Coffee grounds and bicarbonate of soda can help stop flies and mosquitoes from taking over gardens, according to pest control expert Mosh Latifi, co-owner of EcoCare Pest Management. Speaking to Ideal Home, he explained that coffee grounds produce a powerful, bitter aroma that insects find unpleasant and masks the smells that attract them, such as food, sweet drinks and carbon dioxide from humans.
How the mixture works
Bicarbonate of soda used as part of a mixture can produce carbon dioxide when combined with an acid, which confuses mosquitoes whose tracking systems are tuned to follow CO2 towards a host. Used together, they create a reasonably effective scent barrier around a patio.
How to use it
For optimal outcomes, scatter bicarbonate of soda in and around waste bins or in spots where food odours tend to persist. Then, position thoroughly dried coffee grounds in a fireproof dish and ignite them so they smoulder instead of flame. Place the container close to seating spots, away from any combustible materials. The bicarbonate of soda captures unwanted smells while the coffee grounds keep smouldering, though when the smoke starts to fade or fresh odours emerge, flies and mosquitoes are likely to come back.
This approach proves most effective when the garden is maintained, including clearing out rubbish bins, wiping up spillages, and picking up dropped fruit. Mosh stated: "It is a reasonable first line of defence for casual outdoor use and has the advantage of being cheap, natural and widely available." He added: "It will not replace a citronella candle or a pheromone trap for serious mosquito pressure, but as a supplementary measure around a patio table, it is worth doing."
Other deterrent methods
An alternative approach involves suspending water-filled bags from porches to bounce light around and confuse flies' vision, though this wouldn't affect more than a handful of flies. Fly traps using sugar and water can lure flies, but once caught and dead, the deceased flies will draw in living flies. Blue lights are also effective: research by the University of Florida for the U.S. Department of Defence found that flies are more readily drawn to blue-coloured objects. If using a blue-light insect trap, place it well away from spaces you wish to keep free from pests.
