Taking sago back to Bougainville

 By TOSHIRO SHIGAKI

STARCH harvested from the sago palm is an important source of nutrition in coastal areas of Papua New Guinea.  

In Bougainville, the fronds from sago palms are used for thatches for houses. Without sago palms, people have to resort to expensive metal sheets for their housing needs. 

It is important as a source of food, especially in light of changing climate.  

However, since the early 19­90s, sago palms in Bougainville have been declining. There has not been any report to account for the cause of this decline, until now. 

The nature of the sago decline was made clear by two surveys conducted in April and August by a team of scientists from the National Agricultural Research Institute (NARI) and the National Agriculture Quarantine and Inspection Authority (NAQIA).  

A workshop was held in Ara­wa, Central Bougainville, Autonomous Region of Bougainville (AROB), on November 21 to report the details of the survey findings. The workshop was attended by more than 20 officers from the Department of Primary Industries (DPI) of the AROB Government, NARI, PNG Cocoa Coconut Institute (CCI), and NAQIA. DPI officers represented each district of Bougainville.

The workshop was organised by NARI with funding from The Christensen Fund, a San Francisco-based philanthropic organisation that promotes the preservation of cultural heritage and biodiversity around the world. 

The participants gave presentations on the status of the sago palms in their districts and exchanged opinions. Due to the lack of funding and transportation problems, it was the first time for the DPI officers to sit together in one room to discuss issues.  Some participants travelled to Arawa from remote locations as far as Nissan Island.  

In a region where telephone and internet services are unreliable, such meetings play important roles for extension officers.  In fact, the lack of networking could have been one of the problems that delayed the systematic investigation of this devastating decline for many years.

A number of new findings on the sago decline were reported in the workshop. The decline appears to be initiated by weevil larvae that make entry into the tree just above the soil line.  

These weevils are thought to be the carrier of a pathogenic fungus. The fungus spreads in the trunk of the tree by extending thread-like growth (hyphae) under favourable conditions.  

When the hyphae reach the pith, the tree starts to rot, possibly because the starch concentration is high there to provide nutrients for the fungal growth.  

At an early stage of the pith rot, the tree may appear healthy.  However, as the rot advances, older leaves start to show yellowing.  

At the base of the trunk, numerous weevil boreholes become visible, with resin exuding out of the tree. Finally, the tree will collapse. The causal relationship of the decline and the weevil-fungus complex has not been confirmed, but it should be addressed in future projects that are geared toward academic aspects of the problem.  

The goal of the project is a rather practical one, to find the most cost effective, sustainable, and easily adopted strategy to re-establish the sago stands in Bougainville. Sago is often considered a neglected crop and funding for sago research is scarce.  Therefore, the cost-conscious approach is critical for the success of the project.

Three possible options were suggested. First, biological control of the weevils may be an en­vironmentally friendly and low-cost method to reduce the pest population.  Fungi that are pathogenic to the weevils can be utilised, for example.  This strategy, however, may never be popular because the weevil grubs are an important source of protein for the locals.  

If the weevils disappear, the villagers will lose an important food resource. Second, sago varieties that are tolerant to the decline can be introduced from elsewhere.  This option can be complicated by quarantine requirements.  

In addition, the introduced varieties may not provide the same quality materials to cater for the housing needs as the local varieties. Ecological consequences must be considered as well. Because of these uncertainties, this option has been dropped. The third option is to select tolerant sago lines in Bougainville itself.  

Even in the areas completely devastated by the decline, some sago trees still survive to the flowering stage to produce seeds.  These trees and the seeds are considered to have tolerance to the decline, a result of natural selection. This option was selected as the most feasible strategy for the sago restoration.  

Next year, the NARI team will re-visit the island to collect seeds from the surviving trees in Southern Bougainville and screen them for enhanced tolerance to the decline. The seedlings will be finally distributed through DPI officers throughout Bougainville for planting.

At the end of the workshop, the participants unanimously expressed their support for the strategy adopted in the workshop.  NARI will continue to work with DPI, the local government, and local residents to restore the once legendary sago forests in Bougainville.