The pest incursion risk to PNG’s coffee production
Peter Baker, Bryony Taylor and Sean T. Murphy | CABI
The Coffee Berry Borer (CBB) is the world’s most destructive coffee pest. Global damage is hard to estimate, though it regularly causes losses of at least 5% of the crop, which in today’s market means over $1 billion/year.
Over the last 100 years CBB has spread from West Africa to over 50 coffee countries around the world. In 2010 it was found in Hawaii, which some considered could always remain free of this pest because of the great distance from infested coffee countries and because of tight quarantine restrictions. Now there is just one coffee country that is unconquered by CBB: Papua New Guinea (PNG).
CABI has been working on coffee pests in PNG for the past eight years, first on the Coffee Green Scale, a long-time resident made more difficult to control by species of ants and now more recently CBB, which we have studied in many countries on three continents over the past 25 years. Below we will briefly resume some relevant knowledge of this pest in the region and review current surveillance efforts to keep it at bay.
Close to the border
CBB has been present in the Indonesian half of the island of New Guinea for many years and has gradually extended its presence eastwards to within 50 km of the border with PNG. Recently CBB was discovered in a small isolated location at the PNG border but it was quickly eradicated.
The importance of PNG coffee
PNG coffee exports total over $100 million/year and is mostly smallholder grown. They use few inputs and little maintenance; when CBB arrives, yield losses are expected to be high. It is not uncommon for farmers to suffer up to 50% losses when they first experience the pest. After this initial experience, coffee farmers either adjust to the problem by carrying out regular sanitary control or abandon coffee altogether. It is therefore likely that annual losses and costs of control for PNG will initially exceed $10 million/year.
The importance of surveillance
The pest will inevitably establish in PNG, but every year that it can be held at bay is a considerable savings to local economies and is therefore worth a substantial effort to hold it off.
To this end, CABI is carrying out a surveillance and training exercise in PNG for ACIAR (Australian Centre for International Agricultural Research) as part of its project “Incursion prevention and management of Coffee berry borer in PNG and Indonesia”.
How is CBB Transmitted?: Vectors and Pathways
To understand how CBB will move through the country, we mapped the various pathways that coffee takes from farm to export in PNG.
Vectors:
Over a short distance CBB flies but mostly less than one kilometre. Possibly longer distances can be covered, since they take wing from mid-morning to late afternoon when thermals could carry them far, but this is not a principal risk.
Coffee cherries: The beetles can be transported inside coffee cherries (whole or depulped). Once the depulped parchment coffee is dried to 11-12% CBB dies, but rustic processing often fails to reach this level, they can disperse in this form too and hence are major risks for short to medium distance movement. Surveys in the border zone found coffee cherries along main tracks between villages heading towards the border, confirming this risk.
In sacks: since the beetles are small (2mm long) they can easily hide in sacking or other material. This is a likely route to travel by road long distances or even by plane.
Pathways:
Cross-border: there are many tracks and paths crossing the border as well as rivers which are not monitored. These must be a principal risk for the movement of CBB. Continuous monitoring of these by quarantine officials could be prohibitively costly however.
Internal: once across the border, subsequent movement of CBB could be fast if human vectors get to roads. A main route is to local processing plants which become a main focus of surveillance. If infested coffee can be quickly identified at this point and traced back to an approximate origin and eradication attempted.
Surveillance strategy
Based on the IPPC code, a strategy was devised in collaboration with the Coffee Industry Corporation and the National Agriculture Quarantine and Inspection Agency for PNG to prevent incursion and spread throughout the country.
The border area is a key surveillance zone where only little coffee is produced but human transit is high. Much of the coffee from the Sepik region (next to the border with West Papua) is collected at Wewak and should be inspected prior for sending to be processed.
Another high risk area is the West Highlands Province which produces about half of PNG’s coffee. Mt. Hagen airport receives regular flights from border towns and is as well a nodal point for people and goods from the border.
Detection techniques include visual inspection of coffee for small entry perforations, both on the tree or at any time up to entry to processing facilities. Traps using a methanol+ethanol lure can also be used in areas most likely to have flying CBB.
Processing plants are one of the most likely places to detect CBB because quality control checks are carried out there and personnel can be trained to recognize symptoms of damage.
Waiting for Godot
Despite the surveillance and precautions taken, there isstill no idea when CBB will finally arrive. Its close proximity however poses some fundamental questions that every coffee institute has had to face: what should we do? Where will it be most problematic? What control strategy will work best?
When it arrives it will mean that the lowest altitude coffee will tend to disappear since cost of control there will be too high for most farmers. Because of rising temperatures however, these coffee lands are already compromised and hence an additional aspect of the CBB phenomenon is how it will accelerate the process of transformation that climate change makes inevitable. The way that this transformation is approached and managed is a challenge that all coffee stakeholders are only very slowly confronting.