Biological control strategies to reduce Fusarium Head Blight in Argentina

KOLH J; PALAZZINI J.M; KASTELEIN, P; GROENENBOOM-DE HAAS, L; TORRES A.M.; CHULZE , S.N

Congreso; 10 th International Congress of Plant Pathology. Bio Security, Food Safety and Plant Pathology; 2013

Fusarium graminearum sensu stricto (Fg) is the main pathogen associated to Fusarium head blight in Argentina, a devastating disease that reduces yield and grain quality and can produce deoxynivalenol (DON) on small grain crops. Biological control is an important tool to reduce the disease. Several strategies are under evaluation to control or reduce the pathogen inoculum on both stubble and wheat heads. Two antagonistic strains of Clonostachys rosea applied over wheat stubble after harvest were evaluated in their ability to control F. graminearum during a period of six months at two locations; the pathogen inoculum was assessed by species-specific TaqMan quantitative PCR (qPCR). An effective biocontrol effect was observed after three months of evaluation at the two locations under study when applying C. rosea strains, but after six months, Fg population diminished to undetectable levels in control treatments so no biocontrol effect was possible to evaluate. Two formulated bacterial biocontrol strains were evaluated over wheat heads during the anthesis period with artificial Fg inoculations under two consecutive field trials. Bacterial formulations (Bacillus subtilis RC218 and Brevibacillus sp. RC263) showed significant reduction of both disease incidence and severity (below 20 %) in comparison with control treatments (Fg alone, 22 and 35 %, respectively). In addition, DON accumulation was reduced under the biocontrol treatments. A correlation was established between disease severity in wheat heads and quantification of Fg by qPCR, which reveals the importance of this potent tool in detecting the pathogen at different niches.