Cord 2006, 22 (1) Cocoa pod borer threatening the sustainable coconut-cocoa cropping system in Papua New Guinea S. P. Singh¹ and P. Rethinam¹ Abstract Cocoa pod borer Conopomorpha cramerella Snellen is an important pest of cocoa. Its recent invasion of cocoa in Papua New Guinea is threatening the sustainable coconut-cocoa cropping system. C. cramerella occurs only in South-East Asia and the western Pacific. It has been the single most important limiting factor to cocoa production in Indonesia, Malaysia and the Philippines. C. cramerella attacks cocoa, Theobroma cacao; rambutan, Nephelium lappaceum; cola, Cola acuminate; pulasan, Nephelium mutabile; kasai, Albizia retusa, nam-nam,Cynometra cauliflora; litchi (Litchi chinensis); longan (Dimocarpus longan) and taun, Pometia pinnata. The possible mode of its spread is through seed pods/fruits carried from previously infested regions. However, there is possibility of local adaptations of rambutan-feeders or nam-nam-feeders to cocoa. Females lay their eggs (50-100) on the surface of the unripe pods (more than five cm in length), which hatch in about 3-7 days and the emerging larvae tunnel their way to the center of the pod where they feed for about 14-18 days before chewing their way out of the pod to pupate. The pupal stage lasts 6- 8 days. The larval feeding results in pods that may ripen prematurely, with small, flat beans, often stuck together in a mass of dried mucilage. The beans from seriously infested pods are completely unusable and in heavy infestation over half the potential crop can be lost. Over four dozen species of natural enemies (parasitoids, predators, and entomopathogens) attack eggs, larvae, pupae and adults of C. cramerella. Egg parasitoids Trichogrammatoidea bactrae fumata and T. cojuangcoi, egg-larval parasitoid Chelonus chailini, predatory ants particularly Iridomyrmex spp., Dolichoderus thoracicus and Anoplolepis spp. are commonly recorded. The most effective control methods are frequent harvesting, destruction of ripe pods and husks to prevent pupation in the field and selective spraying of resting sites with deltamethrin or cypermethrin or carbaryl. Pheromone mixtures have potential for use in traps as a quarantine surveillance technique and for control. Encouragement of predatory ants and parasitoids, and use of egg parasitoid T. bactrae fumata are potential biological control techniques. Pod sleeving with bags have been able to control cocoa pod borer in smallholders garden but not in larger plantations. Some of the clones have shown resistance against the cocoa pod borer. Success achieved in the project-Sustainable Cocoa Extension Services for Smallholders (SUCCESS) implemented in Indonesia in conjunction with the American Cocoa Research Institute and BCCCA, a British counterpart, ACDI/VOCA could be emulated for C. cramerella management, which included training of farmers to adopt frequent harvesting, pruning, sanitation and fertilization. Key words: Coconut, cocoa, cocoa pod borer, Conopomorpha cramerella, rampasan & harvesting, natural enemies, biological control, pheromone trapping, management. 1 Asian Pacific Coconut Community, Jakarta, Indonesia 76 Cord 2006, 22 (1) Introduction Cocoa pod borer (CPB)Conopomorpha (=Acrocercops = Gracillaria = Zarathra) Coconut palm known as ‘Tree of Life' cramerella Snellen (Lepidoptera: and cocoa tree belonging to the genus Gracillariidae) is known by several other Theobroma, meaning 'food of the Gods' in common names such as cocoa pod borer, Greek are essentially crops of small farmers. cocoa moth, rambutan borer, nam-nam In Papua New Guinea (PNG) coconut-cocoa borer, javanese cocoa moth, polilla javanesa is a popular cropping system, cocoa grown del cacao (Spanish), teigne javanaise du as companion crop in coconut under the cacaoyer (French) Motte, Javanische Kakao shade. Copra and cocoa are major export (Germany), and hama penggerek buah kakao commodities. Recently Dr. S. P. Singh (Bahasa- Indonesia) (CABI,2002). Project Coordinator IPM, Asian Pacific Coconut Community visited Cocoa and C. oceania, C. sinensis and C. litchiella Coconut Institute, Tavelo and National are three congeneric species found in South- Agricultural Research Institute (NARI), East Asia which are very similar to C. Keravat, Papua New Guinea (PNG). He met cramerella. They can be differentiated from Dr. John Moxon, Team Leader, NARI and C. cramerella by wing pattern and male and visited fields around these two Institutes. Dr. female genitalia (Bradley, 1986). Moxon informed about the severe incidence of cocoa pod borer in some of the blocks Strains belonging to NARI. The incidence varies from one to hundred per cent in different C. cramerella was collected from cocoa blocks. The pest was detected for the first and rambutans in the field at four sites in time in March 2006. The staff of NARI is Malaysia in 1984 and analysed by making vigorous efforts to eradicate the polyacrylamide gel electrophoresis. pest. It may be mentioned here that in PNG Hexokinase was polymorphic at one site and and several other countries combination of fluorescent esterase at all four sites. Two coconuts with cocoa is common farming zones of malate dehydrogenase (MDH) were system. But this system is now threatened by observed: c-MDH was monomorphic in all the advent of cocoa pod borer four populations while MDH-1 was (Conopomorpha cramerella Snellen) in polymorphic in three populations (Tan et al., PNG. The work conducted on C. cramerella 1988). Peptidase 2 was polymorphic in the was reviewed earlier (Lim et al., 1987a,b; Sabah sample while alpha-GPDH [glycerol- Ooi et al., 1987). This article provides some 3-phosphate dehydrogenase] was basic information on C. cremerella coupled polymorphic in the other sample. This with its management options. Bibliography differentiation may reflect geographical is also provided. variation of the same species (Saahlan et al., 1985). Although 30 enzymes and general Taxonomy and nomenclature proteins were successfully demonstrated on zymograms, none could be used as The earliest damage caused by cocoa diagnostic markers to separate the two pod bore was noted by Jansen (1860), which biotypes (Muhamad et al., 1989). was first taxonomically described at the beginning of the 20th century as Host plants Acrocercops cramerella (Snellen, 1904). Subsequently the generic placement of this Indigenous sapindaceous and species has been revised to Conopomorpha leguminous species (rambutan, pulasan, cramerella (Bradley, 1985), which is now kasai and nam-nam) appears to be the widely accepted. original hosts of C. cramerella as they are indigenous to the region to which the moth 77 Cord 2006, 22 (1) is restricted, whereas cocoa is a recently cocoa expansion in the late 1980's and early introduced species(CABI, 2002) and the pest 1990's.Approximately 20% of all cocoa in appears to have shifted to this perennial Indonesia could be infected by C. host. Rambutan and nam-nam produce fruits cramerella. In May 1998 Landell-Mills with pulp similar to cocoa (Wood, 1980). estimated the reduction in cocoa production However, they tend to be more seasonal than potential by cocoa pod borer in Southeast cocoa and so may not provide the right Asia at 40,000 tonnes. The estimated losses conditions for permanent establishment. in dollars due to cocoa pod borer This could limit populations in local areas approached $20m in 1998. The cocoa pod (CABI, 2002). borer has been the single most important limiting factor in cocoa production in C. cramerella infests cocoa, Theobroma Indonesia. Cocoa pod borer infestation has cacao; rambutan, Nephelium lappaceum; severely affected the quantity and quality of cola, Cola acuminate; pulasan, Nephelium cocoa production and farmer income. The mutabile; kasai, Albizia retusa, nam- cocoa pod borer is prevalent in all producing nam,Cynometra cauliflora; litchi (Litchi areas, and is causing an income loss of chinensis); longan (Dimocarpus longan) and approximately 40% to individual farmers, or taun, Pometia pinnata. over $400 per hectare per year. With limited control, production losses in infested areas are significant (between 20% - 50%) for Damage smallholders (with average farm size of 1.5 ha) who rely on the year-round cash income The larvae of C. cramerella bore into provided by cocoa. For Sulawesi alone, the soft tissues in the pod wall, which estimated losses caused by cocoa pod borer provide the nutrients for the development of are approximately US$150 million per year, the beans. Once inside it is safe from almost all to smallholder cocoa farmers. In insecticides for most parts of its life. The light infestations the loss may be slight, but attacked pods ripen prematurely, and control efforts may be needed to prevent produce small, flat beans. In heavy higher infestation from developing. infestations, the beans are often stuck together by mucus and in this condition; they have no market value. In heavy Pest status and damage identification infestation over half the potential crop can be lost. C. cramerella has become the most important insect pest of cocoa in many parts When <60% of harvested cocoa pods of its distribution.Quarantine and showed internal attack, yield loss was <5%, surveillance for C. cramerella remains a but with 90% of pods attacked yield loss problem in areas of South-East Asia in was about 40%. In Sabah, Malaysia, annual which the pod borer does not presently yield losses ranged from 22 to 54%. Losses affect cocoa (Thailand and Sri Lanka). for the whole estate were estimated from Rambutan or nam-nam borers are already estate records, and for the same years ranged known from Thailand, Sri Lanka and New from 42 to 49% (Day, 1989).The number of Britain (Papua New Guinea). C. cramerella hardened beans and the number of beans in has also been found from unspecified hosts, the pod were the most vital contributing in Western Samoa and the Northern parameters accounting for more than 80% of Territory of Australia early in the 20th the variation about the mean in the observed century (Mumford, 1986). Live borers can bean loss (Davis, 1989b). travel long distances within rambutan fruit: healthy C.