ORCHARD hygiene has been identified as a key task in helping break the fruit fly lifecycle in Victoria.
The Goulburn Murray Valley (GMV) Fruit Fly Program is helping growers and the broader community to ensure effective post-harvest hygiene.
Fruit flies tend to build up in autumn before the cold hits. If they survive the winter, it will start a new season of fruit damage next spring.
This is where orchard (or post-harvest) hygiene becomes important.
RELATED READING
According to the GMV Fruit Fly Program, breaking the fruit fly cycle includes cleaning up an orchard, home garden and nearby untended land of potential fruit fly host material.
The program recently completed a literature review on post-harvest hygiene with the goal of drawing on the review to assist in core strategies and education activities.
Program coordinator Ross Abberfield said the post-harvest hygiene and its various extensions were a key aspect in the area wide management of fruit fly in the GMV region and critical to effective control of the pest.
The program brings together industry, government and the community to apply an area wide management approach to the management and control of fruit fly and has been successful in decreasing populations in the GMV over several years.
"The integration of effective post-harvest hygiene and the various consideration has certainly been a focal point for the program and its awareness and education activities," Mr Abberfield said.
"The program has supported the implementation of a host of programs and initiatives aimed at reducing spread of the pest, including a comprehensive education and engagement campaign engaging over 25,000 participants, monitoring and maintaining multiple trapping grids, identification of fruit fly 'hot spots' and the removal of unwanted and unmanaged habitat."
There is a wide variety of fruit fly unwanted and unmanaged host plants that can become breeding grounds for new fruit fly populations if not properly managed.
Adults formed towards the end of April when it's too cold to be attracted to traps and will overwinter in warm spots on the landscape so that they are ready to infest fruit in the new season next spring.
Removing these infestation sources before flies can find them will break the fruit fly cycle and reduce the number of adults surviving into next spring.
The list of infestation sources is substantial though, including:
- self-sown feral plants growing on roadsides;national and state parks;
- council land/reserves/picnic areas/nature strips;
- rubbish dumps;
- land adjoining rivers/lagoons/creeks and irrigation channels/rental properties;
- vacant/disused land.
Unmanaged and abandoned orchards also present an ideal habitat for fruit fly to breed.
Individuals can kill unwanted trees and suckers with herbicide treatment or remove by cutting down, slashing or, grubbing out.
"So far, our program has removed over 105,000 established private and public unmanaged fruit trees and plants at no cost to landholders in our region," Mr Abberfield said.
"This represents a huge reduction in unmanaged fruit fly habitat, creating an ongoing legacy that benefits our community and the environment."
One reason for fruit flies being better able to survive the winter is that late fruiting plants are not managed after harvesting in both rural and urban situations.
Leftover fruit plus benign weather conditions promote the survival of fruit flies.
Within the literature review, information adapted from the National Apple and Pear Industry Biosecurity Plan, Vs 1, Plant Health Australia, August 2006 outlines specific focus areas should include:
- avoidance of pest spread by selecting appropriate planting materials;
- removing or reporting volunteer or neglected fruiting plants;
- control of alternative hosts;
- destruction of crop residues after harvest;
- destruction of unwanted and waste fruit;
- reporting suspect pests to appropriate authorities.
In her review Managing Queensland Fruit Fly (Bactrocera tryoni) populations in Albury/Wodonga and improving community awareness Naomi Hodge commented on orchard hygiene.
- In order to maintain good orchard/fruit tree hygiene, she advised growers:
- Don't leave ripe fruit on the tree or let it fall to the ground (this gives fruit flies a chance to breed);
- Pick fruit early (as fruit ripens it becomes more attractive to fruit flies);
- Prune trees so you have easy access to fruit;
- If tree is loaded with fruit (more than you can manage to use) strip some of the fruit off early on - this way you will have better fruit produced and be able to use it all;
- Dispose of spoilt fruit by placing in a heavy-duty black plastic bag, seal and put in the hot sun for a few days to cook the larvae or bury the spoilt fruit in a deep hole (more than 50cm deep and covered and tamped down immediately). Do not place the spoilt fruit straight in the bing or compost;
- Tarps, black plastic or shade cloth could also be placed on the ground under the fruit tree to catch fallen fruit and prevent maggots from pupating (thus breaking the lifecycle).
flail mower so that it breaks down or disintegrates quickly. This practice is important as it reduces places that QFLY females can sting and minimises the possibility of new generations of QFLY developing in the field. It is also a widely used practice in most stone fruit operations to reduce the occurrence of Carpophilus beetle and the incidence of brown rot.
The Goulburn Murray Valley Fruit Fly Program is supported by the Victorian Government.
- For more information about the program, visit: fruitflycontrol.com.au
Sign up here to Good Fruit and Vegetables weekly newsletter for all the latest horticulture news each Thursday...
