Institut für nationale und internationale Angelegenheiten der Pflanzengesundheit
The stolbur phytoplasma ‘Candidatus phytoplasma solani’ (PHYPSO) was first described in potatoes in 1935 and has occurred irregularly since the 1950s. The main vectors are plant hoppers of the family Cixiidae. In recent years, mixed infections of PHYPSO with the gammaproteobacterium ‘Candidatus Arsenophonus phytopathogenicus’ (ARSEPH) have been reported. In contrast to PHYPSO, which is transmitted horizontally, ARSEPH can be transmitted vertically to the offspring of the main vector Pentastiridius leporinus. Mixed infections induce the so-called bacterial potato tuber wilt disease, which is characterized by wilting, discolouration of the leaves and so called gummy tubers. This can cause yield depression and deterioration of quality and storability, thereby causing severe impairments in all downstream sectors of processing. Both pathogens may be widely distributed in Europe but have not been reported because of lacking or insufficient research. Stolbur presents a threat to the production of healthy seed potatoes, as infestations are regulated under the Seed Potato Ordinance. PHYPSO is classified as Unionregulated non-quarantine pest (RNQP), whereas ARSEPH is not regulated. Seed tubers are unlikely to be a main pathway of spread. Nevertheless, the risk of trading infected tubers combined with uncertainties regarding the vector system and genetic diversity of the pathogens must be considered carefully.
Federal Ministry of Agriculture, Food and Regional Identity
