벼 키다리병 방제에 관한 황토유황의 종자소독 효과

Abstract

This study was conducted to evaluate rice seed disinfection efficacy of loess-sulfur for the suppression of Bakanae disease caused by Fusarium fujikuroi. Rice seeds were treated at different concentrations of loess-sulfur, soaking time and temperature, and combination of hot-water treatment. Rice cultivar, Shindongjin harvested from Bakanae disease-infested area in 2015, was used. Loess-sulfur was treated as follows; concentration of undiluted solution, 2%, 1% and 0.5%; soaking time of 24 and 48 hours; treatment temperature of 20℃ and 30℃; hot water treatment or not. Optimal conditions of rice seed disinfection were selected soaking time of 48 hours and the suspension of 0.5% and 1% loess-sulfur by investigating seed germination and isolation frequency of Fusarium spp. on Komada agar medium in vitro, and were established 3 disinfection conditions as hot water (60℃, 10 min.) 1% loess-sulfur (20℃, 48 hours), 1% loess-sulfur only (30℃, 48 hours) and 1% loess-sulfur only (20℃, 48 hours) through additional test in greenhouse. Above 3 conditions were verified by rice seedling box and paddy field test in the way of investigating Bakanae diseased plants (%) and healthy plants (%). Consequently, most effective rice seed disinfection conditions on Bakanae disease were combination of hot water and 1% loess-sulfur and loess-sulfur only at 30℃. Furthermore, treatments with these conditions showed control value of 100% were maintained from seedling to the heading stage in the field. However, treatment of 1% loess-sulfur only at 20℃ showed low control value of 78.2% in paddy field. Hot water only treatment turned out to be an effective disinfection method when conducted thoroughly with 60℃, 10 min. However, it was thought additional soaking process with loess-sulfur after hot water treatment served more high control effect against Bakanae disease when rice seeds were disinfected on a large scale. This results expected rice seed disinfection with loess-sulfur were effectively and easily usable method if farmers had only one of either hot water-disinfector or seed-disinfector. In addition, loess-sulfur is well-known to farmers, simple to manufacture method and cheap.