FAQ on Mosquito Fogging


What is mosquito fogging?


When and how mosquito fogging should be carried out?

Should mosquito fogging be carried out:

 In the raining session of December, or

 Immediately after a day (or days of rain), or

 Impending rain as per weather forecast.


Mosquito fogging is a technique used for killing mosquitoes that involves using a fine pesticide spray (aerosol) which is directed by a blower.

Before commencing fogging consider eliminating the sources of mosquito breeding. That includes:

  • Eliminate all stagnant water (in pet bowls, birdbaths, empty pots and vases or any containers)
  • If cannot get rid of water, consider treating the water with mosquito larvae killer
  • Control tall grass and bushes (in the shaded cool location) where mosquitoes like to live
  • Use mosquito-repelling plants (e.g. peppermint, rosemary, citrosa, catnip)
  • Use mosquito electric zappers (electric killer trap lamps, electric mosquito terminator) Removing stagnant water is to eliminate breeding grounds for mosquitoes and is the first line of defense. If you have washrooms with WC that are not used regularly (especially vacant houses), please close the WC seat cover, and close all the windows and doors, to minimize the breeding by the mosquito in the water in the WC
The following are important considerations for an effective fogging

1. Wind Condition

It is important to fog in low wind or ideally in windless conditions. Low wind conditions are vital for a successful fogging, because particles of the fog are very small and can be easily moved by a tiny wind gust. Low wind or windless conditions will allow the fog to stay on the area fogged for a longer period of time, which results in more terminated mosquitoes and will also repel the mosquitoes from the area for a longer time.

2. Timing of Fogging

The best time to fog is when the activity of mosquitoes is the highest. Most mosquitoes are active in evenings and only a few species are active during the day. In general, mosquitoes don’t prefer sunlight and are looking for shady areas to hide during the day.

The best time for fogging is in the evenings around dusk or early mornings at dawn and when there is no rain before or after the fogging. Mostly fogging is done during evenings for of following reasons:

  • In the evening hours and around dusk the day temperature has lowered. This allows the fog from the fogger to settle on the surfaces (lawn, leaves of plants, pots, bins, drains) easier and therefore the fog is going to stay in the area for longer time.
  • At this time wind is usually still, which is very important for a successful fogging session.
  • Most good insects like butterflies and bees are active during the daytime and their activity has ended before the late evening hours and dusk. So fogging at this time won’t harm these good species as much, which is great since most insecticides will not only kill mosquitoes but the other small bugs and insects that may do good for your garden and biosphere around the fogging area.

3. Weather – Rainy Days The question is:

Do we carry out mosquito fogging during raining season? No, we do not carry out mosquito fogging during raining season because:

a) There is no stagnant water during the raining season as mosquito lay eggs on stagnant water.

b) Rain water would have removed / washed away all mosquitoes.

c) Mosquito fogging should be carried out several days (or at least 1 week) after any rain or raining season, as mosquito could have returned and rain water become stagnated. Weather forecast is very reliable due to technology and easily available online.

4. Where to Fog?
Fogging should be directed “horizontally” onto:
a) Park – lawn ground cover, shrub and tree
b) Garden / Lawn of the houses
c) Manholes of all drains

More attention should be given to the perimeter if the location is adjoining a woody area (park, forest and utilities reserves), industrial area or the construction site A common mistake is to direct spray along the direction of the road or walkway and not onto the park or garden of the houses.