Pesticides & Alternatives

Provided by University of New England Research

Worked on by Autumn Lyndon

What are Pesticides?

A pesticide is any substance that is used to repel, manage or kill any unwanted pests (What is a Pesticide 2025). It is an umbrella term that includes all of the specific types of pesticides like fungicides, insecticides, rodenticides, herbicides, etc (Pathak et al., 2022). Each specific type of pesticide targets a different kind of pest. Herbicides target unwanted plants or weeds. They are commonly used in gardens, farms, and golf courses on both a large scale like in agricultural farms or on a smaller scale like in backyards or public parks (Herbicides 2025). Pesticides like fungicides are used to prevent and manage fungal growths and diseases in gardens, farms, and even inside homes. There many different types and methods of using fungicides and they work by killing the fungi and preventing the spread of spores (Fungicides 2022). Not all pesticides are created equal, some are harsh chemicals designed to kill anything it touches (typically much more than intended) and others are more natural and are designed to deter and prevent pests in a more eco-friendly way.

History of Pesticides

Ancient Pesticides

There are many pesticides used throughout ancient history, some of which are still used today! Many early pesticides were mineral based, using more natural materials than the synthetic chemical ones most common today. The first recorded use of pesticides was a powdered sulfur used to control insects by ancient Sumerians over 4,500 years ago. Some early Chinese insecticides from around 1100 B.C. even used substances like mercury and arsenic. A fungicide from France called the Bordeaux mix became quite popular in the 19th century. The Bordeaux mixture is a blend of copper sulfate and calcium oxide and it was originally used as a visual deterrent for bugs as it changed the color of the fruit it was applied to. The mixture wasn’t very successful in deterring bugs but was found to be extremely effective at preventing mold and fungi growth on the trees. Even today the Bordeaux mixture is used in many organic farms (Grocholl).

DDT and Rachel Carson

More modern science and chemistry eventually led to the creation of more synthetic chemical based pesticides. This creation was brought on by the need for more effective pesticides that could be mass produced. After increases in famine and disease in the 1940s, a swiss chemist named Paul Muller created the famous insecticide, dichlorodiphenyltrichloroethane, also known as DDT. It became extremely popular, as it was cheap to make, easy to use, and worked extremely well. DDT’s effectiveness comes from its ability to linger in the atmosphere and the soil around where it was applied, making its effect last longer than other pesticides at the time. Initially, DDT was used quite successfully to combat many different insect borne diseases like typhus and malaria as well as a common pest control in gardens, farms, homes, and much more. Its success brought it overseas to the US during WWII where it was used for crop protection and pest control. Its use became extremely common, the pesticides eventually being sprayed in the streets, with no concern for its lasting effect on the planet and to our bodies (Grocholl).

Throughout the 50s and 60s evidence was found that DDT had harmful effects to both humans and the environment. It was found that DDT could cause many harmful symptoms including but not limited to tremors, seizures, infertility, cancer, birth defects, and diabetes. Not only that but DDT was found to have detrimental effects to the environment; what makes it such a good pesticide is also one of its major faults. DDT (and many other pesticides) is known for its lingering abilities, being able to linger in the soil for up to 30 years! It is even able to bioaccumulate which means that it is able to accumulate in the fatty tissues of animals, even being able to be passed down through breast milk. Its lingering abilities allow it to travel throughout ecosystems being washed from the soil of farms and into major waterways where it can poison many aquatic animals (and the animals that eat them)  (DDT: The Chemical Revolution stumbles into health and environmental issues). DDTs lingering abilities in combination with its harmful effects made it quite the problem.

Most notably, DDT began to affect Bald Eagle populations. Bald eagles are a type of sea eagle, meaning they spend much of their time by the water, eating mostly fish. This is where the issue lies as DDT’s lingering abilities means that it contaminated many water sources, where it was absorbed by all the living creatures in them. Bald eagles would eat the contaminated fish, poisoning themselves and their babies with DDT. A major symptom of DDT poisoning in birds is that it affects their ability to create strong eggshells. This caused their eggs to not even be able to handle the weight of their parents, the eggs often being crushed when brooding. This on top of the other health effects of DDT rapidly decreased Bald Eagle populations. In 1963, only 417 nesting pairs were known, leaving them extremely vulnerable to extinction (Bald Eagle 2021).

Despite this damning evidence not much was done to decrease the usage of DDT. Not until the release of the book, Silent Spring, in September of 1962. The book was written by Rachel Carson, a marine biologist and environmental writer. She wrote about the harms of DDT, placing the blame on the chemical industries that spread misinformation and the public officials that blindly listened to them. Carson faced much public backlash but her book was enough to start to sway the public opinion on DDT and other synthetic pesticides. Her book was the catalyst that eventually led to the ban of domestic usage of DDT in 1972 after the creation of the Environmental Protection Agency (Grocholl).

Why are Pesticides Bad?

Most modern pesticides are synthetically made chemicals designed to be as toxic as possible. Pesticides are extremely harsh chemicals that can have very unpleasant effects on the human body. Fungicides are one of the most common pesticides to use on your home to prevent mold and mildew however, they can cause all sorts of symptoms. Fungicide exposure can lead to cell damage and cell death, cancer, parkinson’s disease, birth defects, and in extreme cases death (Mohd Ghazi et al., 2023). Nearly every synthetic pesticide is dangerous to humans in large enough amounts. Now imagine how bad the effects are to smaller animals.

Pesticides work great at killing pests but often will be toxic to much more than intended. They are known to cause harm to the health of humans, animals, and even the environment (Mohd Ghazi et al., 2023). They pollute soil, waterways, and the air causing harm to many of the animals and plants that live in them. Many of these animals are then eaten and due to the poison in their systems end up poisoning the animal that eats them (Pathak et al., 2022). This means that the rat poison you use to keep rats out of your basement is probably killing owls and the insecticide you use to keep the aphids away is probably hurting the bees and other pollinators in your yard.

Herbicides even have the ability to alter habitats. After rain or watering, the pesticides lingering on the plants and in the soil wash away into bodies of water being distributed to many different ecosystems, wreaking havoc wherever they go. Herbicides are known for killing plants along riverbanks and shores as well as killing important fungi, phytoplankton, and much more. Ecosystems are extremely fragile and removing any significant amount of plants or animals (even microorganisms) can upset the balance creating a butterfly effect of harm throughout the ecosystem. This will affect the populations of invertebrates (species without a backbone like crabs, shrimp, snails, etc) as well as many vulnerable species (Herbicides 2025).

Fungicides also have detrimental effects on the environment. As much as mold and other fungi are a nuisance and even a risk to us, they often exist for important reasons and support life in nature (Zubrod et al., 2019). A great example is the fungus mycorrhizae, which has a symbiotic relationship with plants. The fungus attaches to the plant’s roots and extends them, allowing for the plant to reach more nutrients, and the plant gives the fungus a host allowing it to keep some nutrients to survive. Approximately, 90% of all plants use and even depend on mycorrhizae to survive (Delahaut). If we overuse fungicides, we risk killing the fungus that supports plants the most. Killing important fungi isn’t the only risk that fungicides pose; they can disrupt important food webs which affect the overall health of an ecosystem, accumulate in the soil, and are toxic to many aquatic organisms (Zubrod et al., 2019). They especially pose risks to pollinators as fungicides can increase the toxicity of insecticides. This specifically affects bees, leading to poor nutrition and increased susceptibility to disease. Fungicides are also known for disturbing bee behavior, impacting their ability to pollinate and reproduce (May et al., 2019). Pesticides are extremely good at preventing pests but are never worth the harm they have on the environment and even you. 

In Maine there are many initiatives to reduce the popularity and usage of dangerous pesticides. Programs like the Obsolete Pesticide Collection hosted by the Board of Pesticides Control and the EPA that hosts an event each October to collect and dispose of banned and unusable pesticides from farmers, gardeners, and homeowners for free. There is also the Pesticide & Fertilizer Task Force out of Portland Maine that assists the Portland City Council in pesticides ordinances, keeping track of local pesticide use and its environmental effects (especially in Casco Bay), and creating plans to reduce the harmful impacts on the environment and human health. Maine has been very involved in trying to reduce pesticide usage and make sure that our gardens, farms, and homes are thriving without taking a toll on our health and environment!

Pesticides in New England

New England is no stranger to pesticides, using all types in different farms, parks, and even homes, but there is one that stands out called neonicotinoids. Neonicotinoids, also known as neonics, are a common type of insecticide. They are applied to the seeds of plants before being put into the soil and the chemicals permeate throughout the plant, which makes the entire plant, bark, leaves, fruit and all, toxic to insects. Neonics linger inside plants for years, having an extremely long lasting effect. They even leech into the soil, killing any insects in the soil around them (Sanderson, 2025).

Neonics are extremely effective insecticides, killing any bug that even tries to get close to a treated plant, however their effectiveness might spread farther than intended. Neonics are not picky, they are toxic to practically any bug that interacts with it. This includes important bugs like pollinators that are essential to plant health and success. This not only affects the health of the crops that feed New England but has had a negative effect on bees and other pollinators. A study from 2023 found that a third of Massachusetts beekeeper hives were lost due to neonics. Not only that but also recent studies have found that the extreme uses of neonics around New England has led to them spreading to areas previously untouched by neonics like farms, streams, and even bee hives. This will cause harm to all sorts of insects throughout New England, harming populations that are already in decline like native honey bees (Sanderson, 2025).

Besides the effects to the environment, neonics may have detrimental effects to human health. Shockingly for an insecticide so generously used, there isn’t much research done on its effect on human health, especially, considering that they are being used on food we eat, the lack of research is very concerning. Early research has shown that neonics could affect insulin regulation and could even cause birth defects (Sanderson, 2025). Hopefully, as more research is done on these harmful insecticides, New England can switch to safer pesticides not only for the environment but also everyone that lives in it.

What are Environmentally Friendly Alternatives?

Many chemical pesticides are extremely toxic and have detrimental effects to the environment in many ways (probably even more than we know right now). They offer many solutions to pests but put way too much at risk to be worth it. But don’t worry, as there are many ways to keep pests out safely! From making your own natural pest control to getting pest eating pets, there are many different options and some will be a perfect fit for you and your garden. 

Pest Repelling Plants

Many plants have properties that can repel insects from your yard. They often work by having strong aromas that bugs do not enjoy. A well known example is citronella that repels mosquitoes. These plants not only repel pests but pose no risk to you or the environment while making your garden as beautiful as ever (Organic Lawncare 2024)! Some insect repelling plants (that are also beautiful and often edible) include:

Lavender: repels mosquitoes, flies, fleas, and moths

Rosemary: repels japanese beetles, carrot rust flies, slugs, and snails

Basil: repels mosquitoes, flies, aphids, mites, and tomato hornworms

Chrysanthemums: repels ants, cockroaches, ticks, fleas, bedbugs, and japanese beetles (not pet safe)

Mint: repels cabbage moths, ants, mice, and fleas

Garlic: repels aphids, cabbage loopers, and japanese beetles (not pet safe)

Catnip: repels mosquitoes, cockroaches, and termites

Marigolds: repels mosquitoes, aphids, and nematodes

Lemon: repels mosquitoes, cockroaches, and termites (not pet safe)

Sage: repels cabbage worms, beetles, and carrot rust flies (Prichard, 2024)

 

Attract Nature’s Pest Control

There are many species in Maine and the New England area that specialize in eating the pests we hate. Putting in the effort to make your yard a welcoming place for those species can help bring in nature’s pest control. Not only will they bring some life to your yard but they get a nice meal out of the mosquitoes or aphids or any pest you despise. Some notable species to attract are many different species of birds. Songbirds are good for eating unpleasant bugs, owls will eat your mice, rats, and other rodents, ladybugs will eat your aphids, bats will eat your mosquitoes, and frogs will eat your flies, and there are hundreds more! Taking the time to put in an owl or bat box, or a pond, or a bird feeder will do wonders to attract nature’s pest control!

Keeping pets like chickens or ducks in your yard are also great forms of pest control. They love eating pesky pets like hornworms and ticks and are often used as a pest control in gardens. You can also introduce some bug species into your yard to combat unwanted bugs but it is vital that you do your research to ensure that they are a native species and they won’t have any negative effects on the environment or your garden.

 

Homemade Natural Pesticides

There are even many natural health and eco-friendly pesticides that you can use in your home and garden! Products like neem oil, spicy peppers, and much more are very safe and effective options! If you want to make some of your own natural pesticides you can go to the Peace Corps website or any other reliable source to find out more! There are even some premade ones on the market like Perfect Plantista’s Houseplant Pest Spray that is pet safe and even safe enough to drink (do not actually drink it, it is not made for human consumption). Please make sure that in your search for natural options that you are being thorough and only using reliable sources, improperly made or faulty products can be very dangerous!

 

Other Resources

Maine Indoor Air Quality Council – Has more information on pesticides in Maine and offers resources for any pesticide question you may have!

Salt Lake City Sustainability – Offers more homemade pesticide recipes and techniques!

Washington State Department of Agriculture – Has information and resources on how to support bee populations and protect them from pesticides!

Maine Organic Farmers and Gardeners – Offers resources to keep your garden organic and as sustainable as possible!

Maine Department of Agriculture, Conservation & Forestry – Has information on a technique of pest control called integrated pest management, that is found to be a great environmentally friendly technique!

Sources Cited

1. Bald Eagle. US Fish & Wildlife Service. (2021, February). https://www.fws.gov/sites/default/files/documents/bald-eagle-fact-sheet.pdf 
2. DDT: The Chemical Revolution stumbles into health and environmental issues. Collaborative for Health & Environment. (n.d.). https://www.healthandenvironment.org/resources/resource-library/eh-history/ddt-the-chemical-revolution-stumbles-into-health-and-environmental-issues#:~:text=It%20has%20a%20disastrous%20effect,and%20maintain%20their%20full%20potential  
3. Delahaut, K. (n.d.). Mycorrhizae. Wisconsin Horticulture. https://hort.extension.wisc.edu/articles/mycorrhizae/  
4. Environmental Protection Agency. (2025, February 7). Herbicides. EPA. https://www.epa.gov/caddis/herbicides  
5. Environmental Protection Agency. (2025, February 13). What is a Pesticide?. EPA. https://www.epa.gov/minimum-risk-pesticides/what-pesticide 
6. Fungicides. National Pesticide Information Center. (2022, January 20). https://npic.orst.edu/ingred/ptype/fungicide.html 
7. Grocholl, L. (n.d.). Pesticides History and Food Safety. Pesticides history and Food Safety. https://www.sigmaaldrich.com/US/en/technical-documents/technical-article/food-and-beverage-testing-and-manufacturing/flavor-and-fragrance-formulation/pesticides-and-residuals-history-and-food-safety?srsltid=AfmBOopQHSyJsMwhahO_ruldJCHfL_goZyS5Vxq3eXlRGvcdP6rJbNX7 
8. May, E., Code, A., & Hoyle, S. (2019). Xerces. Xerces Society. https://xerces.org/sites/default/files/2019-09/Fungicide_Regular_Factsheet_Final_Web.pdf
9. Mohd Ghazi, R., Nik Yusoff, N. R., Abdul Halim, N. S., Wahab, I. R., Ab Latif, N., Hasmoni, S. H., Ahmad Zaini, M. A., & Zakaria, Z. A. (2023). Health effects of herbicides and its current removal strategies. Bioengineered, 14(1). https://doi.org/10.1080/21655979.2023.2259526  
10. Organic Lawncare. Maine Organic Farmers and Gardeners. (2024, December 9). https://www.mofga.org/learn/organic-how-tos/organic-lawncare/#pests  
11. Pathak, V. M., Verma, V. K., Rawat, B. S., Kaur, B., Babu, N., Sharma, A., Dewali, S., Yadav, M., Kumari, R., Singh, S., Mohapatra, A., Pandey, V., Rana, N., & Cunill, J. M. (2022). Current status of pesticide effects on environment, human health and it’s eco-friendly management as bioremediation: A comprehensive review. Frontiers in Microbiology, 13. https://doi.org/10.3389/fmicb.2022.962619  
12. Prichard, P. (2024, July 3). Insect-repelling plants for your garden. Paulding Vine. https://site.extension.uga.edu/paulding/2024/07/insect-repelling-plants-for-your-garden/#:~:text=Marigolds%20(Tagetes)%2C%20is%20often,%2C%20aphids%2C%20and%20other%20insects  
13. Sanderson, S. (2025, March 25). Protecting pollinators and ourselves from toxic neonicotinoid pesticides. Conservation Law Foundation. https://www.clf.org/blog/protecting-pollinators-and-ourselves-from-toxic-neonicotinoid-pesticides/ 

Zubrod, J. P., Bundschuh, M., Arts, G., Brühl, C. A., Imfeld, G., Knäbel, A., Payraudeau, S., Rasmussen, J. J., Rohr, J., Scharmüller, A., Smalling, K., Stehle, S., Schulz, R., & Schäfer, R. B. (2019). Fungicides: An overlooked pesticide class? Environmental Science & Technology, 53(7), 3347–3365. https://doi.org/10.1021/acs.est.8b04392