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Myths

Pest control myths and what works instead

Many popular pest products and habits don't hold up. Ultrasonic devices have drawn repeated FTC action, bug zappers backfire on mosquitoes, and sprays often scatter the very ants and cockroaches you're trying to kill.[1][3][8]

The short answer

  • Ultrasonic and electromagnetic repellers: the FTC has said ultrasound does not control insects and that any rodent reaction is temporary.[1]
  • For cockroaches and ants, baits beat sprays: sprays alone won't eliminate German cockroaches, and spraying while baiting works against the bait.[10][8]
  • For mosquitoes, use an EPA-registered repellent and remove standing water; zappers, wristbands, mosquito plants and vitamin B1 don't work.[3][12]
  • For rodents, no repellent has been found to solve a rat problem for more than a very short time; seal openings and trap.[11]
  • Bed bugs aren't a sign of a dirty home: the University of Kentucky says they feed only on blood, so clean homes are as vulnerable as cluttered ones. Bleach, rubbing alcohol and lighters don't solve them and can start fires.[15][16]
  • Mothballs, sulfur and plants don't keep snakes or other wildlife away. NPIC says mothballs are not wildlife repellents and are meant for closed, airtight containers.[19][20][21]

Myth: plug-in ultrasonic or electromagnetic repellers drive pests out

In 2001 the FTC sent warning letters to more than 60 makers and sellers of ultrasonic pest devices, saying efficacy claims must be backed by scientific evidence. Earlier FTC complaints alleged that rodents get used to ultrasound and return, and that ultrasound does not control insects.[1]

In 2003 the FTC settled charges that one company made unsubstantiated claims that its electromagnetic and ultrasonic devices drove rodents and cockroaches from homes.[2]

UC IPM lists ultrasonic emitters and electronic repellers among mosquito products that are ineffective.[3]

UC IPM's rat guide explains the rodent side: rats are easily frightened by strange noises but quickly get used to repeated sounds, which makes frightening devices, high-frequency and ultrasonic sounds included, ineffective in homes and gardens. Our guide to bug zappers and electronic repellers goes through the research device by device.[11]

Myth: zappers, citronella plants and wristbands stop mosquitoes

Oil of citronella does have a reputation for repelling mosquitoes, UC IPM notes, and citronella candles and mosquito coils work best where there is little air movement, outdoors only. The potted 'mosquito plant' is a different matter: UC IPM lists it with the ineffective products below.[3]

  • Bug zappers are counterproductive: many of the insects they kill are predators of mosquitoes.[3]
  • Repellent wristbands, the 'mosquito plant', incense coils, vitamin B1, and brewer's yeast with garlic are ineffective.[3]
  • What works: EPA-registered repellents with DEET, picaridin, IR3535, oil of lemon eucalyptus, PMD or 2-undecanone, used as directed.[12]
  • Two of those repellents come with an age limit: CDC says not to use products containing oil of lemon eucalyptus or PMD on children under 3 years old. Our insect repellent guide compares the active ingredients.[12]

Myth: 'natural' pest products are tested and registered like other pesticides

Products made only from ingredients on EPA's minimum-risk list are exempt from federal registration, so EPA has not registered them the way it registers other pesticides.[4]

Such products may not claim to control insects or rodents that carry disease; if you need protection from ticks or mosquitoes, use a registered repellent.[5][12]

EPA's rule for these exempt products goes further: the label may only claim to control the pest as a pest, not to control or mitigate insects or rodents that carry disease. Our home remedies guide covers which minimum-risk ingredients and kitchen remedies have held up in tests.[5]

Myth: spraying is the fastest way to get rid of ants and cockroaches

UC IPM says that, used properly, ant baits are more effective and safer than sprays, and that indoor sprays usually aren't necessary. Spraying around the foundation doesn't give permanent control because it kills only the foraging ants. Our ant and cockroach bait guides cover placement.[8]

  • German cockroaches: baits in cracks and crevices are the primary tool; sprays alone won't eliminate them, and foggers don't reach where they hide.[10]
  • Ants: wipe trails with soapy water, use slow-acting baits so workers carry them back to the queens, and don't spray while baiting.[8][9]
  • Baits are slow on purpose. Penn State says workers carry the bait back to the nest, and control can take two weeks or longer; UC IPM says an effective cockroach bait program doesn't give immediate results.[9][10]

Myth: a bug bomb treats the whole house

  • Bug bombs: the mist settles on exposed surfaces and misses voids and cracks; some ingredients repel pests deeper into hiding.[6]
  • NPIC says foggers may not work on pests that like to hide, such as bed bugs and cockroaches, and UC IPM says aerosols and total-release foggers are often ineffective against cockroaches because they don't reach the crevices where the insects shelter.[6][10]
  • Extra cans don't help. NPIC says using more foggers than the label gives for the space won't control pests any better and could increase your risks, and fogger contents can catch fire and explode. Our bug bomb guide has the details.[6]

Myth: bed bugs mean a dirty house, and bleach or alcohol will kill them

Unlike cockroaches and flies that feed on filth, bed bugs often have no relationship to cleanliness, the University of Kentucky says. They feed only on blood, so a spotless home can be as vulnerable as any other.[15]

  • Bleach, alcohol, cigarette lighters and bug bombs should not be used against bed bugs, according to the University of Kentucky: they're ineffective and can lead to fires and other dangerous outcomes.[15]
  • EPA adds that rubbing alcohol, kerosene and gasoline could harm your family and can ignite easily from a spark or cigarette.[16]
  • What works instead is heat for bedding and clothing (hot washing or a hot dryer), encasements, steam and products registered for bed bugs, covered in our bed bug guide and our page on Raid, bleach and alcohol.[15][16]

Myth: food-grade diatomaceous earth is the safe kind to use for pests

NPIC says 'food grade' diatomaceous earth is purified, and FDA lists diatomaceous earth as Generally Recognized as Safe for uses such as anticaking in feed. That doesn't make it a pest product.[18]

For bed bugs, EPA says pool-grade or food-grade diatomaceous earth should not be used, because it can harm you when breathed in; the pesticide version uses a different size of diatoms that reduces the hazard. EPA also says desiccants should be ones registered and labeled for bed bugs and applied only in cracks and crevices. Our diatomaceous earth and pets guide and our insecticide dust guide cover use.[16][17]

Myth: mothballs, sulfur and other home remedies keep snakes and animals away

Mothballs are insecticides made for clothes moths. NPIC says they are meant to be used in closed, airtight containers so the fumes build up and kill moths inside, that they are not wildlife repellents, and that used out in the open they can harm people, pets or wildlife that touch them, eat them or breathe the fumes.[19]

  • Using mothballs outside a sealed, airtight container; children mistake them for food.[13]
  • Snakes: Mississippi State Extension describes tests on black rat snakes in which sulfur, lime, mothballs, gourd vines, sisal rope, cayenne pepper spray, artificial skunk scent, coal tar and creosote, and king snake musk all failed to repel them.[20]
  • UC IPM says no plants repel snakes and that none of the commercial chemical snake repellents has been proven to work well enough to recommend. NPIC adds that chemical snake repellents can pose risks to people, pets or the environment if they aren't used properly. Our snake guide covers what does work: removing cover and food, and sealing gaps.[21][22]

Myth: a repellent will keep rats and mice away

Rats have an initial aversion to some odors and tastes, but UC IPM says no repellent has been found to solve a rat problem for more than a very short time, and there are no truly effective rat repellents registered in California. UC IPM calls exclusion, or building them out, the most successful and longest-lasting strategy around buildings.[11]

The FTC's past complaints about ultrasonic devices made the same point for sound: any reaction by rodents is temporary at best, because they get used to it and return. Our rodent guide and snap trap guide cover sealing and trapping.[1]

Garden myths: grubs and moles, praying mantids and pest-repelling plants

  • Killing grubs gets rid of moles: not reliably. ICWDM says moles eat grubs but also worms and ants, a lawn can be grub-free and still have moles, and moles may dig more while searching for food. UC IPM says the idea that fewer grubs make turf less attractive to moles hasn't been confirmed by research. See our mole control guide.[24][23]
  • Praying mantids control garden pests: UC IPM says the mantids sold by mail order are of no benefit for biological pest control, because they eat any insect they can catch, including bees, butterflies and syrphid flies. Our beneficial insects guide lists the predators that do help.[25]
  • Charts of plants that repel particular pests: University of Arizona Extension says companion planting is based on folklore and experimentation, and in one study it describes, marigolds around zucchini cut pest damage but the results were called indicative, not conclusive. UVM Extension says marigolds against nematodes are not proven, though there is some scientific evidence. Our companion planting guide has the details.[26][27]

Spider myths: daddy-long-legs venom and 'spider bites'

  • Cellar spiders, often called daddy long-legs, are not deadly spiders that just can't bite. The Connecticut Agricultural Experiment Station calls the idea that they are highly venomous an urban legend: their venom is weak and not medically significant, their mouthparts are too small to puncture human skin, and bites are extremely rare.[28]
  • Not every daddy-long-legs is a spider. The University of Kentucky notes that harvestmen, also called daddy-long-legs, are not true spiders and are not closely related to cellar spiders.[29]
  • Many wounds blamed on spiders have other causes. UC IPM says misdiagnosis of recluse bites is widespread, even in places with no recluse spiders, and that several people with skin lesions at once point more likely to a contagious bacterial infection such as MRSA. CAES says that unless the spider is caught at the time of the bite, a spider bite diagnosis remains inconclusive. Our spider guide and bite identification guide cover the spiders that matter and when to see a doctor.[30][28]

Myth: termites are a do-it-yourself job

The University of Kentucky says it's best not to treat a home yourself. Finding the hidden entry points takes knowledge of building construction, and a typical treatment can involve hundreds of gallons of termiticide injected along the foundation, beneath slabs and within foundation walls. A possible exception is a mailbox post or other small wooden object not attached to the house.[14]

Swarmers indoors are a warning sign, not the damage itself: UKY says termite swarmers emerging inside a home can't damage wood, live for about a day, and can be removed with a broom or vacuum. Our termite guides cover what a swarm means and how to choose a treatment.[14]

  • Treating termites yourself: do-it-yourself products seldom eliminate an existing infestation.[14]

Myth: more pesticide works better

  • Using more pesticide than the label calls for: NPIC says applying too much can lead to higher exposure for people, pets and the environment, and for foggers, using more than the label gives won't control pests any better.[7][6]
  • The label also sets where a product can go. NPIC says using a pesticide in a location the label doesn't list is illegal and unsafe. Our label reading guide explains the directions and precautions.[7]

Common questions

Do ultrasonic pest repellers work?
The evidence says no. The FTC has warned more than 60 makers and sellers that their claims need scientific support and alleged that ultrasound doesn't control insects, and UC IPM says rats quickly get used to ultrasonic sounds.[1][11]
Will mothballs keep snakes, squirrels or mice away?
No. NPIC says mothballs are not wildlife repellents and belong in closed, airtight containers, and mothballs failed to repel black rat snakes in tests described by Mississippi State Extension.[19][20]
Does a clean house prevent bed bugs?
Not on its own. The University of Kentucky says there's often no relationship between bed bugs and cleanliness, because they feed only on blood. Clutter does give them more places to hide.[15]
Should I buy praying mantids for my garden?
UC IPM says they're of no benefit for biological pest control: they eat bees, butterflies and other beneficial insects as readily as pests.[25]

Full answers for each myth

Each myth above is covered in depth on these pages.

Sources

  1. Iowa State University Extension, “Ultrasonic Pest Control - Buyer Beware (reprints FTC release of May 3, 2001).” yardandgarden.extension.iastate.edu/article/2001/8-24-2001/ultrasonic.html (accessed 2026-11-10)
  2. U.S. Federal Trade Commission, “Marketer of Pest Control Devices Required to Provide Support for Claims (July 2003).” search.ftc.gov/news-events/news/press-releases/2003/07/marketer-pest-control-devices-required-provide-support-claims (accessed 2026-11-10)
  3. University of California Statewide IPM Program, “Pest Notes: Mosquitoes, Publication 7451 (April 2020).” ipm.ucanr.edu/legacy_assets/PDF/PESTNOTES/pnmosquitoes.pdf (accessed 2026-11-10)
  4. U.S. Environmental Protection Agency, “Minimum Risk Pesticides Exempted from FIFRA Registration.” www.epa.gov/minimum-risk-pesticides (accessed 2026-11-10)
  5. U.S. Environmental Protection Agency, “Personal Insect Repellents and Minimum Risk Pesticides.” www.epa.gov/minimum-risk-pesticides/personal-insect-repellents-and-minimum-risk-pesticides (accessed 2026-11-10)
  6. National Pesticide Information Center, “Total Release Foggers.” www.npic.orst.edu/ingred/ptype/fogger.html (accessed 2026-11-10)
  7. National Pesticide Information Center, “Minimizing Pesticide Exposures.” npic.orst.edu/health/minexp.html (accessed 2026-11-10)
  8. University of California Statewide IPM Program, “Pest Notes: Ants, Publication 7411 (October 2012).” ipm.ucanr.edu/legacy_assets/PDF/PESTNOTES/pnants.pdf (accessed 2026-11-10)
  9. Penn State Extension, “Odorous House Ant.” extension.psu.edu/odorous-house-ant (accessed 2026-11-10)
  10. University of California Statewide IPM Program, “Pest Notes: Cockroaches, Publication 7467 (revised December 2019).” ipm.ucanr.edu/legacy_assets/PDF/PESTNOTES/pncockroaches.pdf (accessed 2026-11-10)
  11. University of California Statewide IPM Program, “Pest Notes: Rats, Publication 74106 (revised June 2024).” ipm.ucanr.edu/legacy_assets/PDF/PESTNOTES/pnrats.pdf (accessed 2026-11-10)
  12. U.S. Centers for Disease Control and Prevention, “Preventing Mosquito Bites.” www.cdc.gov/mosquitoes/prevention/index.html (accessed 2026-11-10)
  13. National Pesticide Information Center, “Pesticides and Children.” npic.orst.edu/health/child.html (accessed 2026-11-10)
  14. University of Kentucky Entomology, “ENTFACT-604: Termite Control: Answers for Homeowners (revised March 2026).” entomology.mgcafe.uky.edu/ef604 (accessed 2026-11-10)
  15. University of Kentucky Entomology, “ENTFACT-636: Bed Bugs.” entomology.mgcafe.uky.edu/ef636 (accessed 2026-11-10)
  16. U.S. Environmental Protection Agency, “Do-it-yourself Bed Bug Control.” www.epa.gov/bedbugs/do-it-yourself-bed-bug-control (accessed 2026-11-10)
  17. U.S. Environmental Protection Agency, “Pesticides to Control Bed Bugs.” www.epa.gov/bedbugs/pesticides-control-bed-bugs (accessed 2026-11-10)
  18. National Pesticide Information Center, “Diatomaceous Earth General Fact Sheet.” npic.orst.edu/factsheets/degen.html (accessed 2026-11-10)
  19. National Pesticide Information Center, “Mothballs: Naphthalene and Paradichlorobenzene.” npic.orst.edu/ingred/ptype/mothball/index.html (accessed 2026-11-10)
  20. Mississippi State University Extension Service, “Reducing Snake Problems Around Homes, Publication 2277.” extension.msstate.edu/publications/reducing-snake-problems-around-homes (accessed 2026-11-10)
  21. University of California Statewide IPM Program, “Rattlesnakes (Pest Notes, Home and Landscape).” ipm.ucanr.edu/home-and-landscape/rattlesnakes/ (accessed 2026-11-10)
  22. National Pesticide Information Center, “Snakes.” www.npic.orst.edu/pest/snake.html (accessed 2026-11-10)
  23. University of California Statewide IPM Program, “Pest Notes: Moles.” ipm.ucanr.edu/home-and-landscape/moles/ (accessed 2026-11-10)
  24. Internet Center for Wildlife Damage Management, “Mole Damage Prevention and Control Methods.” icwdm.org/species/other-mammals/moles/mole-damage-prevention-and-control-methods/ (accessed 2026-11-10)
  25. University of California Statewide IPM Program, “Mantids (Natural Enemies Gallery).” ipm.ucanr.edu/natural-enemies/mantids/ (accessed 2026-11-10)
  26. University of Arizona Cooperative Extension, “The Art of Companion Planting (April 2023 presentation).” extension.arizona.edu/sites/default/files/attachment/CompanionPlantingApr2023.pdf (accessed 2026-11-10)
  27. University of Vermont Extension, “Creating a Biodiverse Vegetable Garden with Companion Plants (April 2023).” www.uvm.edu/d10-files/documents/2024-10/Creating_a_Biodiverse_Vegetable_Garden.pdf (accessed 2026-11-10)
  28. The Connecticut Agricultural Experiment Station, “Spiders Found in the House (G. E. Ridge and K. Dugas).” portal.ct.gov/-/media/caes/documents/publications/fact_sheets/entomology/spiders_in_the_house.pdf (accessed 2026-11-10)
  29. University of Kentucky Entomology, “Urban Spider Chart (B. Newton and L. Townsend).” entomology.mgcafe.uky.edu/spider-chart (accessed 2026-11-10)
  30. University of California Statewide IPM Program, “Pest Notes: Brown Recluse and Other Recluse Spiders, Publication 7468.” ipm.ucanr.edu/legacy_assets/PDF/PESTNOTES/pnbrownrecluse.pdf (accessed 2026-11-10)

Updated 2026-11-10. Built from sourced records. Spot an error? Tell us.