Category: beneficial insects

Sustainable Ways to Combat Mosquitoes in Your Landscape

On By durhammastergardenersIn beneficial insects, durham, NC, mosquito control, pest control in landscape, sustainable gardening, Uncategorized

By Melinda Heigel, NC State Extension Master GardenerSM volunteer of Durham County

Close-up of a yellow eastern tiger swallowtail butterfly with black stripes resting on white flowers in a garden.
Close-up of a mosquito with distinctive black and white stripes on its body, perched on a surface, with a blurred green background.

(Left to right) Planting for pollinators, like this Eastern tiger swallowtail butterfly (Papilio glaucus), is one of the biggest developments in sustainability today. When out fostering pollinator habitat, gardeners might also want to think about ways to reduce or influence mosquito habitats. Mosquitoes, like this Asian tiger mosquito (Ades albopictus), can make time in the landscape less than enjoyable. (Image credit: Melinda Heigel; NC State Extension)

I recently installed a new garden to support beneficial insects in my small urban landscape. While out babying my new plants, I happily discovered they are already attracting a host of pollinators like butterflies, moths, and all kinds of bees. Sadly, I found that I, the red-blooded gardener, was attracting a ton of mosquitoes when tending my new charges. Turns out that mosquitoes are most active early in the morning and later in the evening. They keep gardeners’ hours in your landscape and are out when you most likely are too. And with all the much-needed rain we are getting this week, female mosquitoes have some lovely new water sources where they can lay their eggs.1 Mosquitoes are not only annoying, but of course they can also transmit diseases to humans like West Nile virus and are the carriers for the parasite that causes heartworm disease in dogs.

There are several steps you can take to make your landscape more fun to garden in and less attractive to mosquitoes. Of course, I can use an insect repellant and wear long sleeves and pants, but I wanted to see what else I could do on a foundational level to impact the number of mosquitoes I am encountering in my outdoor space.

Before I outline some simple, sustainable steps we can all take to control pesky mosquitoes, I want to address one potentially controversial option: residential aerosol fogging. You’ve probably seen signs advertising services to spray your yard with the promise of, “No more bites.” Homeowners can also purchase do-it-yourself products as well. This control practice is called adulticiding as these sprays typically target adult mosquitos that are actively flying at the time of treatment or who will rest on a treated surface while the chemical is still active.

While they can be effective, they have some real drawbacks to consider. They don’t address larvae that will hatch later and continue the insects’ lifecycles.3 Environmental factors like rain can impact the efficacy of these treatments and make them terribly short-lived. It can be expensive. And there is always the possibility of drift when either you or a professional are spraying. This means that wind may carry the product where you don’t want it: into a neighbor’s landscape or into your own bed with flowering plants and pollinators.

Personally, my biggest concern about this method is indeed the health of pollinators (and fish if you have a water source or pond nearby). The most common active ingredient in these products is pyrethroids. These chemicals are toxic not only to adult mosquitoes but also to beneficial insects we want around like beetles, ladybugs, green lacewings, and bees. In my landscape, I am trying to support pollinators, not endanger them. To be sure, employing this chemical control method is an individual choice, but what else can a gardener do that is both effective and wildlife friendly?

Understand the Mosquito Lifecycle

A graphic showing the life cycle of a mosquito: Eggs, larva, pupa, and adult.
A cluster of mosquito eggs in water that resemble black grains of rice under magnification on a bright blue background.

(Left to right) The first three stages in the lifecycle of a mosquito are dependent on water. Mosquito eggs in water. (Imager credit: Centers for Disease Control and Prevention; Lauren Bishop, CDC public domain)

First, know your enemy (Joking, not joking). Mosquitoes have four distinct stages in their lifecycle–egg, larva, pupa, and adult. The most important thing to know about these stages is that the first three occur in water. Only the adults fly for a short time. Females of many species dine on the blood of humans and other animals (Note that males don’t; they feed solely on plant nectar). Once females complete a blood meal, they lay eggs in or near water, soil or near the base of some plants that might collect water. Some eggs can persist in dry conditions for a limited period of time, but water is always a necessary ingredient.

Reduce Mosquito Habitat

A green watering can partially filled with water, placed on wooden decking, with a red watering can visible in the background.
Close-up of an orange terracotta plant pot sitting in a matching saucer filled with water, on a wooden surface.
Brown tarp with water pooling on it, surrounded by stones and a concrete block, on a concrete surface.

After some rain this week, I scouted out places in my outdoor areas where standing water was available to serve as breeding sites: a small amount of rain caught in watering cans, plant saucers, and a pile of reserve mulch material I have covered with a tarp in my driveway. Time to “tip and toss!” (Image credit: Melinda Heigel)

Since water is essential for the completion of the mosquito lifecycle, take a good look around your site. Dr. Michael Waldvogel, NC State Extension Specialist, suggests that “(m)odifying or eliminating breeding sites is the long-term solution to mosquito problems.” He suggests the tip and toss method where you frequently empty containers around your landscape and dwelling that can hold water such as dishes under flower pots designed to catch runoff water, buckets, and empty garden pots (doesn’t every garden have these laying around?). Some types of mosquitoes only need 1 tablespoon of water in which to develop.2

If you have a birdbath or other water source for wildlife in your landscape, flushing those out and refiling with fresh water at least twice a week will help eliminate mosquito eggs, larvae known as wrigglers, and pupa.

If you are into eco-friendly irrigation and have barrels or containers to catch rain water, keep them covered with screening to help with mosquitos and debris. Waldvogel suggests also keeping the screens washed off and clean.

Other culprits you might not suspect include clogged gutters, areas in your landscape that have poor drainage where water might stand, pet bowls, wheel barrows, trash cans, woodpiles, cups and bottles out for recycling, and things like catch basins in your drainage system.

Assemble A Mosquito Dunk Bucket

A black bucket with a round opening on top, placed in a garden surrounded by lush green foliage.
A hand holding a circular, gray, textured object resembling a stone disc with a hole in the center.

A simple and effective way to control the non-adult population of mosquitoes in your landscape is with a mosquito dunk bucket, which ends the lifecycle at the larval stage. (Right to left) Here is one in my side yard adjacent to my newly-installed pollinator garden, and this dry donut-shaped object is a biological control (with a bacterium named Bti) for mosquitoes sometimes called a “dunk.” These larvicides also come in other forms, including liquid, pellets, and granules. (Image credit: Melinda Heigel)

While chemical fogs focusing on adult mosquitoes are non-specific, meaning they will harm or eliminate many insects indescriminately, there is a safer more effective method that will only target mosquitos in their larval stage. Enter the mosquito dunk. Looking like a small hard tablet, the mosquito dunk contains a naturally occurring bacterium Bti (Bacillus thuringiensis, subspecies israelensis). When placed in water with mosquito larvae, the larvae ingest the Bti spores and die often within 24 hours. The good news is that Bti target larval mosquito digestive systems and are safe for humans, pets, fish, and beneficial insects.

So how does a dunk bucket work? The dunk bucket approach to mosquito control is sort of like setting a honey pot for female mosquitoes. You are essentially creating a controlled habitat for females to lay eggs that will never mature into adults. Don’t worry — you aren’t likely attracting more mosquitoes to your environment. Remember they are there anyway, and this helps concentrate where breeding is happening.

You don’t need many materials to set up this “Bucket of Doom,” as some folks call it. Just the following:

  • Bucket
  • Something to cover the bucket like screening or a mesh insert
  • Natural material like straw, hay, grass clippings or dried leaves
  • Water
  • Mosquito Dunk® or other brand containing Bti
A black bucket and a black mesh basket on a wooden staircase.
A straw bale sits on mulch in a garden area, accompanied by a black bucket and black mesh bucket lid, with a residential building in the background.

(Left) Materials I used for constructing my dunk bucket included a well-fitting bucket lid that had a plastic mesh top. I found this online at a hydroponic growing site, but you don’t have to get fancy. Something as simple as chicken wire or a bucket lid with holes drilled in it will work as long as the females can enter it to lay eggs. I have even seen this step listed as optional, but I wanted to discourage my dog or any other small critters from getting too curious. (Right) I used packaged straw from a hardware store, but again, yard waste like dried leaves or grass clippings will do the trick.

Setting the Dunk Bucket “Trap”

Here are the easy steps to getting your bucket up and running. It will be set to go within a few days.

A person wearing a black glove holds straw above a black bucket filled with straw, with wood chips visible in the background.
A person sprays water onto straw inside a black container, surrounded by wood chips.

(Left to right) Adding the straw and water, leaving it in the sun, and waiting a few days before I added the dunk for maximum fustiness. Seriously, though, this doesn’t smell foul. And in the landscape in an out-of-the way site, I never caught whiff of any unpleasant odors. (Image credit: Melinda Heigel)

  • Add several big fistfuls of your natural material (hay, straw, dried leaves, etc.) to your empty bucket.
  • Fill the bucket about halfway with water.
  • Let your bucket sit and get “funky” for a few days. This quasi-fermentation process emits gasses that attract mosquitos. Putting your work-in-progress in a sunny location helps speed up this process.
  • After a few days, sit the dunk inside the bucket.
  • Place your bucket in the landscape. Mosquitos like a shaded area that is low-traffic, so think about where you can place yours. Another tip is to locate it in areas that are mosquito-prone. I have some larger shrubs close to my house near my pollinator garden where I put my bucket.
Mosquito Dunk Bucket Maintenance and Considerations

You should check your bucket weekly and replace water levels as needed. Remember if you get a lot of rain (wishful thinking during drought), you will also want to make sure your bucket is not overflowing and adjust the water level as needed. The dunk itself will last about a month, so put a reminder on your calendar so you remember to put out a new one. You do not have to dump the contents at any given period, just keep the water level and Bti tablets consistent. At the end of the warm mosquito season, it is safe to just empty the bucket on the lawn.

While a properly-maintained bucket the is indeed controlling mosquitos, remember that a poorly-maintained one actually just becomes a breeding site once dunks are no longer active.

Depending on our outdoor space, you may want to consider adding more than one bucket. Mosquitoes, like most things organic in this world, don’t observe borders or property lines. Dunk buckets are effective, but they don’t eliminate all mosquito pressure. Consider asking your neighbors to join you in this endeavor to try and broaden the scope of this control beyond your immediate landscape.

While tip and toss and dunk buckets aren’t the only methods to control mosquitos and help ensure both gardener and pollinator health, they are easy, inexpensive, and effective especially when used in tandem. I encourage you to give them a try.

Notes

1–According to the US Environmental Protection Agency, the average span of mosquito lifecycle is 2 weeks. Environmental conditions can shorter that to 4 days or lengthen that to up to a month.

2–https://hgic.clemson.edu/hot-topic/importance-of-reducing-mosquito-breeding-sites/

Resources and Additional Information

Why we should care about pollinators

Pollinator conservation links

NCSU on mosquito control around homes and communities

Podcast link University of Georgia entomologist and public health extension agent on mosquitos and ticks

Article Short Link https://wp.me/p2nIr1-4BF

What are Neonicotinoids and Why Should We Care?

On By durhammastergardenersIn beneficial insects, insects, neonicotinoids, Uncategorized

By Jeanne Arnts, NC State Extension Master GardenerSM volunteer of Durham County

There are 3 billion fewer breeding birds in North America than in 1970, which is one-third of the total bird population that existed 55 years ago.1 Most of us enjoy songbirds, but their value is much more important than bringing joy into our lives; they are an indicator of the health of our environment and their drastically declining numbers raise an urgent alarm about the precarious health of our planet.2 Just as canaries warned coal miners that conditions in mines were life threatening, the decimation of bird populations is warning us that our life on earth is at risk. Coal miners quickly left the mine when the canaries began keeling over but, unlike the coal miners who could exit the mine when conditions threatened their survival, we have nowhere else to go. Therefore, we need to take action.

A chickadee perched on a branch, holding a caterpillar in its beak.

Photo of chickadee with caterpillar. It requires 6,000-9,000 caterpillars to raise one brood of
chickadees to fledglings– (Image credit: New Hope Bird Alliance, Will Stuart)

And it is not just birds that are declining. In 2019, Biological Conservation reported that 40% of all insect species are declining globally and that a third of them are endangered.3 More recently, researchers established that insect populations worldwide have declined by 50%. Because 90% of terrestrial birds rely upon soft-bodied insects, mostly butterfly and moth caterpillars, to feed their nestlings (baby birds cannot digest seeds). This drastic decline in insects significantly affects bird populations as well as those of reptiles, amphibians, fish, and other wildlife that depend upon insects to survive. These startling statistics ring true to those of us who are old enough to remember “the windshield effect”. In the 1950’s and 60’s, insects would swarm around car headlights in the evening. At every stop at the gas station, the attendant would clean the windshield of the multitude of dead insects. In the 2020’s, the only time I clean my windshield is at the car wash.

Close-up of a yellow flower with a beetle resting on its petals, surrounded by green leaves.

Photo of Goldenrod Soldier Beetle-a beneficial insect. (Image credit: Jeanne Arnts)

Most researchers attribute bird and insect decline primarily to habitat destruction, climate change, and insecticide use. I am going to address just one of those issues: Insecticide use, specifically a class of fifteen systemic insecticides known as neonicotinoids (“neonics”). Introduced in the early 1990s, they are now the most widely used insecticide in the world; in the US, they are used on 150 million acres of agricultural land, including 90% of corn crops, 50% of soybean crops, and extensively” on cereal and oil crops, as well as on fruit and vegetable plants. S.D. Frank, an entomology professor at NCSU, noted that “transmission through simple food chains portends widespread, undocumented transmission into entire food webs” with disastrous consequences for the health of our planet. 4

When neonics were introduced, they were considered a panacea, as plants no longer had to be sprayed or dusted—the insecticide was embedded in the seed. Today, neonics are also applied as a spray to the leaves; as a soil drench around the base of the plant; or, by a trunk injection on trees. They can be applied along with other seed treatments and offer the advantage of being less expensive than using multiple treatments for pest control.

Effects of Neonicotinoids on Pollinators, Birds, and Other Wildlife

Most research has focused on the effect of neonics on pollinators and other insects, but neonics also affect bird populations. Birds eat the seeds of plants and they eat the insects that have sought
nourishment from the leaves. This is especially true in regard to caterpillars, which are the primary food source for terrestrial nestlings. In a review of 200 studies, including 2,800 pages of industry research obtained under the Freedom of Information Act (FOIA), the American Bird Conservatory concluded that a single seed treated with neonics is enough to kill a songbird. Smaller amounts can significantly reduce fat stores of birds as well as affect their migratory pathways and reproductive capacity.5

Close-up photo of a striped caterpillar on a green leaf.
Monarch caterpillar on common milkweed (Image credit: Jeanne Arnts)

As systemic insecticides, neonics affect every part of the plant: the buds, leaves, pollen and nectar, with devasting neurotoxic effects on the caterpillars that eat the leaves of the plants, the pollinators that seek nectar from the plants, and the bee larvae that are fed the pollen.

Although neonics fed to bees in laboratory settings can kill them outright, the levels permitted in agricultural plants limit neonics to a subtoxic level in the pollen and nectar of the plants. Sub-lethal exposures, however, threaten bees—our primary pollinators in multiple ways. It reduces reproductive capacity, impedes their ability to find their way back to the nest, reduces larval survival rate, and reduces olfactory response, which is required for finding nectar-rich plants.

While regulations limit the toxicity of neonics used on food crops, ornamental plants may have as much as 30 times the limit allowed for agricultural crops. A 2017 study reported that 70% of ornamental plants are treated with neonicotinoids.5 A 2022 study reported that neonics were found in each of the 33 milkweed plants that were purchased from commercial nurseries across the US.6 Sadly, gardeners who planted milkweed to support dwindling Monarch populations were inadvertently contributing to their demise.

A butterfly perched on an orange flower, showcasing its wings with intricate patterns, surrounded by greenery.
Photo of a dragonfly perched on a stem with iridescent wings and a slender body.
Close-up image of a speared dagger moth caterpillar on a green leaf.

Eastern tiger swallowtail on Carolina lily (Lilium michauxii); Sparkling Jeweled Wing Damsel fly; Speared Dagger moth caterpillar (Image credit: Jeffrery Pippen)

The European Union placed significant restrictions on specific neonicotinoid chemicals in 2013 and in 2023 the European Court upheld the ban and eliminated loopholes that allowed for their continued use. Despite EPA research documenting the toxic effects of neonicotinoids, they are still used widely in the US on both agricultural crops and ornamental plants. However, since 2020, New York, New Jersey, Vermont, Maine, and California have placed some limits on neonic use.

Beyond neonics impact on terrestrial life, aquatic ecosystems have also become contaminated. Neonicotinoids are water-soluble and can leach from treated soils into streams, rivers, and groundwater. Once in aquatic environments, neonics harm aquatic insects that fish, frogs, and other amphibians rely upon, leading to the decline of those populations and disrupting the entire aquatic food web8.

Do Neonicotinoids Have Harmful Effects on Humans?

One reason for neonics’ widespread use is that they have been determined to have low mammalian toxicity. Bayer, a neonic manufacturer, issues company reports in which they espouse the effectiveness of neonicotinoids use on agricultural crops and report low toxicity of neonicotinoids to mammals and humans.8 Because neonics have been considered safe for human consumption, they are pervasive in our food supply. A study conducted by the American Bird Conservatory and the Harvard School of Public Health in 2015 found neonics in more than 90% of food samples tested from the US Congressional dining halls. According to the study, most foods contained multiple different neonics, with fresh squeezed orange juice and green peppers having the highest number.9

Unsurprisingly, the signs and symptoms of acute nicotinoid poisoning are like those of nicotine poisoning: nausea and vomiting, increased blood pressure and heart rate, and loss of muscle control, among other symptoms. The EPA has received over 800 reports of acute poisoning since 2018, but those are primarily limited to farmers and landscapers who have exposure through application of chemicals. There is rising concern, however, about the subtoxic effect of neuro-toxic chemicals on human health through food, especially its effects on neurological development. 10

A study published in an international environmental journal reported associations between chronic neonic exposure and the development of adverse neurological and developmental outcomes in young children.11 Julie Daniels, PhD, an epidemiologist in the UNC Gillings School of Public Health, whose research has focused on neuro-developmental disorders in prenatal development, noted that it is not possible to implement the type of experiments on humans that have been done on insects to prove a causal effect. Dr. Daniels stated that given the pervasive use of neonics in agriculture and their persistence in the environment, there is cause for concern.12 Most researchers agree that more studies are needed to fully understand their effects on human health.13

What can you do?

It seems unlikely that the US government will impose restrictions on use of neonics in the near future. Following are some suggestions of what we can do as consumers and as stewards of our
own yards and gardens.

  • Buy organic fruits and vegetables when available and affordable.
  • Buy vegetable plants, fruit trees, and ornamental plants that are organic or, at a minimum, free of neonicotinoids and other systemic pesticides. The New Hope Bird Alliance lists nurseries and retail stores that offer organic ornamental plants. See the link below.
  • When shopping retail, ask if plants are treated with neonicotinoids. If they don’t know, don’t purchase the plant. If businesses receive multiple inquiries about neonics, especially if customers are walking out of the store, they may rethink buying from suppliers who do not grow plants free of systemic insecticides.
  • Purchase seeds from organic sources. Three sources in NC include Sow True Seeds, Ernst Seeds, and Garrett Wildflower Seed.
  • Avoid treating your garden with neonic products. The Center for Food Safety published a list at the link below of products produced with neonicotinoids.
  • Never use pet collars that contain neonics, which may pose a risk to both children and pets.
  • Contact your local legislators and urge the introduction of bills that limit neonicotinoid use.
A wooden crate filled with a variety of fresh vegetables including red peppers, cucumbers, carrots, beets, and tomatoes, set against a backdrop of green grass and soil. The image features the NC Cooperative Extension logo.

(Image credit: NCSU Cooperative Extension.)

Notes:

  1. K. Rosenberg, A. Dokter, et al.(2019) “Decline of the North American avifauna” Science Vol 366, Issue 6461, pp. 120-124.
  2. John Fitzpatrick, Cornell Ornithology Lab; Peter Marra, Georgetown Environmental Initiative (2019) “A Crisis for Birds is a Crisis for Us All”, New York Times commentary.
  3. Francisco Sanchez-Bayo, Kris A. G. Wyckhuys. (2019) “Worldwide decline of the entomofauna: A review of its drivers”. Biological Conservation, Volume 232, pp 8-27.
  4. S.D. Frank and J. F. Tooker. (2020) “Neonicotinoids pose undocumented threats to food webs” Proceedings of National Academy of Sciences, 117 (37) 22609-22613.
  5. Pierre Mineau, Senior Research Scientist at Environment Canada; Cynthia Palmer, senior editor, Environmental Health News (2013) “The Impact of the Nation’s Most Widely Used Insecticides on Birds” American Bird Conservancy pdf.
  6. A. Lentola, A. David, et al. (2017) “Ornamental plants on sale to the public are a significant source of pesticide residues with implications for the health of pollinating insects”, Environmental Pollution Volume 304 pp. 297-304.
  7. Christopher A. Halsch, L. Forister, Sarah M. Hoyle, et al. (2023) “Milkweed plants bought at nurseries may expose monarch caterpillars to harmful pesticide residues” Biological Conservation, Volume 273.
  8. Nanda, A. Ganguly, M. Mandi, et al. (2024) “Neonicotinoid Contamination in the Aquatic Ecosystems—What We Know?” Springer Nature in Sustainable Landscape Planning and Natural Resources Management pp. 29-42.
  9. bayer-neonicotinoids-report-2025-4-15-final.pdf.
  10. Chi-Hsuan Chang,† David MacIntosh,† Bernardo Lemos, et al. (2018) “Characterization of Daily Dietary Intake and the Health Risk of Neonicotinoid Insecticides for the U.S. Population” J. Agricultural Chemistry Volume 66 , pp.10097-10105.
  11. A. Cimino, A. Boyles, K. Thayer, M. Perry (2016) “Effects of Neonicotinoid Pesticide Exposure
    on Human Health: A Systematic Review” Environmental Health Perspectives Volume 125 pp.155-162.
  12. Duo Zhang,  Shaoyou Lu (2022) “Human Exposure to Neonicotinoids and the Associated Health Risks: A Review” Environment International Volume 163 107131.
  13. Personal Communication, Julie Daniels, PhD. September, 2025.
  14. Darrin A. Thompson, Hans-Joachim Lehmler, et al. (2020) “A critical review on the potential impacts of neonicotinoid insecticide use: current knowledge of environmental fate, toxicity, and implications for human health” Environmental Science Process Impacts, Volume 22 Issue 6, pp 1315–1346.

Additional Reading and Resources

The Center for Food Safety provides a list of insecticides that contain neonics which affect bees and other pollinators. https://www.beyondpesticides.org/assets/media/documents/pollinators/documents/pesticide_list_final.pdf

The New Hope Bird Alliance lists sources for purchasing organic plants. https://newhopebirdalliance.org/bird-friendly-certification/native-plants/

Read about how the use of neonics caused the devastation of a lush, pollinator paradise in North Carolina: Restoring Eden: Unearthing the Agribusiness Secret That Poisoned My Farming Community, Elizabeth Hilborn, Chicago Review Press, 2023.

Short Link: https://wp.me/p2nIr1-6C0

Edited by Martha Keehner Engelke