Photo: Robb Hannawacker, FlickR

In a guest commentary on Mongabay.com, Cathy Watson, Chief of Programme Development with the World Agroforestry Centre, says there are better ways to control the Zika outbreak and the mosquitoes who carry it than the use of pesticides.

Watson interviewed Kenyan entomologist, Dr. Dino Martins, who advocates for healthy landscapes, which are rich in biodiversity and clean of plastic, rather than widespread spraying of pesticides.

Healthy landscapes harbor beneficial species, such as bats, birds and geckos, which feed on adult mosquitoes. Birds, fish, dragonfly nymphs and diving beetles will devour the larvae.

Martins says pesticides along are not the solution. While useful for indoor residential spraying, they only remove flying adult mosquitoes. Spraying in landscapes is extremely dangerous because it kills other beneficial species and can lead to resistance among mosquitoes. Also, “it is impossible to fumigate every corner of a habitat where mosquitoes might possibly breed”.

Martins runs the Mpala Research Centre, a field station affiliated with Princeton, the Smithsonian Institute, the Museums of Kenya and the Kenya Wildlife Service.

“We’ve not invested in the broad research that will address this problem sustainably or in plastic recycling,” he says. Mosquitoes breed in standing water and plastic bags can create favorable conditions; they slow the drying up of water, provide places for mosquitoes to hide from predators and increase temperatures which can speed up breeding.

“We are basically fighting an arms race with mosquitoes rather than cleverly understanding their life cycle and solving the problem there.” He believes the best way to eradicate them is to focus on the larval stage where they are “fixed and findable”.

Land degradation is another factor leading to increased mosquito populations due to its impact on biodiversity. Tor Vagen, a geoscientist with the World Agroforestry Centre, explains that erosion in upper catchments can lead to the silting up of wetlands.

“Instead of shallow but clear water where fish and insects swim eating mosquito larvae, you get stagnant water. With degradation of wetlands, you knock out a lot of predators and the mosquito population explodes,” explains Vagen.

Read the full story: Focus on breeding sites and biodiversity to control Zika, says leading epidemiologist