Cocoa pod borer

General information

The cocoa pod borer (Conopomorpha cramerella) is a serious pest of cocoa and rambutan. The pest was found on a cocoa farm in Far North Queensland in 2011, and has since been eradicated.

Overseas experience suggests that the pest is difficult to control and would probably become a major limiting factor to cocoa production systems in Australia if it were to become established.

The pest damages cocoa and rambutan fruit, causing significant yield loss. In cocoa, this damage makes the processing of cocoa pods difficult and reduces cocoa bean quality. In rambutan, the pest tunnels into leaves, stems and occasionally fruit, making it unmarketable.

Distribution            

The cocoa pod borer is known to occur in Saudi Arabia, China, India, Thailand, Brunei, Indonesia, Malaysia, Vietnam, Papua New Guinea, the Philippines, Samoa, Sri Lanka, Taiwan and Vanuatu.                

Life cycle            
  • Cocoa pod borer is a mosquito-sized moth belonging to the Gracillariidae family.                    
  • It lives for approximately one month, depending on temperature and availability of host material.                    
  • The adult insect survives for only about one week and is a poor flier. Adults are more active within the crop during the early evening.                    
  • In cocoa, fruit is required to complete the life cycle. However, in rambutan, there are records of the pest also damaging leaves and young stems.                    
  • The fully grown larvae may pupate on the fruit surface, but most often leave the fruit and lower themselves on a thread to the ground, weeds or leaf litter, where they pupate within a tiny, brown cocoon.                    
Damage to cocoa            
  • Larvae feed inside cocoa pods on the material that surrounds the individual cocoa seeds.                    
  • The larval feeding causes the seeds to stick together, which produces undersized seeds and poor-quality cocoa beans.                    
  • The fruit pulp becomes hard and the normal fermentation process used to produce the cocoa flavour precursors is made ineffective.                    
  • Young, green cocoa pods are particularly susceptible to attack by the pest.                    
Damage to rambutan            

In rambutan, the pest tunnels into leaves, stems and occasionally the fruit, making it unmarketable.                

Spread            

The material most likely to move cocoa pod borer from infested to uninfested areas include cocoa pods, rambutan fruit, other host fruit, and possibly vegetative material from cocoa and other hosts.                

Hosts            

Below are a list of host species and their common names:                

  • Cola spp. - Kola nut                    
  • Cynometra cauliflora - Nam nam                    
  • Cynometra iripa - Wrinkle pod mangrove                    
  • Lansium domesticum - Langsat                    
  • Nephelium lappaceum - Rambutan                    
  • Nephelium mutabile - Pulusan                    
  • Pometia pinnata - Fijilongan, Pacific lychee, taun, tava, kasai                    
  • Theobroma cacao - Cocoa                    
  • Xerospermum spp. - 'Wild rambutan'                    
Control            

Control of cocoa pod borer is difficult. Overseas, the pest has been managed using an integrated approach that includes good crop hygiene, early pod harvesting, insecticide applications and insect trapping.                

Eradication      

The pest was eradicated from Queensland by disrupting the life cycle of the cocoa pod borer through the removal of host material, application of insecticides, altering agronomic practices and implementing stringent biosecurity measures on the infested property.                

A district wide area freedom surveillance program was completed to prove the pest is no longer present in Queensland. Based on available literature, it is believed that Australia is the only country to have achieved national eradication of the pest.
Report suspect sightings      

If you think you have seen cocoa pod borer, contact Biosecurity Queensland on 13 25 23.

Last updated 04 May 2017