Non-toxic larvicides can aid in dengue fight

I was saddened to hear of Mr V. Balu and his family's encounter with dengue ("Work together to stop dengue"; last Friday).

I applaud him for sharing his experience and urging the public to stay vigilant and be proactive in curbing the spread of dengue.

Despite the ease of applying precautionary measures, many still adopt a reactive rather than proactive mindset towards combating dengue, even in their own homes.

For instance, it takes no more than 10 minutes to ensure that there is no stagnant water collecting in potential mosquito breeding sites. These include roof gutters, water fountains, flower pot plates and drains.

Residents can also help disrupt the life cycle of mosquitoes from as early as the larva stage.

The slow release of non-toxic, biological larvicides such as Bacillus thuringiensis israelensis in standing water can kill mosquito larva before they become adults.

These are readily available in formats that are safe for general use in a variety of habitats, such as around animals (including aquatic life) and children, and can have a residual effect that can last up to five months.

Compared with other chemical-based pesticides - with their wide range of toxic effects on the environment - scientific trials have consistently shown that microbial larvicides do not pose risks to wildlife, non-target species or the environment.

Some of these are even selective in their larvicidal activity and highly specific to only mosquito and black fly larval populations, with no effects on non-target invertebrate or vertebrate organisms when used according to product instructions.

Residents must realise that the fight against dengue is not one that is fought by the authorities or pest control operators alone.

It is both an individual and collective responsibility.

Johnny Wong

This article was first published on August 4, 2015.
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