Identification of Fusarium subglutinans, the Casual Pathogen of Corn Stalk Rot in Korea and Investigation of Effectiveness of Fungicides Against the Pathogen
본 연구에서는 2013년도에 강원도의 옥수수 재배지들을 조사하고, 밑둥썩음병에 걸린 옥수수로부터 Fusarium균을 분리하였다. 분리한 병원균은 translation elongation factor 1 alpha(EF-1 alpha) 유전자 분석과 형태학적 조사를 통해 확인하였으며, F. subglutinans가 밑둥썩음병의 주요 원인균임을 확인하였다. F. subglutinans KWFS-1의 화학적 방제를 위해, 6개의 살균제와 하나의 살충제를 선발하여 항균효과를 검정하였다. 추천농도로 약제를 사용하였을 때, tebuconazole, difenoconazole, fluquinconazole이 각각 균사생장을 무처리구에 비해 64%, 60%, 55% 억제하는 것으로 나타났다. 반면 에 hymexazol, azoxystrobin, clothianidin, benomyl은 각각 20%, 37%, 35%, 23%를 억제하는 효과를 보였다. 포자생장 억제에서 benomyl, tebuconazole, difenoconazole, fluquinconazole은 포자생장을 완전히 억제하였지만 hymexazol, azoxystrobin, clothianidin이 첨가된 배지에서는 포자생장으로 나타난 균총이 각각 1.1 mm, 2.1 mm, 4.1 mm의 직경크기를 보여 농약별 포자생장 억제효과가 상이함을 보였다.
We examined several corn fields in Kangwon province during 2013, collected stalk rot-infected corn plants and isolated Fusarium species. Identification of Fusarium species using analyses of sequences of translation elongation factor 1 alpha(EF-1 alpha) gene and morphological characters revealed that the casual agent for stalk rot is F. subglutinans. We selected six fungicides and an insecticide to find out effectiveness of fungicides against the pathogen. At recommended dose, tebuconazole, difenoconazole, and fluquinconazole more highly inhibited the mycelial growth of the pathogen (64%, 60%, 55%, respectively) than hymexazol, azoxystrobin, clothianidin, and benomyl (20%, 37%, 35%, 23%, respectively). Benomyl, tebuconazole, difenoconazole, and fluquinconazole completely inhibited the conidial growth of the pathogen, while 1.1 mm, 2.1 mm, 4.1 mm colonies of the pathogen were formed on media containing hymexazol, azoxystrobin, and clothianidin, respectively, indicating that each fungicide has a different effectiveness on conidial germination of F. subglutinans.