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

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 the tendency of the disease to peak at certain times during the year.

Detection of resting spores ofSynchytrium endobioticumin soil from vehicles at Port-aux-Basques, Newfoundland

“…2). To our knowledge, this study is the first years (17), are found at soil depths of 50 cm (1 ), and demonstrate (in vitro) seasonal pulses of low rates of germination (7). From this, it may be inferred that these soil infestations exhibit long attenuated loga rithmic decline phases (6).…”

Potato wart disease in Newfoundland: a review of current research studies1

“…A series of experiments at this Research Station demonstrated that there is much variability throughout the year in the levels of infection and germination of the fungus (Hampson, 1984(Hampson, , 1987. Several hypotheses of action can be advanced which include the toxic effect of released ammonia, chitinolysis of resting spores, competition for oxygen or space in the face of an exploding microorganism population, antibiosis by an enhanced actinomycete flora, or lysis of zoospores at the infection courts.…”

“…The need to know more about the biology of S. endobioticum, be it vesicle production, sporangia release, zoosporogenesis or migration of zoospores in soil pores, is paramount at this point. A series of experiments at this Research Station demonstrated that there is much variability throughout the year in the levels of infection and germination of the fungus (Hampson, 1984(Hampson, , 1987.…”