Specific questions, direct answers

Pest questions

These pages answer one search at a time — can rats climb walls, what temperature kills bed bugs, do ants come inside when it rains — then send you to the species article for the full control sequence. 63 questions so far.

Helen Marsh reviews them against EPA, CDC, and extension sources. They are not a substitute for a licensed inspection or clinical care.

Rodents

• Can rats climb walls? Yes. Both commensal rats climb. {pest:roof-rat} are the athletes — vines, brick, stucco…
• Can rats climb brick? Yes. Brick with recessed mortar is a ladder, not a fortress. {pest:roof-rat} use it to…
• How high can rats jump? Plan on about 2–3 feet of vertical jump for a healthy commensal rat, plus whatever…
• Can rats swim? Yes. {pest:norway-rat} are strong swimmers and they use sewers and flooded crawlspaces…
• Do rats come out during the day? They are mostly nocturnal, but daylight rats happen. A rat in the open at noon often…
• How big is a rat hole? A young {pest:norway-rat} can use a gap about ½ inch (think a US quarter as the teaching…
• Can rats chew through concrete? Sound poured concrete is not a food. Rats exploit cracks, the cold joint at a slab, a…
• Can rats chew through plastic? Yes. {pest:norway-rat} and {pest:roof-rat} chew plastic bins, trash can lids, and cable…
• What does a rat nest look like? A {pest:norway-rat} nest is often a burrow in soil or a stuffed void in a lower wall…
• How many rats live in a nest? Do not treat “one nest” as one rat. Commensal rats live in social groups. A burrow…
• How long can rats live without food? A commensal rat will not sit in a sealed empty box for weeks. They need water more…
• Do rats live in attics? Yes — especially {pest:roof-rat}. Attic grease, spindle droppings on joists, and a fruit…
• Can rats climb trees? Yes. {pest:roof-rat} are the tree rats of the US South and West Coast. Palms, citrus…
• Does peppermint oil repel rats? Not as a control program. Essential-oil cotton balls are a scent, not a door sweep. Rats…
• How small a hole can a mouse fit through? A {pest:house-mouse} can use a gap about ¼ inch (6 mm). The pencil test is the field…
• Can mice climb walls? Yes. {pest:house-mouse} climb rough drywall corners, brick, wire, and the back of…
• How many mice is an infestation? If a {pest:house-mouse} is using the building, you already have a control job. They…
• Do mice eat cardboard? They shred cardboard for nesting and they cut cereal boxes to reach grain. Cardboard is…
• What does mouse poop look like? {pest:house-mouse} droppings are small (about ⅛–¼ inch), pointed, and scattered…
• How can I tell rat sounds from mouse sounds in the wall? Light, rapid scratching in a kitchen wall is often a {pest:house-mouse}. Heavier thumps…
• Can squirrels get in through the roof? Yes. {pest:gray-squirrel} chew a fascia return, a plastic vent, or a rotten roof edge…

Cockroaches

• Can cockroaches fly? {pest:german-cockroach} can technically move their wings but kitchen infestations spread…
• Why do I see cockroaches during the day? German cockroaches are nocturnal. Daytime sightings, especially of nymphs on a counter…
• Do cockroaches bite? They can nibble in rare, heavy infestations, usually on sleeping people or fingernail…
• What temperature kills cockroaches? A home thermostat will not cook a {pest:german-cockroach} population. They live next to…
• Do cockroaches die in winter? Outdoor {pest:american-cockroach} and oriental cockroaches slow when it is truly cold…
• Can cockroaches live in the fridge? {pest:german-cockroach} nest in the refrigerator’s warm compressor area, cardboard…
• How long can a cockroach live without a head? The internet number is a stunt, not IPM. Insects do not breathe like mammals; a headless…

Ants

• What temperature do ants die? There is no thermostat number that kills every ant in a yard. Foragers die on hot…
• Does boiling water kill ants? Pouring boiling water on a {pest:fire-ant} mound kills some ants near the top and is a…
• Why do ants come inside when it rains? Rain floods shallow nests in lawns, pavement cracks, and mulch…
• Why are ants in my bathroom? Bathroom ants are usually drinking, not nesting in the toothpaste…
• Do carpenter ants eat wood? No. {pest:carpenter-ant} chew galleries in wet or rotting wood to live in. They dump…
• Do ants sleep? Ants rest in short bouts rather than a human night. You will still see 24-hour traffic…

Termites

• Can termites come through concrete? {pest:subterranean-termite} travel from soil through cracks, plumbing penetrations, and…
• Do termites eat painted wood? Paint does not make lumber inedible. {pest:subterranean-termite} reach wood from soil…
• Do termite swarms mean the house is infested? A swarm inside a living room, with wings on a windowsill, is a strong sign that…
• How long does a termite swarm last? An individual flight can be brief — a humid evening, a few minutes of insects around a…
• What temperature kills termites? You cannot set the furnace to a number that kills {pest:subterranean-termite} in the…

Bed bugs and biting pests

• What temperature kills bed bugs? Lethal heat for {pest:bed-bug} is about 113°F (45°C) held long enough to reach…
• Will a dryer kill bed bugs? Yes, for items that can go in a dryer: high heat for 30 minutes or more is a widely…
• Can bed bugs live in a suitcase? Yes. {pest:bed-bug} hide in zipper folds, lining, and clothing. Hotel luggage racks…
• Do bed bugs fly? No. {pest:bed-bug} have no wings as adults that fly. They crawl to a sleeper. If…
• How long can bed bugs live without feeding? {pest:bed-bug} can survive months without a blood meal in moderate indoor temperatures…
• Can you see bed bugs during the day? {pest:bed-bug} hide by day in seams and cracks. You can still see them in daylight if…
• Do bed bugs live in hair? No. {pest:bed-bug} do not colonize hair. They live in cracks and feed, then leave. Itch…
• What temperature do mosquitoes die? A hard freeze knocks down many adult {pest:mosquito} in temperate states. Eggs and…
• Do mosquitoes die in winter? In cold states, most adult {pest:mosquito} die or become inactive. Eggs of some species…
• How long do ticks live without a host? Unfed {pest:blacklegged-tick} and {pest:american-dog-tick} can persist months in humid…
• Can fleas live in carpet? Yes. {pest:flea} eggs fall off the host into carpet, rugs, and upholstery. Larvae live…
• Does bleach kill fleas? Do not pour bleach on a dog, a carpet, or a lawn as flea control. It is not a labeled…

Myths and DIY

• Do ultrasonic pest repellers work? Not as a stand-alone method. Plug-in ultrasonic gadgets do not close a ¼-inch mouse gap…
• Does vinegar kill ants? Vinegar on a counter removes some trail pheromone so {pest:odorous-house-ant} wander. It…
• Does cinnamon kill ants? Cinnamon powder is a kitchen spice, not a {pest:odorous-house-ant} program. They walk…
• Do mothballs work for mice? Do not pour mothballs in a kitchen, a crawl, or a car as mouse control. Those products…
• Does cedar repel moths? Cedar scent fades. {pest:clothes-moth} larvae eat keratin in dirty wool. A block of…
• Can pesticides be mixed together? Mix pesticides only when every label in the tank says you may. Homemade cocktails —…
• Does dryer heat kill clothes moths? A hot dryer can kill {pest:clothes-moth} stages on garments that survive high heat. It…
• Do fruit flies come from drains? {pest:fruit-fly} breed in rotting fruit, beer residue, and a potato in a bag — not…

Wildlife

• Can raccoons open doors? {pest:raccoon} can work simple latches, lift garbage lids, and use a pet door. They are…
• Do bats in the attic mean rabies? A {pest:bat} colony in an attic does not mean every animal has rabies. Any bat found in…
• Will a skunk spray in the house? {pest:striped-skunk} spray when they cannot flee. A crawlspace, a window well, or a dog…
• Can opossums get in a pet door? A standard pet door is an invitation. {pest:opossum}, {pest:raccoon}, and…