Ongoing research into Queensland fruit fly control
The Queensland fruit fly (QFF) is Australia's number 1 horticultural pest, attacking a wide range of fruits and fruiting vegetables.
Female fruit flies can lay hundreds of eggs in their lifetime, infesting host produce and threatening access to domestic and international markets. Researchers are taking a multidisciplinary approach to address this problem.
Here's an overview of QFF research conducted by Agriculture Victoria Research in collaboration with scientists from:
- Queensland University of Technology
- Stockholm University
- Plant Biosecurity CRC
- NSW Department of Primary Industries
- South Australian Research and Development Institute
- Wine Australia
- Summerfruit Australia
The problem with attract and kill traps
Fruit fly traps contain attractant odours that lure adult flies into a trap and then kill them using an insecticidal bait. These 'attract and kill' traps usually only lure adult male or young, unmated female QFF. There is currently no effective lure for a mated female QFF.
What researchers are doing about it
Agriculture Victoria Research scientists at AgriBio are developing a novel female QFF attractant through a Plant Biosecurity CRC-funded project in collaboration with Summerfruit Australia (building on a Hort Innovation summerfruit project).
The attractant is based on a mixture of chemicals common to ripening fruits, which is showing promise in field trials. The attractant must be strong enough to stand out against the fruit odours in an orchard, so the team's complex designer blends will contain a mixture of:
- synthetic fruit odours
- microbial volatile organic compounds
- insect pheromones
Field trials to improve lures
AgriBio scientists and their regional colleagues at Agriculture Victoria Research centres in Tatura and Mildura have been testing QFF attractants, and extensive field trials are planned to further improve and evaluate the new lures.
The team is also assessing the effectiveness of different protein bait traps used for Mediterranean fruit fly and QFF to see if a single lure could be developed for both species.
Research into whether adult QFF survive winter
Agriculture Victoria Research entomologists based at Tatura are also collaborating on the adaptive area wide management of QFF using SITplus. Scientists are researching when adult QFF emerge from fruit that was infested in autumn.
They aim to determine if flies caught in traps during spring result from adult flies that survived winter in refuges around buildings and windbreaks, or flies freshly emerged from pupae in the soil. This study has the potential to change how QFF is managed over large areas.
This project is being delivered by Hort Innovation — with support from the Australian Government Department of Agriculture, Water and the Environment as part of its Rural R&D for Profit program — and CSIRO.
Identifying species of fruit fly
The Plant Biosecurity CRC is developing molecular diagnostic tools to identify pest and non-pest fruit fly species from Australia and overseas. Scientists will be able to build on what is known about tephritid fruit flies, which comprise over 600 species (including QFF), and rapidly identify insects in traps by their DNA.
This will greatly assist with efforts on the ground to detect fruit fly species and improve market access of produce that is susceptible to fruit fly.
Wasps for biological control of QFF
There are various insects that are natural enemies of fruit flies and feed on them at selective stages of their life cycle. Scientists at AgriBio and QUT are focusing on parasitoid wasps, which hunt for insect eggs and larvae.
A braconid wasp has been identified as a suitable predator for QFF. The wasp is already present in Australia and has an elongated egg-laying device called an ovipositor, which it uses to probe fruits and inject eggs into the larvae of fruit fly. When the egg hatches, the braconid wasp develops inside the fruit fly maggot, killing its host.
Boosting wasp numbers could potentially help control QFF numbers as part of an integrated pest management strategy.
Research into host fruits and crops
The AgriBio team is exploring non-crop hosts that fruit flies might be using to bridge the gap between fruit-growing seasons.
There are several crop species that are not generally thought of as hosts, so the scientists are also studying if these are in fact 'poor hosts' that allow fruit fly populations to survive when other fruits are scarce.
AgriBio scientists are using high-tech approaches to design and test their fruit fly lures. To do this, they:
- analyse fruit odours and insect pheromones using Gas Chromatography-Mass Spectrometry
- use DNA sequencing to identify microbes spread by fruit flies
- test odours in a wind tunnel
- use insect brain imaging and electrophysiology techniques to study insect behaviours and screen attractants in live fruit flies
Electronic nose device to detect infested fruits
AgriBio scientists and a company in the US are conducting research on a portable, hand-held, electronic nose (E-nose) device. This device detects and identifies complex chemical odours in a similar way to the human nose. They are currently testing if the E-nose sensor can pick up specific odours emitted by fruits infested with fruit fly.
If the E-nose device can consistently detect fruit fly maggots in host fruit, it could potentially be used to scan fruit before it is packed for market.