title: Characterization of the Maize Stalk Rot Pathogens Fusarium subglutinans and F. temperatum and the Effect of Fungicides on Their Mycelial Growth and Colony Formation.
abstract: Maize is a socioeconomically important crop in many countries. Recently, a high incidence of stalk rot disease has been reported in several maize fields in Gangwon province. In this report, we show that maize stalk rot is associated with the fungal pathogens Fusarium subglutinans and F. temperatum. Since no fungicides are available to control these pathogens on maize plants, we selected six fungicides (tebuconazole, difenoconazole, fluquinconazole, azoxystrobin, prochloraz and kresoxim-methyl) and examined their effectiveness against the two pathogens. The in vitro antifungal effects of the six fungicides on mycelial growth and colony formation were investigated. Based on the inhibition of mycelial growth, the most toxic fungicide was tebuconazole with 50% effective concentrations (EC50) of <0.1 μg/ml and EC90 values of 0.9 μg/ml for both pathogens, while the least toxic fungicide was azoxystrobin with EC50 values of 0.7 and 0.5 μg/ml for F. subglutinans and F. temperatum, respectively, and EC90 values of >3,000 μg/ml for both pathogens. Based on the inhibition of colony formation by the two pathogens, kresoxim-methyl was the most toxic fungicide with complete inhibition of colony formation at concentrations of 0.1 and 0.01 μg/ml for F. subglutinans and F. temperatum, respectively, whereas azoxystrobin was the least toxic fungicide with complete inhibition of colony formation at concentrations >3,000 μg/ml for both pathogens.
authors.affiliation: Applied Biology Program, Division of Bioresource Sciences, College of Agriculture and Life Sciences, Kangwon National University, Chuncheon 200-701, Korea.
authors.forename: Jong-Hwan
authors.initials: JH
authors.lastname: Shin
authors.affiliation: Applied Biology Program, Division of Bioresource Sciences, College of Agriculture and Life Sciences, Kangwon National University, Chuncheon 200-701, Korea.
authors.forename: Joon-Hee
authors.initials: JH
authors.lastname: Han
authors.affiliation: Applied Plant Sciences Program, Division of Bioresource Sciences, College of Agriculture and Life Sciences, Kangwon National University, Chuncheon 200-701, Korea.
authors.forename: Ju Kyong
authors.initials: JK
authors.lastname: Lee
authors.affiliation: Applied Biology Program, Division of Bioresource Sciences, College of Agriculture and Life Sciences, Kangwon National University, Chuncheon 200-701, Korea ; BioHerb Research Institute, Kangwon National University, Chuncheon 200-701, Korea.
authors.forename: Kyoung Su
authors.initials: KS
authors.lastname: Kim
keywords: DMI fungicides; Fusarium stalk rot; QoI fungicides; corn disease; maize