Both Thailand and Malaysia rely on fruit and vegetable crops for food and export income, and give high national priority to increasing the production of these commodities. However, many crops, especially citrus, carambola, guava and mango fruits are prone to fruit fly attacks, and losses may reach 100%.
In an earlier ACIAR project (8343), scientists from the Queensland Department of Primary Industries (QDPI) and collaborators gathered important data on the fruit fly problem in Malaysiaan exercise essential for planning pre-harvest control strategies and post-harvest disinfestation programs and for drafting plant quarantine regulations. In the course of the project, an effective hydrolysed-protein bait spray, a by-product of stout manufacture in Malaysia, was used with spectacular success in carambola orchards to replace insecticide cover sprays. (The method is based on Australian technology, whereby a small quantity of insecticide combined with an attractive protein bait is applied as spots on the foliage of scattered orchard trees.) Fruit production increased 100% through good fruit fly control and, as a result of survival of bees for pollination, there was also better fruit set.
The new project will extend, both geographically and technically, the results of the earlier one. Collaboration with the Malaysian Agricultural Research and Development Institute (MARDI) will continue, with particular emphasis on East Malaysia, and new collaboration will be developed in Thailand with the Department of Agriculture (DOA) for work in the northern and central regions, and with the Prince of Songkla University (PSU) for work in the south.
In Thailand, the collaborators will identify the economically significant species of fruit flies and their parasites in northern, central and southern regions. In order to do this, they will collect a very wide range of cultivated and wild fruits and rear out the fruit flies breeding in the fruits, and the fruit fly parasites. They will also collect adult male fruit flies using lures. In addition, the researchers will seek a suitable hydrolysed-protein bait material that is cheap and abundant in Thailand, and then test different formulations on fruit and vegetable crops for optimum attraction of fruit flies.
Collection and identification of fruit flies and their parasites will continue on the west coast of Peninsular Malaysia, and will extend to East Malaysia (Sabah and Sarawak), using the methods described above. In addition, the already successful bait spray technology will be modified to extend its shelf life, and field trials will be conducted on major crops other than carambola.
In conjunction with the project, QDPI entomologists, who have accumulated considerable expertise in fruit fly research, will hold two 3-week workshops in Australia for representatives of the collaborating institutions. The workshops will cover techniques for sampling wild and commercial host fruits; rearing fruit flies and their parasites; establishing laboratory cultures of fruit flies; and preservation, mounting, labelling and identification of specimens, as well as other methodology relevant to gaining practical familiarity with fruit flies.
Benefits from the project will flow to all levels of the community in Thailand and Malaysia. They will include: increased production of a wide range of fruit and vegetables; reduced exposure of growers to insecticides, and reduced insecticide residues in fruits and vegetables; and collection of information for development of effective post-harvest disinfestation procedures and quarantine regulations.
Australia will benefit from a more extensive knowledge of threatening tropical fruit fly pests, and from increased experience in fruit fly control techniques for the variety of tropical and sub-tropical fruit crops that are being introduced to expand tropical horticulture production.