Fallik, E., Department of Fruit and Vegetable Storage, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel
Grinberg, S., Department of Fruit and Vegetable Storage, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel

Hinokitiol (β-thujaplicin), a volatile oil extracted from the roots of the Hinoki tree, Hiba arboruitae (Japanese cypress), was tested as a natural biocide to control postharvest decay pathogens. The compound inhibited in vitro spore germination and mycelial growth of Botrytis cinerea and Alternaria alternata. The ed50 of hinokitiol for the inhibition of spore germination was 60 μl L-1 and 100 μl L-1 for B. cinerea and A. alternata, respectively. Hinokitiol completely inhibited B. cinerea spore germination at a concentration of 100 μl L-1 and that of A. alternata at 500 μl L-1. The ed50 values for mycelial growth inhibition were 50 and 80 μl L-1 for B. cinerea and A. alternata, respectively, but for complete inhibition the effective concentrations were 250 μl L-1 and 750 μl L-1, respectively. The effective exposure time of fungal spores to hinokitiol was inversely related to the concentrations used. Very short exposures were required for 50% inhibition of spore germination at 1000 μl L-1 hinokitiol, while up to 30-40 times longer exposures were required when 10 μl L-1 was used. A marked reduction in decay development was observed when commercially harvested eggplants and red peppers were dipped in hinokitiol solution (750 μl L-1). © 1992.