The influence of soil-applied fungicides and previous cropping on the development of violet root rot of sugar beet

The proportion of sugar-beet roots infected by Helicobasidium purpureum increased most rapidly in September and October. Violet root rot was not controlled by fungicides applied at drilling or in July. Heavily infected roots yielded 31% less sugar than healthy or lightly infected roots. Sugar beet following infected carrots lifted or ploughed in during July had no more violet root rot than when following barley or fallow, but the beet crop became heavily infected when it followed carrots left in the ground until December, whether they were then lifted or ploughed in. Eight varieties of sno-ar beet did nnt differ in siiscenrihilitv to violet root rot.