Pest Identifier
Answer four quick questions and find out which pest you are most likely dealing with, plus what to do first.
How the Pest Identifier works
You answer four questions: what the pest looks like, where you found it, what signs you have noticed and when it is most active. Each answer adds points to the pests it is commonly linked with, and the tool shows the best matches with simple first steps.
It covers the pests we write about most: ants, cockroaches, rats and mice, termites, bed bugs, mosquitoes and spiders. It is a guide to point you in the right direction, not a diagnosis.
What each pest tends to leave behind
Many pests are active at night, so the evidence is often easier to find than the animal. This table lists the clue that best separates each pest from the ones it is most often confused with.
| Pest | The clue to look for | Where to look |
|---|---|---|
| Ants | A moving trail between food and an entry point, and tiny mounds of fine soil along edges | Counters, window frames, patio edges |
| Cockroaches | Dark specks like ground pepper or coffee grounds, brown capsule-shaped egg cases, a musty smell | Behind appliances, under sinks, cabinet corners |
| Rats and mice | Rice-shaped droppings (mouse droppings are about a quarter inch, rat droppings are clearly larger), greasy rub marks, shredded nesting material | Along walls, behind stored boxes, attics, basements |
| Termites | Mud tubes, wood that sounds hollow when tapped, piles of discarded wings, tiny pellet-like droppings near wood | Foundation walls, beams, window sills |
| Bed bugs | Rust-colored spots on sheets, shed skins, live bugs about the size of an apple seed | Mattress seams, headboards, bed frames |
| Mosquitoes | Wriggling larvae in standing water, and bites around dusk and dawn | Plant saucers, gutters, bird baths, blocked drains |
| Spiders | A web with a recognizable shape (sheet, funnel, tangle or orb) and small silk egg sacs | Corners, garages, sheds, under eaves |
How to take a photo or sample that can be identified
Size and body shape separate look-alikes more reliably than color, so a photo needs to show both.
- Shoot in daylight from directly above, with the whole body in frame.
- Place a coin or ruler next to it for scale.
- Take a second photo of where you found it and any damage nearby.
- If it is dead, keep it in a sealed container or tape it to a card. Many university extension offices will identify an insect from a clear photo or a sample.
Look-alikes that fool people
| Often mistaken | How to tell them apart |
|---|---|
| Bed bug and carpet beetle larva | Bed bugs are flat, reddish-brown and found near sleeping areas. Carpet beetle larvae are bristly and banded, and live near wool, fabric and pet hair. |
| Cockroach and ground beetle | A beetle has hard wing covers that meet in a straight line down its back and shorter antennae. Roaches have long antennae and no straight seam. |
| Mosquito and crane fly | Crane flies are larger with very long legs and do not bite. |
| Spider and harvestman (“daddy longlegs”) | Harvestmen have one rounded body section and do not spin webs. Spiders have two body sections. |
Before you treat anything
Hold off on spraying until you know what you have. A product made for ants does little against bed bugs, and the wrong treatment can scatter a colony or push pests deeper into walls. A crushed or soaked insect is also much harder to identify.
If the results point to termites, bed bugs or rodents inside walls, treat that as a cue to book a professional inspection. Also contact a professional if you hear activity in walls or ceilings, find droppings in several rooms, or someone has a bite with spreading redness, severe pain or other serious symptoms (seek medical advice for those).
Once you know the pest, our pest control cost calculator can show what treatment is likely to cost.