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Pest identification

Correct identification changes the answer to nearly everything else. A carpenter ant and an odorous house ant need opposite responses.

Start here

The key takes you from what you can observe to a species or a short list, and states how confident that identification is.

Start the identification key

By group

Ants

Ant identification decides the answer completely. A carpenter ant excavating a wet joist and an odor…

Cockroaches

Species matters more than size here. A German cockroach is an indoor, fast-reproducing population pr…

Termites

Mud tubes versus frass pellets is the single most useful diagnostic distinction in the vertical, bec…

Rodents

Droppings shape and size separate mice from rats reliably, and the two differ in where they travel, …

Bed bugs

Bed bugs are identifiable with care, and the evidence they leave — shed skins and fecal spotting — i…

Spiders

Two North American spiders are medically significant, and both are widely over-reported. Most reclus…

Stinging insects

Telling a honey bee from a yellowjacket changes both the urgency and the right response — one is a p…

Pantry and fabric pests

These are the insects most often mistaken for bed bugs. Carpet beetle larvae in particular account f…

Wood-destroying beetles

Flour-fine frass versus hard six-sided pellets separates powderpost beetles from drywood termites, a…

Ticks

Tick species determines which diseases are plausible in your area, which is the only reason tick ide…

By evidence

If you never saw the animal, start from what you did find.

Droppings

Damage to wood

Shed skins and casings

Sounds in walls or ceilings

Mud tubes

Frass, pellets, and powder

Open data

We publish the full species dataset — scientific names, written diagnostic features, and confused-with pairs — as open, machine-readable data. species.json

Reviewed by AgainstPest Editorial Team Last reviewed: