Mosquito Control: a Cape Town guide

Know what you are dealing with

The mosquito keeping most Capetonians awake is Culex, a brownish mosquito that bites at night and breeds in still, often dirty water such as blocked gutters, drains, septic tanks, ponds with no fish and water features left to stagnate. Aedes mosquitoes are smaller, often with black and white markings, and bite during the day, laying their eggs just above the waterline in containers like pot-plant saucers, old tyres, buckets and blocked roof gutters. Homes near vleis and wetlands, such as those around Zeekoevlei, Rondevlei, the Milnerton lagoon and the Diep River, often see bigger swarms in warm, still weather. Inland in the Boland, farm dams, irrigation channels and water troughs add to the breeding sites. The Western Cape is not a malaria area, so the main concern locally is bites and disturbed sleep rather than disease.

Myths, mistakes and lesser-known facts

Children tend to react more strongly to mosquito bites, with bigger swelling and more scratching. A net over the cot and screens on the bedroom window are simple, effective protection.

Restaurants and guest houses with outdoor areas lose evening trade when mosquitoes get bad. Treating resting areas and keeping water features maintained should be part of the summer routine.

The south-easter is not all bad news. Mosquitoes struggle to fly in strong wind, so windy Cape Town days are often bite-free, and the worst nights come when the wind drops.

Warning signs

1. A high-pitched whine near your ear just as you fall asleep.
2. Itchy, raised bites on arms, face and feet that were left outside the covers.
3. Wriggling larvae, sometimes called wigglers, in pond edges, buckets, bird baths or pool covers.
4. Small dark mosquitoes resting on shaded walls, under the eaves or behind curtains during the day.
5. Day-time bites on the ankles while sitting in the garden, which points to Aedes breeding nearby.
6. Swarms in the evening near a water feature, drain or neglected pool.

In the Western Cape, mosquitoes are mainly a nuisance and are not a malaria risk, but the bites can cause swelling and itching that is worse in children and some adults. Scratched bites can become infected, and constant night-time biting leads to poor sleep for the whole household. For hospitality businesses, restaurants with outdoor seating and wedding venues, mosquitoes in the evening can directly affect guest comfort and reviews.

Can you do it yourself?

Most mosquito problems on a normal suburban property can be cut dramatically by the owner just by emptying standing water every week. Plug-in repellents and sprays help you sleep, but they do nothing about where the mosquitoes come from. Call a professional when the breeding site is something you cannot fix yourself, like a large pond, a blocked drain or a neighbouring property, or when you need numbers down for an event.

Seasonal pattern

Mosquitoes start building up once the weather warms in October and peak from December to March, especially after a wet winter has filled ponds, vleis and gutters. Calm, humid evenings are the worst, while the strong south-easter actually keeps them down on windy days. Numbers drop sharply when the cold, wet winter sets in from about May.

Prevention checklist

• Empty pot-plant saucers, buckets, bird baths and pet water bowls at least once a week, because larvae develop into adults in about a week in hot weather.
• Clean gutters after winter so they do not hold water through summer.
• Keep pool water circulating and treated, and drain the water that collects on top of pool covers.
• Stock ornamental ponds with small fish that eat larvae, and keep water features running.
• Fit mosquito screens to bedroom windows and use a net over cots in summer.
• Store old tyres, tins and containers under cover or throw them away.

What affects the price

Cost depends on the size of the property, how many breeding sites there are and whether larger water bodies such as ponds or drains need treating. A once-off treatment is priced differently from a programme of visits through the summer season. Fogging for an event is quoted on the size of the area, and the quote itself is free.

Frequently asked questions

Areas we cover for mosquito control