Insecticide Resistance

Resistance to insecticides may be defined as `a heritable change in the sensitivity of a pest population that is reflected in the repeated failure of a product to achieve the expected level of control when used according to the label recommendation for that pest species` (IRAC).

The  use  of  insecticides  as  such  does  not  create  resistance  but  it  can  develop  through  the overuse  or  misuse  of  an  insecticide  against  a  pest  species.     Resistance  develops  when naturally occurring genetic variation allows a small proportion of the population to resist and survive the effects of the insecticide.   If this advantage is maintained by continually using the same  insecticide,  the  resistant  insects  will  reproduce  and  the  genetic  changes  that  confer resistance   are   transferred   from   parents to offspring   so   that   eventually   they   become numerous within the population.  

Major factors that influence resistance development :

•    Application frequency
•    Dosage
•    Persistence of effect
•    Rate of reproduction
•    Population isolation
•    Population isolation

(Courtesy of IRAC )


Vector control remains the most effective method of controlling malaria and other insect-borne diseases, but is highly reliant on just four classes of insecticide and only pyrethroids for use in LLINs (long lasting insecticide nets). The availability of only a few classes of insecticide for vector control and the heavy use of pyrethroids in LLINs as well as for Indoor Residual Spraying (IRS) and in agriculture has caused significant insecticide resistance in some parts of the world. Areas with higher levels of malaria transmission and therefore widespread use of LLINs, namely Sub-Saharan Africa and India, are most at risk, making the development of new insecticides for use on bed nets a high priority to prevent this increasing problem.

Courtesy of IRAC Public Health


Sumitomo Chemical is working on several strategies to combat resistance in insect vectors and is also collaborating with the IVCC (Innovative Vector Control Consortium)  to develop an innovative  solution to resistance to pyrethroids in LLINs using the latest research and technology.
In the interim, our new IRS product SumiShieldTM 50WG offers a breakthrough new mode of action insecticide and our pioneering Olyset Plus® is the first and only net on the market with a synergist incorporated on all surfaces to deliver knockdown and kill against pyrethroid-resistant mosquitoes exhibiting the major metabolic resistance mechanism.