General
General
Grey rot or southern blight is a disease caused by the fungus Athelia (Sclerotium) rolfsii. It is an important plant pathogen that inhabits the soil, and is responsible for root and stem rot, wilting and damping-off of seedlings. It has a wide range of hosts, around 500 botanical species, including dicotyledons and monocotyledons, distributed in all agricultural regions, predominantly in tropical and subtropical areas, where conditions of high humidity and high temperature followed by periods of drought predominate. It was first observed in tomato crops in Florida in 1892, and it has been regularly reported as causing rotting to the root and stem in tomato plants. Significant losses occur in soils infested by the pathogen, which have a light texture and humidity close to field capacity. In the southern USA, losses can reach 5% of annual production.