|
 |
PLANT
PROTECTION
B. Diseases
The coconut palm is affected by a number of
diseases, some of which are lethal while others
gradually reduce the vigour of the palm causing
severe loss in yield. A brief account of the
important coconut diseases is given.

I. Bud
Rot
 |
Symptoms
-
The earlier
symptom is the yellowing of one or two
younger leaves. Black spots appear on
spindle leaves.
-
In the later
stages the spindle withers and drops
down.
-
The tender
leaf base and soft tissues of the crown
rot into a slimy mass of decayed material
emitting foul smell.
-
Ultimately the
entire crown falls down and the palm dies.
|
|
Control
measures
-
Remove all
affected tissue of the crown and apply
Bordeaux paste on cut end and provide a
protective covering till normal shoot
emerges (Dissolve 100 gm of copper
sulphate and 100 gm of quick lime each in
500ml. water separately and mix to form 1
litre of Bordeaux paste).
-
Spray 1%
Bordeaux mixture on the crown of the
neighbouring palms as a prophylatic
measure.
-
Spray with 1%
Bordeaux mixture during May and September
if the disease occur frequently.
-
Cut and burn
severely affected palms which cannot be
saved.
|

 |
Symptoms
-
Blackening and
shriveling up of distal ends of the
leaflets in the central spindle and
younger leaves which later break off in
bits.
-
Gradual
weakening of the tree resulting in decline
yield.
|
|
Control
measures
-
Improve
general condition of palms through proper
manuring and management.
-
Remove the
decayed portions of spindle leaf and
upmost two leaves only.
-
Pour fungicide
solution of Hexaconazol (Contaf 5E) - 2ml
or Mancozeb (Dithane M45/Indifil M45) - 3g
in 300ml water per palm to the base of
spindle leaf.
-
Apply 20g
Phorate 10G mixed with 200g fine sand
around the base of spindle leaf.
-
2-3 rounds of
spraying is sufficient in case of mild
infection.
|

 |
Symptoms
-
Exudation of
reddish brown liquid through cracks
developing on the stem.
-
Decaying of
tissues at bleeding point
-
Vigour and
yield declining.
-
Development of
big holes inside the trunk
|
|
Control
measures
-
Chisel
affected tissue and dress the wound with
5% Calixin (5ml in 100ml water). Apply
coal tar after 2 days. Burn off chiselled
pieces.
-
Avoid any
mechanical injury to the stem.
-
To avoid
spread of disease on to upper portion of
trunk, root feeding with 5% calixin may be
adopted 3 times a year - April-May,
Spetember-October and January-February.
-
Along with
50kg organic manure, apply 5kg neem cake
containing the antagonistic fungi,
Trichoderma culture to the basin during
September.
-
Provide
adequate irrigation during summer and
drainage during rainy season.
-
Apply
recommended doses of organic manures and
chemical fertilizers.
-
Coconut stem
boring insects like Xyleborus, Diocalandra
should be controlled by applying Carbaryl
50% WP on the trunk @ 3g per litre water.
|

IV. Root
(wilt) Disease
 |
Symptoms
-
Abnormal
bending or ribbing of the leaflets,
flaccidity of the leaves, general
yellowing followed by marginal necrosis of
the leaflets.
-
Abnormal
shedding of buttons, reduced leaves and
crown, gradual reduction in yield.
|
|
Control
Measures
Being a
non-lethal, debilitating disease an
integrated approach is to be followed for
management of root wilt.
-
Recommended
control measures for leafrot disease as
this disease gets superimposed on most of
the root wilt affected palms.
-
Follow
integrated nutrient management
apply organic manure @ 50kg / palm / year.
apply balanced dose of chemical
fertilizers i.e. 500g Nitrogen (1.1kg
urea), 300g Phosphorus (1.7kg Mussouriphos),
1000g Potassium (1.7kg Muriate of potash)
in two splits - 1/3rd during April-May and
2/3rd during September-October under
rainfed condition and in four splits
during January, April, July and October
under irrigated condition. In addition to
this 500g MgO (1kg Magnesium sulphate)
also has to be applied along with second
dose of fertilizer application.
-
Cut and remove
disease advanced, uneconomical palms
yielding less than 10 nuts per palm per
year.
-
Grow green
manure crops - cowpea, sunhemp (Crotalaria
juncea), Mimosa invisa, Calapagonium
mucanoides, Pueraria phaseoloides etc. may
be sown in coconut basins during April-May
and incorporated during September-October.
-
Irrigate
coconut palms with at least 250 litre
water in a week.
-
Adopt suitable
inter/mixed cropping in coconut gardens.
-
Provide
adequate drainage facilities.
|

VI. Tanjavur
wilt
 |
Symptoms
-
Decay of finer
nuts, withering, yellowing, drooping and
drying of outer whorl of leaves and
exudation of reddish brown fluid at the
base of the trunk.
Control
Measures
-
Practice
growing banana as intercrop in coconut.
-
Root feeding
with Calixin (2ml in 100ml water) once in
3 months.
|
-
Drench the
basin with 25 litre of 0.1% Calixin.
-
Apply neem
cake containing Trichoderma @ 5kg
/palm/year.
-
Apply
recommended dose of organic manures.
-
Avoid flood
irrigation and follow drip irrigation.
-
Practice clean
cultivation and burn off diseased plant
pests.
-
Isolate
infected palms by taking trenches of 1m
depth and 0.5m width around the palm at
1.5m away from it.
|

|
Friends of Coconut Tree
Coconut Producers' Society
Photo Gallery
Media says
on coconut
Rejuvenation
online site |