This device is known as an ovillanta – which when translated loosely from Spanish means tyre for laying eggs. It was developed by Gerardo Ulibarri Ph.D, an associate professor of medicinal chemistry and eco-health at Laurentian University in Sudbury, Ontario.
He developed it as a means of destroying the larvae of the Aedes mosquito, a genus of mosquito that carries the notorious Zika virus as well as the dengue, chikungunya and yellow fever viruses.
Read More: 11 Smart Ways To Protect Yourself From Mosquitoes Causing the Zika Virus
This device eliminates the need to use pesticides, which can damage the environment and kill other harmless insects that eat mosquitoes for food. Even if insecticides kill mosquitoes now, subsequent generations of these mosquitoes build up resistance to these pesticides, making them less effective in the long run.(You might have noticed how after applying insecticide to a room, you still hear some mosquitoes buzzing about)
Initial tests show the ovillanta is very effective. During a 10-month study in Guatemala, a country in Central America, researchers found that 84 ovillantas placed in seven neighborhoods in the town of Sayaxche destroyed more than 18,000 Aedes larvae every month! That’s nearly seven times better than standard traps.
And equally as noteworthy is the fact that no new cases of dengue fever were reported in the area during that period, where normally, two to three dozen cases would have been reported.
How Is It Built?
The ovillanta consists of two pieces of tyre, roughly half-metre long, and a tube drain valve. The ovillanta mimics the breeding site of a mosquito. Here is how it works:
- The bottom half of the device gets filled with about 2 litres of water, and topped with landing strips– a germinating paper, for example – on which the female mosquitoes lay eggs.
- Landing strips are needed because mosquitoes will not lay eggs on a dry surface – they need moisture to hatch, says Dr. Ulibarri. In a hot climate, you have to add water from time to time because it evaporates very quickly.
- The water in the device must be drained about twice a week into a container covered with a filter; something as simple as a piece of white cloth works well as a filter because the colour makes the larvae clearly visible.
- After draining, destroy the larvae by burning.
- Then pour the water back into the ovillanta (topping it off with fresh water) and install two new landing strips. It is important to recycle the water because after the eggs hatch, they release a pheromone into the water that tells other mosquitoes it’s a good, safe place to lay eggs, says Dr Ulibarri.
It usually takes about one month – the average life cycle of a female Aedes in hot weather – before you begin to notice a drop in mosquito population. As few as two ovillantas per acre can significantly decrease mosquito populations, but the more there are, the better the results.
So far, the devices have been tested in Guatemala and Mexico, with future experiments to be carried out in Brazil and Paraguay.
If you would like to see how an ovillanta is made, you may want to watch this video. Though, it is in Spanish, it has been subtitled in English.
Source: BBC Autos
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