Abstract
A control method for the red-spots injury caused by Alteromonas sp. occurring on seed twines for the cultivation of makonbu was examined. Among the eight disinfectants tested in vitro, chlorine dioxide (stabilized) and hydrogen peroxide significantly affected the causative organism while other strain of the same genus used a control had been less affected. Bathing mature blades of makonbu artificially contaminated with the causative organism in a 1, 000ppm solution of hydrogen peroxide for 10min at 15°C caused complete disappearance of the causative organism, while one-fifth number of ambient other bacteria on the mature blades survived. The disinfection of mature blades with hydrogen peroxide did not affect the further growth of makonbu.
Since invasion route of the causative organism into the culture vessels for gametophytes of makonbu is through mature blades contaminated in coastal seawater, disinfection of mature blades with hydrogen peroxide can be applied as a control method for the red-spots injury occurring on the seed twines of makonbu. When the injury occurs on seed twines, the injury can be held with a 80ppm solution of chlorine dioxide (stabilized) for 24h at 10-15°C.
