This information has been commissioned by the Goulburn Murray Valley (GMV) Fruit Fly Area Wide Management 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.

Hot spots and fruit fly activity

Historical data from the Goulburn Murray Valley fruit fly trapping grid has been examined to identify locations with activity that saw three or more Queensland fruit fly (Qfly) trapped per week in August and September over the past four years. Past activity is an important trigger for increased monitoring and control. The following locations recorded fruit fly activity in August and September through the regional trapping grid in recent years and so extra vigilance is required in these areas:

  • Euroa • Tatura
  • Katamatite • Shepparton
  • Kyabram • Numurkah
  • Merrigum • Mooroopna
  • Strathmerton • Tongala
  • Yarrawonga

Fruit fly on the move

Fruit fly mate at sunset, provided temperatures at dusk are above about 16˚C. The temperature at sunset has been 16˚C in some areas in August which means new mating may have occurred. Weather outlooks suggest continued opportunity will remain for mating activity at dusks, which may lead to population explosions in coming months. Extra vigilance is recommended in the areas of Shepparton and Tatura as temperatures at dusk were higher in these locations.

The weather outlook for September is likely to see fruit fly that survived winter emerge from refuges in greater numbers. Favourable weather conditions are expected to result in fruit fly active and on the move earlier than usual.

Fruit fly populations were higher than normal in the autumn of 2021 which saw more adults than usual enter the winter of 2021 and find warm refuges across the landscape. September forecasts of higher temperatures and higher minimum temperatures, suggests that surviving fruit fly will be able to leave their refuges in spring and infest fruit found on trees or the ground in September. It is important to pick up or harvest and destroy all unwanted fruit at this time of year

Activisation essential

Fruit fly populations will start to increase in numbers and are expected to be trapped earlier in urban locations than peri-urban and rural areas. It is recommended urban householders clean up unwanted fruit, monitor for fruit fly presence and, if needed, carry out fruit fly control practices.

Community action is essential to assist in stopping the spread. It is suggested that anyone growing fruit and vegetables start building a supply of traps, nets and pesticides approved for home garden use and begin fruit fly management programs such as:

  • Monitor fruit fly presence with a trap or traps
  • Check early or late-hanging fruit for fruit fly sting marks
  • Cover fruit and vegetables with a net to keep fruit fly out
  • Clear away and destroy unwanted fruit
  • Consider complete removal of unwanted fruiting plants, trees and vines
  • Work with neighbours in controlling fruit fly – the more area-wide strategies set up the better for the whole community.

The activisation of action within the community and amongst home gardeners now, will help contained the spread in coming months where by populations in urban areas move out into rural areas.

Goulburn Murray Valley Fruit Fly Area Wide Management Project

For assistance in managing fruit fly , 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 Area Wide Management Project.