Photo: Ebony Jewelwing, Judy Gallagher
Liz Train
At the March 8, 2025 NVBA Wildlife Sanctuary Ambassador Brunch, I delivered a presentation titled “Beyond the Spray: Protecting Wildlife and Biodiversity with Safer Mosquito Control Solutions.” The session highlighted how conventional mosquito spraying is jeopardizing efforts to create thriving wildlife habitats and offered effective alternatives that protect both people and pollinators.
To qualify as a wildlife sanctuary, a residential yard must support native species throughout their lifecycles. However, one of the most critical barriers to sanctuary certification is the use of broad-spectrum mosquito sprays. These pesticides don’t just target mosquitoes—they kill every insect they contact, including essential pollinators like bees, butterflies, and beneficial predatory insects.
Ebony Jewelwing, Judy Gallagher
Scientific studies underscore this alarming impact. Research has shown that malathion, a common organic mosquito fogging pesticide, reduces nesting activity in cavity-nesting bees by 60%, while pyrethroids can reduce larval survival rates in mason bees by 40%. Additional findings reveal that pesticide exposure results in abnormal larval development, delayed emergence, and up to a 70% reduction in butterfly populations. These declines aren’t just environmental tragedies—they threaten entire ecosystems, agricultural productivity, and the future of biodiversity.
Pollinators are vital for sustaining life: 90% of flowering plants depend on them for seed production. With many species already declining due to habitat loss and pollution, widespread spraying adds another serious stressor. Even when used according to label instructions, mosquito sprays kill beneficial insects and reduce food for birds by contaminating foliage, nesting sites, and water bodies, spreading toxins throughout the food web. Native bees—often smaller and more sensitive than honeybees—are especially vulnerable, receiving disproportionately high doses of toxins that their physiology can't withstand.
The presentation emphasized that mosquito fogging is not only ecologically harmful but also ineffective. These sprays kill adult mosquitoes only after they are already biting and fail to address breeding. In contrast, Integrated Pest Management (IPM) offers a science-based, non-toxic approach that effectively reduces mosquito populations without harming other species, by targeting them at their source.
IPM strategies include eliminating standing water (source reduction), using safe larvicides like Bacillus thuringiensis (Bt), (biological control), deploying ovitraps, using outdoor fans to deter mosquitoes, and encouraging community education. These methods target mosquitoes at key points in their lifecycle and avoid the significant environmental damage caused by chemical fogging.
Spring is arriving, and now is the time to take steps to control mosquito populations that will begin emerging in the next few months. The NVBA urges homeowners to “Say No to the Spray” and consider the long-term health of their yards, ecosystems, and communities. The organization’s Wildlife Sanctuary Program promotes healthy, pesticide-free habitats that nurture biodiversity from the soil up.
For those interested in learning more or seeking sanctuary certification, visit our website. You can also find more information on mosquito pesticides and read our policy on spraying.
The choice is clear: protecting pollinators is protecting our future. By moving “Beyond the Spray,” we can build safer sanctuaries, increase biodiversity, and protect our local watershed—one yard at a time.
Catch up on past Wildlife Sanctuary Almanac articles here.