Prioritising post-harvest hygiene strategies over Autumn is critical in protecting next season’s crops from Queensland Fruit Fly (Qfly) and other pests. Effective post-harvest hygiene ensures fruit fly eggs, larvae, pupae or adult flies do not remain on the landscape following the harvest of crops.

The collection and destruction of susceptible fruit is essential in ensuring that eggs and larvae that may be in remaining fruit cannot mature to the pupa stage and emerge later as new populations. Fruit flies that have over wintered and successfully survived the winter months become next season’s populations and pose a risk to future crops.

The Goulburn Murray Valley Regional Fruit Fly Project is reminding growers and the community of the importance of good post-harvest hygiene as part of the successful Area Wide Management of Queensland Fruit Fly.

Local fruit fly populations typically remain in orchards for a week or two following harvest before moving on to another site in search of ripe or ripening fruit. The time immediately following harvest is when action is required to achieve good post-harvest hygiene with any remaining fruit either on trees or the ground becoming a target for infestation.

It is essential to destroy the integrity of unwanted fruit before the larvae can leave the fruit and pupate in the ground. Infested fruit containing eggs and larvae can be destroyed through a range of different methods including:

Maceration of fruit by crushing or mulching.
Running fruit eating animals to clean up fallen fruit – chickens, ducks and guinea fowl eat fallen fruit and scratch out larvae and pupae from the soil. Commercially, some growers are having success using various breeds of sheep.
Around the residence and in urban areas, solarising fruit by placing it in black plastic bags, sealing and leaving in sun for a week is effective.
Freezing fruit until solid (about 2 days)
Microwaving fruit for 3 to 5 minutes (depending on quantity)
Goulburn Murray Valley Regional Fruit Fly Regional Coordinator Ross Abberfield said by applying best practice and undertaking good hygiene measures in the period post-harvest growers were minimising opportunities for over-wintering Queensland Fruit Fly populations next spring.

“In the period following harvest it is important to destroy remaining fruit to ensure larvae and pupate are not left in the ground only to re-emerge as a new population of Qfly in spring,” Ross said.

“Post-harvest hygiene is one component of pest management and prevention that should be applied as a priority action. By acting now, high Qfly populations next spring can be reduced. That means less fruit fly emerging in Spring and possibly reduced expenditure required by growers in having to control those traditionally high fruit fly populations,” Ross said.

Other best practice measures, essential to protecting crops and production outputs include:

  • Placement of a biosecurity sign on the front gate reminding visitors not to bring fruit onto the property as a simple but useful way to reduce incursions.
  • Ensuring workers and contractors do not bring infested fruit onsite.
  • Removal of unmanaged fruit trees within 600m of your crop. Unmanaged orchards located within Victoria’s Goulburn Murray Valley that provide a breeding habitat for fruit fly may be eligible for removal as part of funding available through the Goulburn Murray Valley Regional Fruit Fly Program.
  • Instruct harvesting staff to pull unmarketable fruit from the plant and crush them to speed decay. –