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

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Postharvest Disease Summary 289
ascospores) has also been recorded occasionally (Liu and Rodriguez,
1973). Infection may originate in the field via growth cracks or via insect
punctures, but fungi generally penetrate into the fruit through the cut
stem end when the fruit is removed from the stalk or through injuries
inflicted during harvesting and handling (Rohrbach and Phillips, 1990).
The disease develops rapidly at tropical temperatures. The fungal
optimal growth temperature is approximately 26°C and it becomes
inactive below 10°C. Moist conditions at harvest are important for decay
development. High percentages of decay in a shipment usually indicate
that the fruit was harvested during or shortly after a prolonged rainy
period (Smoot et al., 1983).
2. Fruitlet Core Pathogens
Several fungi, such as species of Cladosporium, Penicillium and
Trichoderma, can invade wounds during harvest but frequently develop
as surface molds (Eckert, 1990). Some fungi, including species of
Fusarium and Penicillium, and bacteria, including species of Erwinia,
Pseudomonas and Acetobacter, either singly or in combination, may cause
"fruitlet core rot" (Rohrbach and Taniguchi, 1984). While Penicillium
funiculosum enters the developing floret through the unopened bud,
Fusarium moniliforme var. subglutinans and the pathogenic bacteria
infect the developing fruit via the open flower (Rohrbach and Phillips,
1990). Fungal spores or bacterial cells are deposited in the floral cavities
by water splash or by insects that both carry the pathogens and damage
the tissue prior to infection (Bolkan et al., 1979; Mourichon, 1983).
Infection results in brown soft rot of the axis of individual fruitlets and
can rarely be detected from the outside of the fruit. A longitudinal section
reveals the extension of the affected area towards the heart of the fruit
(Snowdon, 1990). The decay may develop in ripe or mature fruit, in the
field or during transit and marketing.
Control Measures
Since fungal infection is associated with the presence of wounds,
careful handling is needed at all stages to prevent injury, and packing
has to be designed to prevent the sharp 'crown' leaves from piercing
adjacent fruits (Snowdon, 1990). Damaged and wet fruits and those with
an excessive number of growth cracks should be excluded from fresh fruit
shipments (Smoot et al., 1983). Measures to reduce fruitlet core rot
incited by the various pathogens start in the field, with the control of
insects that spread the disease (Rohrbach and Phillips, 1990).
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