Queensland Fruit Fly Goulburn Murray Valley Outlook April 2020
This information has been commissioned by the Goulburn Murray Valley (GMV) 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 unauthorised alterations to the text or content is not permitted.
Information for commercial growers
Key points:
- Queensland Fruit Fly (QFF) numbers are up this year compared with the same time last year.
- This is likely to be due to benign weather conditions in 2020 allowing more fruit to set and more flies to breed compared with hot, dry conditions experience in 2019.
- The high numbers are due, mainly, to a few sites with very high QFF populations biasing total results. These sites include:
- Cobram
- Echuca
- Kyabram
- Merrigum
- Nagambie
- Numurkah
- Shepparton
- External traps, at present, are capturing many more flies than the older IKC trapping grid – particularly in just a few rogue rural sites.
- The Cobram Area Wide Management (AWM) project, in combination with the SITplus Consortium sterile insect technique (SIT) project, has resulted in excellent QFF reduction statistics.
Lessons learnt
- Successful AWM is heavily dependent on both community engagement and nature. The QFF problem cannot be fixed within a year or two.
- There have been solid indications of AWM contributing to the reduction in fruit fly in the GMV but AWM needs to continue until all at-risk sites have been identified, monitored with traps and engaged in AWM for at least 5 years.
- The feasibility of applying a combined AWM/SIT program to the areas with high QFF populations mentioned above should be assessed.
Fruit fly situation – MARCH 2020
During the first three weeks of March 2020, a total of 1,842 flies were trapped in 385 traps assessed from the 400 traps deployed in the GMV giving an average of 4.79 flies per trap per week (FTW). There were 823 QFF (3.14 FTW) found in rural trap sites (262 traps) and 1,019 QFF (8.31 FTW) in urban sites (123 traps).
The higher trap capture rates recorded in urban areas, compared with rural areas, are typical for this time of the year but rural trapping rates are now on the increase as QFF move from urban areas, where fruit fly host material is now relatively limited into rural sites where a large volume of fruit fly host material is currently ripening. Urban FTW peak, usually, in late September and then again over an extended period from mid-December to late January. The current 2019-20 season has resulted in several peaks in September, November – December and February. Rural FTW, on the other hand, tend to peak over the period from mid-March to early May.
The situation in Cobram urban
There is much better news from the urban areas of Cobram. Here, QFF trap numbers have reduced significantly over the last few years, particularly since the start of the sterile insect technique (SIT) project which commenced in mid-September 2019. There are 33 traps in urban Cobram, with a marked downward trend in fruit fly numbers here, despite the recent upward trend elsewhere in the GMV described above.
Why is this happening? From general GMV data it appears that conditions are very good for QFF survival at the current time of the year especially in a few dominant locations (see above list). The opposite trend recorded in urban Cobram is due to a combination of more intense AWM components along with the SIT project.
Figure 5. Comparison of trap captures in Cobram urban sites from August to March over the last three years.
Fruit fly hotspots – April 2020
It is recommended that commercial orchards situated close to any of the following areas which are, at present, registering high QFF populations should be ready to commence control programs (if not already implemented) – even if the crop is not yet ripening. These sites are under the highest pressure.
Dominant urban-based QFF populations occurred in:
- Echuca
- Kyabram
- Nagambie
- Numurkah
- Shepparton
Dominant rural-based QFF populations occurred in:
- Koonoomoo
- Cobram
- Kyabram
- Merrigum
Goulburn Murray Valley Regional Fruit Fly Project
For assistance in managing QFF, contact the Project Coordinator at GMV Fruit Fly Office by phoning (03) 5871 9222 or emailing gmvfruitfly@moira.vic.gov.au
This report was produced by Andrew Jessup, Janren Consulting Pty Ltd in conjunction with the Project Coordinator and analysis of regional trapping data supplied by the GMV Fruit Fly Project.