or on sugi bark fibre slab. However, sugi bark greatly reduced the incidence of fusarium crown and root rot (Fusarium oxysporum 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 extracts of the bark greatly inhibited Fusarium and Pseudomonas with the extracts from fresh bark having higher activity than aged bark. The inhibition was caused mainly by volatile oils, phenolics and acidic substances in the bark. Isophyllodecene and ferruginol were the main constituents of the oil. Injecting volatile oil from sugi leaves into rockwool also suppressed the incidence of bacterial wilt.