Back to Integrated Pest Management
This Photo Reference Table is meant to be the primary resource to aid in pest identification for Integrated Pest Management activities. Each image links out to a larger version. It is highly recommended that you open these images in new windows, to avoid needing to re-load this table. When possible, image sources have been provided.
| Name | Scientific Name | Approx. size | Main Image | Other Image | Larval/Nymph Image | Notes |
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| Ant | Formicidae family | 2-15 mm | image source |
Blunderer. This family covers a wide variety of any sizes and colors, but all are non-threatening to collections. | ||
| Ant, Flying | Formicidae family | 2-15 mm | ![]() image source |
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Blunderer. Flying ants have elbowed antennae, two pairs of wings of different sizes, and long legs (to differentiate from termites) |
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| Beetle, Asian | Harmonia axyridis | 5-6 mm | ![]() image source |
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Blunderer. These beetles are unavoidable in the fall and early winter after soy crops are harvested. |
| Beetle, Cabinet | Trogoderma angustum | 2-4 mm | ![]() image source |
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Library/Museum Pest. Eats both plant and animal specimens as well as untanned hides and proteins (leathers,gelatin sizing, and animal based glues) |
| Beetle, Carpet | Anthrenus verbasci | 2-3 mm | ![]() image source |
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Library/Museum Pest. Backs covered in colored scales. Larvae are particularly destructive and eat animal specimens, fur and feather, and woolen textiles. |
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| Beetle, Cigarette | Lasioderma serricorne | 2-3 mm | ![]() image source |
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Library/Museum Pest. Also called a tobacco beetle. Similar in appearance to a drugstore beetle, but has finer, more straight antennae and no lines on the back of their wing covers. Eat a wide range of dried plant materials including tobacco, but also known to eat animal proteins. |
| Beetle, Click | Conoderus bellus | 2-6 mm | ![]() image source |
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Blunderer. Identifiable by the pointed protrusions on the corners of the thorax where it meets the abdomen. The larva are also called wireworms. |
| Beetle, Drugstore | Stegobium paniceum | 2-3 mm | ![]() image source |
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Library/Museum Pest. Also called a biscuit beetle. Eat dried vegetable materials and cellulose, including tobacco, nuts, and dried plant specimens. Also noted to eat paper mache, some animal specimens and fungi. |
| Beetle, Furniture | Anobium punctatum | 3-5 mm | ![]() image source |
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Library/Museum Pest: Wood borer, leaves gritty frass and bored exit holes about 1.5-2 mm in diameter. Prefer cool, damp conditions. |
| Beetle, Ground | Carabidae family | 6-38 mm | ![]() image source |
Blunderer. Beneficial predatory beetle that lives in corn and soybean fields. Prevalent in warm weather. A very large, very common family. |
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| Beetle, Hide | Dermestes peruvianus | 7-10 mm | ![]() image source |
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Library/Museum Pest. Eat leather and skins, but not generally good condition tanned leather. An infestation may indicate a dead rat/pigeon or other animal somewhere on the premises. |
| Beetle, Odd | Thylodrias contractus | 1-4 mm | ![]() image source |
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Library/Museum Pest. Male only has wings. Eats dead insects and known to attack natural history specimens. |
| Beetle, Powder post |
Lyctus brunneus | 5-6 mm | ![]() image source |
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Library/Museum Pest. Wood borer, leaves very fine talc-like frass. Tends to eat relatively fresh wood. |
| Beetle, Rove | Staphylinidae family |
1-20 mm | ![]() image source |
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Blunderer. Identifiable by short elytra (wing covers that typically hide the abdomen) and segmented abdomen. |
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| Beetle, Spider | Ptinus tectus | 3-5 mm | ![]() image source |
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Library/Museum Pest. Feed on animal and vegetable detritus, can damage books, paper, textiles and wood if located near food. Frequently a sign of poor housekeeping or animal carcasses or nests in the vicinity. |
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| Beetle, Weevil | Curculionidae family | 3-10 mm | ![]() image source |
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Blunderer. Most have a well-developed downward-curved snout; antennae elbowed, clubbed, and the first segment often fits into a groove in the side of the snout. |
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| Book Louse | Psocoptera | 1 mm | ![]() image source |
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Indicator. Feed on microscopic molds and can infest flour, paper and cardboard. Prefer warm, humid (above 60 % RH) environments. |
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| Centipede, House | Scutigera coleoptrata | 5-30 mm | ![]() image source |
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Indicator. The house centipede, has an average of 17 pairs of very long, delicate legs and a rigid body. The legs also have dark stripes. House centipedes feed on spiders, bedbugs, termites, cockroaches, silverfish and other household pests. |
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| Cockroach, American |
Periplaneta americana | 30-40 mm | ![]() image source |
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Library/Museum Pest. Cockroaches are ubiquitous in campus environments and travel through steam tunnels under campus and into facilities closets. Cockroaches can damage library materials by chewing on them or excreting onto them, which causes staining. American cockroaches are the largest species found indoors in IL and are all brown with large wings. |
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| Cockroach, German |
Blattella germanica | 10-15 mm | ![]() image source |
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Library/Museum Pest. Smaller than the American Cockroach. Identifiable from other cockroaches by the two black striped on the back of the thorax. |
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| Cockroach, Oriental |
blatta orientalis | 10-30 mm | ![]() image source |
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Library/Museum Pest. Smaller than American Cockroaches. Identifiable from other cockroaches by the lack of wings and darker color. |
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| Cricket, Ground | Trigonidiidae Nemobiinae | 5-12 mm | ![]() image source |
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Blunderer. Crickets often "swarm" in the late summer and may enter buildings in large numbers, but pose no threat. |
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| Damsel Bug | Dicyphus hesperus | 4-8 mm | ![]() image source |
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Blunderer. | |
| Fly, Fruit | Drosophilidae family | 3-4 mm | ![]() image source |
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Blunderer. These are often a sign of poor housekeeping and unclean trashcans or rotting vegetable matter. |
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| Fly, variable | Muscidae family | 3-8 mm | ![]() image source |
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Blunderer. | |
| Gnat | Anisopodidae family | 3-6 mm | ![]() image source |
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Blunderer. | |
| Leaf Hopper | Cicadellidae family | 3-6 mm | ![]() image source |
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Blunderer. | |
| Millipede | Diplopoda class | 20-50 mm | Blunderer. Millipedes are commonly found during the Spring and Fall as they enter buildings from the outside. They can live in many different habitats such as mulched flower beds where moisture, humidity, and organic matter are high. |
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| Minute Pirate Bug |
Anthocoridae family | 2-4 mm | Blunderer. Minute Pirate Bugs are most easily recognizable by the V shape their elytra (wing covers) make above the wings. |
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| Mite, Predatory | Several | 1 mm | Indicator. Predatory mites feed on other pests. Frequently, they are orange or red in color. |
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| Mite, variable | Several | 1 mm |
Indicator: Mites are an indicator of high-humidity environments. Most are non-biting, but some varieties can bite humans. |
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| Mosquito | Culicidae family | 3-10 mm |
Blunderer. A nuisance that frequently follows staff and patrons into buildings in the summer months. |
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| Moth, Clothes | Tineola bisselliella | 10-20 mm | ![]() image source |
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Library/Museum Pest. Larva found in dark storage areas on fur, feathers, skins, wool and soiled textiles. |
| Moth, variable | Lepidoptera order | 5-20mm | ![]() image source |
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Blunderer. Except for clothes moths, most common outdoor moths are blunderers into libraries. |
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| Noseeum (biting midge) |
Several | 1-2 mm | image source |
Blunderer. This often come into buildings on people who have traveled through the grass recently. |
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| Pill Bug / Sow Bug |
Armadillidiidae family | 8-12 mm | ![]() image source |
Blunderer. Pillbugs can roll up into a tight ball when disturbed. Although they sometimes enter in large numbers, they do not bite, infest food, clothing, or wood. Since they require moisture, they do not survive indoors for more than a few days unless they are in very moist conditions. |
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| Silverfish | Lepisma saccharina | 5-15 mm | ![]() image source |
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Library/Museum Pest. Associated with high RH (over 75%). Feed on microscopic mold, glue, ink, and starch. Grazers |
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| Spider | Araneae order | 5-40 mm | ![]() image source |
Indicator. Eats other insects. See identification guide for Brown Recluse spiders. Otherwise, usually harmless |
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| Springtail | Entomobryidae family | 1 mm | ![]() image source |
Indicator. Springtails are carrion feeders that prefer high humidity. Very small and easily missed, they are best identified by their distinctive shape. |
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| Termite |
Kalotermitidae |
4-7 mm | ![]() image source |
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Library/Museum Pest. Winged and wingless (worker) termites have straight antennae and a long body with short lets. Winged termites have two pairs of wings of the same size and shape. Can infect timber and wooden objects as well as wooden structures. Dry wood termites can infest wooden objects. |
| Wasp, variable | Vespidae family | 12-16 mm | ![]() image source |
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Blunderer. However can form hives inside buildings. If large population is observed, call about extermination and/or removal of nest. |