抄録
Damping-off disease of Mitsuba (Cryptotaenia japonica HASSK.) caused by Pythium sp. in hydroponic culture was reduced by using of high concentrations of hydroponic culture medium. Concentration higher than 2.0 unit (2.0 fold of the concentration of the standard hydroponic culture solution) was effective in inhibiting disease incidence. At this concentration, zoospore formation of Pythium was reduced, and at 2.5 unit of hydroponic culture solution no zoospore formation was observed.
High concentrations of hydroponic culture solution inhibited the differentiation of vesicle contents into zoospores, and the release of zoospores from vesicle resulting in germination of cysted zoospores inside vesicles.
The inhibition of zoospore formation was likely to be caused by calcium ion present in the hydroponic culture solution, since the ion at concentrations higher than 0.25% could inhibited by the formation.
