Liquid repellents are now widely used to repel mosquitoes. The Liquidator mosquito repellent has a graphite rod in the middle and the bottle is filled with the repellent. There is a heater coil in the liquidator. The repellent chemical when comes in to contact with the heated rod turns into fume which disables the sensors of the mosquitoes. The fumes produced by the repellent blocks the chemo sensors of mosquitoes so that they cannot identify human beings.
Liquid mosquito repellents contain chemicals such as ,Prallelthrin , Allethrin etc. Of these the most commonly used one is Pralletrhin. Prallethrin is a pyrethroid chemical used as an insecticide. It is an Yellow to amber viscous liquid. d -trans-Prallethrin is a potent contact insecticide which produces a rapid knock-down, with same chemical and physical properties as Prallethrin.d-trans-Allethrin is also a powerful repellent used in mosquito coil and liquid.
These chemicals in the form of vapors block the chemo reception and also the respiratory tracts of the mosquitoes and thus they avoid the hostile situation.The chemical repellents used as mosquito repellents are toxic substances. Even though the concentration of the ingredient is in a safe level, this may cause allergic and respiratory problems in some persons. Precautions are recommended by the manufacturers and these include
1. Avoid inhalation and skin contact.
2. Wash contaminated skin & eyes.
3. Destroy empty containers after use.
4. Keep away from food stuff and animal feeds.