Fruit fly activity will continue to increase throughout January until April, with a small drop likely during January when very hot dry weather occurs. There is a risk that adult flies that survived winter were able to survive longer into late spring than in previous years, giving them more time to infest more fruit than usual, which may impact populations.
Advice for commercial growers
It is recommended that growers place traps in orchards and surrounding the house and sheds and conduct regular inspections. Traps, lures and toxicants should be within their use-by date and replaced or re-charged as per label instructions.
If your orchard is close to a hot spot increased monitoring is recommended. Crops and other fruiting plants in and around orchards, house paddocks, front yards, roadsides and creek banks should be closely monitored. In more remote areas fruit fly numbers will commence building up in late summer and early autumn.
Baiting is an efficient control method in controlling fruit fly, so ensure you have stock in storage inside the use-by date. This is particularly important if fruit fly was present in your area last year.
Fruit fly hot spots
Hot spots have been recorded in the following locations:
- Echuca • Kyabram • Mooroopna
Weather forecasts indicate a 50% chance of more rain than average in January, a 50-60% chance of maximum temperatures being higher than average and a 60-65% chance of higher than average minimum temperatures.
These conditions are favourable for fruit fly survival and population build-up, however normal high temperatures will cut the growing fruit fly population significantly. A lower availability of atmospheric moisture, causing fruit drop and smaller fruit and fewer fruit for fruit fly to infest, combined with high heat killing adults, eggs and larvae in exposed fruit and pupae in exposed ground will impact fruit fly populations. This scenario generally occurs in the Goulburn Murray Valley but has not been the case for a number of years due to an extended La Niña weather pattern from March 2020 to early 2021. Another La Niña weather pattern is currently in place but despite this and recent rain, forecasts suggest that La Niña will not lead to increased rainfall during January 2022.