Improved methods in the epidemiology and control of mites and other diseases of bees in Papua New Guinea

• Department of Agriculture and Livestock, Papua New Guinea

The fledgling beekeeping industry of Papua New Guinea (PNG), concentrated in the Eastern Highlands, is thriving because of the favourable environment, the compatibility of beekeeping with village lifestyles, and the relatively good health of the European honeybee (Apis mellifera) colonies. More than 200 smallholders, with around 4000 hives between them, belong to an active Honey Producers Co-operative.
However, the industry is now threatened by the spread of the unproductive Asian bee (Apis cerana), probably from Irian Jaya, carrying parasitic mites Varroa jacobsoni and Tropilaelaps clareae (the most serious parasites of honeybee colonies), and pathogens including the bacterium causing American brood disease, Bacillus larvae. The invasion was first discovered in the West Sepik Province in 1986. A survey in 1989 showed that the intrusion was spreading east and south, destroying or weakening honeybee colonies as it advanced. Scientists believe that there are no barriers to prevent the spread of A. cerana with its associated mites and pathogens in PNG and that most PNG beekeepers can expect to have infected hives by 1993. The economic impact is likely to be significant unless appropriate control measures are devised and implemented: small producers, who cannot afford replacement colonies, will have to give up beekeeping; there will be less honey for local consumption and export (about 35 tonnes are exported annually); and reduced pollination of important Highland cash crops, including coffee, will result in lower yields and returns to growers.
The projecta result of a request from the PNG Department of Agriculture and Livestock (DAL)is aimed at minimising the inevitable losses that the introduced bee mites and pathogens will cause. Research is needed in PNG to develop effective control methods for the country's unique conditions.
Objectives in PNG are to:
. determine whether acaracides and hive manipulation methods used in other countries for controlling bee mites are effective;
. determine the biology of the bee mites;
. identify and characterise pathogens of A. cerana and determine their pathogenicity on A. mellifera colonies; and
. identify and characterise pathogens of bee mites and determine their effectiveness as control agents.
The results will be passed on to agricultural extension workers in PNG, the Australian Quarantine and Inspection Service (AQIS), and the Australian beekeeping industry. They will also be published in beekeeping and scientific journals.
The Commissioned Organisation (CSIRO Division of Entomology) has the appropriate equipment and expertise to ensure that the project succeeds. The Project Leader, Dr Denis Anderson, is a qualified bee pathologist and has worked on most bee pathogens in Australia, New Zealand and the Pacific. In 1990, he attended an international symposium on recent bee research, which focused on V. jacobsoni and its control. He also visited overseas laboratories at the forefront of bee mite research.
Field research will be carried out at coastal Vanimo and temperate Oksapmin in the West Sepik Province of PNG. The Apicultural Section of DAL has established about 100 hives of A. mellifera infested with mites at Oksapmin. A further 20 mite-free hives will be established using healthy honeybees imported from the Eastern Highlands. Twenty nucleus colonies of A. cerana will also be established at Oksapmin by capturing and hiving feral colonies. At Vanimo, the collaborators will establish 20 colonies of A. mellifera and 30 nucleus colonies of A. cerana. Laboratory work will be done in Oksapmin and Vanimo, in laboratories established by Dr Anderson, and in Canberra, on pathological specimens collected at Oksapmin and Vanimo.
The economic impact of the spread of the Asian bee mites and pathogens in PNG will be minimised by the implementation of effective control methods. The results and control methods generated will also be relevant to beekeepers in other developing regions with similar problems, particularly those in Irian Jaya, other parts of Indonesia, and Asia.
The project is of great value to Australia: the presence of Varroa and Tropilaelaps mites, which are exotic to Australia, in PNG is a major economic threat to the beekeeping industry and those sectors of agriculture that rely on bees for pollination. There is a real possibility that the mites could spread from PNG to northern Australia on swarms of A. cerana present in unprocessed logs on timber ships or on other cargo vessels. The project will enable AQIS and the Australian beekeeping industry to monitor the spread of the mites in PNG; develop strategies designed to keep Australia mite free; and be better prepared to control the mites should they eventually gain entry.