Epicoccum purpurascens as a biological control agent of sunflower head rot caused by Sclerotinia sclerotiorum.

PIECKENSTAIN FL; ME BAZZALO, AMI ROBERTS, RA UGALDE

Buenos Aires, Argentina

Congreso; I Congreso Argentino de Control Biológico de Enfermedades de las Plantas, Buenos Aires; 1998

Head rot caused by Sclerotinia sclerotiorum is a serious disease of sunflower. Ascospores are the main source of inoculum and use senescent tissues as a nutrient source at the beginning of infection. Our objective was to evaluate if the colonization of senescent tissues by the saprophytic fungus Epicoccum purpurascens could interfere with the infection process and thus reduce damage. E. purpurascens mycelium successfully colonized senescent flowers after conidia applications, without causing yiel decreases. This treatment significantly reduced disease incidence in greenhouse grown plants submitted to artificial infections. However, conidia applications did not diminish disease incidence on field grown plants, probably due to a poor growth of E. purpurascens mycelium in these conditions. The search for amendments that allow a greater colonization of capitula of field grown plants could contribute to the use of E. purpurascens as a biological control agent of sunflower head rot caused by S. sclerotiorum.