Weed Science Laboratory, College of Agriculture, South China Agricultural University, Guangzhou510642, China
*Correspondence author: E.Mail address: chenyong@scau.edu.cn (Y. Chen).
Online published on 7 November, 2012.
Barnyardgrass (Echinochloa crus-galli L.) is a problematic weed worldwide that competes with crops and reduces their yields. The fungus Exserohilium monoseras (Drechsler) Leonard and Suggs is a potential biocontrol agent for barnyardgrass. This study aimed to isolate and identify the phytotoxic compounds from E. monoceras strain X27. The fungus was cultured in potato dextrose (PD) media. A crude extract of X27 fermentation filtrate (5.0 g/L) drastically inhibited the barnyardgrass shoot growth by 94.9% and root growth by 79.0%. The crude toxins in the fermentation filtrate were isolated using thin-layer chromatography (TLC). Four compounds were isolated and identified by gas chromatography-mass spectrometry (GC-MS) as oleic acid amide (C18H35NO), dibutyl phthalate (DBP; C16H22O4), stearic acid (C16H32O2) and octadecanoic acid (C18H36O2). Of the 4-compounds in the mixture, DBP showed the greatest suppression of plant growth, decreasing root growth by 84% and shoot growth by 76% at 1 g/L concentration.
Barnyardgrass, Echinochloa crus-galli, Exserohilum monoceras, identification, purification
