symptoms are often not visible during the … symptoms are often not visible during the first season when infection occurs, but become progressively more severe in the following generations. Infected plants are stunted and have an upright or erect appearance. The foliage may change colour, becoming either lighter or darker than normal and have smaller, distorted leaflets. Tuber symptoms are more obvious but do take several generations to appear. Affected tubers are small and deformed, becoming cylindrical and elongate ('spindle'). They are often pointed and can show growth cracking on larger tubers. Eyes will often become more prominent and sprouting is slower than with healthy tubers. outing is slower than with healthy tubers.