Developing and demonstrating the role of alternative chemistries and integrated management for crop establishment pests
- Researcher's Name:
- Dr Paul Umina
- Organisation:
- Department of Zoology, The University of Melbourne
- Email:
- pumina@unimelb.edu.au
- Phone:
- 03 8344 2203
- Fax:
- +613 8344 2279
- Project Code:
- UM00033
- Contract Start:
- 30/6/2008
- Contract End:
- 29/6/2012
Background
Invertebrate pests represent a significant challenge to sustainable grain production in many parts of Australia. Of these, establishment pests are perhaps the most important because they attack crops at a critical stage. In southern Australia, use of broad-spectrum chemicals is the major tool used to combat these pests. However, reliance on broad-spectrum chemicals to control agricultural pests leads to problems in pest resurgence, secondary pests and the development of pesticide resistance. This project extends upon our recent discovery of chemical resistance in a single population of redlegged earth mites in Western Australia and also investigates the current levels and distribution of chemical resistance in the field.
Implications
Growers and advisers have been informed of relevant findings of research activities through industry related press, presentations at workshops, NIPI conferences and GRDC updates. Information has also been delivered nationally and internationally through publication in peer-reviewed scientific journals and at scientific conferences.
Objectives
The findings from this project will improve the way crop establishment pests (including redlegged earth mites) are controlled and lead to a reduction in the unnecessary application of broad-spectrum insecticides. We will trial the efficacy of alternative 'soft' chemistries that are compatible with integrated pest management (IPM), against numerous crop establishment pests. This will be achieved through laboratory assays and large-scale field trials. Recommendations on the use of 'soft' chemicals and other management tools for Australian grains producers will emerge from this study, with the aim of providing judicious chemical sprays used in conjunction with beneficial invertebrates.
In addition we will map the distribution and frequency of insecticide resistance in redlegged earth mites in Western Australia. We will also screen multiple chemical classes to determine the level of cross-resistance present in field populations. This information is critical to devise resistance management strategies and delay the spread of resistance within Western Australia and to other states.
The benefits of this work will be delievered on a local, regional and national scale.
Outcomes
Output 1 - This project will assess the effectiveness and impacts of numerous 'soft' (selective) pesticides and conventional broad-spectrum pesticides on the crop establishment pests the redlegged earth mite, blue oat mites, bryobia mites, balaustium mites and the lucerne flea. This has been achieved using laboratory and large-scale field trials in Victoria and WA. Some new active ingredients showed promise against redlegged earth mites and blue oat mites as future IPM-compatible products.
Output 2 - The benefits of 'soft' chemicals on beneficial insects were investigated in field trials on canola and wheat. The impacts of 'soft' and broad-spectrum pesticides were varied; some insect groups were negatively affected while others showed little effects of insecticide applications. This information will be used to develop IPM programs and promote overall biodiversity for southern Australia cropping systems.
Output 3 - We mapped the frequency and distribution of insecticide resistance in redlegged earth mite populations across southern Australia. We have identified >25 paddocks with confirmed resistance, and these are located across 15 individual properties in WA. Screening in other states has failed to identify resistance in redlegged earth mites, although it is predicted to spread in the near future. The resistance mechanisms have not yet been identified but it is known that resistance is to all synthetic pyrethroid insecticides. Growers can still presently control resistant mites using other chemical classes and non-chemical approaches.
Related items
To avoid insecticide spray failures and prevent or delay the development of resistance, it is recommended that growers use a broad range of Integrated Pest Management (IPM) strategies.
The Grains Research and Development Corporation (GRDC) has released a Back Pocket Guide to assist growers in correctly identifying crop mites. Cesar entomologist Dr Paul Umina, who collaborated with GRDC in developing the guide, says mites are small in size and often go unnoticed, but are an important pest group...
Dr Paul Umina from cesar* and the University of Melbourne looks at the worrying rise of chemical resistance in redlegged earth mites in Western Australia
Western Australian growers are urged to report any cases of insecticide sprays failing to control redlegged earth mites (RLEM), which have recently hatched in the grainbelt.
Growers attending Regional Crop Updates in the South Coast region will be warned not to skimp on fungicidal seed treatments, summer and autumn weed control or pre-sowing knockdowns.
Research supported by the Grains Research and Development Corporation (GRDC) will lead to a better understanding of how pesticide resistance in redlegged earth mites (RLEM) spreads.
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