EFFECTS OF SOIL-CONDITIONS ON THE PREVALENCE OF NETTED SCAB

In two held trial series different planting techniques, used to alter soil conditions at planting time, and rates of seed infection with net ted scab were compared regarding their effects on plant development, y ield, tuber size distribution and the prevalence of netted scab in the progeny. A greenhouse pot experiment was also carried out to study th e influence of soil contamination and infection of seed with the nette d scab organism on the prevalence of netted scab in the progeny. Both seed infection and planting technique affected the progeny tuber infec tion with netted scab. Seed infection also negatively influenced plant development and yield. It is concluded that seed infection affects pl ant development and yield more than soil contamination does, whereas s oil contamination is more an important source of progeny tuber infecti on.