Risks

Queensland Fruit Fly Risk

The Yarra Valley has been Queensland Fruit Fly free in the past.

In 2018, QFF was found in three Yarra Valley sites, prompting increased action against the pest, and further areas of increased surveillance to help understand the pest’s movements. Since this season, QFF has been detected each year, and responded to accordingly with the support from the “Keep Yarra Valley Fruit Fly Free” project. Increased anecdotal evidence is suggesting there are QFF issues in inner Melbourne and surrounding suburbs.

Queensland Fruit Fly threatens the Yarra Valley due to imported fruit being carried into the area (very likely) or QFF flying in from nearby populations (least likely, but still possible).

Understanding the lifecycle of QFF, how it spreads, QFF hosts, and what makes suitable QFF habitat, helps us manage QFF populations to reduce damage and losses to fruit production.

Queensland Fruit Fly Yarra Valley

Importing infested fruit increases QFF risk

Importing fruit infested with Queensland Fruit Fly is high risk for the Yarra Valley region.

Infested fruit can be carried in by people travelling from QFF affected fruit growing areas. Infested fruit may come in from commercial or domestic production systems. QFF is most likely hidden in the fruit and unknowingly carried into the Yarra Valley, then the fruit is sold or shared, causing the further spread of QFF.

Good QFF management practices in the production area and strict and efficient fruit sorting systems can prevent the spread of QFF.

To protect fruit production, biosecurity practices are used by commercial fruit growers to reduce the movement of people and fruit coming into their production areas. Good biosecurity practices can be replicated in the home and home garden.

Avoid carrying at-risk fruit when you travel, this is the best method of preventing QFF importation into QFF free areas.

If you suspect QFF infested fruit, cook or consume the fruit whilst you are in the region the fruit was grown in. If you receive suspect infested fruit, process it in a kitchen with adequate fruit disposal methods for any waste, and cook or preserve the fruit.

Should QFF fly into your garden, a grid or network of traps will alert you to the presence of QFF. Additional traps and investigations can be used to learn more about the risk whilst QFF management is started in anticipation of the problem worsening.

Spread in Australia

Once upon a time Queensland Fruit Fly was only in the tropical areas of QLD and NSW. QFF has now established in regions along the East coast of Australia, but not into TAS. W.A. or S.A.

Suitable habitats where there are three main elements such as fruit for breeding, bush and foliage for sheltering in and warm humid environments all increase the risk of QFF spreading.

Each Australian State treats QFF differently. In the QFF free States, the State Government funds and controls the emergency response actions and these continue until the QFF is eradicated. Officials are granted access to individual properties and businesses in order to carry out the necessary QFF management. Fruit movement is severely restricted which can affect production and interrupt all fruit trade. In States with QFF, it is up to community, individuals, businesses and public land managers to all act to reduce the risk of QFF, minimise the impact of QFF, and control the pest.

Trade protocols apply for fruit grown in QFF areas for importation into QFF free States and international markets where there is no QFF. Proof of QFF freedom and accreditation is required by growers participating in the trade arrangements. This reduces the risk of infested fruit movement interrupting growing conditions and international trade.

Good management of QFF in production areas and good emergency response can reduce the risk of QFF spread in Australia.

QLD Fruit Fly
QLD Fruit Fly

Hosts

Queensland Fruit Fly uses fruit growing on unmanaged host plants to both shelter and breed, allowing the QFF lifecycle to complete and the next generation to survive. High QFF risk places exist on both publicly and privately owned land. Common unmanaged hosts include:

  • Weedy areas with blackberries & wild tobacco, prickly pear, self sown apples & pears, plums & peaches
  • Abandoned, unmanaged or neglected fruit production in commercial businesses, home gardens, retail areas, parklands, and community gardens.

All types of fruit hosts must be harvested and protected and must not add risk to the QFF spread or survival.

A list of host fruits has been compiled by Agriculture Victoria.

QFF progress through the season infesting fruits and vegetables as they ripen. Often starting when the weather warms in late Spring (e.g. loquats, cherries & apricots) they move to Summer hosts (e.g. peaches & plums, berries, and tomatoes) and later into Autumn hosts (e.g. apples & pears & quinces, chillies & capsicums, even rosehips.). Native fruits like Lily Pilly and Kangaroo Apple can also host QFF. Citrus can host QFF year-round if fruit is left on the tree.

Habitat

Queensland Fruit Fly seek refuge in bushland and tree foliage. Warmth and humidity are key for QFF livelihood. Suitable QFF habitat in the proximity of water increases QFF survival (e.g. blackberries growing near creek and dams).

In Melbourne, 3-6 generations of QFF can happen in an average Summer. The QFF population can increase as the temperature and humidity each increase, like in a LaNina year.

Most QFF don’t survive extended cold periods in poor conditions. QFF habitat needs to experience 5 continuous nights of –3 deg C to come close to eradicating QFF. This rarely occurs in the Yarra Valley.

The Yarra Valley can keep QFF to a very low population risk. QFF struggle in Yarra Valley fruit production areas due to lengthy periods of cold and uninhabitable conditions e.g. monocrops of deciduous trees, areas of berry production that are removed each year, or non-host environments like beef, sheep and pasture areas. QFF can survive well in gardens in urban residential areas.

QFF that do survive the cold and wet are the reason QFF exist from one season to the next. QFF build up body condition at the end of Autumn and seek hiding spots in warm protected areas like evergreen Camellia and citrus plants, bushland, chook sheds, buildings, and stored timber. Autumn eradication, especially baiting and hygiene can reduce the chances of QFF survival over winter. This reduces the chances of QFF in the next season (until a new QFF is introduced to the area).

Managing habitat can include:

  • Reducing the height and size of QFF host plants by pruning to improve management options such as harvest and netting.
  • Removing host plants that are duplicates, excess to your requirements, less productive or aging.
  • Removing fruiting weeds and managing areas with regenerative plantings of native non-hosts
  • Reducing entry points to greenhouses using insect mesh and double entry doors with an air lock feature.
Risks