Fruit fly trapping numbers

Trapping data from the Goulburn Murray Valley’s regional trapping grid indicates that the number of Queensland fruit fly (Qfly) trapped across the region has increased in November from previous months.

The monitoring program has revealed trapping numbers typically rise dramatically each year in September-October, after a winter low when very few flies are trapped. Numbers have shown to peak in spring, with this spike known as the ‘spring peak’. Numbers typically decline in late October and November, only to rise again to a higher level through summer, with this influx known as the ‘summer peak’.

As of mid-November, most Qfly trapped across the region were in urban locations.

Urban fruit fly hot spots

The below locations have been identified through trapping data as hot spots to monitor.

  • Numurkah
  • Barooga
  • Katamatite
  • Euroa
  • Rochester
  • Nagambie
  • Congupna
  • Shepparton
  • Berrigan
  • Tatura
  • Mooroopna
  • Kyabram
  • Finley

December weather outlook

Weather pattern forecasts provided by the Bureau of Meteorology, show a 60-75 per cent chance of higher than normal rainfall for the region during December 2020.

According to forecasts, maximum temperatures have a good chance of being higher than the medians of 27°C to 33°C, while minimum temperatures have a high chance of being above the medians of 12°C to 15°C.

The optimum weather situation for Qfly survival into summer is for December to receive above-average rainfall and above-average maximum and minimum temperatures. This situation occurred in 2016 which resulted in extremely high spring, summer and autumn Qfly populations all over the central and northern parts of Victoria. It looks like this situation will occur in 2020/21.

Vigilance required

Warmer than normal minimum temperatures plus extra rainfall means there will be more fruit and more fruit flies this coming season. However, if home gardeners and growers have been able to manage fruit flies adequately this trend may be reversed.

It fruit fly control measures are not in place Qfly populations will continue to increase from November 2020, aided by higher than normal rainfall and minimum temperatures.