Trapping mosquitoes with sugar

It was in Standard Four at St. Andrews High School in Blantyre that the now 15-year-old Joshua Mwanda was introduced to science as a subject.

“I have liked it since then. I love opening and observing objects and I dream of pursuing a career in electrical engineering,” said Mwanda, a Form Four student at Lilongwe Academy.

Similarly, 13-year-old Chisomo Gomonda took an interest in science while in Standard One at Clever Cat School in the city.

“I don’t know why, but I just like it,” she says.

The two brains later met at Lilongwe Academy where they proved to be science geniuses. They represented their school at this year’s National School Science Fair that National Commission for Science and Technology (NCST) had jointly organised with Kamuzu Academy.

The fair allows people, both young and old, to display the various skills, innovations and scientific knowledge that they are pursuing in a bid to create a better world.

Mwanda and Gomonda displayed what they referred to as a home-made mosquito trap.

“A mosquito trap is used to reduce the population of mosquitoes in our homes. We tried to make a trap that can be made from cheap materials that are easily accessible,” said Mwanda.

He added: “We did this as part of finding an alternative to chemicals that are manufactured in factories for controlling mosquitoes, which are usually very expensive, hazardous to environment as well as to humans and animals.”

What they came up with was a mosquito trap that is easy to make, cost effective and friendly to environment. It was made by recycling plastic bottles to make the container of the trap.

“The raw materials we used are yeast, brown sugar, black plastic paper, a knife, tape and a two-litre plastic bottle. The plastic bottle is cut into half, then we boil about 200 millilitres of water before pouring it into the bottom half of the bottle,” Mwanda explains the procedure.

They then pour 50 grammes of sugar to the water until it fully dissolves. The solution is then left to cool off. A teaspoon of yeast is added.

“After that you take the upper part of the bottle, turn it upside down and fit it into the other half containing the solution. A sticky tape seals the two halves. Then you cover the trap with a black plastic paper and the trap is ready,” says Mwanda.

The sugar and yeast mixture produce a gas called carbon dioxide and act as a trap. The gas indicates to the mosquito about presence of something it can bite and probably suck blood from it. They then get trapped to the sticky mixture.

The black plastic sheet traps heat and create a warm environment which is also attractive to mosquitoes. Once the mosquitoes land on the mixture they won’t be able to go out again.

Mwanda says the carbon dioxide in the trap attracts all kinds of mosquitoes including anopheles, the type that causes malaria. He says 200 millilitres of water can trap hundreds of thousands of mosquitoes as long as they enter the solution.

“This is our own idea. We just thought of the outline and we made it at our homes,” he says.

His colleague Gomonda said the idea took them between three to four months.

“The solution can last two weeks because the carbon dioxide stops being produced afterwards. You can then make a new one,” she says.

She said for this technology to spread, there is need to teach people in the rural areas how to make this trap.

“This will ensure that more people are protected from mosquitoes. Fortunately, if they can’t afford sugar they can use sugarcane or honey because they also contain glucose. This can help reduce malaria in our country,” said Gomonda.

Professor Francis Martinson, country director for University of North Carolina, a centre that is researching on a malaria vaccine says he is not aware of such an innovation trap but expects that just like any major scientific work; this will have to be shared among scientists.

“We do a peer review for scientific works,” Martinson said, adding that he supports the idea of the trap.

“You might have probably heard about a light that is used to trap mosquitoes. So, there are other ways of trapping it,” he said.

Mosquitoes are a nuisance to humans because they transmit malaria, which is the biggest killer particularly among children under the age of five.

Currently, Malawi has a number of interventions to fight against mosquitoes. They include use of insecticides, long lasting insecticide-treated mosquito nets, indoor residual spraying and clearing of stagnant water to disturb their reproduction and others.