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

FREEDOM PALESTINE FREEDOM PALESTINE FREEDOM PALESTINE
Postharvest Disease Summary 303
controlling B. cinerea, when applied to fresh wounds on apples (Mercier
and Wilson, 1995), while Candida sake was effective against P. expansum
when applied preharvest (Teixido et al., 1998). Preharvest application of
Bacillus subtilis, the yeast Rhodotorula and the yeast-like fungus
Aureobasidium suppressed postharvest decay of apples by P. expansum, B,
cinerea and Pezicula malicorticis (Leibinger et al., 1997). Postharvest
control of P. expansum rot in pear fruits, was achieved with antagonistic
yeasts, used either as field sprays or as postharvest applications
(Chand-Goyal and Spotts, 1996a). (See the chapter on Biological Control).
Refrigeration is the most commonly used method for suppressing
decay after harvest. Apples are generally held at temperatures above
0°C, the optimal storage temperature varying with the sensitivity of the
cultivar to chilling injury. Pear cultivars are able to benefit from storage
at -1°C. Chilling the fruit in the packinghouse by refrigerated forced air
or by hydrocooling slows ripening and reduces pathogen growth. The
addition of chlorine to the cold water disinfects the fruit surface and
prevents the buildup of pathogen propagules in the water (Eckert and
Ogawa, 1988). Rapid removal of the field heat by hydrocooling to about
4.5°C markedly reduces Monilinia growth and arrests Rhizopus and
Colletotrichum development, although the fungi remain alive and resume
growth when the fruit is returned to higher temperatures.
Further extension of the storage life of apples can be achieved by
controlled atmosphere storage, frequently accompanied by the removal of
ethylene. This involves a careful regulation of the temperature, the
humidity and the levels of oxygen and carbon dioxide in the atmosphere
(see the chapter on Means for Maintaining Host Resistance - Modified
and Controlled Atmospheres).
STONE FRUITS
Stone fruits are highly perishable and decay is the major problem in
handling them, both for the fresh market and for processing (Eckert and
Ogawa, 1988). The susceptibility of stone fruits diminishes in the order:
cherries, nectarines, peaches, plums and apricots. The main postharvest
pathogens of stone fruits are: Monilinia spp., Botrytis cinerea, Rhizopus
stolonifer, Penicillium expansum, Mucor piriformis, Colletotrichum
gloeosporioides, Alternaria alternata and Cladosporium herbarum. The
relative importance of these pathogenic species differs in different fruits:
http://arab2000.forumpro.fr