Technique and timing for blowfly

Merchandise Oct. 6, 2023

Correct application technique and timing are critical for optimal blowfly strike protection, according to Elanco account manager – southern NSW David Rathbone.

Elanco is a major supplier of blowfly prevention products to Australian lamb and wool producers. Its range includes CLiK Extra, CLiK and CLiKZiN, which all contain the active ingredient, dicyclanil.

“Dicyclanil has been used successfully to prevent flystrike in Australia for more than 25 years. Resistance can develop to any chemical so it’s not unexpected that resistant blowfly populations have been identified,” Mr Rathbone said.

“However, it’s important to note that dicyclanil resistance is demonstrated as a reduced length of protection period, not as a complete loss of efficacy.

“High levels of resistance can reduce protection periods, but we also know that low levels of resistance do not significantly impact protection periods.

“For the majority of sheep producers, CLiK Extra will still provide the longest period of protection against flystrike.”

Mr Rathbone said there are some easy steps producers can take to ensure they get the most of their investment in CLiK Extra.

“Elanco investigates every reported case of reduced protection period and we’ve found that these are often multifactorial with incorrect application technique or significant rainfall after application often contributing.

“A number of other factors, such as application to daggy wool or ‘dermo’, can also reduce the period of protection, as outlined on the label.

“You can’t control the weather, but you can control your application technique and timing.

“Firstly, choose the right product for the job.

“If you want long-acting protection, then choose a high concentration dicyclanil formulation to get the longest protection possible while considering withholding periods and how this may affect your farm management practices.

“Secondly, where possible, apply fly preventative treatments early in the season to prevent the build-up of the blowfly population and minimise production losses and blowfly strike treatment costs.

“Applying a long-acting blowfly preventative before the season’s first generation of flies emerge denies the flies the opportunity to find a host sheep and reproduce.

“Don’t wait until the first sheep is struck because you might not detect that strike.

“Covert or hidden strikes are exactly that – you can’t see them because there’s no derangement or fleece staining.

Mr Rathbone said it is estimated that covert strike is up to five times more common than overt or obvious strikes (as cited some years ago by Wardhaugh and Dallwitz in the article, Covert Flystrike. Wool Technology and Sheep Breeding).

“Even though these strikes are smaller, maggots are still there causing discomfort and irritation to your sheep and developing into the next generation of flies – and may also depress wool and body growth.” (This is explained in under management and monitoring for sheep blowfly).

“Thirdly, always read and follow the label directions of the product before use, particularly dose rate. Make sure you are using accurately calibrated and recommended applicators per the product selected.

“I recommend visiting the online CLiK Extra application guide to review a comprehensive application video which provides additional information on using either a hand-held applicator or a Genesis Power Doser.”

Mr Rathbone encourages wool and lamb producers to adopt best management practices to help protect the ongoing efficacy of all effective chemistry.

“All blowfly strike preventatives should be applied as part of an integrated pest management program, which may include a range of management practices to reduce risk of flystrike, including careful timing of shearing and crutching, attention to worm control and nutrition, and genetic selection,” he said.

“Industry guidelines on recommend rotating chemical groups within a flystrike season if more than one chemical application is required, to help prolong the effective life of all available treatments.

“For this reason, do not make two consecutive applications of products that contain dicyclanil or cyromazine during the same fly season as they are related chemicals from the same chemical group.

“These guidelines also recommend rotating between different chemical groups for blowfly strike prevention and lice control within the same season.

“Finally, if a wound dressing is necessary, select a product that has a different mode of action to any product previously applied for blowfly strike prevention in the same fly season.”

Producers and advisors should always read and follow the label directions. Good agricultural practice is essential for optimal blowfly prevention.

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