Although only 8mm in length the Queensland fruit fly, or Q-fly, is a highly mobile insect capable of infecting a wide range of major fruit and vegetable crops, including stone and tropical fruits. The spread of Q-fly in Australia’s eastern states is threatening the nation’s $6.9 billion horticultural industry, which relies on both domestic and international trade.
Until recently, farmers located in areas where Q-fly is present have used agri-chemicals – such as dimethoate and fenthion – to prevent and manage incursions. However, after a long period of review, the Australian Pesticides and Veterinary Medicines Authority has recently restricted the use of these insecticides.
According to CSIRO researcher Dr Paul De Barro, increased Q-fly numbers can also threaten status of pest free areas.
"We believe that our sterile insect technology (SIT), through development of a male-only line of Q-fly, will offer a new environmentally friendly, sustainable and cost effective approach to assist in managing this damaging pest," Dr De Barro said.
"SIT is a scientifically proven method for suppressing or eradicating fruit fly populations and managing their potential impacts in horticulture production areas."
This biological control method has already been used with great success around the world and in South Australia to combat the Mediterranean fruit fly. However, the development of male-only sterile Q-fly is a first.
"Despite all our knowledge of fruit flies, we do not actually know where they go to breed," Dr De Barro said.
"When you’re looking to deploy sterile male flies to disrupt the mating cycle this information is a critical piece of the puzzle."
By using micro sensing technology on Q-flies, as we have done with honey bees in Tasmania, CSIRO will be able to answer that question and, most importantly, understand where to deploy sterile Q-flies and also how to make better use of other management options such as new trapping systems and pheromone baits.
"It will tell us how many sterile flies we will need to release and most importantly, when to release them," Dr De Barro said.
"Combining SIT with other sensor technologies represents a game-changing opportunity as it not only provides us with information about how the Q-fly interacts with its natural environment, but offers real opportunities to reduce the cost of current monitoring networks for fruit fly."
According to Horticulture Australia Limited’s David Moore, General Manager R&D Services, this initiative is the first effort in a long time at investing in medium to long term research that will provide a sustainable solution to Australia’s fruit fly problem and its impact on production and market access.
"There is still a lot of work to be done but compared to examples of overseas best practice along with the shared vision and dedicated support of key investors and industry, we’re confident that this project will deliver real impact for Australian farming communities," Mr Moore said.
CSIRO, Horticulture Australia Limited, Plant and Food Research, the Department of Primary Industries and Regions South Australia and New South Wales Department of Primary Industries are working together to develop a male only line of sterile Q-fly.
Facts and stats:
- Q-fly is native Australian fly, about 8 mm in length and is one of Australia’s most damaging pests of horticulture
- South Australia is the only mainland Australian state that is fruit fly free. Tasmania too is free of the pest
- In 2002–2006, the total average export value for Australia’s top 25 commodities that are host to fruit fly was A$432 million. The value of interstate trade of all host commodities subject to fruit fly quarantine requirements is estimated at A$1 billion annually (NFFS 2008)
- Over the five year period from 2003-2008, Australian industry and government invested more than A$128 million in the management of fruit flies. This estimate did not include the costs to growers in fruit fly endemic areas of Australia for managing crops to prevent infestation and generate a product fit for both sale and consumption (NFFS 2008)
- Fruit Fly Area Freedom in Australia allows access to a number of domestic and international markets and the fruit fly freedom status needs to be protected to allow access to export markets
- It has been estimated that fruit fly freedom for Tasmania is worth around A$20m per annum and the South Australian Riverland around A$80-100m per annum.