The short answer
- Crack-and-crevice: small amounts of pesticide placed directly into the cracks and crevices where insects hide or get into a building, such as expansion joints, gaps between parts of the structure, and gaps between equipment and floors.[1][2][4]
- Spot: a treatment of small, distinct areas where pests are likely to occur. Indoors, a spot shouldn't exceed 2 square feet, and the current Bifenthrin TC label applies the same 2-square-foot limit to outdoor spot treatments around homes.[2][1][3][4]
- General surface and broadcast: a general spray covers broad surfaces such as walls, floors and ceilings, and a broadcast application covers an entire area uniformly, as on a lawn. The Bifenthrin TC label forbids broadcast applications to interior surfaces of homes.[2][1][3][4]
- Space treatment: pesticide released into the air of an enclosed area by foggers, misters, aerosols or vapor dispensers to hit flying pests and exposed crawling pests. A label that doesn't allow it may say 'not for use as a space spray'.[2][3][4]
- Outdoors, the bifenthrin label limits residential sprays to spot or crack-and-crevice treatments except on soil, lawns and other vegetation, in a perimeter band up to 7 feet wide, under protected eaves, in one-inch bands around doors and windows, and on some walls.[3]
Why the method matters
Georgia's Structural Pest Control Commission tells professionals that any method of application they use must be permitted by the pesticide label, and to check the actual label because no list of methods covers every product.[2]
EPA's Label Review Manual, which its staff use to check labels before registration, lists the same spray types (space, general area, spot, and crack and crevice) and requires every label to carry the statement that using a product in a manner inconsistent with its labeling violates federal law.[4]
Which method fits depends on the habits of the pest, the properties of the pesticide, the equipment, and the cost and efficiency of the alternatives.[2]
Labels also signal who a product is for. California's Department of Pesticide Regulation says homeowner products give rates per 1,000 square feet or per gallon, pint and so on, and carry special precautions to protect children and pets, while directions given per acre generally indicate a product meant for commercial use.[1]
Crack-and-crevice treatments
A crack-and-crevice treatment puts small amounts of insecticide directly into the cracks and crevices where insects hide or through which they may enter a building. Typical openings are expansion joints, gaps between different elements of construction, and gaps between equipment and floors.[1][2][4]
The equipment has to fit the job. California's Department of Pesticide Regulation says an emulsifiable or oil-based spray, including a non-pressurized ready-to-use product, must go on as a pin stream; a pressurized spray needs an injection or insertion tube; and a dust needs a bulb duster or other tool that puts it directly into the crack. Only minimal amounts of pesticide should remain on the surface.[1]
Extension guides describe the same tools. Nebraska Extension suggests a crack and crevice applicator tool for pressurized liquid products and, for dusts, a hand duster with a tube and tip that fits snugly into the opening, or the crack and crevice tip supplied with the product.[7]
Indoor directions on the Bifenthrin TC label show where these treatments go: baseboards, corners, storage areas, closets, around water pipes, doors and windows, attics and eaves, behind and under refrigerators, cabinets, sinks, furnaces and stoves, and the undersides of shelves and drawers, using a low-pressure, coarse crack-and-crevice or spot spray.[3]
Gel baits are often placed the same way. UC IPM says to apply gel with a bait gun or syringe in small dabs in the cracks and crevices where cockroaches will find it.[8]
Void and foam treatments
A void treatment is applied into wall and equipment voids. A foam treatment mixes the pesticide with a foaming agent for places such as voids.[2]
Turning a liquid into foam lets it reach through structural voids. The Bifenthrin TC label gives foam concentrations and says to make sure the foaming agent is compatible with the product before applying.[3]
Advice for homeowners is more cautious. For carpenter ants nesting in a wall void, Nebraska Extension says to place a dust insecticide inside the wall and not to use liquid insecticides mixed with water or ready-to-use liquids there, because water inside a wall void can damage insulation, plaster board or electrical wiring. Use only products labeled for wall voids of homes, and you may need to drill small access holes.[7]
Spot treatments
Indoors, a spot treatment is limited to areas where insects are likely to occur but that won't contact food or utensils and won't ordinarily be touched by workers. Georgia and EPA give floors, walls, and the bases or undersides of equipment as examples. A spot should not exceed 2 square feet.[1][2][4]
Where the 2-square-foot rule comes from differs a little by source. Georgia's notice states it without a setting. California applies it to the institutional setting, and EPA's Label Review Manual ties it to limiting exposure in commercial food areas. The Bifenthrin TC label sets it for outdoor spot treatments around homes.[2][1][4][3]
Outdoors, a spot treatment covers small, irregular areas, usually the specific places a pest is active within a larger area. The 2026 Bifenthrin TC label caps outdoor spot treatments around homes at 2 square feet as well, for example 2 feet by 1 foot or 4 feet by half a foot.[1][3]
Not every pest suits spot work. For ticks in lawns, the same label says to treat the entire area where people may contact ticks and not to make spot treatments.[3]
General surface, broadcast and directed sprays
A general surface or general spray treatment covers broad expanses of surface such as walls, floors and ceilings, or the outside of a building.[1][2][4]
A broadcast application spreads a granular, bait or liquid pesticide uniformly over an entire area. The lawn directions on the Bifenthrin TC label, for instance, call for a broadcast treatment.[2][3]
Broad sprays are the most restricted indoors. The Bifenthrin TC label says not to make a broadcast application to interior surfaces of homes. In food-handling businesses it allows general surface applications only when the facility isn't operating and food isn't exposed, while spot and crack-and-crevice treatments can be made during operation with food covered or removed.[3]
A directed spray targets the pest itself, such as an insect nest, and keeps pesticide off plants and animals you don't mean to treat.[2]
Perimeter and other outdoor sprays
An exterior perimeter application treats the border or outer boundary of an area, such as the band of ground along a building's foundation.[2][3]
For residential outdoor sprays, the Bifenthrin TC label as revised in 2026 limits every outdoor spray to spot or crack-and-crevice treatment except for these uses:[3]
- Soil, lawns, turf and other vegetation (pervious surfaces).[3]
- A perimeter band no more than 7 feet wide from the base of a building onto soil, mulch or lawn.[3]
- The undersides of eaves and soffits, and doors or windows, that a covering, overhang or awning permanently protects from rain.[3]
- Bands no more than an inch wide around doorways, windows and other places pests could get in.[3]
- Walls above driveways, sidewalks and other hard surfaces, up to 2 feet above the ground.[3]
- Walls above soil, lawn, mulch or other vegetation, but only if that ground doesn't drain into ditches, storm drains, gutters or surface waters.[3]
- The same label bars spraying sidewalks, driveways and patios directly except as a spot or crack-and-crevice treatment, and bars spraying during rain, in wind over 15 mph, or to the point of runoff. It also says to avoid spraying when rain is expected before the product has had at least 4 hours to dry, since rain within 24 hours can cause runoff.[3]
- These are one product's limits. Follow the label on the product you're actually using.[3][2]
Space treatments, mists and fogs
A space treatment disperses pesticide into the air of an enclosed area with foggers, misters, aerosol devices or vapor dispensers, to control flying pests and exposed crawling pests. A mist, common in mosquito and other flying-insect control, is a finely divided liquid suspended in a gas.[2][4]
A label has to allow this method. The Bifenthrin TC label's indoor directions, for example, end with 'Not for use as a space spray.'[3]
Why foggers miss hidden pests
A space spray or fogger mostly hits what is out in the open. NPIC says total release foggers spray a mist into the air that falls onto exposed surfaces, and they do not reach into unexposed voids, cracks and crevices where pests hide, so they may not work on pests such as bed bugs and cockroaches.[5]
EPA makes the same point for bed bugs: the pesticide in a fogger has to contact the insect to kill it, and if it does not reach the cracks and crevices where they hide, they will not be killed. EPA says foggers should not be the only bed bug control.[6]
Some fogger ingredients repel pests, which can push them further into their hiding places, where they are harder to reach. That is why a crack-and-crevice or bait placement, which puts the product where the insects live, is the method most indoor pest labels and guides lean on.[5][1][2]
If you do use a fogger, use no more than the number the label gives for the space; more does not control pests better and can raise the risk of fire or explosion.[5][6]
Bait placement, scattering and painting
Placement means putting or arranging the pesticide exactly where it's needed, which is common with self-contained bait stations, gel baits, fly baits and many rodenticides. Sprinkling or scattering distributes drops or particles and is common with granular products, and painting means brushing or swabbing a liquid pesticide onto a surface.[2]
Crawl spaces, 'exterior use only' and food areas
California's Department of Pesticide Regulation treats any application inside a crawl space as an indoor use, so applying a product labeled 'For Exterior Use Only' in a crawl space conflicts with its labeling even if the space has vents or air ducts.[1]
In the department's reading, 'For Exterior Use Only' means applying only to the exterior wood surfaces of windows, window frames, doors, steps, porches and foundation sills, and not, during construction, to surfaces that will be indoors when the building is finished.[1]
In businesses and institutions, labels for food areas may allow only crack-and-crevice or spot treatment there. Food areas include places where food is received, served, stored, packaged or prepared, while garages, garbage rooms, entries, offices and boiler rooms count as non-food areas.[1]
Common questions
- Can I spray a crack-and-crevice product along my baseboards?
- If the label lists baseboards, yes, but put it into the gap as a pin stream, or through the tube on an aerosol, so that only minimal amounts remain on the surface.[1][3][7]
- Is a perimeter spray the same as a broadcast spray?
- No. A perimeter application treats the border of an area, such as a band along a foundation, while a broadcast application covers an entire area uniformly, as on a lawn.[2][3]
- What does 'not for use as a space spray' mean?
- A space treatment releases pesticide into the air of an enclosed area, as a fogger or mister does. A product labeled 'not for use as a space spray' should only be applied by the methods its label lists, such as crack-and-crevice or spot application.[2][3]
- Can I spray liquid insecticide into a wall void?
- Only if the label lists voids. Professional labels may allow foam or liquid in structural voids, but Nebraska Extension advises homeowners to use a labeled dust there instead, because water in a wall can damage insulation, plaster board and wiring.[3][7]
- Why not just set off a bug bomb instead?
- Foggers settle on exposed surfaces and don't reach the cracks, crevices and voids where cockroaches and bed bugs hide, and some fogger ingredients drive pests deeper into hiding.[5][6]
Sources
- California Department of Pesticide Regulation, “Pesticide Use Enforcement Compendium, Volume 8, Chapter 4: DPR Specific Use Site Interpretations.” cdpr.ca.gov/wp-content/uploads/2025/01/volume_8_chapter4.pdf (accessed 2026-11-10)
- Georgia Structural Pest Control Commission, Georgia Department of Agriculture, “Notice 11-1: Pesticide Methods of Application (revised March 12, 2013).” agr.ga.gov/sites/default/files/documents/pest-control/spcc-notice-11-01-methods-of-application.pdf (accessed 2026-11-10)
- U.S. EPA Pesticide Product Label System, “Bifenthrin TC (alternate name Bifen I/T) label, EPA Reg. No. 53883-118 (EPA-stamped, September 1, 2026).” www3.epa.gov/pesticides/chem_search/ppls/053883-00118-20260901.pdf (accessed 2026-11-10)
- U.S. Environmental Protection Agency, “Label Review Manual, Chapter 11: Directions for Use (revised December 2024).” www.epa.gov/system/files/documents/2024-12/lrm-chapter11_2024.pdf (accessed 2026-11-10)
- National Pesticide Information Center, “Total Release Foggers.” www.npic.orst.edu/ingred/ptype/fogger.html (accessed 2026-11-10)
- U.S. Environmental Protection Agency, “Should I Use a Fogger?.” www.epa.gov/bedbugs/should-i-use-fogger (accessed 2026-11-10)
- Nebraska Extension, University of Nebraska-Lincoln, “Carpenter Ant Management (G1738).” extensionpubs.unl.edu/publication/g1738/na/html/view (accessed 2026-11-10)
- 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)