The overarching aim of this project is to protect the viability of the important oil palm industry and the economic and social benefits that flow from production on plantations and smallholdings in Papua New Guinea. Specifically, the work concerns Finschhafen disorder (FD), a problem that was first observed on coconut palms near Finschhafen, Morobe Province, Papua New Guinea (PNG) in 1960, and is now a potential threat to the production of palm oil. The very limited amount of previous research suggested that FD may be a direct consequence of feeding by a native PNG planthopper Zophiuma lobulata Ghauri (Hemiptera: Lophopidae). Previous studies however, pre-dated the availability of molecular biology methods that enable detection of possible plant pathogens. Z. lobulata belongs to a group of insects widely implicated in vectoring plant pathogens in other crops.
A full time Postdoctoral Fellow (Dr Catherine Gitau) has been recruited to the project from the International Centre for Insect Physiology and Ecology in Kenya. She, and the project leader (Prof Geoff Gurr), have visited PNG to work with Charles Dewhurst Head of Entomology at PNG Oil Palm Research Association. Molecular biology and taxonomic expertise have been contributed by the ongoing involvement of Drs Andrew Mitchell and Murray Fletcher, respectively, of NSW Department of Primary Industries.
The first objective of this project is to develop a comprehensive biological understanding of the causes of FD. In pursuit of this, bibliographic information on FD and Z. lobulata as well as similar disorders and pests has been sourced from various scientific databases and an electronic library has been compiled using a proprietary bibliographic software package. Copies of all relevant publications have been collected and complemented by a significant volume of personal communication material that has been obtained from liaison with palm health researchers around the world. All of this information has been synthesised into a comprehensive review article that will be submitted for publication in a scientific journal.
The identity of Z. lobulata has been confirmed by comparing specimens collected from a range of locations in West New Britain with the formal taxonomic description for specimens from various parts of mainland PNG. This project has employed morphological characters, particularly male genitalia, and molecular methods using the CO1 gene. Results indicated consistency of all morphological and molecular characters and there was no evidence found for additional or cryptic species.
Screening of Z. lobulata and palm material for possible microbial pathogens is well advanced and a series of large insect-proof cages has been constructed to establish an experiment to elucidate the role of Z. lobulata and its relationship with FD. Laboratory studies have shown that planthoppers will feed on a 5% sucrose solution presented through a semipermeable membrane. This will enable samples of saliva to be collected from individual planthoppers for DNA testing for the presence of potential pathogens.
Field work aiming to identify natural enemies of Z. lobulata that could be used as biological control agents resulted in the collection of several taxa of parasitic wasps belonging to the family Mymaridae and a currently undetermined genus. These were common parasitoids of Z. lobulata egg masses on West New Britain. Samples of the Myrmaridae have been sent to Canada for identification and formal description (they are likely to be new species). Samples of Z. lobulata that had been killed by insect diseases especially fungus have been collected from various sites in West New Britain and preserved material delivered to Australia. Preliminary identifications suggest most are a species of Sporothrix whilst others are from Gliomatix or similar genus. Further taxonomic and pathogenicity studies are planned.

Monthly monitoring of Z. lobulata numbers and FD symptoms on betel nut, oil and coconut palm has been running since January 2008 on a small holder oil palm block in West New Britain.
Work on the second objective of the project - to develop preliminary control methods for FD is at an early stage because it is contingent on the findings of the first objective.
Yellow sticky traps have been evaluated in the field for monitoring adult Z. lobulata but proved to be ineffective. An experiment comparing a range of alternative trap colours is in progress.
Laboratory experiments have taken place to evaluate the influence of nectar rich ground cover plants on the lifespan of the mymarids. Results showed that adults lived longer with access to the flowers compared with those that were fed on water alone. Further work will be conducted in June 2008 using a variety of different cover crops and additional species of natural enemies to identify the scope for these plants to be used as a management approach that attract and support biological control agents of Z. lobulata.

The objective of this project is to protect the viability of the oil palm industry in Papua New Guinea. It aims to enhance the social and economic benefits that emanate from production of the oil palm in plantations and smallholdings. The main work concerns Finschhafen disorder (FD), a problem first reported from coconut palms near Finschhafen, Morobe Province, Papua New Guinea (PNG) in 1960, that is now a threat to palm oil production. Research conducted in the 1980s implicated a native PNG planthopper Zophiuma lobulata Ghauri (Hemiptera: Lophopidae). Methods used to in that study pre-dated the availability of molecular biology tools that enable detection of possible plant pathogens. This project has so far used these tools to screen plant and insect material for a variety of pathogens known to be vectored in other crops by a group of insects to which Z. lobulata belongs. Transmission experiments in large cages and small sleeves have also been used to study FD causality.
In the last year, the project leader (Prof Geoff Gurr) and the Postdoctoral Fellow (Dr Catherine Gitau) visited PNG once and four times respectively, to conduct experiments and work with Mr. Charles Dewhurst, Head of Entomology at PNG Oil Palm Research Association (OPRA). Molecular biology and taxonomic expertise have been contributed by Drs Andrew Mitchell and Murray Fletcher, respectively, of New South Wales Department of Primary Industries.
The first objective of this project is to develop a comprehensive biological understanding of the causes of FD. The second objective is to develop preliminary control measures for FD.
In pursuit of the first objective, bibliographic information on FD and Z. lobulata as well as similar disorders and pests of palms has been sourced from various scientific databases and an electronic library has been compiled using the EndNote bibliographic software package. Copies of all relevant publications have been collected and complemented by a significant volume of personal communication material that has been obtained from liaison with palm health researchers around the world. All of this information has been synthesised into a comprehensive review article that has recently been accepted for publication in the Australian Journal of Entomology.
The identity of Z. lobulata has been confirmed by comparing specimens collected from four locations in PNG. We have used the formal description made by Ghauri (1966) to confirm the identity of Z. lobulata collected from mainland PNG and West New Britain and those associated with coconut, oil palms, as well as betel nut. Results showed consistency in Z. lobulata male genitalia of all the specimens. Molecular methods using the CO1 gene showed the same consistency. Results indicate consistency in all morphological and molecular characters and there is no evidence for additional or cryptic species. We therefore conclude that there is only one species associated with FD. In addition, another congeneric planthopper, similar to Z. lobulata, namely Z. pupillata (Stl) collected from coconut and sugarcane in mainland PNG has been compared with Z. lobulata using both morphological taxonomy and barcoding. Currently, the CO1 sequence data is being analysed and a formal article to be submitted into a taxonomic journal is in preparation.
Comprehensive screening for possible microbial pathogens in Z. lobulata and oil palm material has been conducted. Insect and plant material were thoroughly screened using current molecular biology tools for pathogens, particularly phytoplasmas and bacteria-like organisms (BLOs). Saliva samples that were collected in 5% sucrose solution were also screened for pathogens. The saliva was collected by presenting sucrose solution contained in an Eppendorf tube which was covered with a semipermeable membrane, to the planthoppers for feeding.
Large insect-proof cages (1.8mx1.8mx2.5m) were constructed and used in a study that aimed at elucidating the role of Z. lobulata in FD. Z. lobulata that were raised from eggs in the laboratory and those collected from the field were released into the cages in an additive process over a period of 8 months. Both the lab-reared and field-collected Z. lobulata induced FD symptoms in previously healthy coconut and oil palms. Small sleeve experiments were further set up to corroborate the large cage experiments. Results from the sleeve experiments are expected by year 2 month 8.
Field work aimed at identifying natural enemies of Z. lobulata that could be used as biocontrol agents resulted in the collection of several taxa of parasitic wasps belonging to the families Mymaridae and Encyrtidae. These were the common parasitoids of Z. lobulata egg masses on West New Britain and Milne Bay in mainland PNG. Samples of the Mymaridae were sent to Canada and UK for identification and revealed that they are new species. The mymarids are Parastethynium sp. near P. mayeri and the encyrtids are Ooencyrtus near O. minor or O. major.
Samples of Z. lobulata that had been killed by insect diseases, especially fungi, have been collected from various sites in West New Britain and preserved material delivered to Australia. With the help of Dr Michael Priest, DPI Orange and Dr Hywel-Jones in Thailand, preliminary identifications of the fungus suggest that most are from Gliomatix or a similar genus and Hirsutella citriformis, an entomopathogenic fungus with a pantropical distribution, although it could be a complex of related species.
Work on the second major objective of the project - to develop preliminary control methods for FD - is contingent on the findings of the first objective. However, monthly monitoring of Z. lobulata numbers and FD symptoms on betel nut, coconut and oil palm was conducted between January 2008 and February 2009 on a smallholder oil palm block in West New Britain. Another site at Dami Research Station has been identified and monthly monitoring will be conducted in a similar manner in 2009/2010. Results suggest that direct visualisation of Z. lobulata egg masses may be viable as a monitoring tool.
A variety of coloured sticky traps was evaluated in the field to assess trapping as a monitoring tool for Z. lobulata. Eight colours were evaluated. Results did not reveal significant differences in attractiveness, based on colour. Moreover the numbers of Z. lobulata adults and nymphs captured were very low. Future experiments using trap-and-kill approaches will be considered.
Laboratory experiments evaluating the influence of nectar rich-ground cover plants on the lifespan of mymarid and encyrtid parasitoids were conducted. Results showed that adults lived longer when they had access to flowers compared with those that were fed on water alone. Further work on the biology and applicability of these parasitoids in oil palm habitats is planned in the next phase of the project.