Free RLEM insecticide resistance testing

Have you noticed a chemical control failure or suspect insecticide resistance in redlegged earth mite (RLEM)? If so, we can help to test whether your local RLEM populations have evolved insecticide resistance.

Insecticide resistance in RLEM

Control of RLEM is largely reliant on three registered chemical classes; neonicotinoids (as seed dressings), synthetic pyrethroids (SPs) and organophosphates (OPs) (as foliar insecticides). Continued use of these limited chemical options has resulted in resistance issues.

Populations of RLEM that are resistant to either SPs or OPs, or possess resistance to both, are now present across large areas of Western Australia and parts of eastern Australia. This includes confirmed resistance in multiple redlegged earth mite populations from South Australia in 2017 and a recent detection in Victoria.

For more information on redlegged earth mite see Pestnotes and our RLEM management tools webinar

Free resistance screening service

Cesar Australia is offering a screening service to test for insecticide resistance in RLEM within South Australia, Victoria, NSW and Tasmania. The screening is at no-cost for Australian grain growers and advisers, thanks to funding from the GRDC.

We are particularly interested in hearing from growers or advisors who have had experienced recent or past chemical control failures or have paddocks that are frequently impacted by the mites, and often require spraying.

The service will not only help detect any resistance before it becomes widespread but will also help identify the best control options for growers. 

Cesar Australia will be undertaking field trips to collect RLEM for resistance screening, so get in touch if you would like us to collect RLEM from your area.

How to send samples for screening

If you wish to send in mites for screening, package and post collected mites in a non-crushable container with some of host plant material.

More information about how to send in samples can be found here.

Make sure you send samples to our new office: Level 1, 95 Albert St, Brunswick Victoria 3056 Australia

A collection kit can also be provided containing the necessary equipment to send mites in if required.

Please note: samples sent directly will only be screened for SP resistance given the large number of mites required for OP testing. Please get in touch regarding a collection if OP resistance is suspected.

Avoiding the evolution of insecticide resistance

Keeping track of resistance is essential for the ongoing management of RLEM.

To reduce the risk of your local mites evolving resistance, only spray paddocks when mite numbers warrant it, inspect paddocks post-spraying and report any suspected spray failures.

We encourage using non-chemical control tactics to assist in reducing reliance on chemical controls as outlined in the Redlegged earth mite insecticide resistance management strategy.

For further information or to access the testing service, please contact:

Dr Aston Arthur

0427 875 040

Cover image: Photo by Cesar Australia

What is Pestfacts south-eastern?

PestFacts south-eastern keeps growers and advisers informed about invertebrate pests and beneficials in broadacre crops and pastures during the winter-cropping season in Victoria and southern New South Wales.


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Since 2019 PestFacts south-eastern has been running through IPMforGrains: Best Practice Insect Pest Management, a project delivered by the National Pest Information Network (Cesar Australia, DPIRD, QDAF, NSW DPI, and SARDI). This project aims to provide grain growers and advisors with information on invertebrate grain pest occurrence and equip industry with the knowledge needed to implement integrated pest management practices. This initiative is a GRDC investment and includes in-kind contributions from all project partner organisations.

The online PestFacts south-eastern collection also includes a selection of articles published between 2015 – 2018 when the service was run through a previous GRDC investment, The National Pest Information Service.

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