Bacterium-mediated control of Fusarium head blight disease of wheat and barley and associated mycotoxin contamination of grain

Fusariumculmorum causes Fusarium head blight (FHB) disease of cereals, resulting in yield loss and contamination of grain with the trichothecene mycotoxin, deoxynivalenol (DON). In a test for potential disease control organisms, Pseudomonas fluorescens strains MKB 158 and MKB 249 and Pseudomonas frederiksbergensis strain 202 significantly reduced both the severity of FHB disease symptoms caused by F. culmorum on wheat and barley (⩾23%; P ⩽ 0.050) and the disease-associated loss in 1000-grain weight (⩾16%; P ⩽ 0.050) under both glasshouse and field conditions when applied 24 h pre-pathogen inoculation. Glasshouse studies showed that these bacteria were more effective in controlling disease when applied 24 h pre- as opposed to 24 h post-pathogen inoculation. The most striking finding was that, in the F. culmorum-inoculated field trials, treatment with either of the two P. fluorescens strains (MKB 158 or MKB 249) also significantly reduced the DON levels in wheat and barley grain (74–78%; P ⩽ 0.050). This is the first report detailing the ability of fluorescent pseudomonad bacteria to control FHB disease and simultaneously reduce mycotoxin contamination of wheat and barley under field conditions.