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Synchytrium endobioticum – risk from biogas plants?

Schleusner, Y., Müller, P., Bandte, M., Heiermann, M., Büttner, C.
Bulletin OEPP 2019 v.49 no.1 pp. 92-103
Synchytrium endobioticum, anaerobic digestion, arable soils, bioassays, biogas, cultivars, fertilizers, industry, pathogens, potatoes, risk, spores, viability, warts, wastes
Synchytrium endobioticum is one of the most important pathogens of potato and is known for its persistent propagation structures. Under favourable conditions, infection of highly susceptible potato cultivars leads to clearly visible cauliflower‐like tissue warts, the typical symptom of potato wart disease. However, unfavourable infection conditions or low infection pressure may result in symptoms being overlooked. Thus, the introduction of pathogen structures into stages of the processing industry cannot be ruled out. As the amounts of processed potato products continue to rise, phytosanitary risks from processing discarded potatoes and potato waste in biogas plants have to be considered. Hence, the resilience of resting spores against mesophilic anaerobic digestion was analysed in stirred tank reactors. Laboratory‐scale results show that S. endobioticum not only withstands mesophilic anaerobic digestion but also subsequent storage of the digestate for at least 4 weeks. Large numbers of viable resting spores were detectable by microscopic assessment in all samples. Viability was proved and verified additionally by bioassay. Consequently, potatoes, potato waste and processing water from potato processing industries used in biogas plants pose a phytosanitary risk if the accruing digestates are returned as fertilizer to arable land.