Seed health in potatoes (Liveseed Practice Abstract)

Summary

Organic seed potatoes A typical variety for organic farming allows for moderate fertilization levels, has a stable product quality under stress conditions, is broad resistant against Late Blight and virus and has a short field period.
Virus Potato virus X and Y are spread by aphids or by cross-contamination. They can show symptoms, like ‘squeezed’ or rolled leaf growth, yellowing or mosaic patterns, mostly on top of the plant. However, the expression is dependent on variety, crop maturity and growing conditions. Rogueing basic seed lots is key, which takes experience. A diseased plant can be missed, particularly in varieties that show no symptoms; causing ‘secondary disease’ next season. Bacterial soft rot or blackleg Pectobacterium and Dickeya (Erwinia): plants fall due to stem rot or wilting, with creamy tuber spots and a fishy smell. Virus rogueing is a notorious path for Erwinia spread. Like virus, infested tubers may be symptomless, enabling ‘invisible’ spread through a seed lot. Farm hygiene is the only control measure.