P.PSH.1283 - Improved management of red legged earth mite
The TIMERITE tool for managing redlegged earth mites has been updated to make it more accurate for better control, reducing pesticide use and enabling adaptation to regional climate change impacts.
| Project start date: | 20 January 2021 |
| Project end date: | 01 January 2025 |
| Publication date: | 10 September 2024 |
| Project status: | Completed |
| Livestock species: | Grain-fed Cattle, Grass-fed Cattle, Sheep, Goat, Lamb |
| Relevant regions: | National |
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Summary
The redlegged earth mite (RLEM) is a widespread pasture pest that significantly affects the profitability of pasture-based industries.
This project aimed to:
1. understand the current extent of resistance in pastures
2 improve the precision of control by developing spray and egg hatch timing tools
3. identify new synthetic insecticide options
4. benchmark current knowledge and develop a Producer Demonstration Site (PDS).
The project found a substantial increase in detections of resistance to organophosphate and synthetic pyrethroid in RLEM populations in eastern Australia, particularly in SA. Testing of novel modes of action and biological products under microcosm and bioassay trials ruled out many products as having potential for RLEM control, with two products showing high efficacy. Climatic variables were found to enhance diapause prediction and improve the accuracy of predicting diapause onset in RLEM, compared to using only daylength and growing season length as in the original TIMERITE®. Similarly, the hatch timing tool successfully predicts the hatch timing of RLEM.
New knowledge gained through the project will be fed into the new version of the RLEM Resistance Management Strategy, ensuring it provides the best practice recommendations for RLEM control. The hatch timing tool will increase the monitoring precision of RLEM and thus minimise pest risk. The updated TIMERITE® offers significant benefits to the red meat industry by minimising RLEM impacts, improving pasture productivity and quality, reducing pesticide use and input costs, and enabling adaptation to climate change.
Objectives
The specific objectives of the project were to:
(1) conduct targeted field collections of RLEM populations across eastern Australian red meat production regions to understand the current extent of resistance issues and control failures
(2) deliver decision support tools through validating a web tool predicting RLEM egg hatch and updating TIMERITE® diapause tool based on current regional environmental conditions in red meat production systems
(3) identify new synthetic insecticide options against RLEM and explore the potential of biological molecules through lab trials and pasture trials
(4) expand grains industry focused social research on current knowledge, attitudes and practices into pasture-based industries
5. work with producer groups and the Producer Demonstration Site (PDS) team at MLA to explore and design a project to support producers in testing research-led management advice and share findings within and outside of the group.
Key findings
• There was a significant increase in detections of RLEM insecticide resistance in eastern Australia, particularly within SA. Of the 49 populations screened as part of this project, five populations were found to possess OP resistance, two with SP resistance, and four with dual resistance to both OPs and SPs.
• The testing of novel MoA and biological products under microcosm and bioassay trials ruled out many products as having potential for RLEM control, identifying two candidate chemicals that indicted high efficacy. Field testing of these two products did not show the same level of efficacy.
• Climatic variables enhance diapause prediction and significantly improved the accuracy of predicting diapause onset in RLEM, compared to using only daylength and growing season length as in the original TIMERITE® model. Climate change impacts TIMERITE® efficacy with changing temperature and rainfall patterns over the past three decades reducing the effectiveness of the original TIMERITE® model, leading to lower control efficacy. The hatch timing tool successfully predicted the hatch timing of RLEM, enhancing early season monitoring under variable climates.
• The benchmarking study provided insights into the spray frequency of different chemical groups used by producers and recommended by advisors, with producers and advisors exhibiting distinct risk attitudes, with economic impacts a primary concern for producers and advisors, emphasising the importance of trialling new practices.
• Cesar Australia and MLA have been working closely together to successfully produce extension and communication outputs for the project, including the development of online training modules and articles. The PDS project has been an opportunity to showcase and promote key outputs.
Benefits to industry
• New knowledge gained through the project will be fed into the new version of the RLEM Resistance Management Strategy (RMS), ensuring it provides the best practice recommendations for RLEM control.
• The hatch timing tool will increase the monitoring precision of RLEM and thus minimise pest risk.
• The updated TIMERITE® offers significant benefits to the red meat industry by minimising RLEM impacts, improving pasture productivity and quality, reducing pesticide use and input costs, and enabling adaptation to climate change.
• The gained insights from the social benchmarking study will play an important role in enhancing communication and extension outputs.
• The PDS project ‘Less Mites, More Feed’ is being conducted in collaboration with 15 core producers (representing 28,000 ha of managed land, 86,000 sheep, and 3,000 cattle) and 93 observer producers (representing over 150,150 ha of managed land, over 505,000 sheep, and 15,000 cattle).
• Forthcoming extension outputs will benefit the industry by increasing awareness about the identification and biology of different pest mites and highlighting the longer-term implications of resistance.
MLA action
At this point there is no immediate follow-up actions for MLA. The project has met its objectives and there is an active PDS in place to disseminate project outcomes to producers. In future if there is further leverage opportunity for co-investment with GRDC/CESAR then addressing recommendations above, in particular follow up research on new modes of action for chemical control should be pursued.
Future research
• Future management of RLEM should aim to reduce the use of chemicals to limit selection pressures and decrease the risk of further local resistance evolution.
• Ongoing resistance surveillance to monitor the distribution and levels of field resistance is crucial to identify emerging resistance issues. Understanding the incidence, patterns of spread, and current distribution and nature of resistance is also important for the RMS. In addition to OPs and SPs, it is important to explore any arising potential resistance to neonicotinoids in RLEM. Providing growers and advisors a resistance testing service allows them to implement effective resistant management strageties and improve management outcome to ensure effective pest control in the future.
• It is important to continue to explore and support any novel MoA and biological products being considered for RLEM control and registration.
• It will be critical to ensure that the RLEM RMS is continually updated with the latest research and best management practice recommendations. It is recommended that the RLEM RMS is extensively promoted to increase awareness and adoption of its recommendations by meat and livestock growers and advisors.
• Facilitating the extension of research findings holds a crucial role in advancing industry knowledge and fostering adoption in future initiatives addressing RLEM resistance and control. Education is a key component, empowering growers and advisers to confidently adopt new resistant management strategies and decisively move away from control strategies that increase the risk of resistance evolving in RLEM and other pests.
• It is recommended that MLA continue to work in collaboration with other industries impacted by RLEM to improve the management of RLEM and reduce its significant current economic impact.
More information
| Project manager: | Ross Mann |
| Contact email: | reports@mla.com.au |
| Primary researcher: | Cesar Pty Ltd |
