?Biocontrol strategies to reduce Fusarium Head Blight and deoxynivalenol accumulation in wheat?.

PALAZZINI, J. M; YERKOVICH, N; ALBERIONE, E.J; TORRES A.M.; CHULZE , S.N

Berlin

Congreso; XVIII International Plant Protection Congress,; 2015

International Society on Plant Protection

Fusarium head blight (FHB) caused by Fusarium graminearum species complex is a devastating disease that causes extensive yield and quality losses to wheat in humid and semi-humid regions of the world. The disease can cause not only yield losses but also grain contamination with mycotoxins such as deoxynivalenol (DON). Several epidemics have occurred in Argentina in the last 50 years. Control of the disease is partially achieved by crop rotation, fungicide application, bredding for resistance and tillage practices, but reduction of FHB is not allways succesfull. Biocontrol strategy can be used as part of an integrated pest management. The objetives of this study were: 1- to evaluate the biological control effect of two bacterial formulations on FHB disease incidence, severity and DON accumulation under a field trial and 2- to evaluate the formulated strains on wheat stubble to reduce F. graminearum inoculum after harvest. Bacillus methylotrophicus RC 218 and Streptomyces sp. RC 87B were applied both at anthesis period for FHB parameter´s control and over wheat stubble left after harvest for F. graminearum control. FHB incidence and severity were visually estimated, DON content was assessed by HPLC after harvest. On stubble, F. graminearum prevalescence was monitored by TaqMan PCR during three months. A significant disease severity and DON reduction were observed at the field trial with the formulated strains applied alone or in combination (25.8-30% and 85-100% for severity and DON reduction, respectively); but no reduction on disease incidence was achieved. On wheat stubble, Streptomyces sp. 87B reduced F. graminearum inoculum after 40 days (82%). After three months, F. graminearum inoculum was reduced to undetectable levels under the Streptomyces sp. 87B treated plot, meanwhile in the control plot the pathogen was detected (9.85 pg DNA/mg). No biocontrol activity with Bacillus methylotrophicus RC 218 was observed on stubble. The two formulated biocontrol strains showed high potential for contributing to the reduction of FHB on wheat at different levels in the F. graminearum life cycle.