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Managing Mosquitoes While Protecting Pollinators Part I

Managing Mosquitoes While Protecting Pollinators Part I

They’ve been around for roughly 200 million years and are most active at 80°­­F and unable to function below 50F. They can sense the lactic acid and carbon dioxide from an animal’s breath up to 100 feet away. They can throw even a most stoic person into an arm-flailing, yelping frenzy. The females beat their wings up to 500 times per second producing a piercing high-pitched whine that unmistakably and annoyingly announces her presence.


Considered by most to be an aggravating nuisance and by many a disease-carrying adversary, mosquitoes in their adult and larval stages serve an important purpose in ecology – a food source to frogs, small fish, aquatic beetles, dragonflies, damselflies, bats, birds, turtles, and even other – predacious – mosquitoes. Thus despite the fantasies of many, wiping out mosquito populations could render the food chain irreparably broken. In addition to the females using blood as a protein source for egg development, both male and female mosquitoes feed on plant nectar as adults and are also, surprisingly, pollinators. And while plants would survive in the absence of mosquitoes if there were, let’s say, a mosquitogeddon, one plant could disappear. The rare Arctic bog orchid has a dependency on mosquitoes for pollination.

Of the more than 2500 species of mosquitoes worldwide, about 50 are found in my state of residence, Oregon. Very few species prey on humans with less than 1% of all mosquitoes carrying West Nile Virus according to Oregon Department of Fish and Wildlife.

National Geographic claims only three species bear primary responsibility for the spread of human diseases: 1) Anopheles mosquitoes are the only species known to carry malaria, 2) Culex mosquitoes carry encephalitis, filariasis, and the West Nile virus, and 3) Aedes mosquitoes, of which the voracious Asian tiger is a member, carry yellow fever, dengue, and encephalitis. Humans are not the first choice for female mosquitos looking for a protein snack. Wild birds are the primary hosts.

Zika does not currently exist in the northwestern U.S., and in Oregon from 2012-2016 there have been only 36 cases of West Nile Virus reported in humans. There were no human infections 2010 and 2011, and one human death – a person with a compromised immune system – was reported in 2006 according to the Oregonian. The virus, found in mosquitoes, usually first appears in the Northwest in July but warmer temps could cause the insects to hatch sooner.

According to the Audubon Society of Portland, the arrival of West Nile Virus in the United States has generated sensational headlines and a great deal of fear. However, it is a response that is driven more by its sudden arrival and quick spread than by the threat that it poses to human health. In fact another mosquito borne virus quite similar to West Nile Virus, Saint Lewis Encephalitis, has been among us for more than five decades, but hardly generates any coverage or interest at all.

Approximately 80% of people who are infected with West Nile will show no symptoms at all. Up to 20% of people infected will display symptoms that can include fever, headache, body aches, nausea, vomiting, and sometimes swollen lymph glands, and skin rash. Less than 1% will develop serious illness. This may include high fever, headache, neck stiffness, disorientation, muscle weakness or paralysis. These symptoms may last several weeks; neurological effects may be permanent. More here.

A fascinating article on Live Science, The Odds of Dying, shares some curious stats. In 2014, six people in the entire United States died after being bitten or stung by a nonvenomous insect. To put that into perspective, eighty-three people died after being struck by a mammal (not including dogs), such as a cow or a horse. Twenty-five people died from lightning strikes whereas 591,000 died of cancer. Considering pesticides are emerging as one of the causes of cancer, our fears may be misdirected. Isn’t it time to reevaluate the common more toxic solutions to mosquito problems and instead consider other methods? If I can answer my own questions, yes!

The above graphic shows which counties in Oregon have Vector Control agencies and the incidence of WNV in humans from 2012-2016. Anyone can look at mosquito data on the CDC site.

The data show that having or not having a spraying program doesn’t appear to impact case rates. So what are the other valid reasons for spraying toxic substances on our wildlife?

According to a paper by Scott Hoffman Black, Executive Director, and Aimee Code, Pesticide Program Director of the Xerces Society for Invertebrate Conservation, “In many parts of the world, including the United States, spraying pesticides is the knee-jerk reaction to mosquitoes. Some people think that pesticides are a silver bullet, and that we can control mosquito-borne diseases by simply spraying where adult mosquitoes are found.

Such simple approaches rarely work. Data from the last 150 years illustrates that relying on broad-scale insecticide spraying is not effective at managing mosquitoes. Insecticides can also have profound impacts on the natural world, harming insects that are food for birds and fish as well as the bees that pollinate our food.”

Black claims that spraying for mosquitoes contributed to a decline of Florida’s endangered Schaus swallowtail and Miami blue butterflies. Scientists have also found that monarch butterfly caterpillars have a significantly lower survival rate when milkweed (the monarch’s host plant) is sprayed for mosquitoes even on leaves collected three weeks post-spraying.

The average mosquito’s lifespan is less than two months. The males living only about 10 days. Check out more skeeter facts.

According to entomologist Dino Martins, PhD, this short life cycle predisposes a mosquito’s subsequent generations to mutate with each application of pesticides. Already, some mosquitoes are showing a resistance to pesticides growing increasingly less effective. There are over 125 mosquito species with documented resistance to one or more insecticides as reported by the CDC.

Most importantly, adulticides (pesticides used to kill adult mosquitoes) have not shown to reduce West Nile Incidence, yet pesticide applications are killing off predatory species that would otherwise keep mosquito populations under control.

Mosquito management insecticides are also linked to human health risks, including leukemia, non-Hodgkins lymphoma, brain, bone, breast, ovarian, prostate, testicular and liver cancers.

The nonprofit, Beyond Pesticides, provides well-researched information on both mosquito-borne and pesticide-borne illnesses on their website. They discuss the limited efficacy of spray programs and the public health hazards associated with widespread pesticide exposure.

Making informed decisions about the impacts of mosquito-borne illnesses versus the synthetic pesticides used to control them is vitally important to your health and that of the wildlife in your community.

Xerces Society states that “to stem the tide of harm caused by mosquito-borne diseases, it is vital that we act strategically — and take an approach informed by science, not fear. A century and a half of experience clearly demonstrates that indiscriminate use of insecticides throughout our communities is not the answer.”

Jackson County Oregon’s taxpayer-funded Vector Control, in addition to finding and controlling mosquito larvae (most effective control), sprays throughout the county from May to September, between the hours of 3:00-6:00 AM with an insecticide, DeltaGard, that is “extremely toxic to fresh water and estuarine fish and invertebrates” and “highly toxic to bees” according to its label. While the honey bees may seem to be safely ensconced in hives between the hours of 3-6, our wild male bees are outside sleeping in flowers along the very neighborhood streets and roadways that are sprayed.

Center for Biological Diversity released a report in March 2017 with key findings: 347 of the 1437 native bee species are imperiled and at risk of extinction blaming habitat loss, heavy pesticide use, climate change, and urbanization.

In 2015, a Palo Alto, California beekeeper lost hundreds of honey bees after a mosquito fogging which also rendered his organic honey tainted. Last year in Dorchester County, South Carolina, millions of bees were killed by aerial spraying of Naled to combat Zika even though no one in the county contracted the disease from a mosquito bite. A handful of people contracted Zika through travel. These are two of countless incidences highlighting the fatal consequences of mosquito spraying or fogging.

Jackson County residents can protect pollinators by signing up for the no-spray list so no adult mosquito control applications will be made within three hundred feet of their property unless mosquito borne disease is documented in the area. JC residents can also sign up for email spray notification to track spraying throughout the summer.

Does your county have a vector control? How do they handle mosquitoes?

By following some of the tips here and coming up in the next post, you can create backyard habitat that repels mosquitoes without causing harm. Together we can reduce potential problems while protecting the health of our pollinators, wildlife, pets, and families.

Tip #1: Eliminate all potential breeding areas – any place that water collects in your yard

Mosquitoes can breed in puddles the size of dimes, so restricting breeding habitat is key to providing long-term control over mosquito populations. You can do this by removing standing water, which would eliminate the eggs and/or larvae.

  • Check your yard after each rain.
  • Remove standing water from old tires, buckets, flower pots, drains, and anywhere that it pools like on tarps covering woodpiles.
  • Unclog gutters.
  • Fix leaky hoses and faucets.
  • Refresh birdbaths or dog bowls weekly (sooner if you see larvae present) to prevent those little buggers turning into adults. For example, larvae of the mosquitoes that can transmit Zika (primarily Aedes aegypti, not found in Southern Oregon) take a week to develop into adults. To keep mosquito larvae from maturing, change the water in your bird bath every few days. In the summer, bird bath water should be refreshed frequently anyway. If you have sources of water, check for signs of mosquito larvae often.

Learn more fascinating mosquito facts at Beyond Pesticides – the Truth About Mosquitoes, Pesticides, and West Nile Virus.

The next post will focus on tips for DIY repellent, simple preventative solutions, natural predators, the importance of reporting dead birds, and the surprising bonus of coffee.

What tips do you have for managing mosquitoes while protecting pollinators?

If you like food, the wonder of wildlife, and beauty of flowers, please protect our precious pollinators.



  1. Pingback: Earth Day 2024: The Answer is Pesticides

  2. Amrita Cottrell

    Thank you for this article. I put our property on a “No Spray” list for Jackson County, Oregon. We have a 400 square foot dedicated pollinator garden that we want to protect.

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