Discover 10 Invasive Species in Utah

Utah is well-known for its stunning landscapes and diverse ecosystems and is home to a remarkable array of native flora and fauna. However, amidst the natural beauty lies a silent threat that often goes unnoticed: invasive species. These unwelcome intruders disrupt the delicate balance of Utah’s ecosystems, posing a significant challenge to native plants and animals and even impacting human activities. Understanding the scope and impact of invasive species is crucial to safeguarding Utah’s natural heritage.

In this article, we will explore the world of invasive species in Utah, highlighting 10 notable examples that have taken root in the state. From plants that choke out native vegetation to animals that outcompete native species, each of these invaders carries its own unique story and ecological consequences.

American Bullfrog (Lithobates catesbeianus)

The American bullfrog originates from the eastern parts of North America and is one of the largest frog species in the region. They started out in Utah as pets and found their way into the wild by being released or getting lost. They now have a prominent population throughout the state.

These amphibians can grow to be between 3.6 to 6 inches long and weigh from half a pound to 1.5 pounds and beyond. These frogs have smooth skin. Their color is olive-green or brownish-green in color, with a white belly, and blotches of dark patches on their backs.

American bullfrogs have a wide range of prey, including insects, spiders, worms, small fish, and even other amphibians! Unfortunately, American bullfrogs harm native populations, especially other amphibians, as they can outcompete these species for both food and habitat.

There are several control methods in place to control the population of this invasive animal. Some of these methods include removal programs, thorough monitoring of the species, and raising public awareness about the effects these frogs have on the environment.

Starling (Sturnus vulgaris)

The starling is a medium-sized bird, native to Europe and Mongolia. It was introduced to New York City in 1890. The motivation behind this introduction was to establish populations of all birds mentioned in the works of William Shakespeare, and the starling was one of those mentioned in his plays. This beautiful bird is around 8 inches long and weighs between 2 and 3.6 ounces. It has glossy black plumage, which is speckled with white, and its legs are pink in color. The bill of the starling is black in the winter and yellow in the summer. These birds are noisy and have a gift of mimicry. 

The starling is largely insectivorous, and its diet includes spiders, moths, grasshoppers, flies, wasps, and ants. They also feed on grains, seeds, fruits, nectar, and food waste. Starlings are invasive in Utah due to their destructive abilities. They are agricultural nuisances as they enjoy eating fruits. They also steal food and spread diseases on farms. Lastly, the droppings of the starling are odorous and contribute to the spread of respiratory disease.

Control measures to keep starlings away include mesh netting, bird spikes, sealing off openings, and trapping and removal. Because the population of starlings is so large, these methods alone are unlikely to eradicate the species. These birds can easily invade new areas and reproduce incredibly quickly!

Spotted Wing Drosophila (Drosophila suzukii)

The spotted wing drosophila is a type of fruit fly native to southeast Asia. This insect is around 5/64 to 9/64 inches in length. The body is yellow to brown, with dark bands on the abdomen. And the eyes are a striking red. Male spotted wing drosophilas have a distinct dark spot near the tip of each wing. The spotted wings of the male flies are what gives the fly its name.

Spotted wing drosophila is a fruit crop pest and is a serious economic threat. Some fruits affected by these insects include cherries, blueberries, raspberries, peaches, and grapes. The fly attacks fresh, ripe fruit, and females lay eggs under the fruit’s skin. Since its first detection in Utah, the insect has not caused economic injury but is still an invasive species, as other areas have had significant economic losses.

Control measures include traps, fruit monitoring, sanitization, netting, early harvest, and insecticides. Because control is not recommended unless the insect is caught in traps or fruit infestation is detected, monitoring is the best way to prevent an infestation.

Brown Marmorated Stink Bug (Halyomorpha halys)

The brown marmorated stink bug is native to countries in Asia, including China, Japan, and Korea. This species was accidentally introduced in 1998 to the United States. These bugs are around 0.67 inches long and wide and have a shield-like shape. They are dark brown from above with a creamy white-brown underside. This stink bug has unique markings that are almost marble-like.

This stink bug emits an odor through holes in the abdomen as a defense mechanism against predators. The odor is pungent, and the insect’s body fluids are irritating and toxic to humans. 

These insects are capable of causing widespread damage to both fruit and vegetable crops. Because the brown marmorated stink bug does not require a specific plant to feed on, this insect is extremely versatile and adaptive and can cause damage to different species of plants.

As this insect is so widespread, eradicating the species is very unlikely. Management of the insect includes measures such as exclusion, physical removal, cultural control, and biological control. One effective measure is using traps to lure the insects with pheromones. Insecticide strips are then used to kill the insects that enter the trap. 

Spongy Moth (Lymantria dispar)

The spongy moth is native to Eurasia and was accidentally introduced to the United States in 1869. This pest was first found in Utah in 1988 and was eradicated by extensive trapping and insecticides. Even though the spongy moth has since been eradicated, it is still considered an invasive species in Utah. Female spongy moths have creamy-white colored wings with dark sawtooth-like markings. The wingspan is between 2.5 and 3.5 inches, and the antennae of the female spongy moth are thin. Males have greyish-brown wings with black markings and a wingspan of around 1.5 inches. The antennae of the male spongy moth are feather-like to detect female pheromones.

The larvae of the spongy moth live on different types of deciduous and coniferous trees. They feed on the foliage of more than 300 species. Some species of trees they feed on include oak, aspen, willow, apple, mountain ash, sweetgum, and birch. The larvae can cause severe damage to these trees. During outbreaks, the larvae can defoliate trees and shrubs, cause decreased plant growth, increase the susceptibility of the trees, and even kill large sections of landscaping and forests. Outbreaks can also destroy habitat and food sources for other plants and animals.

Management typically targets the egg and caterpillar stages of the insect. Biological control measures involve utilizing natural enemies of the spongy moth, which include small mammals, birds, invertebrates, pathogens, and parasitoids. Chemical control, such as insecticides, can also be used to manage the spongy moth. However, because insecticides are nondiscriminatory, they are not used in large-scale treatment programs.

Velvet Longhorned Beetle (Trichoferus campestris)

The velvet long-horned beetle is native to Asia and Russia. It was first detected in Utah in 2010 and is considered an invasive species. Adult velvet long-horned beetles have elongated bodies around ½ to ¾ inch long. They have wing covers that are dark brown to orange-brown, and their legs and antennae are lighter. These insects have fine hairs that are irregularly distributed, which form light-colored patches on their bodies and wing covers. This is where the name “velvet” comes from.

The velvet long-horned beetle is a wood-boring beetle that attacks living and dying trees. It can also infest apples, cherries, peaches, and many deciduous and conifer tree species. The beetle is invasive as it negatively affects fruit yield, tree longevity, and wood marketability. 

The most important way to manage the infestation of the velvet long-horned beetle is by prevention. Early detection and identification can be accomplished through monitoring methods such as traps. Control measures include biological and chemical measures. Natural enemies of the velvet longhorned beetle can be used as well, but the management of the velvet longhorn beetle is not reliant on these biological controls. Instead, insecticides can be used to reduce the number of larvae in infested trees. 

Giant Reed (Arundo donax)

The giant reed is native to Eurasia and is a tall perennial cane. This plant can grow to an incredible 20 feet in height! The stems are hollow and are 0.8 to 1.2 inches in diameter. The leaves are grey-green, swordlike, and grow between 12 and 24 inches long. The flowers produced are feathery and are between 16 and 24 inches long. They are usually seedless or, if they have seeds, they are infertile. This plant reproduces vegetatively through underground rhizomes that form knotty mats which penetrate the soil. 

The giant reed is a highly adaptable plant but is generally found in wetland areas. This plant is one of the fastest-growing terrestrial plants in the world! They are capable of growing around 4 inches in a single day. This plant does not provide any food sources or nesting habitats for wildlife. Because the giant reed is so adaptable and able to thrive easily, displacing native flora because they cannot compete.

Control measures to reduce the giant reed population include biological, mechanical, and chemical measures. Biological measures include using insects that damage the plant – these insects include the Arundo wasp, the Arundo scale insect, and the Arundo fly. Mechanical measures can be used by removing the root structure or preventing the plant from getting sunlight. Chemical measures include the use of herbicides.

Yellow Starthistle (Centaurea solstitialis)

Yellow Starthistle is native to Europe. It made its introduction to the United States in the late 1800s. The yellow starthistle is a thorny plant that can grow up to 3.5 feet in height when flowering. There are lobed leaves at the base and unlobed leaves on the stem. The stem produces many spinous flower heads that contain 10 to 50 yellow flowers. The spines are between ⅜ and 1 inch long. The plant produces hundreds or thousands of seeds. Once the seeds mature, the plant dies. The seeds are widely distributed and can remain viable for years, ensuring the plant’s success in invading new areas.

The yellow starthistle is on roadsides, vacant lots, fields, parks, pastures, and more. This plant can displace native plants, decrease native plant and animal diversity, reduce native wildlife habitat and forage, alter water cycles, change soil composition, and affect soil nutrient availability. The plant is particularly invasive after disturbance. Prevent invasion by limiting disturbance.

Control measures for the yellow starthistle include fire, physical and mechanical control, livestock grazing, biological control, and chemical control. These methods can collectively control the population of yellow starthistle. However, establishing desirable plants in the first place is the solution for long-term control of this invasive species.

Dyer’s Woad (Isatis tinctoria)

Dyer’s woad is a flowering plant native to Eurasia. It is now also in Europe and North America. This plant can grow up to 4 feet tall and has a taproot that is 3 to 5 feet long. The basal leaves produced are stalked, bluish-green in color, and covered with fine hair. The basal leaves can grow up to 7 inches in length. Stem leaves are not stalked and are lance-shaped. The flowers produced are small and yellow and found in clusters on the branch tips. 

Dyer’s woad establishes in rocky soils and is in rangelands, pastures, and forests. This plant is invasive because it crowds out native species. The plant can also reduce forage availability and degrade wildlife habitat. It can also lower species diversity and decrease land value. Lastly, Dyer’s woad increases the potential for soil erosion.

Control methods for Dyer’s woad include physical control, cultural control, biological control, and chemical control. Physical control methods include manual processes such as hand pulling and mechanical measures such as mowing and tillage. Biological control measures include grazing and biological agents such as rust fungus. Chemical control measures include herbicides to control the populations of Dyer’s woad.

Perennial Pepperweed (Lepidium latifolium)

Perennial pepperweed is a plant that is a member of the cabbage and mustard family. This invasive plant is native to southern Europe and Asia. After an accidental introduction in North America, it is now an invasive species. This plant can grow as tall as 6.6 feet. It has many woody stems, waxy leaves, and small white flowers. The flowers form dense clusters at the tip of each stem, and the fruit produced is small and contains two seeds. The roots of the perennial pepperweed are extensive and can reach 9 feet in depth.

The perennial pepperweed thrives in wetland habitats and is a threat in Utah. The plant invades not only coastal wetlands but also riverbanks, marshes, rangelands, and roadsides. This plant can crowd out native species, making it an ecological threat in Utah. 

Prevention is the best way to manage perennial pepperweed infestations. However, if there is an infestation, use chemical and mechanical measures. Chemical measures include the use of herbicides to remove the plants. Repeat applications are generally necessary for a few years to fully eliminate this invasive plant. To control seedlings, use hand pulling or tillage. Other measures such as mowing, burning, and revegetation can also help to control this invasive species.

Summary of Invasive Species in Utah