Species: Aedes aegypti, Yellow Fever Mosquito. Photo courtesy of Ed Freytag

IMERGARD™ is being positioned as an active ingredient for targeted indoor residual applications to combat both Anopheles and Aedes vectors


Imerys initiated an internal project to combat Pyrethroid resistance mosquitoes to reduce malaria incidents in sub Saharan Africa. Imerys secured funding from the Innovative Vector Control Consortium, IVCC, for a proof of principle project to provide supporting data that a mechanical insecticides can be used to kill adult mosquitoes. The work, conducted by North Carolina State University, NC State, focused on the insecticidal properties of mechanical insecticides applied to bed nets and solid surfaces.

Primary research was conducted with adult female Anopheles gambiae (static cone bioassay test, no host cues). Probit models where developed using physiological death as the end point (no movement when mosquito is touched or probed).

Kill rates were much faster and higher than expected, even in absence of host seeking behavior and under high humidity conditions. Some results of the proof of principle study include;

  • At 75% relative humidity, LT50 is achieved in
  • No significant difference in susceptibility between ovipositional cycles I and II
  • Proven efficacy on Pyrethoid resistant Anopheles gambiae Akron strain
  • 8.5 month residual activity on a solid surface with control release of mechanical insecticide: 100% mortality after 11hrs at 28oC, 79% relative humidty
  • 30 min dose response exposure achieved 100% mortality overnight
  • Large scale cage test, in presence of host cues: >80% mortality overnight with anecdotal comment that host seeking behavior may be affected

The primary output of this project is that IMERGARD™ is being positioned as an active ingredient in Indoor Residual Spray, IRS, formulations as either a standalone solution or use in conjunction with existing chemistries as part of an Integrated Vector Management program to control Anopheles vectors.
Insecticide resistance is compromising the success of existing intervention to control the urbanized Aedes aegypti we see an opportunity to position IMERGARD™ as a novel, non-chemical tool to complement existing household vector control strategies, specifically the development of targeted IRS applications.

Residual long run activity is very promising:

  • 8 month residual activity on a solid surface with control release of mechanical insecticide: 100% mortality after 24hrs at 29oC, 81% relative humidity

So how does it work?

If a mosquito does not survive longer than the extrinsic incubation period then no parasites can be transmitted – data demonstrates initial kill rates within a few hours and 100% mortality overnight even in high humidity environments.
Flying mosquitoes generate static charge. Landing on a surface treated with IMERGARD™ mechanical insecticide results in static transfer of the mechanical insecticide. It has been noted that the mosquito exhibits unusual and unexpected behavior when exposed to mechanical insecticide – the mosquito remains mostly stationary until death.

For more information about our products, pack sizes or sales outside the USA please contact us to discuss further with an Imerys specialist.


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David Stewart