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Ongoing project

Parasitoids for the management of fruit flies in Australia (MT19003)

Key research provider: Victorian Department of Jobs, Precincts and Regions

What’s it all about?

This investment is delivering the knowledge needed to evaluate the use of parasitoid wasps as a potential strategy for fruit fly management. The use of natural enemies such as parasitoids against insect pests is regarded as a core component in sustainable pest control and will provide horticulture industries with another method to use for fruit fly management.

This research is being conducted through two complementary components – firstly by improving current knowledge of fruit fly parasitoid distribution in Queensland and northern New South Wales, and secondly by trialling a new mass rearing and release strategy for the southern states.   

Parasitoid distribution is being studied by collating and analysing existing data, as well as through a targeted survey and a detailed review of the scientific literature on fruit fly parasitoids. The resulting information will enable prioritisation of fruit fly parasitoids for future research and identify new RD&E required to rapidly integrate parasitoids into the fruit fly management toolkit.

Mass rearing and release will ultimately be trialed in fruit orchards and urban/peri-urban areas of Victoria. Working alongside the distribution component, wild fruit fly parasitoids will be collected for culturing and a mass-rearing protocol developed for two parasitoid species. Research will focus on optimising parasitism rates in culture, adult wasp fitness and longevity and ensuring good survival on delivery to release sites. Release trials are expected to be conducted during the 2020/2021 season.

  • New protocols for mass rearing arisanus have been developed and presented in a technical document. The document is being reviewed and includes methods for collection and culture of wild F. arisanus, key weekly tasks for culture maintenance, and a ramping schedule to enable a controlled scale-up of parasitoid production prior to releases.
  • Wild D. kraussii were collected and cultured and are now in culture at both QUT and Tatura.
  • kraussii was selected as the most suitable Diachasmimorpha species for mass rearing, due to its prevalence and distribution across Australia, and ease for rearing in captivity.
  • Parasitoid field surveys have been completed in Victoria, with five kraussii reared out from over 2600 infested fruits collected from 19 different fruit fly host species in 23 localities across the state. All five parasitoids emerged from fruit collected in Rutherglen in north eastern Victoria, and this represents the first detection of D. kraussii (and any tephritid fruit fly parasitoid) in Victoria.
  • First season pilot releases have been completed, with over 34,000 arisanus released at two orchard sites and four urban / semi-urban sites in Victoria.
  • Parasitoid monitoring to date has shown that arisanus can persist in the environment and locate and parasitise Qfly for at least 10 weeks post release in Victorian “end of season” (April to May) conditions, with initial parasitism rates at an orchard and urban site at 58% and 30% respectively, falling to 3% ten weeks post release. This lower % parasitism was in late autumn, and might represent changes in environmental conditions, presence of hosts (flies and fruits), and dispersal of the parasitoids.

ACT NOW

 

This update covers activities from August 2020 to February 2021, with the team seeing some exciting progress.

  • A data mining study was completed which showed that native parasitoids Diachasmimorpha kraussii and tryoni, and introduced parasitoid Fopius arisanus, are suitable biological control candidates for use in agricultural systems
  • A comprehensive written review of Australian fruit fly parasitoids was prepared, which will be ready for journal submission shortly
  • Survey work of more than 2,500 fruits from across Victoria revealed the presence of Diachasmimorpha kraussii in the state’s North East. This represents the first detection of this species (and any tephritid fruit fly parasitoid) in Victoria.
  • Good progress continues for the augmentative biocontrol (mass rearing / release) program. A culture of arisanus from wild collected parasitoids was established, with around 7,000 sent from Queensland (QUT) to Victoria (Agriculture Victoria, Tatura) in November 2020 to begin mass culture. The Tatura facility was modified to enable rapid mass rearing, with a capacity of approximately 40,000 wasps per week achieved.
  • Project team members met with growers to discuss the Qfly biocontrol project. Several sites were assessed for suitability for parasitoid release, including urban sites in the Goulburn Valley, Moira Shire and Sunraysia, and a biodynamic orchard in the Goulburn Valley. Three inoculative releases of Fopius arisanus were conducted at the Goulburn Valley location. These have been monitored for initial and ongoing parasitism using ‘sentinel fruit’ and the collection of Qfly infested fruit from the orchard.
  • In February 2021, the team provided a project update to 99 webinar participants as part of the National Fruit Fly Council Webinar series coordinated by Plant Health Australia. Participants included industry, government, growers, scientists, and the public.

Details

This project is a multi-industry strategic levy investment in the Hort Innovation Apple and Pear, Citrus, Raspberry and blackberry, Strawberry, Summerfruit, Table Grape and Vegetable Funds