Agriculture Reference
In-Depth Information
Importance
Alternaria rot is a postharvest disease. It is slow to develop
and is likely to be serious only after fruit has been stored
for a long time. Usually, the disease is seen only when
anthracnose and stem-end rot, which would normally
develop earlier in the ripening process, have been well
controlled. Other fungi that may cause fruit rot after
prolonged storage include
Stemphylium vesicarium
,
Botrytis
cinerea
,
Penicillium
expansum
and
Mucor circinelloides
.
Management
•
Use the same preharvest and postharvest fungicide
sprays that are used to control anthracnose. The disease
is unlikely to cause losses in fruit consumed within two
weeks of harvest.
Fig 12.13 Anthracnose symptoms on new growth and a young
mango fruitlet (inset).
ANTHRACNOSE
■
Cause
Predominantly, the fungus
Colletotrichum gloeosporioides
,
but occasionally
Colletotrichum acutatum
.
Symptoms
Leaves: small, black spots expand and coalesce, forming
large, dark, dry areas. These often crack and fall out. New
growth f flushes are particularly susceptible.
Flowers: small, black, irregular spots expand and coalesce
to cause shedding and death of f flowers.
Fruit: very young fruit can develop small dark spots,
leading to fruit drop. Once fruit reach approximately 4-5
cm in diameter, infections grow in the skin of fruit but
usually remain quiescent and asymptomatic until the fruit
Fig 12.14 Anthracnose symptoms on a mango leaf.
Fig 12.12 A tray of healthy mango fruit and a tray of fruit showing
anthracnose symptoms.
Fig 12.15 Anthracnose symptoms on mango flowers.
