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

FREEDOM PALESTINE FREEDOM PALESTINE FREEDOM PALESTINE
Factors Affecting disease Development 39
TABLE 2
Minimal temperatures for postharvest
decay fungi *
Fungus Minimal Temperature °C
Alternaria alternata -3
Aspergillus niger 11
Botrytis cinerea -2
Cladosporium herbarum -4
Colletotrichum gloeosporiodes 9
Colletotrichum musae 9
Diplodia natalensis -2
Geotrichum candidum 2
Monilinia fructicola 1
Penicillium digitatum 3
Penicillium expansum -3
Penicillium italicum 0
Phomopsis citri -2
Rhizopus stolonifer 2; 5**
* Reproduced from Sommer (1985) with permission of the Canadian
Journal of Plant Pathology.
** Reproduced from Dennis and Cohen (1976).
As to Rhizopus, significant differences were found between dormant
and germinating spores in their susceptibility to low temperatures.
Dormant spores in the pre-germinating phase were not damaged by the
chilling temperatures, but when they entered the primary germination
stages, their susceptibility to chill increased, and at 0°C they perished
within a few days (Matsumoto and Sommer, 1968); in some fungi it was
found that a young mycelium within a tiny decay spot was more
susceptible to low temperatures than a mature mycelium within a
developed decay spot.
One should bear in mind that the environmental temperature affects
both the host and the pathogen simultaneously. Exposing the fruit or
vegetable to temperatures that cause tissue damage does not inhibit decay
development, but even enhances the infection rate of those pathogens that
penetrate through a wound or a damaged tissue (Segall, 1967).
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