This information has been commissioned by the Goulburn Murray Valley Area Wide Management Fruit Fly Program and is funded by the Victorian Government. 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.
Summary
Most of the Goulburn Murray Valley’s commercial horticulture is harvested over the next couple of months. These crops are especially prone to attack by Queensland fruit fly (Qff). At the same time Qff is moving away from the protection of fruitful refuges in urban areas of the GMV to the more attractive commercial orchards surrounding many GMV towns and villages. As harvest there continues Qff moves further out into outlying orchards following a pathway of ripening fruit.
Weather forecasts for the GMV suggest that Qff buildup will continue at least until May due to maximum and minimum temperatures remaining in Qff’s comfort range. Maximum temperatures for most of April are likely to be from about 17°C to 30°C and minimum temperatures mostly from 6°C to 15°C. A small amount of rainfall is forecast for the week from 6 April. Relative humidities will be medium to high favouring Qff survival and spread.
Sunset temperatures are starting to decrease as winter approaches. Currently sunset temperatures are generally but not low enough to stop Qff from mating so new eggs will be laid into any available fruit. This is an especially dangerous time for commercial harvests currently occurring.
Removal of fruit (or the whole plant if it is not wanted) now is an important measure in reducing future fruit fly problems – especially in urban and peri-urban areas that are close to commercial orchards.
Trapping data reveal a buildup of the Qff population from late February to March.
Qff numbers are still relatively high in some areas of the GMV especially in the towns of Kaarimba and Merrigum. Lemnos and Nagambie are in the next highest category of Qff risk and Mooroopna, Yarrawonga and Gunbower are of concern.
New Campaspe trapping grid
A new Qff trapping grid was installed throughout the Campaspe Shire around 19 February 2026. Trap inspectors deployed 32 new Lynfield traps charged with the Qff attractant, cue-lure, and the toxicant, malathion across 8 areas: Echuca (7 traps), Tongala (2 traps), Kyabram (7 traps), Girgarre (2 traps), Stanhope (4 traps), Rochester (5 traps), Torrumbarry (2 traps) and Gunbower (3 traps). Campaspe traps were deployed in urban (17 traps), peri-urban (9 traps) and rural (6 traps) locations.
Current GMV trapping grid
The current trapping grid across the GMV consists of 301 Qff traps covering 4 shires including 51 locations.
Results
Traps were inspected between 19 December 2025 and 3 April 2026 – i.e. a period of just over 16 weeks. A total of 2,355 adult Qff was trapped from a maximum of 301 traps in that time. Qff populations fluctuated in that time (Fig. 1). There is, at present, an upward trend in Qff numbers trapped per fortnight since early February (Fig. 1).
Autumn is often a time of increased Qff due to proliferation of ripening and ripe fruit in commercial orchards and home gardens.
88 of these traps did not trap any Qff. This figure is down from last month (102 traps) and the previous month (116 traps) suggesting that Qff are spreading out further into the region.
Over the last 4 weeks 15 traps captured more than 10 or more Qff (Table 1). The majority of these traps, 11 of the 15, are located on rural sites. This reflects a significant migration of Qff from nearby townships and buildup of Qff populations in these sites.
Table 1. Trap sites with high numbers of captured Qff from 5 March 2026 to the current date.
| Total no. of Qff | Trap site | Land use |
| 66 | KAARIMBA | RURAL |
| 63 | MERRIGUM 1 | RURAL |
| 40 | MERRIGUM 2 | RURAL |
| 36 | MOOROOPNA 1 | RURAL |
| 28 | LEMNOS 1 | RURAL |
| 23 | MERRIGUM 3 | PERI-URBAN |
| 15 | COOMBOONA | RURAL |
| 13 | NUMURKAH | URBAN |
| 13 | LEMNOS 2 | RURAL |
| 12 | SHEPPARTON EAST | RURAL |
| 12 | COBRAM | URBAN |
| 11 | MOOROOPNA 2 | RURAL |
| 11 | SHEPPARTON | RURAL |
| 10 | MOOROOPNA 3 | URBAN |
| 10 | COBRAM EAST | RURAL |
Trends
Fig. 1 shows that, in total, Qff numbers trapped are currently on an upward trend, especially during the period commencing 5 February 2026. Unless there is significant impact on community led Qff management programs in the GMC this trend will continue as the weather becomes milder, more humid and when more local fruit, especially those on commercial blocks, become ripe.
Towns
The order of highest Qff prevalence has changed over the past 4 to 6 weeks with Qff becoming more dominant in peri-urban and rural locations. Table 2 shows that Qff populations are now high in Kaarimba and Merrigum with 4 or more Qff per trap over the last 4 weeks. Qff numbers on the rural locations of Lemnos and Nagambie have also increased while Mooroopna, Yarrawonga and the new trap site of Gunbower also have significant numbers present.
Table 2 shows that by early April 2026 some towns had larger Qff populations than others. This is reflected by the volume and type of Qff host plants in each location as well as the level of fruit fly management being employed there.
Table 2. GMV towns ranked in descending order of Qff prevalence (data from traps (n=249) monitored from 19 Dec 2025 to 3 April 2026).
| RANK | AVE QFF/TRAP | TOWN |
| 1 | 10.00 | KAARIMBA |
| 2 | 4.06 | MERRIGUM |
| 3 | 2.50 | LEMNOS |
| 4 | 2.00 | NAGAMBIE |
| 5 | 1.31 | MOOROOPNA |
| 6 | 1.13 | YARRAWONGA |
| 7 | 1.00 | GUNBOWER |
| 8 | 0.87 | COOMBOONA |
| 9 | 0.81 | ORRVALE |
| 10 | 0.80 | NUMURKAH |
| 11 | 0.79 | SHEPPARTON |
| 12 | 0.63 | KIALLA |
| 13 | 0.50 | CONGUPNA |
| 14 | 0.50 | KOONOOMOO |
| 15 | 0.50 | SHEPPARTON NORTH |
| 16 | 0.50 | STRATHMERTON |
| 17 | 0.50 | TONGALA |
| 18 | 0.50 | TORRUMBARRY |
| 19 | 0.50 | TUNGAMAH |
| 20 | 0.46 | SHEPPARTON EAST |
| 21 | 0.43 | COBRAM |
| 22 | 0.43 | ECHUCA |
| 23 | 0.38 | TATURA |
| 24 | 0.33 | AVENEL |
| 25 | 0.33 | KATAMATITE |
| 26 | 0.33 | TATURA EAST |
| 27 | 0.33 | VIOLET TOWN |
| 28 | 0.29 | KYABRAM |
| 29 | 0.25 | MUCKATAH |
| 30 | 0.25 | STANHOPE |
| 31 | 0.23 | ARDMONA |
| 32 | 0.17 | COBRAM EAST |
| 33 | 0.17 | KATUNGA |
| 34 | 0.17 | MOOROOPNA NORTH WEST |
| 35 | 0.17 | TOOLAMBA WEST |
| 36 | 0.15 | GRAHAMVALE |
| 37 | 0.15 | TOOLAMBA |
| 38 | 0.13 | EUROA |
| 39 | 0.08 | INVERGORDON |
| 40 | 0.00 | BUNBARTHA |
| 41 | 0.00 | COOMA |
| 42 | 0.00 | GIRGARRE |
| 43 | 0.00 | KIALLA EAST |
| 44 | 0.00 | MOOROOPNA NORTH |
| 45 | 0.00 | MUNDOONA |
| 46 | 0.00 | ROCHESTER |
| 47 | 0.00 | TALLYGAROOPNA |
| 48 | 0.00 | UNDERA |
| 49 | 0.00 | WUNGHNU |
| 50 | 0.00 | YARROWEYAH |
| 51 | 0.00 | ZEERUST |
Hot spots
There are two methods of describing hot spots used here. They are based on:
- Threat to home gardens and nearby commercial horticulture and
- Threat to commercial crops
Threats to home gardens and nearby cropping were labelled as urgent (1 site) or, worse, critical (3 sites) (Table 3).
Based on the Risk Matrix employed by Agriculture Victoria for the designation of Qff hot spots eleven trap sites satisfied high (10 sites over 6 towns) or, worse, very high (1 site) risks of Qff to commercial production (Table 4).
NOTE – Definition of a Qff Hotspot: Under current Qff populations, this early in the Qff season for the GMV, a trap site where more than 2 Qff are trapped per week is considered a Qff hotspot
Table 3. Urban hot spots (highest Qff averages to lowest)
| LOCATION | THREAT |
| KAARIMBA | CRITICAL |
| LEMNOS | CRITICAL |
| MOOROOPNA | CRITICAL |
| MERRIGUM (2 locations) | CRITICAL |
| MERRIGUM | URGENT |
Table 4. Hot spots potentially affecting commercial crops
| LOCATION | THREAT |
| KAARIMBA | VERY HIGH |
| LEMNOS | VERY HIGH |
| MERRIGUM (3 locations) | VERY HIGH |
| MOOROOPNA | VERY HIGH |
| ARDMONA | HIGH |
| COBRAM (4 locations) | HIGH |
| COBRAM EAST (2 locations) | HIGH |
| COOMBOONA | HIGH |
| INVERGORDON (2 locations) | HIGH |
| KOONOOMOO | HIGH |
| LEMNOS (3 locations) | HIGH |
| MOOROOPNA (2 locations) | HIGH |
| ORRVALE | HIGH |
| SHEPPARTON (2 locations) | HIGH |
| SHEPPARTON EAST (3 locations) | HIGH |
| TATURA | HIGH |
| TATURA EAST | HIGH |
| TORRUMBARRY (2 locations) | HIGH |
People living in all areas, especially those listed in Tables 3 and 4, should be vigilant in checking traps and for fruit infestation.
Tip: make sure your traps are charged with new lures and are not damaged. Otherwise replace. Also make sure that the traps are clear of foliage and branches and out of the sun in the hottest part of the day.
Tip: Make a habit of checking any nearby fruit for sting marks and/or infestation with maggots – even if the fruit is a roadside feral plant. If there are signs of infestation remove the fruit or the entire plant if you can.
Qff in the Strathbogie and Campaspe Shires
In the 6 and 2 trapping weeks since the deployment of Strathbogie and Campaspe traps, respectively, some Qff have been found. Avenel and Nagambie trapped more Qff than the other locations in the Strathbogie Shire (Table 5). Torrumbarry, Tongala and Kyabram topped the list for the Campaspe Shire (Table 6).
Table 5. Qff trapped in Strathbogie Shire traps from 18 February 2026 to 3 April 2026.
| LOCATION | Ave. QFF/trap |
| AVENEL | 1.56 |
| EUROA | 0.38 |
| NAGAMBIE | 1.56 |
| VIOLET TOWN | 0.33 |
Table 6. Qff trapped in Campaspe Shire traps from 19 February 2026 to 3 April 2026.
| LOCATION | Ave. QFF/trap |
| ECHUCA | 0.62 |
| GIRGARRE | 0.00 |
| GUNBOWER | 1.00 |
| KYABRAM | 1.04 |
| ROCHESTER | 0.55 |
| STANHOPE | 0.27 |
| TONGALA | 1.13 |
| TORRUMBARRY | 2.33 |
Land use type
Urban trap sites are the usually main source for higher populations of Qff when compared to peri-urban and rural location. As urban fruit ripens and drops, is harvested or is eaten by birds Qff migrates from urban areas into peri-urban sites and then into commercial crops. This is currently occurring in the GMV as evidenced by the high Qff population pressure in peri-urban and rural trap sites. There is an upward trend in Qff numbers trapped in rural locations currently (Fig. 3).
Peri-urban crops are now at higher risk of infestation. This means that nearby commercial horticulture is at an elevated risk of future infestation.
Currently, some rural trap sites have recorded significantly high Qff numbers. Kaarimba and Merrigum have higher capture rates then most other urban and peri-urban sites. This is a dangerous situation for commercial horticulture properties close to these locations.
Table 7 shows several towns with moderate levels of Qff activity in urban locations. Table 8 shows elevated Qff activity in peri-urban Merrigum. Table 9 shows that Kaarimba has very high Qff activity despite being in a rural location. People managing gardens and orchards close to these areas should exercise Qff monitoring and control. These areas act as conduits to nearby commercial horticulture. Peri-urban and rural Qff should be of high concern to growers in these areas. Growers should have implemented regular Qff monitoring and control.
Table 7. Towns where URBAN locations have significant Qff presence (highest Qff averages to lowest) since 5 MARCH 2026.
| LOCATION | Ave. QFF/trap |
| COOMBOONA | 3.75 |
| NUMURKAH | 3.25 |
| MERRIGUM | 3.13 |
| GUNBOWER | 2.33 |
| KOONOOMOO | 2.25 |
| LEMNOS | 1.50 |
| KIALLA | 1.38 |
| KYABRAM | 1.33 |
| MOOROOPNA | 1.25 |
| TONGALA | 1.17 |
| YARRAWONGA | 1.00 |
Table 8. Towns where PERI-URBAN locations have significant Qff presence (highest Qff averages to lowest) since 5 MARCH 2026.
| LOCATION | Ave. QFF/trap |
| MERRIGUM | 5.25 |
| LEMNOS | 3.25 |
| ECHUCA | 3.00 |
| NAGAMBIE | 2.00 |
| NUMURKAH | 1.67 |
| COBRAM EAST | 1.58 |
| AVENEL | 1.00 |
| CONGUPNA | 1.00 |
| KATAMATITE | 1.00 |
| TATURA EAST | 1.00 |
Table 9. Towns where RURAL locations have significant Qff presence since 5 MARCH 2026.
| LOCATION | Ave. QFF/trap |
| KAARIMBA | 8.25 |
| MERRIGUM | 3.58 |
| TORRUMBARRY | 2.33 |
| LEMNOS | 1.65 |
| MOOROOPNA | 1.20 |
| SHEPPARTON | 1.00 |
| YARRAWONGA | 1.00 |
Tip: Urban gardeners should feel a responsibility to reduce Qff populations in their yards not only to produce good quality fruit in their own gardens but also to reduce the influx of Qff into other areas – especially commercial orchards.
Forecast
In the GMV, fruit fly numbers generally increase in severity from late November and peak in December with a second peak in the autumn. From November and through December Qff builds up very rapidly in urban and peri-urban sites where there is usually a mixture of high amounts of untended fruit, garden irrigation and evergreen refuges while rural sites remain quite low as there is still not much ripe fruit around. Any rural sites which have high Qff numbers at this time are likely to have persistent Qff populations surviving in untended home gardens and untended non-commercial fruit trees on the block.
Tip: Even if your commercial crop is well-managed with respect to Qff you must ensure that all other fruiting plants in and near your orchard are well-managed (or removed), too. Qff will move from the old apricot tree in the fowl yard into the next ripening crop nearby.
As urban crops decline with harvest and bird predation in the summer Qff populations also decrease while peri-urban and rural increase. This reflects the movement of Qff from urban, through peri-urban and into rural areas from mid-summer to autumn. This occurs due to the “pull” of large volumes of commercial crops ripening in rural areas at this time.
It appears that this is occurring right now as seen in Fig. 3. It is expected that similar upward trends will occur during autumn 2026. The size of the peaks and their timing will depend on weather and fruit fly management measures implemented during the spring and early summer.
Weather
Past 4 weeks
March temperatures in the GMV were lower than February’s but they are still relatively comfortable for Qff survival and spread (Fig. 4). There has been little rain, but the relative humidity has remained at medium to high levels throughout March. These conditions favour Qff survival and spread (Fig. 5).
Is it too cold for Qff to mate?
Qff mates only at sunset and only when temperatures exceed 15°C. These conditions have persisted throughout March and, when current sunset temperatures are compared with the average, they have been somewhat higher than normal up until mid-March (Fig. 6). Consistent low temperature sunsets are not anticipated until mid-May.
Short term forecast
Forecast weather conditions for Shepparton for 6 – 20 April 2026 (https://www.visualcrossing.com/weather/weather-data-services – accessed 6 April 2026) indicate less severe conditions experienced during January 2026.
During March there will be lower max. (Fig. 7) and min. temperatures (Fig. 8) , higher relative humidity (at the start of March but lower towards mid-March) (Fig. 9) than for the previous month and probably less rainfall (except at the beginning of March). These are close to ideal conditions for Qff survival and population spread. This is especially problematic as commercial crops, in the main, are now beginning to ripen and therefore will become highly attractive to Qff infestation with potential consequent crop loss.
Longer term forecast
MAY 2026 – The Bureau of Meteorology forecasts (Figs 10, 11 and 12), for the GMV, higher maximum temperatures (an 80% chance of being higher than the average of 15°C to 21°C) and average minimum temperatures (3°C to 6°C) for May 2026. Rainfall is likely to be less than average (only a 25% to 30% chance of exceeding the average of 10mm to 25mm for March). Daily minima will impact adversely on Qff survival, especially if the insect is at an immature stage (i.e. egg, larva or pupa) and is exposed to these temperatures and durations. Qff adults are likely to have found warm refuges somewhere on the landscape by this time and may overwinter there if not killed off or controlled by predators, subsequent exposure to cold or wet weather or by strategic baiting.
Vigorous area-wide management programs will enhance Qff control significantly if set in place.
Adapted from the Bureau of Meteorology: http://www.bom.gov.au/climate/outlooks/#/overview/summary/ – accessed 6 April 2026:
Rainfall—Summary
Below average April to May rainfall likely for most of Australia
- Rainfall for the 3-month period from April to June is likely to be below average (60% to more than 80% chance) for most of Australia.
- There is an increased chance of unusually low rainfall1 (over 50% chance) for large parts of the Murray Darling Basin.
1Unusually low rainfall is that in the driest 20% of April to June records between 1981 and 2018.
Temperature—Summary
Warmer than average days and nights across much of Australia April to June
- Maximum temperatures for April to June are very likely to be above average (more than 80% chance) across much of Australia.
- The southern two thirds of Australia have an increased chance of unusually high maximum temperatures2 (over 50% chance), with the highest chances (over 80% chance) across New South Wales and neighbouring border regions.
- For parts of inland eastern and southern Australia, there is no clear signal for either warmer or cooler than average minimum temperatures.
2Unusually high maximum and minimum temperatures are those in the warmest 20% of April to June days and nights, respectively, between 1981
Fig. 10. Chance of above median rainfall for May 2026
Fig. 11. Chance of above median maximum daily temperature for May 2026
Fig. 12. Chance of above median minimum daily temperature for May 2026
Another weather forecast program, Agriculture Victoria’s “The Fast Break” (https://agriculture.vic.gov.au/support-and-resources/newsletters/the-break/the-fast-break-victoria – accessed 6 April 2026), also supports the likelihood of a neutral to drier and warmer period than normal from April to June 2026 based on model outputs.
Fig. 13.
Fig. 14.