Wednesday, May 31, 2023

Resistance set to change how farmers manage flystrike this season

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TROY Animal Health, Media Release, 9 September 2021

Application of flystrike treatment.
Photo: Troy Animal Health

For the first time in more than 20 years, farmers are having to rethink their strategy for managing flystrike. Recently documented chemical resistance1, coupled with wet and warm conditions this spring, means there is the threat of a big flystrike season ahead.

Until recently, farmers have been able to apply a chemical treatment that has got them through the main flystrike season. However, increasing dicyclanil resistance may rapidly change the landscape for treatment options, particularly for resistance impacted producers.

Australian Wool Innovation (AWI) and the NSW Department of Primary Industries (DPI) recently published one of the largest insecticide resistance studies ever undertaken2. The Australia wide study tested all the major blowfly preventative chemical groups to determine their resistance profiles.

73% of submissions received across Australia showed resistance to both dicyclanil and cyromazine, whilst a further 15% of submissions showed resistance to cyromazine.

The study showed that just 12% of submissions had susceptibility to both chemicals.

Furthermore, in NSW (where the most tests were done), 100% of submissions had resistance to both chemicals while Victoria had 82% of submissions resistant to both dicyclanil and cyromazine.

Craig Lyons. Photo: Troy Animal Health

Craig Lyons, Marketing Manager from Troy Animal Health, explains how resistance is managed is critical to ensuring effective fly control options are safeguarded.

“Studies like this one by AWI & NSW DPI are important to keep farmers informed of how the effectiveness of flystrike control products are changing over time and the importance of integrated pest control,” he said. 

“Findings from this study demonstrate that dicyclanil resistance is a major concern for the Australian sheep industry. The research showed that with a resistant fly population, a significant reduction in protection period from dicyclanil based spray-on products, compared to their registered claims, can occur. CLiKZiN™ provided only up to 3 weeks protection while CLiK™ gave up to 4 weeks protection and CLiK™ EXTRA up to 9 weeks protection1,2.”

“With the limited number of insecticides registered for flystrike prevention, the strategic use of insecticides through chemical rotation is critical for the industry.”

“We’ve seen widespread resistance develop to valuable chemicals, and this reminds us of the importance of rotating chemical groups used for fly prevention, and ensuring producers are familiar with the different treatments for flystrike.”

“Reductions in length of protection periods means it’s critical farmers are planning their flystrike management, keeping up to date with latest information and products, such as AVENGE® + FLY, and incorporating chemical rotation into their management program.”

“If you have used the same flystrike treatment for the past few years, it is time to rotate your preventative treatment. AVENGE® + FLY is a great rotation option as it provides protection for up to 14 weeks against flystrike in long wool, which is the longest alternative to dicyclanil.”

Don Macdonald, AWI Director and wool producer, says a flystrike preventative is particularly important for planning this year if the industry faces another shearer shortage due to the ongoing impact of COVID-19.

“Something to consider this year is the likelihood of another shearer shortage due to COVID-19. This can make wool and fly management tricky when management timeframes have to be adjusted,” Mr Macdonald said.

“One thing that drives panic into woolgrowers faster than anything is labour shortfall and timing issues and then risks associated with that.”

“Growers need to know there’s another tool in the toolbox like AVENGE® + FLY, if they get pushed out of normal routine.”

  1. Sales, N, Suann, M, Koeford, K, 2020, ‘Dicyclanil resistance in the Australian sheep blowfly, Lucilia cuprina, substantially reduces flystrike protection by dicyclanil and cyromazine based products’, IJP: Drugs and Drug Resistance 14:118-125.
  2. Sheep Ectoparasite Resistance Update 2018-2020 (2020). NSW DPI Project no. ON-00491. Narelle Sales.

Avenge® + FLY is a registered trade make of Troy Animal Health. CliKZiN and CLiK are trademarks of Elanco or affilates.


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