Queensland Fruit Fly Outlook – March 2026

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

The majority of the Goulburn Murray Valley’s commercial horticulture is harvested over the next couple of months. These fruit 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 occur due to maximum and minimum temperatures remaining in Qff’s comfort range. Maximum temperatures are likely to be from 26°C to 32°C and minimum temperatures mostly from 14°C to 20°C. A cold period, forecast from 13 to 15 March will result in a decrease in numbers of Qff found in traps but that will be reversed when temperatures rise again after 16 March. These conditions are favourable to Qff mating, laying eggs and damaging fruit.

Constant rainfall from 22 February to 2 March resulted in lower Qff capture rates over that time. When the rain stops Qff numbers will increase again.

Qff numbers will decline when the weather dries out and westerly and northerly winds keep the relative humidity low but irrigation and the moist microclimates found within fruiting trees at this time of year will reverse that.

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 slight slowing of Qff population buildup from December 2025 to early March 2026. When compared with previous years this season’s Qff numbers are significantly lower.

Qff numbers are still relatively high in some areas of the GMV especially in the towns of Numurkah, Yarrawonga, Katamatite, Strathmerton and Koonoomoo. Kaarimba collected a significant increase in Qff numbers over the past month and is now in the relatively high Qff zone. Currently mid-range populations are present in, Congupna, Cobram and Shepparton.

New Strathbogie trapping grid

A new Qff trapping grid was installed throughout the Strathbogie Shire around 18 February 2026. Trap inspectors deployed 20 new Lynfield traps charged with the Qff attractant, cue-lure, and the toxicant, malathion across 4 areas: Nagambie, Avenel, Euroa and Violet Town in a mix of urban (9 traps), peri-urban (5 traps) and rural (6 traps) locations.

Results

Traps were inspected between 19 December 2025 and 3 March 2026 – i.e. a period of just over 11 weeks. Qff populations fluctuated in that time (Fig. 1), probably due to weather impacts and, hopefully, the successful implementation and continuation of Qff control options.

A total of 1,436 adult Qff was trapped from a maximum of 249 traps in the 11 weeks since 19 December 2025 – an increase of 342 Qff since last month. There is, at present, a downward trend in Qff numbers trapped per fortnight since the setting up of the current trapping grid (Fig. 1). Autumn is often a time of increased Qff due to proliferation of ripening and ripe fruit in commercial orchards and home gardens.

102 of these traps did not trap any Qff. This figure is down from last month (116 traps) and the previous month (172 traps) suggesting that Qff are spreading out further into the region.

There are 9 locations with more than 30 Qff in their traps (Table 1). There are two trap sites with large numbers of Qff (totals over 30) in each of Numurkah, Cobram and Shepparton and one site in each of Kaarimba, Koonoomoo and Yarrawonga. The rural locations of two of these sites (i.e. Kaarimba and Koonoomoo) suggest either an early migration of Qff from nearby townships or Qff is more permanently located in these sites.

Table 1. Trap sites with high numbers of captured Qff

This implies that, currently, Qff has spread more widely across the GMV since January. Qff populations are now no longer concentrated in a relatively few locations.

Comparisons of Qff trapping data made with previous years show an interesting trend (Fig. 2). The average total number of Qff trapped each month in the GMV from December to March in each year from 2020 to 2024 is much higher than is current (i.e. December 2025 to March 2026). It is likely that very hot and very dry weather in January 2026 will have had a significant impact on Qff numbers found in traps (Table 2).

Table 2. Weather comparisons for January 2024, 2025 and 2026

Trends

Fig. 1 shows that, in total, Qff numbers trapped are on a downward trend in the 11 weeks from 18 December 2025. This trend has been apparent in most of the previous 10 years and is most likely due to adverse weather conditions (hot and dry). Unless there is significant impact on community led Qff management programs in the GMC this trend will reverse as the weather becomes milder, more humid and when more local fruit, especially those on commercial blocks, become ripe. Based on previous years’ data the general trend from March to early May is up.

Towns

Some towns have already shown high numbers of trapped Qff while others are still minimal. Table 3 shows that Qff populations are relatively high in Numurkah and Kaarimba with 2 or more Qff per trap over the 11 week period from 19 December 2025 to 3 March 2026. Yarrawonga’s Qff population has declined a little while Kaarimba’s has increased over the last month.

Of the 39 towns and nearby areas trapped for Qff, 6 towns had trapped zero Qff by early March (down from 9 last month). This is lower than for the period up to early January where 21 towns trapped zero Qff. This is another indication of the spread of Qff from areas where Qff survive the winter and then, as the weather warms up, throughout the GMV. The next phase of Qff movement will be from urban and peri-urban areas into nearby areas with commercial horticulture.

Table 3. GMV towns ranked in descending order of Qff prevalence (data from traps (n=249) monitored from 19 Dec 2025 to 3 March 2026).

Hot spots

There are two methods of describing hot spots used here. They are based on:

1. Threat to home gardens and nearby commercial horticulture and
2. Threat to commercial crops

Threats to home gardens and nearby cropping were labelled as urgent (3 towns) or, worse, critical (1 site) (Table 4).

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 5).

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 4. Urban hot spots (highest Qff averages to lowest)

Table 5. Hot spots potentially affecting commercial crops

Table 3 shows that by early March 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.

People living in all areas, especially those listed in Tables 4 and 5, 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 Shire

In the two trapping weeks since the deployment of Strathbogie traps some Qff have been found. Avenel has trapped more Qff than the other locations (Table 8).

Table 8. Qff trapped in Strathbogie Shire traps from 18 February 2026 to 3 March 2026.

Land use type

Urban trap sites are the 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 will migrate 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 trap sites. There is also an upward trend in Qff numbers trapped in rural locations currently.

Peri-urban crops are now at higher risk of infestation. This means that nearby commercial horticulture is at an elevated risk of future infestation.

Table 3 shows several towns some whose peri-urbans trapping sites show elevated Qff presence. People managing gardens and orchards close to these areas should exercise Qff monitoring and control. These areas act as conduits to nearby commercial horticulture.

Table 6. Towns where peri-urban locations have significant Qff presence (highest Qff averages to lowest).

Unusually high levels of Qff have also emerged in some rural locations (Table 4). These should be of high concern to growers in these areas. Growers should have implemented regular Qff monitoring and control.

Table 7. Towns where rural locations have significant Qff presence.

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 has 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 although numbers are a long way down compared with previous years (Fig. 2). 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

Adapted from the Bureau of Meteorology  http://www.bom.gov.au/climate/outlooks/#/overview/summary/ – accessed 5 March 2026:

Long-range forecast overview

Issued: 5 March 2026

The long-range forecast for April to June shows for the GMV:

• Rainfall is likely to be below average for most of Australia.
• Daytime temperatures are very likely to be above average across most of Australia.
• Overnight temperatures show no trend (i.e. no clear warm or cool signal).

Forecast weather conditions for Shepparton for March 2026 (https://www.visualcrossing.com/weather/weather-data-services – accessed 6 March 2026) indicate less severe conditions experienced during January 2026. During March there will be lower max. and min. temperatures, higher relative humidity (at the start of March but lower towards mid-March) 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 and consequent crop loss.

The Bureau of Meteorology forecasts (Figs 6, 7 & 8), for the GMV, average maximum temperatures (24°C to 30°C) and higher than average minimum temperatures (65% to 70% chance of being higher than the average of 12°C to 15°C) for March 2026. Rainfall is likely to be average (5mm to 10mm for March).

Vigorous area-wide management programs will enhance Qff control significantly if set in place.

Fig. 6. Chance of above median rainfall for March 2026

Fig. 7. Chance of above median maximum daily temperature for March 2026

Fig. 8. Chance of above median minimum daily temperature for March 2026