HOST- COFFEE PATHOGEN- Phytomonas leptovasorum Necrosis is the commonest and most destructive type of effect. As a result of successful infection of host plant by the pathogen a number of physiological changes occur in plant. Respiration, photosynthesis, nitrogen metabolism and transpiration are affected. There will be reduced rate of photosynthesis. This in turn occurs a huge economically losses to the owner of plantation as it causes low yield and low quality of yield.

1. PHLOEM NECROSIS IN
COFFEE
PRESENTER
RASHMI M G
1st YEAR MSc. Botany
Maharani’s Science College For Women
Mysore

2. Introduction to plant disease
Disease is malfunctioning process that is caused
by continuous irritation.
It is the complex phenomenon and is an
interaction among the host, the parasite and the
environment.
It is a disturbance in the rhythmical equilibrium of
a host in respect of structure or physiology or both
and may lead to the death of a part of or the entire
host or reduce the economic value of its products.

3. CLASSIFICATION OF COFFEE
KINGDOM- PLANTAE
DIVISION- ANGIOSPERMAE
CLASS- DICOTYLEDONS
SUBCLASS- GAMOPETALAE
SERIES- INFERAE
ORDER- RUBIALES
FAMILY- RUBIACEAE
GENUS- Coffea
SPECIES- C. arabica,
C. robusta,
C. liberica .

4. PHLOEM NECROSIS IN
COFFEE
HOST- COFFEE
PATHOGEN- Phytomonas leptovasorum
History of this disease- reported from
SURINAM, GUYANA, SAN SALVADOR,
COLUMBIA, BRAZIL
It has not been reported from INDIA as far
In recent years, coffee will caused by
trypanosomatids has been hard to find anywhere,
as it was abandoned in Surinam, from where the
disease had been reported early in 1900s and up
to 1970

5. CAUSAL ORGANISM
Pathogen is flagellate – Phytomonas
leptovasorum
As a result of the pathogen internally the roots
and trunks of the trees show multiple divisions of
cambial cells
Production of a zone of smaller and shorter
phloem elements of disorderly structure right
next to the wood cylinder

6. FLAGELLATE PROTOZOA
Kingdom- Protista
Phylum- Euglenozoa
Order- Kinetoplastida
Family- Trypnosomatidae
Nature- Parasitic to plants
flagellate,
cell wall absent

7. SYMPTOMS
 Trees show sparse, yellowing and dropping of leaves.
 In advance cases only the top most leaves remain on the
branches.
 Roots begin to die.
 Trees that is infected will die.
 During beginning of dry season, trees wilt and die
within 20 days to 45 days.
 Internally the roots and trunk of trees show multiple
divisions of cambial cells and production of a zone of
smaller and shorter phloem vessels of disorderly
structure right next to the wood cylinder.

9. HISTOPATHOLOGY OF INFECTED
PLANT
Abnormal phloem production takes place.
Flagellates can be traced from the roots
upward into the trunks where they seem to
migrate vertically in the phloem and laterally
through sieve plates into healthy sieve tubes.
They also move downwards into unaffected
roots .

11. DISEASE CYCLE
Transmission through,
Root grafts but not through grafts of aerial
parts
Disease spreads,
if the healthy trees are grafted with roots
infected with flagellates, the external
symptoms are visible in 4 -5 months later dies.
Insect vector- of genus Lincus (pentatomid
insect)

12. DISEASE MANAGEMENT
Nurseries should be free from pathogenic
flagellate protozoans.
Healthy plant should be planted far away from
the infected plants.
Phytosanitation
Chemical pre treatment prior to grafting.
Sterilization of grafting tools, and grafts.

13. Conclusion
Necrosis is the commonest and most destructive
type of effect. As a result of successful infection of
host plant by the pathogen a number of
physiological changes occur in plant. Respiration,
photosynthesis, nitrogen metabolism and
transpiration are affected. There will be reduced rate
of photosynthesis.
This in turn occurs a huge economically losses to
the owner of plantation as it causes low yield and
low quality of yield.

14. Reference
• PLANT PATHOLOGY by AGRIOS, 5 TH EDITION,
PAGE NO. 878-880
• PLANT DISEASE by Dr. B.P PANDEY – S CHAND
PUBLICATION.
• https://www.sciencedirect.com/topics/agricul
tural-and-biological-sciences/phytomonas