Pythium periplocumDreschler has been found to be an aggressive mycoparasite ofBotrytis cinerea, the causal agent of the
gray mould disease of the grape-vine. When grown together, the former enters the latter's mycelium, branches freely within,
coagulates its cytoplasm and finally tears its hyphae apart, bringing about widespread destruction of the grape-vine pathogen.
Extensive coiling around the host, as reported in the case of other mycoparasites belonging to the genusPythium, has not been
observed here. The infected mycelium ofB. cinereafails to infect the grape-vine and does not induce the characteristic gray
mould symptoms. SinceP. periplocumis not a grape-vine parasite, it could be useful for the biological control of B. cinerea.A
brief account of this mycoparasitism is discussed in this article. ß 1999 Federation of European Microbiological Societies.
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