Tactically and economically blowfly strike is best approached at docking using a proactive attitude, within which product choice and application play crucial roles. A proactive approach will mitigate the negative economic impact that may arise from waiting until flystrike is present.
Ideally, the prevention plan you put in place will take into consideration things like time until shearing, chemical class previously used for lice control and regional knowledge about seasonal weather forecasts/patterns and the relative blowfly challenge. The old adage that ‘the best defence is a good offence’ holds true when looking at your blowfly prevention programme.
When it comes to chemicals insect growth regulators (IGRs) are the most common chemical family used for flystrike prevention, mainly due to their persistence. The two categories of IGRs are:
Triazine-pyrimidine derivatives – this category is sufficient for fly control only and actives include cyromazine and dicyclanil
Benzoyl Phenyl Urea (BPU) compounds – suitable for fly & lice control which includes the actives diflubenzuron and triflumuron
The above chemicals are common choices for those proactively approaching the upcoming season; however should there be a need to treat blowfly strike it is important to look for products that have two actives, one of the above for ongoing strike control and the secondary ensuring rapid knockdown of maggots. For example, Cyrazin® K.O which contains the IGR cyromazine in combination with ivermectin.
Chemical application involves adhering to the label instructions with the correct method to ensure appropriate coverage of the target areas (pour-on/spray-on products) or complete coverage and saturation to skin level (dipping products) to provide the best outcomes.
When assessing the comparative protection periods of different products (usually stated as “up to” X weeks) it is important to remember that actual length of cover will be determined by factors such as effectiveness of application, fly pressure, environment and other influences.
If in doubt, talk to us about the best product for your situation. We will be able to advise whether sticking with a chemical compound or group previously used will continue to offer long-term protection or if it is time to change. New Zealand is still on the front-foot with regards to chemical efficacy, with lessons learnt from Australia, however without responsibly using the currently available chemicals we will risk breakdowns and lack of efficacy.
Be proactive, act before there is a problem
Follow the product label guidelines
Use the correct equipment for the product and the job
Carefully consider (and seek advice if needed) about the correct chemical for the job based on your usage pattern and on-farm product history