Question: How do bed burgs form resistance to chemicals when they are continuously sprayed with certain chemicals.

Makobu Kimani answered on 22 May 2018:

When you spray a chemical, you hope to eliminate all the pests you have targeted. However it is possible that you may only kill those that the chemical agent directly comes into contact with. Those that the agent does not get into contact with will probably survive. This could include those that were eggs and only hatched after you had sprayed the chemical.
These ‘survivors’ may then come into contact with reduced levels of the chemical agent. The reduced dosage is not enough to kill them and they may actually learn how to counter the effects of the chemical. This phenomenon is called ‘development of tolerance’.
Subsequently, the generations of off spring that they give birth to will have increasingly improved inborn resistance to the chemical agent. When you now try to spray these offspring the chemical is almost useless to them.
The best way to reduce this form happening is frequent re-spraying to avoid ‘survivors’ of first spray getting a chance to develop any tolerance for the chemical. So if you spray today and find may dead insects, repeat again in 2-3 days to catch any that have hatched recently.