Study: Fogging doesn't really kill mosquitoes, other insects dying

 

Of the 1,874 insects found dead from fogging at the Kota Damansara Community Forest (KDCF), none were mosquitoes, according to a study by Sunway University and Monash University Malaysia.

Fogging is commonly used to control the number of mosquitoes but the study suggested that it may no longer be effective to reduce the risk of a dengue outbreak.

“Our results suggest that mosquitoes in the area have either developed resistance towards fogging chemicals, or have learned to fly away to avoid being affected,” said Nicole Lee, lead author of the study published recently in the international journal PeerJ.

For the study, fogging was carried out twice a week at 11am across five weeks from August to September 2019.

According to the study, the optimal time for fogging should ideally be around dawn or dusk for the most effective mosquito control.

However, for the purpose of the experiment, a time was chosen when there was a minimum number of hikers and a high number of active insects.

The team of researchers also identified 10 trees within KDCF for its experiment, and each three was fogged for 10 minutes at a time, the minimum standard duration set by the Health Ministry.

"KDCF itself is not normally fogged directly, but the study sites chosen were likely to experience spillover effects from nearby fogging and are thus ideal to investigate the indirect effects of fogging," stated the study.

According to the study's senior author Yek Sze Hui, their findings not only suggest that fogging has minimum effectiveness against mosquitoes, but also a wider impact on the forest's ecosystem.

“Continuous fogging may not just mean a lot of money wasted but could result in a sharp reduction in insect diversity that can cause a ripple effect across the food chain in our urban parks.

"This is because insectivorous animals living there, such as birds, lizards, and frogs, will be left with a reduced food source,” said Yek, a senior lecturer at Monash University Malaysia School of Science.

Among the insects found dead in the activity include pollinators such as butterflies, indirectly impacting the pollination of new plants in the area.

As a conclusion to its study, the authors suggested that alternative methods of mosquito control should be explored in order to reduce health risks in tropical cities while preserving urban biodiversity.

Despite various awareness campaigns and enforcement against Aedes breeding grounds, deaths from dengue remain high with 127 fatalities recorded this year as of Oct 3, according to the Health Ministry.

Last year, Malaysia reportedly recorded the highest number of dengue cases in four years at over 130,000, rising 61 percent from 2018. - Mkini