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

FREEDOM PALESTINE FREEDOM PALESTINE FREEDOM PALESTINE
280 Postharvest Diseases of Fruits and Vegetables
The infection of uninjured, immature fruit before harvest results in
the formation of numerous, small dark circular spots which enlarge and
tend to coalesce (Simmonds, 1963). However, Colletotrichum may cause a
"non-latent" anthracnose, which is initiated at abrasions and scars
sustained during harvesting and handling (Slabaugh and Grove, 1982).
In this case, large lesions are produced (Shillingford and Sinclair, 1978).
Both types of lesion eventually carry salmon-pink spore masses.
3. Botryodiplodia theobromae Pat.
In addition to being a component of the crown rot complex pathogens,
B. theobromae is also responsible for banana finger rot. The abundance of
conidia produced on decaying vegetation in banana plantations form the
source of primary infection. Conidia are disseminated by air currents and
rain to dsdng flower parts and are later capable of infecting the fruit
when it ripens. Rotting usually begins at the tip of a finger but may occur
at any wound on the fruit surface. The rot progresses rapidly at high
temperatures, its optimum being about 30^C. Under these conditions,
within a few days the rot becomes soft and dark, and typical black
pycnidia appear, which give rise to conidia (Williamson and Tandon,
1966). Thus, in hot and humid weather, the harvested fruits can be
expected to develop finger rot during transport and ripening. The disease
may be serious in fruits held at a high temperature for more than 14
days in transit (Strover, 1972).
Control Measures
Control of postharvest diseases of banana fruits depends on several
steps. The fruit should be harvested at the correct stage of maturity and
handled carefully to avoid injury. Fallen leaves and flower bracts should
be removed in the plantation and the packing station to reduce the
numbers of infecting spores. The washing water in the tank, in which the
banana 'hands' float to permit latex to flow from the cut crown, should be
changed frequently to minimize the inoculum level. Along with reducing
the inoculum level, wounds should be protected against fungal infection
(Shillingford and Sinclair, 1978; Slabaugh and Grove, 1982). Application
of a fungicide soon after dehanding is important, to protect wounds and
to prevent infection of the cut crown surface (Eckert and Ogawa, 1985).
Postharvest treatment with a systemic fungicide was found to be more
effective in controlling decay than preharvest sprays (Ram and Vir,
1983). Cooling is important to suppress decay development, and it should
be initiated as soon as possible after cutting the fruit.
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