BCS in PNG

Common Name

Bogia coconut syndrome, banana-wilt associated phytoplasma.

Scientific Name

The phytoplasmas associated with coconut and banana in Papua New Guinea have not been given scientific names. However, analysis of ribosomal RNA has found that they are in the phytoplasma group code named 16SrIV.

Distribution

Narrow. The phytoplasma associated with Bogia coconut syndrome has only been found in the Madang Province, Papua New Guinea. The same phytoplasma occurs widely in banana; it has been recorded in the East Sepik, Madang, Morobe, and Western provinces.

 Hosts

Coconut, banana and betel nut.

Affected Areas in Madang

Madang District

2009 Furan was affected

2014 Sagalau, near Madang town

2015 Gum bridge area to Mambu market, Siar village, Madang

2016-17 4-Mile market and Vidar/Maivara

2017-2018 – Rivo village/Jais Aben

Sumkar District
2013 Kuseng village
2013 Mobdub village/near to CCI Murnas
2017-2018 Katom village, Karkar Island

Bogia District
1980-81- reports of Yaro & Vidaro plantations, Bogia affected.
2012 Ulingan/Tupira Guesthouse area affected
2012 Korak was affected

BCS in its current state of distribution in Madang is no longer in its prevention stage but has progressed to containment and eradication and management.

 Containment

Sanitation (cut down & destroy disease palms). Only slows down epidemiology.
Sanitation training and awareness done by NAQIA/KIK/Madang DPI in April 2016 (Only in Coconut Gene bank and its buffer zones).
Genebank sanitation – weed control, c

Eradication

This is a permanent option that is hoped be reached. Plans are underway for a provincial sanitation program to be carried out. This program will involve the removal of all infected palms and those palms at risk of infection. KIK is in the process of planning this activity and will shortly implement it.

Detection & Inspection

Inspection of BCS begins with a visual assessment of the palm. Signs of infection usually are paramout on the crown of the plam. First signs are yellowing, drooping outer leaves, early nutfall, and rapid death (within 3 months). For other palms such as banana it is easier to tell as the yellowing will be paramount. There will be a bright yellow pigmentation of colour in the leaves and vascular tissues with streaks and patches of brown or black rot. It is important to note that before concluding that a plant has BCS, make sure that a visual assessment of nutrient deficiency and lightning is also carried out. This is to isolate other related issues on plant health before visual confirmation of BCS is made. Once a visual confirmation is made samples of either petiole, leaf or trunk tissue is collected and preserved for DNA extraction and molecular analysis of BCS presence in the tissue. IMPORTANT NOTE: The identification of phytoplasmas can only be done using molecular analysis of ribosomal RNA; the analyses done on banana in Papua New Guinea have found plants with symptoms typical of BWAP containing phytoplasmas closely related to those in coconuts with Bogia syndrome.

Future Work

GoPNG to provide funding for
o Implementing a sanitation program

o Improving check points at Tapo and various ports

o Relocating the Coconut Genebank to Punipuni, Milne Bay Provice

Regular monitoring and surveillance of BCS in Madang and other provinces in PNG.
ACIAR project on insect vectors, develop IPM for BCS

Impact

The disease in coconuts was first reported in 2008 in the Bogia district of Madang Province, hence its common name. It occurs in both newly planted and old palms. To date, many hundreds of palms have been killed and plantations abandoned due to the disease, and the epidemic continues unchallenged. The concern is that is will impact food security and the economic wellbeing of the people in the area as coconut is an important food as well as a traded commodity. Export of copra and coconut oil in Papua New Guinea is worth approximately US$30 million and US$45 million per year, respectively; if the disease were to spread it would have major socio-economic consequences.

The disease threatens the Stewart Research Station of the Cocoa & Coconut Research Institute, Papua New Guinea. The Research Station hosts the International Coconut Genebank for the South Pacific under IPGRI/COGENT and FAO agreements.

Issues & Concerns

BCS Containment on sanitation work an enormous task and need resource requirements and support.
Research into BCS related areas is slow (takes time) and very expensive.
BCS is still spreading to new areas in Madang.
Continues BCS Monitoring and Surveillance lacking within, Madang and throughout PNG.
Social related studies lacking in BCS.

Management

Current known management practices of BCS include;

• General block sanitation-( weed control, removal of infected plant material, implementation of buffer boundaries)
• Improvement and maintenance of soil nutrient quality and healthy water levels.
• Avoidance of host plant intercropping- Plants such as banana, taro and betelnut are strictly not to be intercropped with coconut as it increases the risk of infection)
• Avoid introduction of disease planting materials.

Other options such as the use of anti-biotics and pesticides are still being investigated. In time KIK will be able to roll out a complete IPDM package for BCS to allow farmers to be able to effectively manage the disease.

Quarintine

The FAO/IBPGR Technical Guidelines for the Safe Movement of Coconut Germplasm recommend that coconuts should be moved as embryos growing in a tissue culture medium. As a special note, the Guidelines recommend that embryos, seedlings and palms from which pollen is collected should be tested for viroids and Coconut foliar decay virus. If that is not possible, seednuts may be transferred only if they are germinated in intermediate (third country) quarantine, and indexed for viroids and Coconut foliar decay virus. (http://www.bioversityinternational.org/e-library/publications/detail/coconut/.)

In an effort to contain the epidemic of Bogia coconut syndrome in the Madang area, there are restrictions on plant movements from the province.

There are no recommended methods of managing the disease, apart from the embargo on plant movement. The priority is to find out which insects spread the phytoplasma and whether there are coconut varieties that are tolerant or resistant to the disease.

Movement of BCS

Through use of diseased planting materials – long distance movement
Insect vectors – re-distribution of BCS locally by infected insects (short distance).

Symptoms & Life Cycle

The symptoms in coconut in Papua New Guinea are similar to those of coconut palms with lethal yellowing disease in many countries worldwide: the outer fronds become pale yellow and droop, nuts drop early, followed by the collapse of all but the spear leaf (Photos 1,2&3). From the time of the first symptoms to death is only 3 months (Photo 4). Although loss of nuts is an early sign of the disease, there is no associated death of the flower bunch (stalk and cluster of flowers) that is a common sign of lethal yellowing disease.

The symptoms in ABB banana varieties differ from those caused by Fusarium wilt (see Fact Sheet no. 176). Leaves turn yellow, but inside the stems there are short brown or black streaks in the vascular areas (water and food conducting tissues) associated with larger areas of wet rot (Photo 5). Bananas with these symptoms contain phytoplasmas that are identical to those found in coconuts. The disease has been given the name banana-wilt associated phytoplasma (BWAP).

Coconut Industry Threats

Coconuts do have threats but not too lethal cf. BCS
BCS is very deadly (like lethal yellowing in other countries) & caused by a phythosplasma
BCS is only present in Madang based on 2012 survey.
In a research study done (Furan site, Madang) on the rate of killing, BCS kills1-2 palms per month.
BCS phytoplasma has 3 confirmed host plants i.e. Banana,
Betelnut and Coconut (Suspected in taro, yams, sago & cassava)

Within 3 months a palm dies when BCS phytoplasma is present.

Symptoms on Banana

Spread of the phytoplasmas in coconut, banana and betel nut is thought to be by insects. Sap-feeding insects that pierce and suck sap from leaves and soft tissues spread similar phytoplasma diseases in other countries. Although the insect that spreads the phytoplasma is not known, interest has centred on Zophiuma pupillata (Hemiptera: Lophopidae), which breeds on coconuts. This insect is common on coconuts and betel nuts, but less so on banana, and phytoplasmas are frequently detected in both adults and nymphs.

Symptoms on Betelnut

Several other insects from different families are also common on coconuts and found to contain phytoplasmas; one of them is a species of Proustia, an insect that is known to spread phytoplasma diseases of coconut (India) and sugarcane (Southeast Asia).