Fact Sheets - Landscape Ornamental Insects
For more landscape and ornamental insect information reference the Common Ornamental Pests of Utah Guide
Balsam woolly adelgid (BWA) is a tiny sucking insect that was introduced to North America from Europe. In the U.S., it is a serious pest of true firs in forests, landscapes, and in seed and Christmas tree production. BWA was first observed killing subalpine fir in northern Utah forests in 2017, and has been confirmed in eight counties since then.
Bark beetles are one of the most destructive forest pests in the world. They are different than the larger longhorned and roundheaded/metallic woodboring beetles commonly infesting the inner wood of trees.
Boxelder bugs are a common nuisance insect to many homeowners. Although boxelder bugs are active throughout the summer, many people don’t notice them until they start “sunning” themselves on structures, particularly the southern-facing walls.
Boxelder leafroller damage results from larval feeding activities on the leaves. Young larvae form webs along folds and veins of the leaves and consume the tissue between the veins. Older larvae roll individual leaves and may web several leaves together.
Brown marmorated stink bug (BMSB) is an invasive insect pest from eastern Asia. In Utah, it was first detected in 2012 in Salt Lake City. Its broad host range includes fruit, vegetable, ornamental, and field crop plants; in Utah, it has primarily infested ornamental deciduous trees and shrubs in urban and residential landscapes.
Bumble flower beetles are common throughout the growing season on flowers, oozing sap, and other sweet, overripe, or fermenting matter. Bumble flower beetles seldom warrant the use of chemicals for control. Control methods include removing organic material from near affected plants, and hand removal of the adult beetles from plants.
Cankerworms, also known as inchworms, are in the order Lepidoptera and family Geometridae. Geometrid moth adults have slender bodies and relatively large, broad forewings. Both fall and spring cankerworms occur in Utah, with the fall cankerworm being most common.
The larval stage of the carpenterworm, Prionoxystus robiniae is a wood-boring insect that affects various ornamental trees. Unlike most other wood-boring pests of ornamentals, which are mostly beetle larvae, the carpenterworm is a caterpillar belonging to the moth family Cossidae.
Centipedes are predatory relatives of the insects, and are considered beneficial. Occasionally, centipedes enter homes and become a nuisance, but management options are available. Centipede bites on humans are rare.
Chinch bugs are occasional pests of turfgrass in Utah. Chinch bugs feed on a variety of turfgrass species including Kentucky bluegrass, perennial ryegrass, the fescues, bentgrass and zoysia grass. Damage is usually heaviest in sunny locations during hot, dry periods.
This fact sheet provides descriptions and images of stink bugs, including the adult and immature stages, that are commonly encountered in gardens and farms in Utah.
Springtime, while grasshoppers are still nymphs, is the best time for communities or neighborhoods to work together to suppress grasshopper populations. Treating as wide an area as possible is the key to success.
Crickets will eat almost anything, including fabrics, other insects (dead or alive), food products, and furs. Occasionally crickets may enter the home or chirp near the home, and become a nuisance. Regular sanitation around the exterior of the home will discourage cricket infestations.
Two major bark beetle species attack elm trees in Utah; both can transmit Dutch Elm Disease (DED) , leading to tree death, decline, or chronic stress. Preventive treatments such as foliar insecticide applications, severing root graphs between trees, injectable fungicides, and proper pruning of affected areas can minimize transmission of DED.
The Emerald Ash Borer (EAB) is a recent invasive pest, and is considered to be one of the most destructive forest insects to ever invade the U.S. EAB adults are very good fliers, but new infestations are primarily caused by people moving wood from infested areas.
Eriophyid mites cannot be seen without a 20x hand lens or greater magnification. Eriophyid mites seldom cause serious injury or stress to plants; damage is normally aesthetic. Damage from eriophyid mites usually consists of leaf galls, bud or flower galls, blisters, scabbing, and deformities of leaves, stems, buds, and flowers.
The European earwig is an omnivore; it feeds on detritus, fungi, plants, and insects. Earwigs can injure the buds, leaves, flowers, and fruits of a broad range of plants, including fruits, vegetables, and ornamentals; they can be a nuisance pest by entering buildings.
Fall webworms are a common pest in urban and forest areas from mid July through August. Fall webworms can feed on over 100 species of trees, but cottonwood and chokecherry are preferred hosts. While unsightly, fall webworm damage rarely causes serious stress to trees and control is usually not recommended.
Pacific flatheaded and flatheaded appletree borers are two wood-boring pests of many fruit and ornamental trees. The most susceptible trees are drought-stressed, newly planted, or those with trunk or limb wounds. Maintaining tree health is key to preventing infestation.
Greater peachtree borer is an important pest of peach, nectarine, apricot, cherry, and plum. Adults are clearwing moths and larvae are caterpillars that burrow and feed in the cambium beneath the bark near or just below the soil line. Severe larval feeding can girdle and kill trees.
Aspens are one of the more popular forest trees in the Intermountain West. They add a brilliant yellow glow to the collage of fall colors. In an attempt to enjoy these beautiful trees around the home environment, many well-intentioned homeowners purchase or otherwise acquire aspens and transplant them into their landscapes.
Pest identification is the cornerstone of integrated pest management, but is a skill that can be difficult to master. Mistakes in identification are common, as many insects look and act alike, and/or can cause similar injury.
Japanese beetle was initially detected in Orem, Utah, in July 2006. Eradication efforts have been highly successful. Adults have a broad host range (over 300 plant species) and can cause significant damage.
Leafhoppers are common problems in home gardens and orchards throughout the state of Utah. There are many species of leafhoppers, several of which attack apples, roses, grapes, and potatoes. Most species overwinter in the egg stage in the bark of the host plant or among the fallen host plant leaves.
Lilac-ash borer, a clear-wing moth common in Utah, can be a destructive pest of many species of ash, privet, lilac, and related species. Adults emerge from host trees and lay eggs in the spring; larvae feed on wood within branches, overwinter in the heartwood, and emerge as adults the following spring.
The lily leaf beetle (LLB) is a an important pest from Eurasia that threatens native and cultivated true lilies and fritillaries. LLB adults and larvae create large holes as they feed, and all parts of host plants can be consumed. LLB has not been detected in Utah, but it is likely capable of establishing throughout most of the U.S. where plants in the Liliaceae family occur, which includes Utah.
The locust borer occurs in eastern Canada and in most of the United States, wherever its host, black locust, grows. For the past 35 years, locust borer has spread and damaged black locust in the Wasatch Front and northern Utah. Honey locusts or other trees are not affected by this species, whose only host is the black locust.
The oystershell scale belongs to a group of insects called the armored scales. The adult insect is enclosed in a shell made up of its own shed skins and waxy secretions. Under this covering is a sac-like animal that is quite different in appearance from most insects. It has no legs, eyes, or antennae.
Pear sawfly hosts include pear, cherry, hawthorn, plum, buttonbrush, Juneberry, mountain ash, cotoneaster, and quince. There are 2 generations of pear sawfly each year; second generation larvae cause the majority of the damage. Damage from pear sawfly feeding rarely warrants control.
The poplar borer is a common wood borer in quaking aspen and other poplars in Utah. While large trees are seldom killed by this pest, it can cause tree decline, weakened branches, and allow the introduction of pathogens
The poplar bud gall mite belongs to the eriophyid mite family. These mites are microscopic and about one-fourth the size of a spider mite. Adults are about 0.2 mm in length, reddish in color, and spindle-shaped. Like other eriophyid or gall mites, this species is most easily recognized by its host plants and characteristic damage.
This long-horned beetle is native to western North America and lives for 3 years or more underground, feeding on tree roots. Severe infestations can cause the death of stone fruit trees. In northern Utah, the rootborer is found most commonly in sweet cherry and peach orchards growing in sandy soils.
Root weevils are common pests of landscape ornamentals and small fruits. Root weevils cause notching of leaf margins and root damage leading to canopy dieback or plant death.
San Jose scale is a sporadic pest in well maintained commercial fruit orchards. Severe infestations can kill limbs, cause deformed and poor colored fruit, reduce yields, and eventually kill trees. Monitor fruit during picking and packing (check cull bins), and check tree limbs during pruning for signs of scale and injury.
Sequoia pear moth is not typically considered a serious pest of pines, but may cause limb dieback, unsightly resin masses, tree stress, or even tree death in severe cases.
There are more than 1,000 different species of soft scales found throughout the world. Less than 5% are considered serious pests. Soft scales feed on a wide range of woody ornamental plants and often go unnoticed until they stunt growth or cause severe plant stress.
Fruitworms chew holes in fruits and leaves, and can cause localized defoliation of fruit trees. Fruitworms can be monitored with beat-samples (abrupt shaking of tree branches over a tray). Applications of reduced-risk insecticides, such as Bacillus thuringiensis (Bt) and spinosad formulations, are effective for control.
Spider mites feed on a wide range of plants, including fruit trees, field and forage crops, ornamentals, and weeds. Adult and immature mites feed on leaves causing white stippling, bronzing, and defoliation. Tree vigor and fruit color, size, and production can be reduced.
Spongy moth is formerly known as European gypsy moth, whose name was changed in 2022 to remove a culturally insensitive term. Spongy moth is among the topmost devastating pests in North America. It has previously been detected and eradicated in Utah.
SLF is a new invasive pest from China first detected in the U.S. in Pennsylvania in 2014. SLF attacks more than 70 host plants that include grapes, fruit trees, hops, and hardwood ornamental trees. Extensive feeding by SLF can impact plant vigor and crop yield.
The spotted wing drosophila (SWD) is an invasive pest from Asia that has been detected in many counties in northern Utah. Control SWD by using insecticides common in fruit IPM plants. If SWD is caught in monitoring traps, insecticide applications must be used during the unripe fruit stage to prevent damage.
Spruces tend to prefer abundant moisture and may not do well on droughty sites. Water stress caused by too little soil moisture or too much heat can predispose spruces to insect attack. 80% of spruce trees submitted to the UPPDL are diagnosed with stress due to abiotic conditions such as drought stress and deep planting.
Sycamore scale is a pest of sycamore trees (Platanus spp.), especially London planetree. Scale life stages are difficult to see with the naked eye, and therefore, symptoms of leaf damage are often noticed first. The primary symptom is yellow-to-brown leaf spots. The timing of treatment is at bud break and involves oil application and/or a soil-applied systemic insecticide. A fungicide can be mixed with the oil application to treat sycamore anthracnose.
Thousand cankers disease is caused by the fungus Geosmithia morbida. It is transmitted by the walnut twig beetle (Pityophthorus juglandis). Once symptoms are visible, trees can die within 2 to 3 years.
The velvet longhorned beetle (VLB) is an invasive wood-boring beetle native to Asia and Russia that was first detected in Utah in 2010. VLB will attack living and dying trees, as well as green and dried wood; it can infest apple, cherry, mulberry, peach, and a number of deciduous and conifer tree species. Fruit yield, tree longevity, and wood marketability can all be negatively impacted by VLB.
White apple leafhopper is an indirect pest with two generations per year. Decision for control should be based on economic justifications as well as orchard and other pest considerations.