Trapping efficacy in table grape vineyards for area wide management of Queensland fruit fly (TG19001)
What’s it all about?
This investment will further develop mass trapping methods as a tool to assist in the control of Queensland fruit fly, while evaluating the effectiveness of trapping at decreasing fly populations for table grape growers. This research will ultimately improve area wide management programs for the pest and contribute to continued market access by delivering best practice guidelines for growers. It aligns closely with the current levy-funded program Building capacity in area wide integrated pest management for Qfly in table grapes (TG18001), as well as a state-funded project in Victoria that focuses on Queensland fruit fly mass trapping in stone and pome fruits.
The project team will commence on-farm trials to confirm trap efficacy in table grapes, with a focus on assessing optimal trap placement in and around the crop as well as in nearby host sources and refuges. This will contribute to designing a table-grape-specific mass trapping strategy that growers can implement. Following that, on-farm mass trapping programs will be initiated to evaluate the effectiveness of this strategy at decreasing fruit fly populations in and around selected commercial vineyards, and in reducing pre-harvest fruit fly damage to grapes.
Three grower workshops will be held as a way to assess current perceptions and knowledge of mass trapping in the management of fruit flies and to discuss the potential for integrating mass trapping with integrated pest management and current area wide management approaches. This will inform the production of best practice guidelines for growers. On-farm field walks will also be held as a practical means of demonstrating how mass trapping works and its potential impact to growers, consultants and industry stakeholders.
In the mid-year report for Year 2, the team shared the following progress:
- Mass trapping field trials in two table grape vineyards were conducted to collect data on trap placement, trap efficacy, and the influence of host tree ‘hotspots’. Findings indicated hotspots may be the source of fruit flies which disperse into the vines, with a trapping strategy that targets these sites having potential to help reduce numbers in vines. Results also indicated perimeter trapping may be more cost effective than trapping throughout the vines. Trials will continue in the 21/22 season.
- In contrast to studies conducted in stone- and pome- fruit, the Biotrap was found to be more effective at trapping female flies compared to the new AVR trap. Dust sticking to the AVR trap from storms likely reduced its effectiveness. A laboratory study was undertaken to assess a modified AVR trap that uses a localised insecticide in lieu of a sticky glue.
- Laboratory trials were also conducted to compare variation in oviposition preferences and larval survival in five grape varieties. Statistical analysis revealed differences in alighting and stinging behaviours between varieties, as well as differences in larval survival, which was low across all varieties.
- Recurring COVID-19 restrictions prevented a planned workshop for industry representatives, growers and scouts. Alternative arrangements are being explored.
- Field sites and aims for the 2021/2022 season were identified.
During the first six months of the project (the 2020 season), the team talked with growers to ask about their experiences with Qfly, mass trapping and current management strategies. This information has been critical in guiding initial studies on mass trapping for the 2021 field season.
The first mass trapping trial is underway, using a combination of mated female traps (which use a synthetic fruit lure) and protein-baited Biotraps (which target virgin female flies). Additionally, male and female monitoring traps were deployed at seven vineyards in Mildura, with a plan to conduct more mass trapping field trials when fly populations are identified in these locations.
Monitoring trials during the 2020 season revealed that most Qfly were captured in nearby host trees rather than within the vineyard itself, suggesting these ‘hot spots’ might be more important for mass trapping than a within-block strategy. Further work is being conducted to clarify this, including the potential for perimeter trapping.
The team found that frequent dust storms around Mildura limited the effectiveness of mated female traps, which use a sticky glue to capture insects. Plans to develop and trial a non-sticky modification to this trap is underway for June-August 2021.
Growers who took part in the 2020 monitoring trials continue to participate in this research. An online grower workshop is being planned for June 2021 to share the findings from this season’s field trials, and better understand the potential for mass trapping from an industry perspective.
This project is a strategic levy investment in the Hort Innovation Table Grape Fund