Two pronged strategy to overcome :
Weligama coconut leaf Wilt Disease
Weligama Coconut Leaf Wilt Disease (WCLWD), now confirmed as a
phytoplasma-borne disease was first detected in the Weligama area in
late 2006. The first suspicion of this disease arose when the scientists
of Coconut Research Institute (CRI) were informed by officers of noted
the appearance of a new coconut disorder in the Kamburugamuwa area which
is in the vicinity of Weligama with symptoms characteristic of the
phytoplasma-borne disease known as ‘Kerala Wilt’ in India.
Save our coconut estates
Kerala Wilt disease is highly prevalent in coconut palms of the
Kerala state of India and has been in existence for over 80 years.
The most notable symptom observed in palms suffering from the
disorder in Weligama was the yellowing of leaves, which often falsely
diagnoses as deficiency of Magnesium in the palm over a larger extent in
the southern province extending from Weligama on all directions.
CRI has reacted immediately from the very outset by sending the Plant
Pathologist of the institute to Kerala to familiarize with the symptoms
of Kerala Wilt disease and study the disease management plan currently
being practised in India.
This immediately helped in training staff of CRI and CCB, Agriculture
Research and Production Assistants and GNN in the three districts,
Matara, Galle and Hambantota to infected palms.
Identification of this disease requires a well trained eye since the
early symptoms of the disease are difficult to distinguish from normal
palm and an infected palm. Subsequently an initial suvery was conducted
jointly by CRI and CCB to determine the extent of the disease.
The survery revealed that the extent of spread was around 40,000 ha
encompassing the entire Matara District and bordering sections of Galle
and Hambantota Districts.
CRI by developing an accurate molecular diagnostic procedure has
confirmed the casual agent of the disorder as a phytoplasma and named it
as Weligama Coconut Leaf Wilt Disease (WCLWD). The Kerala Wilt disease
in India is also believed to be caused by a phytoplasma though there is
no conclusive evidence to say whether or not the two phytoplasmas are
It may be speculated that both are the same and the disease may have
come to Sri Lanka either by wind transmission of phytoplasma carrying
insect vectors of illegal importation of infected palms from India.
Another possibility is evolving of a phytoplasma from other
phytoplasmas already existing in the vicinity, for instance phytoplasmas
causing grassy shoot or white leaf diseases in sugarcane.
Coconut Lethal Yellowing Disease (CLYD) is the most commonly known
phytoplasma disease in the world which is widespread in the Caribbean
region and some countries of Africa and Central America. CLYD is the
most dreadful coconut disease known to date which kills an infected palm
within a pace of two years.
The most dreadful consequence of phytoplasma-borne diseases is that
so far no treatment is available for making an infected palm free from
the pathogen because it is an undifferentiated bacterium, which in
habits the phloem tissues of plants.
Only option available to eradicate a phytoplasma disease is to remove
and dispose all infected individual plants. Such an action is
impracticable for a crop of the nature of coconut which is so
extensively planted and intrinsically bound with socioeconomic basis of
the Sri Lankan culture.
Thus the only alternative is to manage the disease by taking maximum
precautions to prevent it from being spread to other areas of the
country while gradually diverting the farmers in the infected area for
opting for alternative crops/livestock to compensate their loss of
income diminishing from the coconut crop loss in the long run due to
Having known the gravity of this fearsome disease CRI had immediately
come out with interim recommendations through consultations of
scientists within the institute and outside organizations; CARP,
Department of Agriculture, universities and other research institutes.
At the very outset a steering committee comprising members from CRI,
CCB, CDA, DOA, RRI and Wayamba University of Sri Lanka was appointed to
discuss, improve and approve immediate strategic actions. A two-prong
1. Immediate management plan to prevent the spread of disease to
other coconut growing areas of the country by demarcating and
maintaining a 3-km border as a disease free buffer zone and barring
cross border movement of all kinds of palms through law enforcement,
2. Conduct a multidisciplinary research program and a survey to
obtain detailed information on disease diagnosis, symptomology,
epidemiology, modes of transmission, diesese and palm health
association, alternative crops and livestock, crop loss and socio
economic factors related to the disease for making much more commanding
recommendations for disease management was formulated for immediate
The progress of actions taken date are as follows:
1. An immediate suvery was conducted and the boundary of the infected
area was identified. A 3-km buffer zone was demarcated for maintaining a
disease free boundary.
The border of the diseased area identified was A 17 road from Galle
to Akuressa, Akuressa to Kirinda-Puhulwella through Kamburupitiya,
Kirinda-Puhulwella to Walasmulla, Walasmulla to Beliatta and Beliatta
Tangalle. The 3km width buffer zone was demarcated with 1 km outside and
2 km inside from the bordering roads.
2. Action was taken in collaboration with DOA to declare the pest as
a quarantine pest and legislation was made for barring cross boundary
transport of any plant material with the risk of carrying the disease.
A gazette notification No. 1542/7 of 24th March 2008 was issued
giving provisions to carry out actions to control and prevent spread of
the diseases and authorized officers were appointed for the task.
3. In order to maintain the disease free buffer zone a ‘Project Team’
was established under CCB by appointing a leader and a group of three
Coconut Development Officers stationed in the area.
So far an approximately 20,000 coconut plantations in the boundary
zone have been inspected and action has been taken to remove 1,237 palms
from a total of 1,715 diseased palms detected. A relief payment of
around Rs. 1,500,000 was paid for affected growers.
4. In order to assist growers badly affected by WCLWD and the Leaf
Rot disease in areas inside the border, financial assistance was
provided for uprooting around 1,000 unproductive palms amounting to
approximately Rs. 400,000. Three hundred bottles of 100 ml ‘Folicur’
(fungicide) were issued at half rate to around 200 coconut growers to
treat leaf rot affected palms.
As an incentive to carry out proper agronomic practices to enhance
palm vigour around, 11,000 kg of Urea, 15,000 kg of IRP and 23,000 kg of
MOP fertilizer were issued for around 200 growers at a subsidized rate.
5. Public awareness: Several publications and media materials were
produced and awareness programmes were conducted jointly by CRI and CCB
to make the coconut growers and general public aware of the disease and
recommended management strategies.
The grass roots level officers in Agrarian Services Department,
Samurdhi GSS etc., were given a through training on the disease to carry
the message to growers. Several publications and media materials were
produced and awareness programs were conducted to make the coconut
growers and general public aware of the disease and recommended
6. A field laboratory was set up and a multidisciplinary research
program was commenced to study all aspects of the disease; diagnosis,
symptomology, epidemiology, modes of transmission, disease and palm
health association, alternative crops and live stock, crop loss and
socio - economic factors related to the disease.
Plant Pathologist and an Agricultural Economist of CRI were stationed
at the CCB Regional Office, Matara with three contracted Research
Assistants to carry out these studies.
Further scientists of CRI in other disciplines, Physiology, Agronomy,
Soils and Plant Nutrition, Breeding and Biometry have also commenced
studies in their disciplines and are frequently visiting the area to
strengthen the research efforts.
7. A detail survey was commenced and data collection was completed
with the assistance of Agriculture Research and Production Assistants of
the Department of Agrarian Services to obtain detailed information on
disease incidence, extent, damage, crop loss, environmental and socio -
economic issues, alternative farming strategies and farmer perceptions.
In general the progress of the consorted efforts of CRI, CCB and
other organization to date have been successful in developing and
implementing the strategies developed for managing the WCLWD despite the
tremendous pressure from the community to implement the disease free
buffer zone where all infected palms have to be uprooted.
The research program is also making a good progress because of the
multidisciplinary approach and the involvement of scientists from many
WCLWD should be dealt as a national priority since it is the most
serious threat for coconut the country has ever faced since coconut
became a commercial crop. If this disease spreads islandwide there would
not be any solution for salvaging the country’s coconut industry.
The crop loss would become enormous leading to serious consequences
for all people in the country who depend on coconut for more than 20% of
their caloric requirement. In addition the loss of employment and
economic repercussions in bridging the foreign trade balance could not
Therefore, a consorted effort from all relevant sectors of the
coconut industry and the cooperation of the public are very much
anticipated to manage the disease in the infested area and prevent
spread of the disease to other coconut growing areas in the country.
- Dr. Priyanthi Fernando Head Crop Protection Division, CRI and
Everard Jayamanne, Deputy Director (Research), CRI.