This information has been commissioned by the Goulburn Murray Valley Fruit Fly 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.
Early action required to manage population increase
Higher than normal numbers of adult fruit flies are expected to have entered the winter season and sought refuges in warm spots, where they are able to survive until temperatures increase. These refuges exist in evergreen trees such as orange, lemon, grapefruit, feijoa, olive, loquat, guava and avocado located in urban and peri-urban areas and near houses and buildings on farms. Inspection may reveal Queensland fruit fly in a slow metabolic state on the under-side of leaves of lemon and other evergreen trees. When temperatures rise above 16°C flies become active and seek out food sources and a mate to breed.
Queensland fruit fly numbers were high last season due to the La Nina weather pattern and a shortage of harvest labour resulting in excess fruit left on the tree and ground. It is likely higher than normal numbers of adult flies have entered the winter season and sought refuges in warm spots where they may survive until temperatures increase.
Early activisation of control measures critical
Growers will need to act early this year to manage the expected increased fruit fly pressure anticipated later in the year.
Essential control measures for activisation include:
- Applying protein baits to crop boundaries, untended fruiting trees and crop trees before fruits mature or early in the season to reduce the fruit fly load in and near the orchard. Follow label directions and cautions.
- Commence placement of fruit fly traps and male annihilation blocks around and within orchards. Maintain trap placement throughout the year. Follow label directions when placing traps.
- Learn the differences between pest and non-pest fruit fly species caught in traps.
- Check for untended early fruit crops such as apricots and loquats and treat trees and fruits with the approved chemical (follow label directions and cautions), grubbing-out or fruit-stripping and destruction if required.
- Evaluate the benefits or otherwise of exclusion netting / covers.
Essential timeframes and tasks
Prior to fruit set:
- Check for the presence of apples or quince fruit still on the tree into winter and strip and destroy all unwanted fruit.
- If there are house trees or feral trees untended that drop fruit late in autumn
(plums, guavas, feijoas) there may be pupae surviving in the soil beneath or adults in surrounding broadleaf evergreens such as citrus trees.
After fruit set and prior to harvest:
- Keep an eye on the number of pest fruit flies caught in traps. Identify the pest species and decide on how many pest fruit flies in traps will trigger action.
- Set up a list of anti-fruit fly activities based on trapped fly numbers.
- Apply cover sprays following approved label directions and repeat applications also following approved label directions.
- If there are low numbers of flies in traps and the crop is some way off ripening bait sprays may replace cover sprays and pull the fruit fly population down prior to harvest.
- If you are registered under an Interstate Certification Assurance scheme (ICA) you must adhere to its requirements.
Goulburn Murray Valley Fruit Fly Project
For assistance in managing Queensland fruit fly, contact the Project Coordinator at the Goulburn Murray Valley Fruit Fly Office by phoning (03) 5871 9222 or emailing gmvfruitfly@moira.vic.gov.au. For more information on fruit fly control and Area Wide Management strategies visit www.fruitflycontrol.com.au