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

FREEDOM PALESTINE FREEDOM PALESTINE FREEDOM PALESTINE
292 Postharvest Diseases of Fruits and Vegetables
at the stem end, or at the distal end in the region of the persistent calyx.
Affected areas of the skin turn soft and wrinkled along with the
appearance of numerous pycnidia with the asexual spores.
Control Measures
Sanitation activities in the orchard, careful harvesting and handling
and preventive preharvest fungicide sprays may reduce postharvest
diseases of guava incited by wound pathogens (Srivastava and Tandon,
1969; Ito et al., 1979; Ramaswamy et al., 1984). Good control has been
achieved by postharvest fungicide dips of guava inoculated with the
wound pathogens Pestalotia, Phoma, Gloeosporium and Aspergillus
(Singh and Bhargava, 1977; Arya et al., 1981). Wills et al. (1982) found
that under natural infection conditions, a heated fungicide was more
effective than some single fungicides at ambient temperatures.
Refrigeration at 5°C enables prolongation of the postharvest life of
guavas by up to 3 weeks while lower temperatures may cause chilling
injury (Brown, B.I. and Wills, 1983).
LITCHI
Litchis may be infected by many postharvest pathogens during storage
and transport (Prasad and Bilgrami, 1973; Scott et al., 1982). Pathogens
characteristic of tropical and subtropical fruits, such as Botryodiplodia
theobromae and Colletotrichum gloeosporioides, do not spare this one.
Wound pathogens, such as Rhizopus spp. or Geotrichum candidum, for
which wounding is a prerequisite for infection, may penetrate the fruit
shell via cracks resulting from sun scorch or via punctures produced by
fruit-piercing insects (Scott et al., 1982). Such injuries not only provide
an avenue for fungal penetration into the fruit but may also allow the
exudation of juices that stimulate mold development (Prasad and
Bilgrami, 1973). However, the main postharvest problem with litchis is
associated with physiological changes exhibited in darkening and loss of
the natural red color of the fruit. This phenomenon involves the formation
of polyphenols in response to desiccation and injury (Akamine, 1976).
Control Measures
Disease control should begin in the orchard, with preventive measures
against fruit insects, including 'bagging' of developing fruits (Prasad and
Belgrami, 1973). In order to reduce postharvest decay, the fruits can also
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