Monitoring Sclerotinia stem rot development in commercial canola crops in southern NSW

Abstract

Key findings »» Sclerotinia stem rot is a very sporadic disease in southern NSW. Variations in the level of disease can occur between districts, between years and between paddocks. »» The best indicators of a high Sclerotinia risk district are a high intensity of canola production, frequent development of Sclerotinia stem rot (e.g. every year) and reliable spring rainfall during flowering. »» Results indicate that prolonged (at least 48 hours) durations of relative humidity above 95% can trigger Sclerotinia stem rot development. »» A high level of petal infestation with Sclerotinia ascospores does not guarantee that stem rot will develop.