Pathology -jcharleswesley

1. BUDROT IN COCONUT
-J Charles wesley(URK17AC200)

2. Systemic position-phytophthora palmivora
Kingdom : Fungi
Phylum : Heyerokontophyta
Class : oomycota
Order : Peronosporales
Family : Peronosporacae
Species : P.palmivora

3. Pathogen and its characters
 Drooping of successive leaves and falling of leaves
one by one, leaving only mature leaves in the
lower whorls at the crown
 Sporangiophores are hyaline and simple or Branched
occasionally.
 The sporangia are hyaline thin walled pear shaped with
prominent papillae ,the sporangia releases reniform
Biflagellate zoospores upon germination.
 The fungus also produces thick walled spherical
oospores in addition thick walled,yellowish brown
chlamydospores are also produced.

4. Favourable conditions:
 High rainfall, atomspheric Humidity(above
90%),low temp.(18-20°c)and wounds caused by
Tappers and Rhinocerous beetles.

5. Mode of speard and survival
The fungus remains as dormant
mycelium in the infected tissues and
also survives as Chlamydospores and
Oospores in crop residues in soil.
The disease spread is mainly through
Air borne sporangia and zoospores.
Rainfall also helps in spreading the
disease.

6. Symptoms:
 The earlier symptom is the yellowing of
one or two younger leaves .
 Blackspots appear on spindle leaves Basal
tissue of the leaf rots quickly and can be
easily separated from the crown.
 In later stages the spindle withers and
drops down.
 The tender leaf base and soft tissue of
the crown will rot into a slimy mass of
decayed material emmiting foul smell.

7. Symptoms
 Ultimately the entire crown falls down and the
palm dies.
 In adult palms,the first visible symptom is the
coloured change of the spear,which becomes
pale and breaks at the base and hangs down.
 The rotting slowly prgresses downwards,finally
affecting the meristem and killing the palms.
 This is accompanied by drooping of successive
leaves.even then nuts that are retained on the
palm may grow to maturity.

8. Pale leaf
Drooping

9. Leaf rot

10. Management:
CHEMICAL METHOD:
 Remove all the affected tissue of crown region and
crown drenching with Copper chloride 0.25%.Apply
Bordeaux paste and protect it from rain till normal
shoot emerges.
 The infected tissues from the crown region should
be removed and dressed with Bordeaux paste
sprayed with 1%Bordeaux mixture as pre-mansoon
spray .(may-sep)

11.  Leaf axil filling with sevidol 8G,25g mixed with
200g sand is recommended to red palm weevil
infestication of affected plams.
 Spray with Copper oxychloride 0.25% after the
onset of mansoon.
Thank you..