Mosquito Control Methods
When mosquitoes arrived in Hawaiʻi, native birds rapidly disappeared from the warm lowlands, succumbing quickly to avian malaria and pox. To help native birds survive, conservation organizations focused on habitat preservation and restoration in high-elevation forest preserves, which were too cold for mosquitoes. But as temperatures have warmed, mosquitoes have begun moving upslope, requiring mosquito control methods such as reducing breeding areas and spot-applying larvicides.
Unfortunately, these measures alone cannot address the mosquito issue at a landscape scale across thousands of acres. An integrated management approach is necessary, including forest management tools such as fencing, invasive species removal, and native plant restoration, as well as more effective mosquito suppression tools.
Through extensive research into different methods utilized for human health, BNM has recognized the Incompatible Insect Technique as the most effective conservation tool to suppress mosquito populations and safeguard the Hawaiian honeycreepers from extinction. The Incompatible Insect Technique will augment and bolster the effectiveness of integrated management, expanding upon other mosquito control methods and giving these endangered birds a renewed opportunity to thrive and flourish in the years to come.
I Ola Nā Manu Nahele.
Mosquito Control Tools
Available Options
1
Biological Insecticides Targeting Mosquito Larvae
Currently being used
Biological insecticides, such as BT or "dunk" are commercially available for small or point-source control of mosquito larvae. However, effective landscape-scale application is difficult due to highly variable environmental conditions and dense forest habitats.
Learn more about current efforts to increase the effectiveness of these tools by reviewing these resources [link].
2
Mosquito Habitat Reduction
Currently being used
Mosquito habitat reduction refers to the process of eliminating or modifying areas that serve as breeding grounds for mosquitoes. This approach involves identifying and targeting places where mosquitoes lay their eggs, such as stagnant water sources, and taking measures to eliminate or alter these breeding sites. Conservation groups have worked to erect fences to reduce the presence of pig wallows and have backfilled existing wallows and ruts in roadways to reduce mosquito habitat.
Landscape-scale mosquito habitat reduction is impractical in Hawaiʻi’s multi-layered forests, which contain micro-pools for breeding mosquitoes.
Incompatible Insect Technique
Currently being used on East Maui and Kauaʻi
The Incompatible Insect Technique is a biological control method used in mosquito management and disease prevention. It involves releasing incompatible male mosquitoes into the target area, which mate with wild females. Due to the incompatibility between males and females, the eggs are not viable, reducing the mosquito population over time. The technique helps suppress disease transmission by reducing mosquito numbers and has shown promise in safeguarding humans, birds, and other wildlife from mosquito-borne diseases.
3
4
Lethal Traps
Not used
Deploying lethal “ovitraps” containing an insecticide is impractical across a vast, inaccessible landscape. If left in place for more than a few weeks, these traps can become breeding grounds and cause an increase in mosquito populations.
5
Spraying Chemical Insecticides
In Hawaii's forests, conservation organizations sometimes carefully spot-apply herbicides to control invasive weeds. However, the broadscale application of chemicals to control mosquitoes, such as DDT, is complex due to dense forest cover and dangerous as it could harm plants and animals.
Not used
6
Genetic Modification
While this project does not use genetic modification, researchers worldwide, including scientists at the University of Hawai‘i, are studying the potential of genetic techniques to protect human health and native species from the impacts of mosquitoes.
Like with Wolbachia IIT, genetic control strategies must carefully consider ways to ensure project safety and must be registered with federal and state agencies before use. Any future projects in Hawai‘i that utilize genetic technology would require public engagement, input, and regulatory approval.