BCS Study

BCS Experimental Site

Located 15Km inland from the main road is the BCS experimental site. Locally named Mobdu, this site is a current BCS hotspot having first reported a BCS outbreak in 2012. The site is family farm with coconut intercropped with cocoa and food gardens. ( will include map of Mobdu)

o Activity 1.1: Identify the range of plant species affected by BCS.
Key research questions: what is the host range of the pathogen? Are there crop species or cultivars that are unaffected?

Methodology: Different plant species of both crop and non- cop was collected at complete randomized locations in 20 m radius sub-sites in a 1256.64 m2 sampling area. The different plant species collected were identified and tested for the presence of the BCS phytoplasma.

The site was scoped an experiment site in 2012 when ACIAR incepted a BCS project that was aimed at generating biological information on the Bogia Coconut Syndrome and its associated phytoplasmas.
Experiments however began in 2015 with the initiation of three main study activities;

o Activity 1.2: Identify the insect species capable of vectoring BCS phytoplasma.
Key research questions: what vector species can transmit the disease? What is their host range?

Methodology: Insect species of six (six) different species from the Family Hemiptera were collected in a 20m radius sub sites in a 1256.64 m2 sampling area. These insects were identified and tested for the presence of the BCS phytoplasma.

o Activity 1.3: Confirm the causality (rather than current ‘association’) of the coconut lethal yellowing phytoplasma in BCS and to definitively assess the efficacy of each putative vector species.

Key research questions: are all insect species in which the phytoplasma has been detected functionally capable of transmitting the disease? is more than one pathogen implicated in the disease ‘syndrome’?

Methodology: Large single species insect cages containing multiple palm species were placed inside aphid proof cages. These palm species include; coconut, betelnut, oil palm and two varieties of banana, Kalapa and Cavendish. The plants introduced in the cages were clean material having been tested negative for the presence of BCS. These plants were planted in complete randomization in the cages. There is a total of 20 cages with 18 with treatments of different insects introduced while the other two are controls. The treatment for each cage varied but a total of six treatments were studied;

1. Zophiuma
2. Lophops
3. Derbids
4. Flattids sp.1 (F. taprealla)
5. Flattids sp. 2 (F. colgar)
6. Ricaniids
(Will provide images later)

o Activity 1.4: Determine modes of spread for BCS.
Key research question: In practice, is the disease mainly spread by insects or by human agency? (e.g. in planting material) Is BCS able to actively be transmitted from infected mother palm to seedling?

Methodology: To test the viability of active transmission of phytoplasma via other modes. A seed transmission study was carried out. In this study, coconut and betelnut seeds were collected from infected stage one and stage two mother palms and were raised in an insect free environment. Each seedling was pre- treated and allowed to germinate in polybags with germination being measured. The seedlings will sampled at 3 months, 6 months and 12 months. For coconuts local talls were selected from four different sites; Kananam, Riwo, Banab and the International Coconut Genebank for the South Pacific (ICG-SP). Control collected from Karkar Island Tall from the ICGSP, a native tall abundant in Madang province. For betelnuts all collections were from the Mobdu area.