Seasonal changes in the germination behaviour ofSynchytrium endobioticum,the causal agent of potato wart disease

Abstract

Abstract A detailed series of observations were made throughout the year on in vitro collections of Synchytrium endobioticum, the causal agent of wart disease of potato. Each month a fresh sample of the fungus estimated at 10.000 spores per dish was incubated in water. The numbers of resting spores with attached vesicles and numbers of subsequently empty ones were estimated for 22 days each month. The numbers of empty resting spores which accumulated each month varied from month to month, and from week to week in any month. Large numbers of empty spores indicated massive germination. Germination was greatest in the spring/early summer season and late fall/early winter. Vesicle production also varied, and the rates of germination of vesicles varied during the year so that vesicles remained ungerminated longest in winter, and to some extent in sumer and late fall. Vesicle production was greatest on the average by the start of the third week of incubation. The wax and wane of empty spore production explains ...