APPROACHES IN THE MANAGEMENT OF FUSARIUM HEAD BLIGHT OF WHEAT IN ARGENTINA

YERKOVICH NADIA; PALAZZINI JUAN MANUEL1; PALACIOS SOFÍA; RONCALLO PABLO; CANTORO RENATA; RAMÍREZ MARIA; ECHENIQUE VIVIANA; KARLOVSKI PETR; TORRES ADRIANA; CHULZE SOFÍA

Gent

Conferencia; 1st Mycokey International Conference; 2017

Universiteit Gent

Fusarium Head Blight (FHB) is a devastating disease that causes extensive yield and quality losses to wheat, barley and other small cereal grains in humid and semi-humid regions of the world. Species within the Fusarium graminearum complex are the main pathogens associated with the disease, being F. graminearum sensu stricto the main pathogen isolated in Argentina. Chemical treatments, crop rotation, breeding for resistance and tillage practices are among the main strategies to control the disease. The application of antagonists and other chemicals such as chitosan are additional strategies to be used as a part of an integrated pest management. The aims of this study were: -to evaluate the control effect of Bacillus velezensis RC218, Streptomyces albidoflavus RC 87B, chitosan and a combination of them on FHB disease incidence and severity on durum wheat under field conditions; -to evaluate the effect of Bacillus velezensis RC218 (Bvel), F. graminearum (Fgram) and their interaction on the induction of salicylic acid (SA) and jasmonic acid (JA) at different period times under greenhouse conditions ; -to carry out a survey of new potential biocontrol agents against F. graminearum and the evaluation of them under in vitro and greenhouse conditions. Biocontrol at field level showed effectiveness of the two biological control agents and chitosan in reducing both FHB disease incidence (29.5-63 % reduction) and severity (25-50 % reduction). Under greenhouse, the phytohormone´s assay showed that the production of JA was induced after F graminearum inoculation at 48 and 72 h, meanwhile JA levels were reduced in the co-inoculated treatment. No differences in JA or SA induction were observed between the B. velezensis treatment and the control. In the spikes inoculated with F. graminearum, SA production was early induced (12h) as it was shown for initial FHB basal resistance; meanwhile the late induction of JA reveals a defense state against the hemibiotrophic pathogen F. graminearum. New bacterial strains were isolated from wheat soil samples and evaluated under in vitro conditions through an index of dominance assay as antagonist of F. graminearum. A total of eight strains were selected to evaluate the ability to control FHB under greenhouse conditions. Three out of eight strains evaluated were able to significantly reduce FHB severity under greenhouse conditions by up to 63 %.