Utah Plant Pest Diagnostic Lab

Top 20 Identified Insects

Aphids (Aphididae)

aphidThere are over 1300 aphids in North America that vary in color from green, brown, red, to black. These small (< 0.5 inches), sap-sucking insects can be identified by the tubes sticking out of their back side (cornicles), however not all aphids have well-developed cornicles. Healthy plants can tolerate substantial feeding, but excessive feeding can cause plant stress, excess honey dew production, and the growth of sooty mold on honeydew-covered leaves. Some aphids produce galls, while others produce white wax-like material on their bodies (woolly aphids)-some are vectors of plant pathogens.

Carpet Beetle & Warehouse Beetle (Dermestidae)


Dermestid beetles, also called carpet, hide, or warehouse beetles, are the second most frequently submitted insect group to the UPPDL. These household pests can infest everything from stored grains, powdered milk and protein mixes, etc., to leather furnishings, animal-based products, wool clothes, sweaters, human hair, and dead insects and animals. Given the variety of feeding habits, it is critical to have your beetle identified to help locate and eliminate the infestation source.

Commonly called carpet beetle, this insect's name is a little out of date. Historically, when carpets were made from animal-based products (e.g., wool), these beetles could cause major damage via larval feeding. Today, synthetic carpets and fabrics dominate; carpet beetles will not consume synthetic carpets or clothing.

Larvae are small-1 to 10 mm in length-and usually have longer hairs at the end of the body. They are normally light to dark brown in color. When larvae grow, they shed their skin leaving behind a shell (exuviae), which can also be used to locate infestations. While not poisonous, some dermestid larvae are covered in arrow-shaped hairs which can cause throat and mouth irritation if consumed.

Dermestids are commonly found outside. Leaving any door or window open in the spring or summer could allow these beetles to enter the home. Dermestids are also commonly introduced on freshly cut flowers used as indoor decoration, or in infested products purchased from the store.  All food items must be properly stored in airtight containers to keep beetles from invading and establishing. Also be aware that animal hide and mammal hair are susceptible to infestation-vacuum and clean regularly. 

Armyworms, Cutworms, and Earworms (Noctuidae)

army cutwormNoctuids are a large group of mostly night-flying moths that are major pests around the world. The plump, nearly hairless larvae are usually active at night or in hidden areas like in corn husks, just below the soil surface, or at the base of grass, plants, etc.

Most adult noctuid moths are difficult to distinguish from other related moths. In general, noctuids are mostly robust, brown, and have lighter-colored, kidney-shaped patches on their wings. Proper identification of related species requires dissection and examination of the genitalia.

Longhorned/Roundheaded Wood Boring Beetles (Cerambycidae)

pine sawyerImmature borers (larvae) feed on wood tissues within the tree, moving from under the bark deeper into the tree with time. Eventually, larvae pupate and emerge from the tree as adults, leaving large circular holes in the bark. Adult beetles will seek a new host tree, mate, lay eggs, and continue the cycle. Insecticide applications should be timed to occur just before adult beetle emergence.

Longhorned borers are easily recognized by their long antennae, and a more rounded shape when compared to flatheaded borers. These borers lay their eggs on the bark of stressed trees. Upon egg hatch, the small larvae bore their way through the bark and into the wood causing damage. Control of larvae already under the bark is not feasible. Control of longhorned borers must be preventative.

Weevils, Billbugs & Bark Beetles (Curculionidae)

weevil adultWeevils are beetles easily recognized by their long snouts. In Utah, root weevils are the most commonly encountered group. These beetles are responsible for the small notching patterns seen on leaf margins of lilac and other plants. The immatures, or larval stages, can be destructive to plant roots. Look for these beetles at night with a flashlight, as they are nocturnal.

The next most frequently encountered weevils in Utah are the notorious turf pests-billbugs. These beetles are most frequently seen walking on sidewalks next to turf, and the larvae can cause major damage to turf roots/stems in the thatch layer. 
Immature weevils, including bark beetles, are similar in appearance.  The larvae are small, legless, white grubs with a brown head capsule. Look for these in turf thatch (billbugs), at the base of lilac or other plants (root weevils), or under the bark of trees (bark beetles). 

Recently grouped into the weevil family, bark beetles are one of the most destructive forest pests in the world. Within the urban landscape bark beetles are major pests of spruce, pines, fruit and nut trees, and ornamental hardwoods. In Utah, species of Ips beetles are the most destructive to urban pines, while species of Scolytus are most detrimental to fruit and some ornamental trees. 

Ants (Formicidae)

pavement ant

By far the most common household pest Utahn's experience during the spring months is the pavement ant (Tetramorium caespitum). These ants like to make their nests in cracks in the driveway, sidewalk, and foundation, and can often be seen forming large aggregations just outside of their nests. While they do not sting, they can become nuisance pests when the come inside to rummage through your garbage or cabinets.

The other major group of ants of concern in Utah are the carpenter ants. Certain species of these ants can cause major structural damage to homes and businesses if they are left uncontrolled. Identification of the exact ant is critical because different carpenter ant species are more destructive than others. The presence of some species may require extensive measures for eradication, while others may be handled by the average homeowner. 

Leaf Beetles (Chrysomelidae)

leaf beetle

Commonly known as leaf beetles, many members of this large, diverse family are pests of vegetable and grain crops, as well as ornamental pests. Some species of this group could be mistaken for longhorned beetles, but their larval habits are very different. Chrysomelids are usually brightly colored, smaller beetles that give leaves a shothole or a tattered/skeletonized appearance under heavy infestations. Some leaf beetles are nuisance pests in the winter when they overwinter in peoples' homes in large numbers.

White Grubs/May/June/Beetles (Scarabaeidae)

june beetle

In Utah, white grubs are second to billbugs as turf pests. The adults of most May/June beetles are dull brown in color, with some notable exceptions such as the 10-lined June beetle. In some cases the adults can cause minor damage to crops and ornamental plants, however it is usually the larvae (grub) that causes most of the damage while feeding on host roots. White grubs are distinguished from billbug larvae by the presence of 6 legs near the front of the larval body, and the classic "C" shape in which white grubs are always found. Adults are often collected at porch lights at night because they are attracted to lights; larvae are normally found while digging in the garden or yard. 

*Japanese beetle was detected in Orem, UT and a few other locations in Utah. Currently, an eradication program for this beetle is underway in Orem. Established populations are not believed to exist in other UT locations. If you think you've captured a Japanese beetle, please contact the UPPDL for an immediate identification. Pictures of Japanese beetle can be found here.

Seed Bugs (Lygaeidae)

seed bug

One of the most common seed bugs submitted to the UPPDL is the false chinch bug. It prefers to feed on plants from the Brassicaceae (mustard family) including broccoli, cauliflower, cabbage, turnip, radish, etc. This insect can become very abundant during hot, dry conditions when their host plants begin to dry up. The habit of aggregating on, in, and around peoples' homes during drought periods is exacerbated by irrigation of turf, or nearby freshly cut alfalfa fields, etc., as the insects search for moisture. Aside for their aggregating habit, false chinch bugs rarely cause damage that warrants insecticidal control.

Clearwing Moth Borers (Sesiidae)

clearwing moth

Clearwing moths are a little-known pest in Utah, however they cause major damage to fruit and ornamental plants every year. Many of these moths closely resemble wasps, and may therefore be overlooked as the stem and woodboring insects they truly are. In Utah, these borers cause the most damage to peach, lilac, ash, and raspberries.  One diagnostic feature of clearwing moths is their shed pupal case, which can be found protruding from exit holes in the bark.

The lilac-ash borer closely resembles paper wasps and yellowjackets, but can cause major damage or death to ash and lilac trees. Young, stressed trees are particularly vulnerable.

Indian Meal Moth (Pyralidae)

indian meal moth

Indian meal moth is one of the most frequently submitted pests of stored food products in Utah. Infestations are often discovered by the presence of adult moths in the home, or by finding larvae and silk in stored food. Control measures for this pest are non-insecticidal. Identify and remove all infested food products. Thoroughly clean areas around the infestation. Store new products in air-tight containers to prevent reinfestation. 

Codling Moth (Torticidae)

codling moth

Codling moth is the major pest of apple and pear in Utah. The larvae are the damaging stage of this pest, boring into fruit and causing a loss of marketability of fruit. Control of this pest is best with an integrated approach. Pest monitoring and insecticide treatments should be strictly timed to minimize unnecessary sprays. Utah State's Integrated Pest Management Program reports weekly on codling moth, and other pests, advising when to apply sprays, and other control methods.

Please sign up for the pest advisories here: IPM Advisories

Predaceous Ground Beetles (Carabidae)

ground beetleMost species of ground beetles are predaceous and should be considered beneficial. Identifying beetles can be difficult; if you have any doubt that the beetles around your home are predators or plant pests, please send them to the UPPDL for identification. Distinguishing between pest and beneficial insects is important so that natural pest controls are not unnecessarily killed. View the links to the right to learn about Utah's beneficial insects.

Millipedes (Diplopoda)


Millipedes are submitted to the UPPDL when they are found invading homes, or in the garden under rocks, duff, or logs. They pose no threat to humans, and rarely cause damage to plants. They are easily recognized as 1-1.5 inch brown "worms" that coil up when disturbed. They feed primarily on decaying plant material, not on healthy plants. Indoors, they are highly susceptible to drying out, so they usually die inside of a home unless there are moisture issues that need resolving.

Duff millipedes can often be mistaken for carpet beetle larvae. Control methods for these two insects are very different. Have your suspect duff millipede identified to receive a targeted management plan.

Peach Twig Borer (Gelechiidae)

Peach twig borer is a major pest of peach, nectarine, and apricot in Utah. Spring and early generations can cause damage when larvae bore into new shoots, while summer and fall generations can cause damage to fruit. Control of this pest is best using an integrated approach. Pest monitoring and insecticide treatments should be strictly timed to minimize unnecessary sprays. Utah State's Integrated Pest Management Advisories report on peach twig borer, and other pests, advising when to apply sprays, giving examples of some available products.

Please sign up for the pest advisories here: IPM Advisories 

Thrips (Thysanoptera)

Western flower thripsThrips are small insects, barely visible to the unaided eye. Despite their small size, thrips can be very destructive to numerous plants. Typical damage appears as small yellowish specks on foliage (stippling), flowers, and fruit, wilting/stunting of plants or fruit, leaf drop, petal streaking, and fruit scarring. Their habit of feeding in sheltered places such as curled leaves, flower petals, or in buds makes control difficult. Their shiny silvery-black excrement can also be an indication of their presence.

Assassin Bugs (Reduviidae)

assassin bugAssassin bugs are predatory true bugs that have piercing-sucking mouthparts. Their mouth parts (rostrum) are shorter than plant-feeding true bugs and only have 3 segments. The short, stocky rostrum allows easy penetration of their prey's hardened exoskeleton, through which they suck out their "juices." Assassin bugs can inflict a painful bite if mishandled, however they should still be considered beneficial insects.

Immature assassin bugs sometimes resemble ants.

  • Commonly Identified by UPPDL: Assassin Bug
  • Fact Sheets: , Images Bugguide

Hard Scales (Diasphididae)

black pineleaf scaleScales are a common pest insect in Utah. There are two general types of scales: hard and soft. Hard scales are more difficult to control because of their impervious shell and because of the specific tissues (mesophyll) on which they feed. Hard scales spend most of their life stuck in one spot, covered by a hard shell secreted by the insect under it. Eggs are generally the overwintering stage. When eggs hatch in spring/summer, crawlers are produced. This is the most vulnerable part of the scale's life cycle, which is susceptible to insecticides. Once the crawlers have settled, they secrete the shell and become more difficult to control.

Because hard scales feed in the leaf mesophyll (which is different from phloem feeding soft scales) most systemic insecticides are not effective against it. Currently, systemics with the active ingredient Dinotefuran are the only effective chemicals, albeit expensive. Well timed foliar applications can target crawler stages to reduce overall scale populations, however control depends on completeness of coverage.

Immature scales, or crawlers, are very small and orange in color. Monitor for crawlers by using double-sided tape wrapped around branches above the current scale infestation and below the new growth. When crawlers emerge they will stick to the tape as they look for new feeding sites. When they are present on the tape an insecticide application can be made.

Darkwinged Fungus Gnats (Sciaridae)

darkwinged fungus gnatDarkwinged fungus gnats are small, long-legged flies that can become a nuisance indoors when they establish in potted plants, etc. While the adults are not harmful to plants, the larvae can damage roots and stem crowns. Indoor potted plants that are over watered and that have a high humus-content potting mix are at highest risk. If adult fungus gnats are noticed in the home, check all potted plants for signs of adults or larvae. Letting soil dry completely between waterings can help reduce their numbers by killing larvae. Other control methods can be found in the fact sheets listed here. 

Darkwinged fungus gnat larvae have pale white to translucent bodies with black head capsules.

Flatheaded/Metallic Wood Borer (Buprestidae)

flatheaded wood borerFlatheaded or metallic woodboring beetles can be major pests of fruit and ornamental trees in Utah. Similar to the longhorned beetles, flatheaded borers lay eggs on bark crevices. The eggs hatch and the larvae bore through the bark into the tree where they spend their immature life. Treatments include maintaining tree health, minimizing tree stress, and preventative insecticide sprays applied to the bark before beetle flight.

Flatheaded borer larvae are named so because of the flattened area just behind the mouthparts and first segment.