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Fruit Flies in the GMV in February 2018

March 7, 2018

This information has been commissioned by the Goulburn Murray Valley Regional Fruit Fly Project and is funded by the Victorian Government’s Managing Fruit Fly Regional Grants Program. Use of this material in its complete and original format, acknowledging its source, is permitted, however, any unauthorised alterations to the text or content is not permitted.


In May 2017 the Victorian Government and Horticulture Innovation Australia funded the deployment of over 300 male-targeting Queensland fruit fly (QFF) traps in and around 21 towns between Strathbogie and Cobram in the Goulburn Murray Valley (GMV).

Traps have been placed in rural and urban areas. Goulburn Murray Valley Regional QFF Coordinator Ross Aberrfield said each trap contained a male QFF attractant (cuelure) and a pesticide (malathion) and are checked every week from October to March.

“These traps do not attract female QFF. They detect the presence, or confirm absence of, QFF populations and they measure changes in populations over time,” Mr Abberfield said.

The QFF trapping program is a component of a larger project with the objective of reducing populations of QFF in the GMV to a point where production, productivity and export earnings are not restricted.

COMMUNITY

Current situation – February 2018

QFF adults are still being trapped in urban areas of the GMV. This means that, right now, the GMV QFF population is present as a mixture of adults, eggs, larvae and pupae. The weather is suitable for growth and maturation of QFF and there are many ripe and ripening fruit and vegetables that QFF will infest easily. These fruits exist in home gardens, orchards, untended properties, roadsides, channel banks and bushland.

However, trapping data show a decline in captures in urban areas for the first two weeks of February compared with previous months. This could be the result of:

  1. High temperature days causing death of QFF
  2. High temperatures causing reduction in QFF going to traps
  3. Reduced volume of suitable host fruit in urban areas caused by:
    1. Heat
    2. Backyard and other urban fruit being eaten by birds
    3. Fruiting, on the whole, has finished in urban areas
    4. Gardeners being diligent in QFF control
    5. Tree removal program
  4. Combination of points 1, 2 & 3.

 

QFF predictions – February to March 2018

On the whole, it is likely that QFF numbers will continue to decrease in urban areas. This desirable benefit can be ensured only if the tree removal program continues and home gardeners are diligent in their control of QFF in their own backyards.

“Due diligence in QFF control in urban areas will become very important as weather conditions start to improve for QFF, with cooler days and relatively warm nights, throughout late March and April,” Mr Abberfield said.

“This situation will be especially favourable for QFF if there are ripe fruits available at this time. The most likely QFF host fruits include feijoas, apples, ripe oranges, plums, late peaches.

“It is extremely important to reduce the number of QFF being able to lay their eggs into fruit at this time. It is the offspring of these flies that will survive over winter and cause problems to the community and the commercial grower alike next season,” Mr Abberfield said.

General precautions for home gardeners with fruiting plants

Home gardeners can produce good quantities of their own fruit and vegetables by keeping QFF in check and, in so doing, they will help stop QFF from spreading out of town and into commercial orchards. If QFF can be tackled now, especially by picking up and destroying fallen fruit and harvesting any fruit that’s still on the tree and processing, eating or destroying it, the QFF threat for the rest of the summer and autumn will be reduced, Mr Abberfield said.

Home gardeners should place male- and female-targeting fruit fly traps in their yards. They should take advantage of offers to remove unwanted trees and use fruit fly control methods such as home garden hygiene, fruit bagging, tree netting and fruit fly baiting. They should also consult with local friends and neighbours to see if fruit flies are nearby. Your local Fruit Fly Co-ordinator, Agriculture Victoria staff and produce store can help with suggestions on possible options.

Please support the unwanted tree removal program.

FARMERS

Current situation – January 2018

QFF trap captures in urban and rural locations have shown a turn-around in the first two weeks of February when compared with previous months. “There has been an increase in QFF captures in rural traps and a decrease in urban traps,” Mr Abberfield said.

This reversal could be due to:

  1. Movement of urban QFF into commercial horticultural production areas due to:
    1. Lack of suitable fruit in urban areas
    2. Lack of QFF control in urban areas
    3. More suitable host fruit present in commercial orchards
    4. Better climatic conditions in commercial orchards (water, cooler)
  2. Build-up of small populations within rural areas (on fruit fly host fruit in untended house gardens, along roadsides and channel banks and other untended areas) and consequent spread into more favourable conditions (more host fruit, cooler, more moisture) in orchards
  3. Combination of points 1 & 2.

QFFpredictions – February to March 2018

It is likely that QFF numbers will increase over the next couple of months in rural areas of the GMV unless QFF control strategies are set in place. Mr Abberfield said, not all rural areas are currently at risk but those which are adjacent to urban areas will more likely be targeted by urban QFF moving out.

“QFF can use rural farms/ properties that have fruiting plants, and which are close to town, as ‘stepping stones’ from urban areas to commercial orchards in summer and autumn and back again to urban areas during the autumn. Therefore, it is important that occupiers of such peri-urban gardens should follow the general precautions outlined below,” he said.

By doing this they will help commercial horticultural production which is a significant provider of business for the local area.

Hot, dry conditions, which prevailed during January may continue during February but will lessen in severity over late March and April, at least while night temperatures remain relatively comfortable for QFF. By removing egg-laying sources for QFF right now, farmers in peri-urban areas will reduce the numbers of

  1. QFF that will proceed on to commercial orchards and
  2. QFF that will move back into nearby urban areas to find refuge from winter conditions

“Particular attention should be given to fruit on feijoas, late peaches and oranges, apples and plums for QFF control. It would be very wise treat Indian figs (prickly pears) with fruit fly baits or remove them totally as they are also a significant source of over wintering QFF,” Mr Abberfield said.

General precautions for farmers with fruiting plants

All farmers should carry out QFF control measures right now. If QFF can be tackled now, especially by picking up and destroying fallen fruit and harvesting any fruit that’s still on the tree and processing, eating or destroying it, the QFF threat for the rest of the summer and autumn will be reduced.

“Farmers can produce good quantities of their own fruit and vegetables by keeping QFF in check and, in so doing, they will help stop QFF from spreading into commercial orchards,” Mr Abberfield said.

Farmers should place male- and female-targeting fruit fly traps in their yards. They should remove unwanted fruit trees and use fruit fly control methods such as garden hygiene, fruit bagging, tree netting and fruit fly baiting. They should also consult with friends and neighbours to see if fruit flies are nearby. Your local Fruit Fly Co-ordinator, Agriculture Victoria staff and produce store can help with suggestions on possible options.

Please support the unwanted tree removal program or simply remove as many unwanted fruiting plants as you can.

COMMERCIAL GROWERS

Current situation – February 2018

Over the last two weeks QFF trap captures in rural areas have increased significantly while those in urban areas have decreased. This is a reversal of the usual pattern.

The reasons for this trend reversal are most likely to be due to:

  1. Less favourable conditions in urban areas with fewer fruit due to
    1. Heat
    2. Birds
    3. Tree removal programs
  2. More favourable conditions in rural areas due to
    1. Later maturation of QFF host fruit
    2. More available fruit attracting QFF into orchards
    3. Cooler, moister, more attractive climate in orchards
  3. Movement of QFF from urban areas into rural areas
  4. Expansion of small QFF populations already established in rural areas due to better climatic and host crop conditions
  5. Combination of points 4. & 5.

QFF predictions – February to March 2018

Whatever pathway QFF uses, there is an increase in QFF in rural areas of the GMV.

However, not all areas of the GMV are at risk, currently. Several locations within the Kyabram and Cobram districts, in particular, plus some small occurrences in Ardmona, Undera and Shepparton have registered significant increases in numbers of QFF trapped.

“All growers should now have deployed, in their orchards, house paddocks and other positions likely to be attractive to QFF, monitoring traps which are in good condition (i.e. lures and toxicants have been replaced according to product label conditions) AND have a regular trap checking schedule of at least once a week but preferably more often,” Mr Abberfield said.

Growers located in Kyabram and Cobram, in particular, but also other areas (as a recommended safeguard) should now be checking ripening fruit for evidence of QFF through the presence on ‘sting marks’ on fruit. They should have a supply of baits and/or allowable pesticides for use as soon as the QFF risk is too great.

Particular attention should be given to fruit on feijoas, late peaches and oranges, apples and plums for QFF control. It would be very wise to remove or treat Indian figs (prickly pears) with fruit fly baits as they are also a significant source of over wintering QFF.

General precautions for commercial growers of fruit

“Right now, the GMV QFF population is present as a mixture of adults, eggs, larvae and pupae. The weather is suitable for growth and maturation of QFF and there are many ripe and ripening fruit and vegetables that QFF will infest easily,” Mr Abberfield.

“These fruits exist in home gardens, orchards, untended properties, roadsides, channel banks and bushland,” he said.

Commercial growers should carry out QFF monitoring and control measures right now.

Commercial growers should now have male- and female-targeting fruit fly traps in their house yards and orchards and set up a trap monitoring program. They should remove unwanted fruit trees and use fruit fly control methods such as orchard hygiene, baiting, cover sprays, etc. Your local Fruit Fly Co-ordinator, Agriculture Victoria staff and produce store can help with suggestions on possible options.

Please remove as many unwanted fruiting plants from your orchards, house gardens, creek and channel banks, roadsides and boundaries, as you can.