Transcript PP Problems on Mango, Arecanut and Citrus

PP Problems on Mango,
Arecanut and Citrus
Mango decline syndrome
Synonyms:
– Die-back
– Mango quick decline
– Mango sudden death
• What is gummosis?
• Exudation of gum
Mango quick decline
• Most dramatic form of the decline
syndrome
• The tree appears normal but suddenly
starts to wilt.
• Within a couple of days the affected
portions of the tree (twigs or branches)
completely wilts and dies.
• Usually begin on one side and later
spreads to the entire tree.
• Trees exude ambercolored gum from the
bark of their trunks or
branches
• Vascular tissues are
discolored. Xylem
tissue appears as
striated brownish
streaks
Cause: Fungi
•
The fungus Ceratocystis fimbriata,
Lasiodiplodia theobromae (syn.
Botryodiplodia theobromae)
•
Bark beetles (Hypocryphalus
mangiferae) are shown to carry C.
fimbriata and L. theobromae and
are presumably responsible for
transmitting both pathogens to
healthy mango trees.
•
In Pakistan, the Asian Ambrosia
beetle (Xylosandrus crassiusculus
(Motschulsky) is associated with
the disease complex. The beetle
is known to spread the fungus to
healthy trees. As the fungus
grows, the beetle feeds on them.
Mango Die-back
• Die back is one of the serious diseases of
mango in India too.
• The disease is most conspicuous during
Oct.-Nov.
• The disease is characterized by drying of
twigs and branches followed by complete
defoliation, which gives the tree an
appearance of scorching by fire.
Management
(i) Prune the diseased twigs and spray with
copper oxychloride (0.3%) on infected
trees. Pruning should be done in such a
way that the twigs are removed 2-3 inches
below the affected portion.
(ii) In small plants, pruning of twigs is
followed by pasting of copper oxychloride.
Bordeaux paste could be used instead of
copperoxychloride.
Bud rot of arecanut
• Cause: Fungus
(Phytophthora palmivora)
Losses up to 10-25% of
trees (Yuden and
Dorji[1]). This disease
affects palms of all ages.
• It starts with yellowing of
one or two young leaves
surrounding the spindle.
• The spindle and the older
leaves droop down followed by
the rotting of tender leaf bases
and soft tissues of the growing
shoot.
• The leaf bases forms a bulge
and is filled with foul-smelling
liquid.
• After the death of the central
bud, the outer leaves and
bunches remain intact for
several months.
• The disease is mostly seen
during the rainy season when
the humidity is high.
Management
• In the early stages of infection, split the
palm longitudinally at the bulging section
• Scoop the rotten tissues should
• Remove and destroy affected spindle and
leaves.
• Apply bordeaux paste on the exposed
healthy tissues or drench crown with 1%
Bordeaux mixture.