Cooperative Extension: Insect Pests, Ticks and Plant Diseases

Pesticide Myths and Facts

Some folks don’t think twice about using pesticides. Others want to see most of them banned. Both perspectives sometimes develop from common misunderstandings and half-truths. So nix the neighbor’s outmoded prescription, ditch the social media diatribes, and get the facts, below.

Myth #1: Pesticides = insecticides and weedkillers

FACT: Any substance or mixture of substances used to manage a pest is a pesticide.

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  Insect repellents, disinfectants, rodent baits, mothballs, weed & feeds, mold & mildew control products, ant baits, wood preservatives, flea collars, botanicals, and microbials are all examples of pesticides.
• Defoliants, plant desiccants, plant growth regulators, nitrogen stabilizers, and plants genetically modified to kill or mitigate pests, like Bt corn, are regulated as pesticides too.
• Biological control animals (insects, nematodes, etc.), traps, and exclusion devices are not pesticides.

Myth #2: You need a pesticide to solve a pest problem.

FACT: Prevention, mechanical, cultural, and biological control strategies can be used to successfully manage many pests.

• Pesticides should be the last resort, not the go-to. Crushing a stray bug or pulling a stray weed is usually much simpler, cheaper, and safer than spraying one.

  

• Integrated pest management—a comprehensive system of pest control that employs multiple strategies (which may or may not include pesticides)—can provide safer, economical, long-term, and environmentally responsible resolutions to pest problems.
• Before deciding to use chemical control, make sure:
  • The pest is really a pest. Oftentimes a pest is in the eye of the beholder. If the organism isn’t doing any harm, is it worth the time, effort, and expense to manage it?
  • Expectations are realistic. Most pests can’t be completely eradicated from an area, and if the resources they need remain available and accessible to them, they will return.
  • The pest has been identified. Effective chemical control requires knowledge of the pest’s life history. Different species are susceptible to different chemicals and some are only susceptible at certain stages in their lifecycles.
  • The pest is there. For example, spraying the manicured lawn to control deer ticks wouldn’t kill very many because their habitat is brush and leaf litter. And some pests are temporary (like swarms of flying ants, most of which quickly die on their own) or passing through. Others spend different life stages in different habitats. Applying pesticides where the pest isn’t or when it will soon be gone is a waste. Again, know the enemy.
• Prevention measures, such as purchasing high-quality seedlings to avoid disease problems in the garden or sealing any gaps around the home to keep mice and insects from entering, can stop pest problems before they start.
• Cultural controls, like choosing plant varieties appropriate to the site/climate, rotating crops, ensuring proper plant spacing, and removing residues at the end of the season can help manage a variety of pests in gardens and landscapes.  
• Mechanical and physical controls, such as mousetraps, handpicking insects or pulling weeds in the garden, installing fences or screens, removing pest habitat (old tires for mosquitoes, brush piles for rodents, etc.) can also help with many pest problems around the home.

  

• Biological controls, like insects that prey on or parasitize other insects, can suppress some pests. Encouraging pest natural enemies, or at least leaving them alive, can help keep pest numbers low.
• Chemical control is probably appropriate when:
  • Human health depends on it (using insect repellents to prevent tick and mosquito bites, using disinfectants to clean contaminated surfaces, etc.)
  • Other methods have failed or aren’t feasible.

Myth #3: Pesticides are bad.

FACT: Pesticides are valuable tools when used judiciously and correctly.

• Pesticides are hazardous and their use always presents risk, but they are sometimes a necessary part of a pest management system.

  

• Pesticides contribute to food security by drastically reducing losses of some crops.
• When used against human pathogens and vectors of human pathogens, pesticides can save lives.
• Pesticides protect pets, livestock, property, and infrastructure from a variety of destructive pests.
• Pesticides can help maintain attractive landscapes and recreational areas.
• When used against invasive species, pesticides can help protect natural resources.

Myth #4: Natural means safe.

FACT: All pesticides have risks.

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  The naturalness of a product is not an indication of how safe it is to use. Some synthetic pesticides have very low toxicity and some natural pesticides are highly toxic. The most toxic substance in the world is produced naturally by a bacterium. Arsenic, cyanide, ricin, radon, nicotine, are all natural substances (and some have been/are used as pesticides).
• If used improperly, products marketed as ‘green’ can still harm people and the environment.
• Even familiar substances like vinegar can be dangerous at the concentrations used to control pests.
• Follow the label directions carefully, even if the product seems ‘safe’. Failure to take the proper precautions can result in a less toxic product causing harm.

Myth #5: If you can buy it, you can use it.

FACT: Only pesticide products registered by the Maine Board of Pesticides Control may be used in Maine, and many uses require an applicator’s license.

• All products used and sold in Maine must be registered in Maine, even products exempted from federal registration.
• Pesticide products used legally in other states may not be legal to use in Maine. Before purchasing a pesticide product online, make sure it’s registered here. Use the National Pesticide Information Retrieval System to check or contact the Maine Board of Pesticides Control.
• Beware of fraudulent products sold online or by individuals. Unless the product has an EPA registration number, it has not been tested for safety or efficacy. Unregistered pesticide products may not claim to control public health threats such as disease-causing organisms, COVID-19, or ticks that vector disease.

  

  

• Some pesticide products, called restricted-use pesticides, can only be legally bought and used by licensed pesticide applicators.
• Using pesticides in areas accessible to the public (such as a store, restaurant, parking lot, school, park, hospital, etc.) requires an applicator’s license or a licensed applicator’s supervision with the following exceptions:
  • The use of personal insect repellents
  • Applying general-use disinfectant products in the course of cleaning, by hand.
  • Applying general-use pesticides to control stinging insects.
  • Applying most general-use wood preservatives.

Myth #6: You don’t need to read all the container directions.

FACT: The label is the law.

• The directions are not suggestions—the product label is a legal document.
• Adherence to the label prevents most improper use and greatly decreases the risk of poisonings and injuries, environmental harm, and property damage.
• Improper application may also fail to control the pest.
• Users may only apply pesticides in places and on crops/surfaces listed on the label.
• Users must wear any personal protective equipment (PPE) listed on the label.
• Users may not apply more pesticide to an area than is listed on the label.
• User must adhere to any application restrictions listed on the label, including application equipment and method restrictions, timing restrictions, weather restrictions, re-entry restrictions, etc.
• Users must store and dispose of pesticides as instructed on the label and as permitted by state law.
• See Label Interpretation for more information.

Myth #7: Personal protective equipment (PPE) is optional.

FACT: Risk = toxicity X exposure. If it’s listed on the label, wear it.

• The greater the exposure, the greater the risk, regardless of a pesticide’s toxicity. Wearing PPE dramatically reduces exposure. 
• Some pesticides can cause cancer and other chronic health issues including Parkinson’s disease, asthma, and reproductive and developmental problems. Acute poisonings and pesticide-related injury can result in permanent damage to the eyes, lungs, nervous system, and other organs. Some pesticides can kill humans at very low doses.
• The PPE listed on the label is required to use the pesticide. If no PPE is listed, users should still wear long pants, a long-sleeved shirt, socks, closed-toed shoes, and gloves to reduce their exposure.
• Make sure to wear all PPE correctly, and to maintain and store reusable PPE according to the manufacturer’s directions.
• If the label lists a respirator, be sure it fits correctly. Respirators do not offer sufficient protection without a seal. See Respirators for more information.
• Inspect PPE for damage before using it.
• Clean reusable PPE after use so it doesn’t become a source of contamination.
• Wash clothing worn during pesticide application separate from the family laundry.

Myth #8: More is better.

FACT: More is illegal. Do not apply more pesticide than directed on the label.

• The rate permitted by the label often varies by where it’s applied. Users cannot exceed the label rate for any given site or crop.
• Exceeding label rates risks harm to exposed individuals, the environment, and property. It also wastes money on extra product.

  

• Do not apply a greater volume of product per unit area than directed by the label.
• Do not apply the product more often than permitted by the label.
• For concentrated products, dilute as directed by the label.
• The amount of a product required to control a pest often varies by pest. If the target pest is listed on the label, use the recommended rate for that pest. If it isn’t listed, consider another product.
• In Maine, users can apply less pesticide than the label directs, but using too little product may not control the pest and could lead to pest resistance over time.

Myth #9: Under the sink is a good place to store pesticides.

FACT: Pesticides should be stored in a cool, dry, well-ventilated, and secure location—in their original containers.

• Keep pesticides in a storage area where children and pets can’t access them, preferably locked away.

  

• Many pesticides are flammable. Do not store them near a heat source.
• Don’t store pesticides in spaces that may get wet—a leaky sink or flooded basement could result in movement of contaminated water.
• Keep pesticide products in their original containers. If a container becomes damaged, make sure the new container is clearly marked, and print off a new label to keep with it. NEVER transfer a pesticide into a food or beverage container. Children (and adults) have died after an accidental sip of pesticide product that had been placed in a soda or sports drink bottle.
• Always follow the storage instructions on the product label. Some pesticides have special storage requirements.
• Try to buy as much product as will get used, no more.
• Dispose of extra product and empty containers according to label directions. Never dump pesticides down drains, neither septic systems nor wastewater treatment plants are designed to handle them.

Myth #10: Insecticides are killing all the bees.

FACT: Pesticides, parasitism and disease, habitat loss and fragmentation, climate change, and other factors all contribute to pollinator decline.

• As insects, bees can be killed by many insecticides.
• Fungicides and herbicides can also harm pollinators.
• Even low doses of some pesticides can have sub-lethal effects that weaken bees.
• Look for the bee icon on pesticide labels. Products bearing it are especially toxic to bees and have special use restrictions.
• Whenever possible, avoid spraying blooming plants, including weeds, with any type of pesticide.
• The greatest burden on honey bee health is probably the parasitic mite, Varroa destructor, and the viruses it transmits.

  

• A lot of honey bees’ pesticide exposure comes from in-hive applications to control Varroa mites.
• Stressful management practices and low genetic diversity have also eroded honey bee health.
• Bees need quality forage to thrive and native bees need nesting sites. Pavement and perfect lawns provide neither. 
• In Maine, not all bee species are disappearing, some are holding stable and some are increasing in abundance.

Myth #11: Pesticides have caused the rise in cancer.

FACT: Certain pesticides sometimes cause certain cancers, through certain exposure routes, at certain doses, in some individuals.

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  There isn’t enough data to assess how many cancer cases can be attributed to pesticides in the U.S.
• Most cancer is associated with tobacco use, ultraviolet (UV) radiation exposure, alcohol use, infections, and/or obesity rather than exposure to synthetic chemicals.
• Farmers, who generally have higher pesticide exposure, have less cancer overall—but more of certain types of cancers—than non-farmers.
• The annual rate of new cancer cases has actually trended downward in the U.S. since the 1990s.

See the American Cancer Society’s How to Interpret News about Cancer Causes. (This link is provided purely for educational purposes. No responsibility is assumed for any content on the linked site.)

Myth #12: Organic means pesticide free.

FACT: Organic production uses fewer pesticides and pesticide residues are less common in organic produce.

• If preventative and non-chemical control methods fail to control a pest, the use of approved, naturally derived (and a very few synthetic) pesticides is permitted in organic production.

  

• Organically grown produce can pick up synthetic pesticide residues from the environment, spray drift from conventional operations, and post-harvest cross contamination.
• Consumers can reduce their dietary pesticide exposure by choosing organic produce, but it’s unclear if this has a significant effect on human health. See Myth #13.

Myth #13: Eating produce that was treated with pesticides will cause health problems.

FACT: The dose makes the poison.

• If the dose is tiny enough, even highly toxic substances do not cause harm. Conversely, substances as benign as water can be fatally toxic at extreme doses.
• The EPA sets a limit on how much residue of each pesticide can legally end up in/on food, called a tolerance. They take into account aggregate and cumulative exposure and the potential sensitivity of some demographics, among other factors. Tolerances are set at least 10 times lower than the dose believed to result in any effect on humans.
• If a pesticide is applied in compliance with the label, any residue should not exceed the tolerance.
• There hasn’t been enough conclusive research to determine what effects, if any, chronic dietary exposure to legal pesticide residues has on human health.
• The health benefits of eating a variety of fresh fruits and vegetables outweigh the risks of consuming legal residues.

  

• Wash fresh produce in clean water before consuming it. This can remove some pesticide residues as well as pathogens.

DISCLAIMER

Pesticide safety information may change over time. This information is provided for educational purposes only and was published in 2020.

Although pesticides can be an essential tool in pest management, the improper use and disposal of these chemicals present a continuing risk to humans, animals, and the environment. It’s important for applicators to understand that pesticide safety is not only about protecting themselves—it’s also about protecting our domestic and wild animals, environment, our landscapes, and our communities.
Misuse of pesticides can result in, or contribute to, serious injury, illness, or death. Cooperative Extension does not guarantee the safety or effectiveness of any product or practice. Users of any pesticides, and Extension’s educational materials, do so at their sole risk and assume all risk from using such pesticides and materials, whether they follow recommendations or not. The user bears all responsibility for resulting damages to property, human health, or the environment. Cooperative Extension and the University of Maine System shall not be responsible for any damages INCLUDING, BUT NOT LIMITED TO, ANY AND ALL DAMAGE OR LOSS TO REAL OR PERSONAL PROPERTY, PERSONAL INJURY OR DEATH, RESULTING FROM THE NEGLIGENCE OF COOPERATIVE EXTENSION, THE UNIVERSITY, ITS TRUSTEES, FACULTY, AGENTS, EMPLOYEES OR VOLUNTEERS.

Always follow directions on pesticide labels! Failure to do so violates federal law. Application timing and proper calibration are as important as using the right product.

Cooperative Extension makes no warranty or guarantee of any kind, expressed or implied, concerning the use of any stated products. Trade names and product images are used for identification/example only; no product endorsement is implied, nor is discrimination intended.

The University of Maine is an EEO/AA employer, and does not discriminate on the grounds of race, color, religion, sex, sexual orientation, transgender status, gender expression, national origin, citizenship status, age, disability, genetic information or veteran’s status in employment, education, and all other programs and activities. The following person has been designated to handle inquiries regarding non-discrimination policies: Sarah E. Harebo, Director of Equal Opportunity, 101 North Stevens Hall, University of Maine, Orono, ME  04469-5754, 207.581.1226, TTY 711 (Maine Relay System).

SOURCES

Source material includes publications from the American Cancer Society, Maine Board of Pesticides Control, National Institutes of Health, National Pesticide Information Center, U.S. Center for Disease Control, U.S. Department of Agriculture, U.S. Environmental Protection Agency, U.S. Food and Drug Administration, and the World Health Organization. Photos courtesy of USDA-ARS, USFWS, NIH, and UMaine Extension personnel.