Signs you need pest control, and signs you can wait
Updated · KeystoneProGuide editorial team
Does one bug mean you need an exterminator?
Not always. The EPA's integrated pest management principles say that sighting a single pest does not always mean control is needed, and that many insects are harmless and some are beneficial. The question is whether the signs point to an established problem, a pest that damages the house, or one that affects health. The signs below are the ones the agencies describe.
What are the signs of termites?
Termites rarely show themselves. The EPA says most people do not know they have termites until they see a swarm or find damage during construction. Look for:
- Swarms or shed wings indoors. Penn State Extension says swarming termites or their wings are a sure sign termites are working in a building, and that in Pennsylvania swarms usually emerge between February and June. Shed wings near windows and doors are often the only evidence.
- Mud tubes. Earth-colored tubes on cellar walls, posts, studs, sills and trim are protected runways from the soil to the wood.
- Hollow or soft wood. The EPA suggests probing exposed wood for hollow spots with a flathead screwdriver. Wood attacked by termites has passages lined with an earth-like material.
Swarming ants are often mistaken for termites. The EPA and Penn State give the same test: ants have a narrow waist, bent antennae and front wings longer than the hind wings; termites have a broad waist, straight antennae and wings of equal length.
Penn State adds a point that should slow you down: damage is usually the result of years of infestation and is not a sudden onslaught, so a sign of termites is a reason to arrange inspections, not to sign the first contract offered.
What are the signs of carpenter ants?
Large, dark, wingless ants about half an inch long indoors, which Penn State says are usually the first sign. Penn State says that alone does not prove a nest is inside; it may be outside, near the building. Signs of an indoor nest are numerous winged ants at windows inside, and piles of coarse, stringy wood shavings mixed with insect parts sifting from cracks, moldings or the attic. Unlike termite galleries, carpenter ant galleries are smooth and contain no soil. Penn State says carpenter ants seldom damage sound, dry wood; they look for moist or rotting wood, so a nest also points to a leak worth fixing.
What are the signs of mice and rats?
Droppings, urine spots, gnaw marks, nesting material and nibbled food, which the CDC names as the places to set traps. The CDC says that if new droppings or gnawing continue after a week of trapping, you may be dealing with rats rather than mice, since rats are cautious and avoid new objects.
Look also for the way in. The CDC says a mouse can fit through a hole the width of a pencil, and lists gaps around pipes, vents, utility lines, the foundation and the roof eaves among the places to check.
What are the signs of bed bugs?
Not bites alone. The EPA says bites are a poor indicator, because they look like other insect bites or rashes and some people do not react at all. The more reliable signs are:
- rusty or reddish stains on sheets or mattresses;
- dark spots of excrement that may bleed into fabric like a marker;
- tiny pale eggs and shed skins, about 1mm long;
- live bugs in mattress seams, tags and the bed frame.
The EPA warns that carpet beetles are easily mistaken for bed bugs, and that finding an infestation early makes it far less costly and easier to treat.
When is a wasp or yellowjacket nest a problem?
When it is where people will disturb it. Penn State Extension says foraging wasps away from their nest are usually not defensive, but that nests near entrances, busy walkways or where children play are likely to be disturbed. Yellowjackets often nest underground, and the only sign may be a small hole with insects flying in and out. A nest found in fall will die off over winter on its own; one found in May or June may be small enough to ignore but could become a problem by August or September.
Which signs are not a reason to treat the house?
- Stink bugs gathering in autumn. The EPA says brown marmorated stink bugs do not bite, do not damage buildings and do not reproduce in homes. Sealing gaps and vacuuming are its main advice.
- A few spotted lanternflies. Penn State says low numbers may not need treatment and the insect cannot bite or sting.
Which signs need a call the same day?
Any possible contact with a bat, or a bat found inside the house. The CDC says bat bites can be too small to notice, and to contact animal control or the health department so the bat can be tested for rabies before it is released.
What a homeowner can handle alone is in DIY or hire, and seasonal timing is in how often and when. Companies are on the pest control directory page.
Sources
- Integrated Pest Management (IPM) Principles, U.S. Environmental Protection Agency
- Termites: How to Identify and Control Them, U.S. Environmental Protection Agency
- Eastern Subterranean Termites, Penn State Extension
- Carpenter Ants, Penn State Extension
- How to Trap Up to Remove Rodents, U.S. Centers for Disease Control and Prevention
- How to Seal Up to Prevent Rodents, U.S. Centers for Disease Control and Prevention
- How to Find Bed Bugs, U.S. Environmental Protection Agency
- Getting Rid of Paper Wasps, Yellowjackets, and Other Stinging Insects, Penn State Extension
- Brown Marmorated Stink Bug, U.S. Environmental Protection Agency
- Preventing Rabies from Bats, U.S. Centers for Disease Control and Prevention
- Spotted Lanternfly Management Guide, Penn State Extension