Mosquitoes thrive in warm and damp conditions. Photo / 123RF
Starting to itch and scratch in this humid weather? You’re not alone.
From the first buzz to small prick, mosquitoes are making their homes in our homes and workplaces, and causing havoc this summer – but why?
Pest Management Association of New Zealand (PMANZ) member Dr Paul Craddock previously told the Herald a lot of mosquito activity is driven by climate, and that they tend to hang around stagnant pools of water and damp areas.
“In Auckland now, we’re getting a bit of rain, so you’re getting pockets of water where the larvae are breeding, and then they are coming through the windows at night because it’s so hot and humid,” he said.
Reuben Muusers, owner and technician at PMANZ-accredited Ecosan Solutions, agrees.
“Increased temperatures and humidity will increase mosquito activity, so summer and rainfall are ideal [for them],” he says.
“In the last three years, we have seen a definite increase [in mosquito numbers]. They seem to be more difficult to control also. This could be due to higher numbers, but we do need to change up our routine methods and find other solutions that work effectively.”
Stagnant water and foliage from garden greenery are the main places you’ll find mosquitoes congregating, experts note. Hot spots could be anything from old tyres and unclean gutters to water tanks and ponds.
“[Getting rid of stagnant] water can seem like an easy fix and can sometimes be hiding in plain sight, such as a downpipe with a blocked drain, but often it can be more difficult to find or not even on your property,” Muusers says.
“Other areas [you can find them], both residential and commercial, are gardens and landscaping. Mosquitoes like to dwell in warm but shady or sheltered positions under leaves of trees and plants.”
Inspecting nearby drains to make sure they are clearing properly and emptying stagnant pools is a good preventative measure, Muusers says.
“Mosquito larvae start in standing water, so they need some time in undisturbed and constant conditions for the lifecycle to succeed, not just some pooling water that dries out in the next day or two.”
He says if mosquitos find an indoor environment hospitable, more will likely come in.
“So, seal up gaps around doors. [In commercial premises,] entry points are common where there are sliding doors for customer/staff entry points. These often do not seal completely, so may need some brushware or stop-gap measure as mosquitos will surf the air current inside.”
Craddock notes a simple fan or screen acts as a good non-chemical approach.
“Flies and mosquitoes don’t really like it when it’s windy. You can create artificial wind in your house with things like ceiling fans, air movement, pedestal fans, just to push air around so that it deters them from landing and being in that space.”
Airborne insecticide or repellent can be “really, if not most, effective”, with Muusers suggesting diffusers, automatic insecticide dispensers or even aromatic plants as means of application.
“The product is wet and hanging in the air, so it possesses a much faster knockdown effect and real-time repellency.”
Dr Mariana Musicante, principal entomologist at the New Zealand BioSecure Entomology Laboratory, says for stagnant water like ponds, which can’t be removed, a method called Bacillus thuringiensis ssraelensis (BTI) is very effective if applied monthly.
“The larvae eat the bacterium, which releases a toxin in their stomachs and destroying them from the inside.”
Body sprays are also another way to keep mosquitoes off your skin. Musicante uses the Health New Zealand Te Whatu Ora website as a good guideline for which products are most effective.
You might also hear of people being called “mosquito magnets”, claiming they are bitten more than others.
Turns out this claim is grounded in science – and that it pays not to smell.
Musicante says different people’s skin chemicals impact their attractiveness to mosquitoes, and you become more of a magnet when you sweat.
Carboxylic acids, a molecule that is part of the skin’s moisturising layer, have an odour that mosquitoes can smell.
“You probably need to be careful how you smell. If you have stinky feet, you may attract many mozzies. If you smell like flowers, you will also be attracting mosquitoes. So, the more natural you smell, the better.”
She says scientific research also found there was a relation between the type of blood you have. The research showed that people with the blood type B tend to get bitten more than others.
Inevitably, itchy lumps and bumps are almost guaranteed after being sucked by a mosquito.
According to Health NZ’s website, these bites will “usually go away on their own after a few days”, but people should try to avoid scratching them, as this will make it worse.
Household treatments for mosquitoes include soaking in a cool bath, calamine lotion and aloe vera.
While there is a limited risk of infection at home, Health NZ still encourages people to call their healthcare provider if they get a rash around the area of a bite or start to feel unwell. People bitten overseas should also contact Healthline to rule out diseases like dengue fever and its associated complications.
“Do not take aspirin, ibuprofen or other non-steroidal anti-inflammatory drugs until you have had medical advice to rule out dengue fever. These can increase the risk of bleeding,” the organisation says.
Muusers says besides the physical implications, mosquitoes also create psychological impacts, which is why getting on top of the issue is important.
“From what I’ve seen, they can cause quite a bit of anxiety in situations with chronic problems, especially in the staffed workplace where mosquitoes are an issue in summer every day,” he says.
“This definitely upsets staff and breaks task concentration. In the home, it also causes anxiety if the family with small children is being harassed. Often, a solution is welcome.”
Mitchell Hageman joined the Herald’s entertainment and lifestyle team in 2024. He previously worked as a multimedia journalist for Hawke’s Bay Today.