Abstract
Fungicidal properties of methyl bromide was studied with spores of Absidia sp., the fungus of moldy rice grains.
Spore mortality was assessed under microscope in most cases, but colony counting on Koji extract agar in petri dish combined with direct spore counting was also applied in case of high mortality.
At air humidity of 75 per cent, the fungicidal effect was not much different at 25°C and 30°C. At this humidity, 100 per cent mortality could not be attained within 72hrs., at temperatures from 15°to 30°C.
Probit of mortality plotted against logarithm of fumigation time yielded straight lines. At a given air humidity, slopes of these straight lines are almost constant, irrespective of temperature and concentration of methyl bromide.
The fungicidal effect markedly increased with air humidity. At 95 per cent air humidity and 25°C, at gas concentration of 25.5mg/l, 100 per cent mortality was attained in 12hrs.
