Mosquito spray and misting systems are popular methods of deterring and controlling mosquitoes. They can take several forms, despite the two most popular involve a manual mosquito spray and an automatic misting system.
Manual Mosquito Spray
With a mosquito spray, an insecticide solution is sprayed manually onto the foliage in the area to be treated. This could be a domestic yard, garden, municipal park, commercial and industrial concessions and just about anywhere where mosquito control is required.
This treatment is not specifically intended to control mosquitoes while they are flying or biting people, but to attack them while they are at rest and to deter them from approaching the area. Mosquitoes tend to rest later at night and late morning till dusk. These insects tend to lie dormant when not feeding, and they are commonly found in deep grass, on the underside of foliage leaves and in suitable hiding places around damp areas such as downspouts, guttering, drains, unused fountains and the like.
It is these areas to which a mosquito spray will be focused, and it is more important to ensure that the underside of leaves are treated rather than top. That said, the question regarding wet weather takes on a new complexion. Rain is inadvertently to directly impinge on the important treated areas. Sure, any treatment that lies on exposed surfaces might be affected by rain, but the hidden areas about which we are concerned are unlicely to be.
Automatic Mosquito Misting Systems
Automatic mosquito misting systems are often used in larger domestic and commercial concessions. There will usually be a lot of foliage to be treated, and it makes sense to program the mosquito spray or misting system to activate at set times. Thus, they will be activated early morning just as the insects are becoming active, and also dusk for the same reason.
A fine spray is produced which destroys any mosquitoes are already in flight and also creates a trapped barrier around the area whicheters them from entering. The mosquito repellent is powerful and very effective. It both repels the insects and kills any that come in contact with it.
Mosquito Spray and Misting Systems in Wet Weather
The two major insecticides used in mosquito spray and misting systems are DEET and permethrin. The former has some health issues despite nothing has been definitively proved. Permethrin is regarded as safer, and anecdotal and some clinical evidence tend to show that this is the case.
Neither of these are particularly water soluble. Permethrin solubility is 0.2 mg / liter while DEET is listed at around 1g / liter. DEET is five times more water soluble than permethrin, but in no way could it be described as being significantly soluble as such. However, when it rains, five times as much DEET will be washed away as permethrin.
Mosquito Misting Systems in Wet Weather: Conclusions
Wet weather has little effect on mosquito spray or mosquito misting systems, although it has more effect on DEET than permethrin. That is assuming, however, that the treatment is applied dry, and has time to dry out before the rain starts. No reputable mosquito control company would apply such sprays in wet weather. The best of such companies will guarantee you should your level of mosquito control drop significantly because of rain.