Post harvest diseases fruits and vegetables - Xavier University ...

FREEDOM PALESTINE FREEDOM PALESTINE FREEDOM PALESTINE
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-• Half fruit rot
Postharvest Diseases of Fruits and Vegetables
4 6 8
Days after inoculation
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Fig. 8. Rate of development of Botrytis rot in inoculated tomato fruit at different
temperatures. (Barkai-Golan, unpublished).
conditions, can have different minimal temperatures, which explains why
the differing minimal temperatures are cited in the literature for a given
fungal species. For some fungi, the minimal developmental temperature
is below 0°C (Sommer, 1985). That is why Botrytis cinerea, whose
minimum is -2°C, continues to develop in cabbage, celery, lettuce and
other vegetables stored at 0°C, and why various isolates of Penicillium
expansum and Alternaria alternata, whose minimum is -3°C, continue
their development in certain apples stored at 0°C or below.
On the other hand, some pathogens, such as species of Colletotrichum
or Aspergillus niger have a mycelium susceptible to low temperatures,
and their growth minima are 9°C and 11°C, respectively. Nevertheless,
the Colletotrichum fungus, which is characteristic of tropical and
subtropical fruits, can easily develop in these fruits during storage since,
because of their susceptibility to low temperatures, they are stored at
relatively high temperatures. Rhizopus stolonifer spores are also
susceptible to low temperatures and do not develop at temperatures
under 5°C; though a certain percentage of the spores can germinate at
2°C, their germ tubes cannot continue their growth at such a
temperature (Dennis and Cohen, 1976).
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