Scientists on track to eradicate Australia’s biggest crop pest

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 A$6.9bn (US$6.3bn) 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 like 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.

Sterile insect technology​

According to Commonwealth Scientific and Industrial Research Organisation [CSIRO] researcher Paul De Barro, increased Qfly 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​," he 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 success around the world and in South Australia to combat the Mediterranean fruit fly. However, the development of a 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​," added De Barro.

"When you're looking to deploy sterile male flies to disrupt the mating cycle this information is a critical piece of the puzzle​.”

Still some way to go​

By using micro sensing technology on Q-flies, as has been done with honey bees in Tasmania, CSIRO expects to be able to answer that question and, more 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​," said De Barro.

"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 the fruit fly​."

According to Horticulture Australia’s David Moore, this initiative is the first effort 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… we're confident that this project will deliver real impact for Australian farming communities​," Moore said.