Agriculture Reference
In-Depth Information
MANGO MALFORMATION - BIOSECURITY THREAT
Cause
The fungus
Fusarium mangiferae
.
Symptoms
Mango malformation is seen as the production of thick
vegetative shoots at the growing tip (vegetative
malformation) and transformation of f floral parts into
a compact mass of sterile f flowers (f (floral malformation).
Vegetative malformation: usually occurs in young
seedlings, although vegetative malformation can
sometimes also be observed on mature trees on both
grafted and seedling types. Vegetative buds produce
misshapen shoots with shortened internodes and small,
stubby leaves. If all buds on a plant are affected, the
plant will remain stunted.
Fig 12.25 Mango malformation symptoms on flowers. Inset:
healthy flowers.
become greatly enlarged with large discs and the
peduncle bearing the f flower is also much thickened.
It significantly affects production, because affected
blossoms do not set fruit. Primary or secondary axes
on affected panicles are often shortened, thickened and
highly branched. Blossoms may not develop, remain
closed and can be up to twice the normal size.
Flower malformation: abnormal development of
inf lorescences where individual f flowers in a panicle
The affected panicles continue to bear f flower buds and
thus malformed panicles may produce up to three times
the normal number of f flowers.
Source of infection and spread
Generally, malformation spreads from infected plants
to healthy seedlings or trees in nurseries or orchards.
Fig 12.24 Mango malformation. Insets: various symptoms on new
growth.
Fig 12.26 Severe mango malformation.
