Agriculture Reference
In-Depth Information
Cool fruit promptly after harvest to 10-12
°
C. Lower
•
temperatures may cause chilling injury.
Ripen fruit at 18-20
C with ethylene to reduce the
variation in ripening between fruit and the amount
of anthracnose development.
°
•
Store ripe fruit at 10-12
°
C for a maximum of
•
three days.
ASPERGILLUS FRUIT ROT
■
Cause
The fungi
Aspergillus
spp.
Symptoms
The disease begins as a yellowing of the affected areas,
usually at the stem-end or side of the fruit, and spreads
rapidly to produce a watery, light brown rot. The centre
of the lesion may become sunken and brown or black
spore masses may appear.
Source of infection and spread
The fungus is widely distributed in soil or in decaying
organic matter where spores form under moist conditions.
The fungus is common on mouldy hay, grain and decaying
foodstuffs. Spores are both air-borne and soil-borne.
Infection occurs through natural openings in the peel,
wounds, or areas of the skin where injury (e.g. sapburn,
heat damage) has occurred.
Fig 12.19 Advanced symptoms of anthracnose on ripe fruit. Inset:
symptoms caused by
Colletotrichum
acutatum
.
Importance
Anthracnose is the most important fungal disease of
mangoes, with major losses occurring between f flowering
and fruit set and again after harvest.
Importance
Aspergillus rot is a postharvest disease occurring
occasionally on consignments of early season and
immature fruit. It is a minor disease problem affecting
individual fruit in a carton.
Management
Field
•
Spray with the recommended fungicides to reduce
infection of new growth fl ushes, fl owers and fruit.
Prune dead twigs and branches before fl owering.
Remove dead leaves entangled in the tree canopy.
•
Optimise nutrition - high fruit nitrogen levels can
exacerbate anthracnose. Timing of nitrogen fertiliser
application can also be important.
•
Do not harvest during wet weather.
•
Postharvest
•
Dip fruit after harvest in hot water (usually 52
C for fi ve
minutes) containing a recommended fungicide. It may
also be necessary to apply an unheated fungicide using
an overhead spray on the packing line.
°
Fig 12.20 Aspergillus fruit rot. Large, tan, watery lesions are covered
by a large mass of black, sooty fungal growth.
