Potential for biocontrol of sclerotinia rot of carrot with foliar sprays of Contans® WG (Coniothyrium minitans)

Abstract

A glasshouse and field trial were conducted to evaluate foliar sprays of Contans® WG (Coniothyrium minitans) conidial suspensions for control of sclerotinia rot of carrot and infection of Sclerotinia sclerotiorum sclerotia by C. minitans. In the glasshouse trial, foliar sprays (1×104–108 conidia mL−1) decreased the viability of sclerotia recovered from diseased plants and increased infection by C. minitans. In the field trial, three successive foliar sprays applied at 14-day intervals failed to reduce foliage disease severity, but significantly reduced viability of sclerotia recovered from diseased plants/crop debris and increased infection by C. minitans. No significant differences in sclerotial viability or infection were observed between two conidial concentrations (2.4 and 4.8×106 conidia mL−1). Foliar sprays of Contans® WG have potential for reducing viability of sclerotia produced on diseased foliage.