Most people call a pest control company after they have already tried the spray from the hardware store. Sometimes twice.
That is not a mistake in itself. The problem is that retail sprays and foggers can hurt the people applying them, and they can make an infestation harder to clear. In Las Vegas, with bark scorpions and summer temperatures well above 100 degrees, a few of those risks get worse.
Here is how DIY pest control vs professional treatment actually compares, where the real dangers are, and when handling it yourself is perfectly reasonable.
Is DIY pest control as effective as professional treatment?
DIY pest control can work for occasional invaders and light, visible activity. It often fails against established infestations such as German cockroaches, ant colonies, bed bugs, and scorpions, because retail sprays kill the insects you can see while the colony, eggs, or harborage stays untouched. Professionals treat the source, not just the sighting.
| DIY retail sprays and foggers | Professional treatment | |
|---|---|---|
| Pest identification | Usually a guess based on appearance | Species identified first, because treatment differs by species |
| Where product goes | Broadcast across visible surfaces | Crack-and-crevice, voids, bait placements, exterior perimeter |
| Product type | Mostly fast-acting, repellent contact killers | Mix of baits, non-repellent residuals, growth regulators, and dusts |
| Targets | The insects you see | The colony, nest, or harborage |
| Resistance management | None, same product repeatedly | Rotating active ingredient classes |
| Non-chemical steps | Rarely | Exclusion, sealing, sanitation, monitoring under IPM |
| Training | None required to buy or apply | Nevada license exam plus annual continuing education |
| Follow-up | Buy another can | Scheduled re-inspection |
The row that matters most is “targets.” A spray that kills 40 visible ants does nothing about the queens. That is the pattern behind most failed DIY attempts.
What are the dangers of DIY pest control sprays?
The dangers of DIY pest control fall into two groups: harm to people and pets from misapplication, and harm to the treatment itself when the wrong product scatters or strengthens the pest. Anyone can buy these products without training, and most injuries trace back to not following the label.
The EPA’s position is short: the label is the law. Using a pesticide in a way the label does not allow is a violation of federal law (FIFRA), even for a homeowner in their own Las Vegas kitchen. The label sets the dose, the sites where it can be used, the protective equipment, and the re-entry time.
The mistakes that cause most harm at home:
- Overapplication. If a little works, more must work better. It does not. Extra product raises exposure without raising control, and concentrates mixed stronger than directed are a common cause of irritation and illness.
- Wrong site. Outdoor perimeter products used indoors, or indoor products sprayed on surfaces where food is prepared.
- Mixing products. Combining two insecticides, or an insecticide with a cleaner, to “boost” it. Do not combine products unless the label tells you to.
- Unlabeled containers. Pouring concentrate into a water bottle or spray bottle. This is how children and adults end up drinking pesticide by accident. Keep product in its original container, always.
- No protective equipment. Spraying overhead into cabinets without gloves or eye protection, then touching your face.
- Spraying where people breathe it. Aerosols applied in closed rooms, or near someone with asthma.
Keep the label. If anyone in the house is exposed, call Poison Control at 1-800-222-1222, which connects Nevada callers to the Nevada Poison Center. They will ask for the product name and EPA registration number, and both are on the label.
Why do bug bombs and foggers cause so many injuries?
Total release foggers, often called bug bombs, empty a whole can of aerosol insecticide into a room at once. The CDC tracked 3,222 fogger-related illnesses and injuries in 10 states from 2007 to 2015, including 4 deaths. The most common causes were people not leaving, or coming back too soon.
The CDC’s breakdown of contributing factors for that period:
| Contributing factor | Share of cases |
|---|---|
| Failed to leave during the application | 16.6% |
| Went back in too early | 14.8% |
| Could not leave before the fogger went off | 10.7% |
| Did not ventilate enough | 9.2% |
| Sprayed in the face or at close range | 9.0% |
| Used too many foggers for the space | 5.5% |
An earlier CDC report covering 2001 to 2006 noted that fogger propellants are flammable, and described fires and explosions when foggers were set off near ignition sources such as gas pilot lights and appliances that cycle on and off. If your water heater or furnace has a pilot light, that is exactly the setup fogger labels warn about.
The bigger issue is that foggers often do not work. The mist settles on open surfaces. Cockroaches, bed bugs, and ants live in cracks, voids, and behind baseboards, where the fog never reaches.
Can spraying make a pest problem worse?
Yes. Repellent sprays can split ant colonies into several new ones, scatter bed bugs into adjoining rooms, and push cockroaches deeper into walls. Repeated use of the same product also selects for resistant insects. A homeowner can end up with a larger, harder-to-treat infestation than the one they started with.
Ant colonies split
Some ant species keep multiple queens in one colony. When a repellent or fast-acting spray disturbs them, the colony can break into satellite colonies that move to new spots in the house. Texas A&M entomology resources warn that spraying pharaoh ants is likely to split the colony and spread the infestation. Professionals use slow-acting baits instead, so workers carry the product back to the queens.
Bed bugs scatter
Ohio State University researchers tested three over-the-counter foggers against bed bugs collected from homes in Columbus, Ohio. The foggers had little to no effect, and the mist did not affect bed bugs hiding in harborages at all. Repellent products can also push bed bugs from one room into the next. Bed bugs need a planned protocol, which is why our [bed bug treatment] follows a specific sequence.
Cockroaches build resistance
German cockroaches are the clearest example of resistance. A 2019 Purdue University study found that cockroach populations exposed to one insecticide also developed resistance to other insecticide classes, sometimes increasing resistance four- to six-fold within a single generation. The researchers concluded that chemicals alone may not be enough to control them. Spraying the same retail product on repeat is close to a best-case scenario for building that resistance.
Repellent residue left behind by DIY sprays can also make it harder for a professional to succeed afterward, because roaches and ants avoid treated areas, including where baits get placed. If you have already sprayed, tell your technician exactly what you used.
What goes wrong with DIY sprays in Las Vegas?
Southern Nevada adds two problems most national DIY advice skips: bark scorpions that shrug off casual spraying, and heat that can degrade products stored in garages. Both mean a homeowner can spend more and get less from retail products here than in milder climates.
Bark scorpions. Bark scorpions are the scorpion species of medical concern in the Las Vegas Valley. Poison centers in the Southwest treat the bark scorpion as the one scorpion whose sting can be life-threatening. They hide in block walls, under landscape rock, and in wall voids, and can go a long time without feeding. A surface spray hits a scorpion only if it walks across fresh residue, and the ones you see indoors are rarely the whole population. Scorpion control depends on exclusion, sealing, harborage reduction, and treatment placed where they actually live. Our [scorpion control] service covers what that involves.
Heat and storage. Pesticide labels include storage directions, and many call for keeping the product away from heat. Las Vegas garages can get hotter than the air outside in summer. Aerosol cans stored in heat are a pressure hazard, and product that has cooked on a shelf for two summers may not perform the way the label says it will.
Monsoon invaders. After Southern Nevada’s summer monsoon storms, crickets, beetles, and other occasional invaders show up in large numbers. Spraying every one of them indoors adds exposure for little benefit, since most of these subside on their own. This is a good time to seal gaps rather than reach for a can.
What does a professional do differently?
A licensed professional identifies the exact pest, chooses a product and placement based on that species and your home, applies it according to the label, and combines it with non-chemical steps. In Nevada, anyone applying pesticides for hire must be licensed through the Nevada Department of Agriculture, which requires passing a general knowledge exam, a Nevada laws exam, and an exam for each pest category.
The difference in practice:
- Identification first. Treatment for German cockroaches is different from treatment for American cockroaches. Pharaoh ants need different handling from Argentine ants. A wrong ID means the wrong product.
- Integrated pest management (IPM). Exclusion, moisture correction, harborage reduction, and monitoring come before or alongside chemical treatment.
- Placement matched to the pest. Product goes into the voids, cracks, and nest sites that particular species uses, not across open floors.
- Non-repellent products and baits. Products the pest does not detect and avoid, so it carries them back to the colony.
- Rotation. Changing active ingredient classes to slow resistance.
- Access to products you cannot buy. Some products are classified as restricted use and require a certified applicator.
Licensed Nevada applicators must also complete six continuing education units every year, including at least one on pesticide laws and regulations and one on safe handling. For what those credentials actually mean and how to check them, see [Las Vegas pest control team and training].
When is DIY pest control fine?
DIY is reasonable for a handful of occasional invaders, a single wasp or spider, and preventive work like sealing gaps and fixing leaks. If you use a retail product, follow the label exactly. Call a professional when activity keeps coming back, when you suspect a colony or nest, or when the pest is dangerous.
Handling it yourself makes sense for:
- A few crickets or beetles after a storm
- A single spider or insect indoors
- Exclusion work: weatherstripping, door sweeps, and screen repair
- Retail baits placed exactly as the label directs, for light ant activity
Call a professional when:
- You have treated twice and the problem is back
- You see German cockroaches, especially during the day
- You find bed bugs or bite patterns you cannot explain
- You find bark scorpions indoors, particularly in a home with small children
- There is a wasp or bee nest you would have to get close to
- There are rodent droppings anywhere in the house
- You were about to buy a fogger
Frequently asked questions
What should I do if I feel sick after spraying bug spray?
Leave the area and get fresh air, wash any skin contact with soap and water, and call Poison Control at 1-800-222-1222 (the Nevada Poison Center answers for Nevada callers). Have the product container in hand so you can read them the name and EPA registration number. Call 911 for trouble breathing, seizures, or loss of consciousness.
What do Caution, Warning, and Danger mean on a pesticide label?
These signal words indicate the product’s short-term toxicity. Caution is the lowest level, Warning is moderate, and Danger is the highest. The signal word tells you how carefully to handle the product, not how well it works.
Is it illegal to use a pesticide differently from the label?
Yes. Under federal law (FIFRA), using a pesticide in a way that is inconsistent with its label is a violation, whether you are a homeowner or a professional, and that federal rule applies in Nevada. Common examples are applying more than the labeled rate or using it on a site the label does not list.
Can I use an outdoor bug spray inside my house?
Only if the label lists indoor use. Many perimeter and lawn products are labeled for outdoor sites only. Using them indoors is a label violation and can raise exposure in enclosed rooms where people and pets breathe the residue.
Can homeowners buy the same products professionals use?
Some general-use products sold to professionals are also available to consumers. Restricted-use pesticides are not. Those can only be bought and applied by certified applicators or people under their direct supervision.
Will a pest control company still treat if I already sprayed?
Yes. Tell the technician which products you used and where, and keep the containers. Repellent residue can affect where baits will work, so knowing what is already there changes the treatment plan.
How do I get rid of leftover bug spray safely?
Follow the disposal section of the label. Never pour pesticides into a storm drain. In the Las Vegas Valley, storm drain water reaches Lake Mead untreated, and Lake Mead is the valley’s main drinking water source. Take partly used containers to the Republic Services household hazardous waste drop-off, which accepts pesticides in sealed containers. Check the current calendar first, because the open site rotates between North Las Vegas and Henderson.
How long should I stay out of the house after using a fogger?
Follow the label, which sets the wait time and ventilation steps for that product. The CDC found going back in too early was one of the most common causes of fogger illness. For re-entry after professional treatment, see [is pest control safe for pets and kids].
The bottom line
The real difference between DIY pest control and professional treatment is not the chemical. A professional identifies the pest, puts product where the colony lives instead of where you saw one insect, and stops pests from coming back.
Retail sprays have a place. Used exactly as labeled, on a light problem, they are fine. The trouble starts when a can becomes the plan for a problem that keeps coming back.
What to do next:
- Read the label of every pest product you own, including the storage section
- Move pesticides out of the hottest part of the garage and out of reach of children
- Never pour product into a drink bottle or unlabeled sprayer
- Skip foggers entirely, especially near gas pilot lights
- Stop spraying ants and switch to bait, or call someone
- Save the containers of anything you have used so a technician can see them
- If a problem has survived two rounds of DIY treatment, request a quote and tell us what you have already tried
