CAPS is a combined effort by Federal and State agricultural organizations to conduct surveillance, detection, and monitoring of agricultural crop pests and biological control agents. Survey targets include weeds, plant diseases, insects, nematodes, and other invertebrate organisms. In Tennessee, the CAPS program is coordinated from within the University of Tennessee Entomology and Plant Pathology Department.
Invasive pests are of serious concern for Tennessee’s agriculture, forestry, and wildlife. Many educational resources are available from UT Extension, Protect Tennessee Forests, and the Tennessee Invasive Plant Council focused on protecting our native species.
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Exotic species on the move!
Insects
The Asian longhorned beetle (ALB; Anoplophora glabripennis) is a federally quarantined wood-boring insect that inflicts severe damage on trees in North America. Although it has not been found in Tennessee, the beetle has been detected and quarantined in several states since its initial discovery in New York in 1996. The most effective methods to safeguard Tennessee forests from this pest include avoiding the movement of untreated firewood, early detection, and eradication efforts.
Native to China and Korea, the ALB was first identified in the U.S. in 1996, likely brought over multiple times in wood packaging materials from its native regions. Presently, populations of this beetle exist in only four states, all of which have active quarantine zones with ongoing eradication efforts. The beetles are often unintentionally transported to new areas in cut firewood or wood packaging material.
The ALB damages trees by tunneling through the sapwood and heartwood of trees or branches. This larval tunneling significantly weakens the tree, making infested trees potentially hazardous. Additionally, tunneling in the sapwood disrupts the tree’s ability to transport water and nutrients, leading to the tree’s death within 7 to 9 years. Since no treatment is known for infested trees, removing them is essential to reduce hazards and prevent the pest’s spread to new areas.
Photo courtesy of Michael Bohne, U.S. Forest Service, Bugwood.org
The box tree moth, originating from East Asia, has become a significant invasive pest in Europe, where its spread continues. The caterpillars primarily feed on boxwood, and severe infestations can defoliate these plants. After the leaves are consumed, the larvae attack the bark, leading to girdling and eventual plant death.
Females lay eggs singly or in clusters of 5 to over 20 in a gelatinous mass on the underside of boxwood leaves, with most females producing over 42 egg masses during their lifetime. These eggs typically hatch within 4 to 6 days.
Pupae usually first appear in April or May and remain present throughout the summer and into the fall, depending on the local climate and generation timing. Adults from the overwintering generation emerge between April and July, depending on climate and temperature, with subsequent generations active from June to October. After emerging, adults typically live for about two weeks.
Box tree moths are highly mobile and capable fliers. In Europe, the natural spread of this moth is approximately 3 to 6 miles per year. One European analysis suggested that natural dispersal from continental Europe to the United Kingdom was possible, indicating sustained adult flights of over 20 miles.
Photo courtesy of the U.S. Animal and Plant Health Inspection Service
Adult brown marmorated stink bugs (BMSB) measure about 1 inch in length and ¾ inch in width. Belonging to the insect family Pentatomidae, BMSB and other stink bugs emit a strong, cilantro-like odor when disturbed, which is produced by a gland located between the first and second pairs of legs and on the upper abdomen.
These adults display a mottled coloration of various browns or light pinks/purples and can be distinguished from other stink bugs, such as the native brown stink bug, dusky stink bug, and spined soldier bug, by the alternating white bands on the last two segments of their antennae and the alternating dark and light bands along the edge of their abdomen. Similar banding is also found on the legs of the nymphs.
BMSB undergo five nymphal stages (instars). The first instars are orange and black, staying near the egg mass after hatching. From the second to the fifth instar, they are dark brown with some beige and purple coloration, growing larger with each molt. BMSB eggs are typically laid on various surfaces, often found on the underside of leaves, with an average of 28 eggs per mass. In our region, BMSB typically produce two generations per year. After the second generation, adults overwinter in sheltered areas, including homes and other structures, and then resume their life cycle the following spring.
Photo courtesy of Julian Cosner, University of Tennessee
The emerald ash borer (Agrilus planipennis), a beetle native to Asia, was first identified in Michigan in 2002. Since then, it has caused significant damage and death to ash trees (Fraxinus spp.) across 35 states, including Tennessee. The primary means of spreading this pest is human activity, particularly through the movement of infested nursery stock, firewood, unprocessed saw logs, and other ash-related materials. Although it was subject to quarantine upon its discovery in the United States, both state and federal restrictions were removed in 2021 after federal deregulation of the beetle.
Photo courtesy of the U.S. Animal and Plant Health Inspection Service
European grapevine moth (Lobesia botrana) is a significant pest of berries and berry-like fruits. It feeds on the flower or fruit of host plants, most often grapes. The moth is a significant agricultural pest throughout much of the world. It was first detected in the United States in California in 2009 and fully eradicated in 2016.
Photo courtesy of Jack Kelly Clark, Regents of the University of California
Originating from Asia, the hemlock woolly adelgid (Adelges tsugae), or HWA, is a small, aphid-like insect that poses a serious threat to the health and sustainability of eastern hemlock (Tsuga canadensis) and Carolina hemlock (Tsuga caroliniana) in the Eastern United States. HWA is considered the greatest single threat to hemlock health in the eastern U.S., with potential ecological impacts comparable to those of Dutch elm disease and chestnut blight. First reported in the U.S. in 1951 near Richmond, Virginia, HWA has since spread to 21 states, ranging from Maine to Alabama. Since its detection in Tennessee in 2002, HWA has spread to 43 counties in East Tennessee and the Cumberland Plateau, advancing from east to west at an average rate of 15 to 20 miles per year.
The primary vectors for the rapid spread of HWA are storm winds, migratory birds, and “hitchhiking” on mammals and humans. Infested nursery stock can also introduce the insect to new areas. While hemlock is not highly valued as a timber species, it provides critical ecological benefits, such as habitat, stream temperature regulation, and stream bank stability. The loss of these benefits would disrupt delicate forest ecosystems and negatively affect aesthetic and recreational values.
Due to the near-microscopic size of HWA crawlers (mobile instar phase) and their ease of transport by birds, mammals, and weather, traps are not effective for monitoring infestation movement across the state. However, traps are used in research settings to detect presence and spread rates. For detecting new infestations or assessing hemlock health, visual inspection of hemlock trees remains the most effective survey method. Several agencies have established annual survey locations to record infestation presence, hemlock tree health, and other relevant data.
Photo courtesy of U.S. Forest Service
The red imported fire ant, Solenopsis invicta Buren, the black imported fire ant, Solenopsis richteri Forel, and their hybrid are nuisance insects and their stings can cause serious medical problems. Imported fire ants interfere with outdoor activities and harm wildlife throughout the southern United States. Ant mounds are unsightly and may reduce land values. In some cases, imported fire ants are considered to be beneficial because they prey upon other arthropod pests. In urban areas, fire ants prey on flea larvae, chinch bugs, cockroach eggs, ticks and other pests. In many infested areas, the problems outweigh the benefits and controlling fire ants is highly desirable. However, eradication of this species is not currently feasible.
When deciding whether or not to control fire ants, one must weigh the benefits of fire ant control against the cost and environmental impact of control methods. Consideration of biological control of fire ants may not be compatible with some types of insecticide use. Insecticides are not always 100 percent effective, nor are most approved for use everywhere that ants occur. Insecticides are also expensive and potentially hazardous to the environment and other animals. Chemicals provide only temporary control of fire ants and must be reapplied periodically. Where applicable, you should select programs (for urban or agricultural areas) that use a combination of non-chemical and chemical methods that are effective, economical and least harmful to the environment. For more information regarding fire ants in Tennessee, visit UTIA’s fire ants page to learn more.
Photo courtesy of the U.S. Animal and Plant Health Inspection Service
The Old World bollworm (Helicoverpa armigera) is a significant agricultural pest that affects over 180 plant species, including corn, cotton, small grains, soybeans, peppers, and tomatoes. While adult moths are strong fliers, it is the larvae (caterpillars) that cause substantial damage by boring into the flowers and fruits of plants and feeding inside.
The life stages of the Old World bollworm are almost identical to those of the native corn earworm (Helicoverpa zea), and both species feed on the same plants. Only a trained professional can distinguish between the two species. The corn earworm is widespread across most of North America, and there is an extensive history of pest management strategies for this species.
Photo courtesy of Gyorgy Csoka, Hungary Forest Research Institute, Bugwood.org
The spongy moth (formerly known as the “gypsy moth”; Lymantria dispar dispar) is a nonnative moth responsible for defoliating over 95 million acres of hardwood forests in the northeastern United States over the past century. Native to Europe and northern Africa, it was introduced to Massachusetts in 1869. Since then, it has spread southward through the northeastern states into southwestern Virginia, with a major front advancing toward Tennessee at approximately four miles per year. The name “spongy” refers to the spongy-like appearance of the egg masses. This page has been updated to reflect the name change; for more information, please see the link in the Resources section below.
The spongy moth’s range now covers 19 states, causing significant defoliation in many areas. While small-scale defoliation events rarely result in permanent damage to trees, large-scale outbreaks can cover thousands of acres and recur over multiple years, weakening trees over consecutive seasons. These forests, weakened by repeated defoliation, become more susceptible to various pests, pathogens, and abiotic stressors that can lead to tree mortality. The damage caused by the spongy moth has had substantial economic impacts throughout the northeastern U.S.
Currently, there are no established spongy moth populations in Tennessee. Although isolated spongy moths have been detected in Tennessee annually since the statewide trapping program began in the 1970s, none have developed into established populations. Each year, Tennessee places traps to monitor spongy moth detections. When a positive identification is made, an extensive pattern of traps is installed around that location. These traps help the Tennessee Department of Agriculture determine the source, extent, and direction of a potential infestation. Often, infestations can be eradicated through extensive trapping, but sometimes spray operations are necessary. The success of the extensive trapping and treatments conducted over the past 50 years has prevented the establishment of spongy moth populations in Tennessee.
Photo courtesy of Milan Pernek, Forestry Research Institute, Bugwood.org
Weeds
Kudzu, Pueraria montana var. lobata (Willd.) Maes. & S. Almeida, often referred to as the “vine that ate the South,” is an invasive plant known for its rapid growth and widespread presence in the southeastern United States. Originally from Japan, kudzu was marketed as an ornamental plant and ground cover to stabilize soil, but it quickly spread beyond its intended areas. Due to its extensive planting and rapid growth, many states have been managing kudzu for over seventy years. This invasive plant has now also spread to parts of the Midwest and northeastern U.S.
Kudzu’s rapid growth and ability to blanket trees and structures in a thick layer of vines have raised concerns for forested areas and old field sites. It often prevents native plants and trees from establishing, creating a monoculture that reduces species biodiversity and diminishes the ecological and economic value of affected areas.
Kudzu primarily spreads through vegetative runners, where nodes that touch the ground can establish roots and expand. While it can grow over a foot a day, there are management options available to control small areas of kudzu and prevent the vines from spreading.
Photo courtesy of James H. Miller, U.S. Forest Service
Mile-a-minute weed primarily self-pollinates. This plant produces fruits and viable seeds without the need for pollinators. The vines typically die with the first frost, but the weed is a prolific seeder, producing numerous seeds from June to October in Virginia, with a slightly shorter season in northern regions. Seeds can persist in the soil for up to six years, with staggered germination.
Birds are likely the primary agents for the long-distance dispersal of mile-a-minute weed. Utility rights-of-way, such as powerlines, provide important dispersal corridors. Seeds can also be transported short distances by at least one ant species, which may aid in the survival and germination of seeds, though further investigation is needed. The seeds have an elaiosome (a nutritious food body) that may attract ants. Local bird populations help disperse seeds under utility lines, bird feeders, fence lines, and other perching locations. Other animals observed eating the fruits include chipmunks, squirrels, and deer, with viable seeds found in deer scat.
Water plays a significant role in dispersing mile-a-minute weed. Its fruits can remain buoyant for 7 to 9 days, enabling long-distance dispersal in streams and rivers. Fruits from long vines overhanging waterways are easily carried away by water currents. Storm events increase the likelihood of seed spread throughout watersheds.
Photo courtesy of Britt Slattery, U.S. Fish and Wildlife Service
Plant Pathogens
First discovered in 2002, laurel wilt has rapidly emerged as a serious disease in the southeastern U.S. Caused by the fungus Harringtonia lauricola, laurel wilt can kill mature trees very quickly. The primary vector of the fungus is the redbay ambrosia beetle (Xyleborus glabratus), a small beetle from Asia, although several other insect species can also spread the fungus. This disease affects plants in the Lauraceae family, most commonly targeting redbay in coastal areas where it was first discovered. In Tennessee, it primarily impacts sassafras and spicebush.
Laurel wilt is of significant concern due to its ecological impacts on coastal redbay groves and its potential economic impact on avocado crops in Florida, which are also susceptible. The disease was detected in Tennessee in 2019 on sassafras and has since spread to 23 counties.
More information can be found on our laurel wilt factsheet.
Photo courtesy of Ronald F. Billings, Texas A&M Forest Service, Bugwood.org
Soybean rust (SBR), caused by the fungus Phakopsora pachyrhizi, is a disease that, like other rusts, can only survive on living tissue for extended periods. The fungus overwinters in the southeastern U.S., with spores traveling to the upper Midsouth each year to initiate infection. Symptoms of SBR can closely resemble those of other diseases such as Septoria brown spot and bacterial pustule. However, distinguishing features can be observed with a 30x hand lens or dissecting microscope.
SBR is characterized by raised, pimple-like structures called uredinia or pustules, which resemble small volcanoes. These structures develop in angular lesions, primarily on the underside of leaves, and release spores through a circular central opening, which is diagnostic. In contrast, Septoria brown spot lesions are flat, and bacterial pustule lesions have irregular, cracked openings. SBR symptoms first appear on leaves in the center and lower canopy.
Photo courtesy of Melvin Newman – Emeritus, University of Tennessee
First discovered in 1995, sudden oak death has become a significant problem in northern California and Oregon. The pathogen, Phytophthora ramorum, is currently killing tanoaks, coast live oaks, and California black oaks in these western states and poses a threat to the extensive oak forests of the eastern United States. Despite its name, “sudden oak death” is somewhat misleading, as trees often succumb to the disease over several years. The disease causes severe girdling cankers on the main stem and large branches of the affected trees.
Phytophthora ramorum is known to infect hundreds of plant species, most of which do not display obvious symptoms. This asymptomatic infection increases the risk of the pathogen being introduced to new areas via infected landscape plants shipped from nurseries in the Pacific Northwest. Although this disease is not established in Tennessee, the Tennessee Department of Agriculture conducts annual surveys to monitor for the pathogen and prevent its accidental introduction.
Photo courtesy of Bruce Moltzan, U.S. Forest Service, Bugwood.org
In 2010, the discovery of a disease affecting black walnut trees in Knox County, TN, raised significant concerns for Tennessee’s forest industry. Thousand Cankers Disease (TCD), caused by the fungus Geosmithia morbida, led to walnut tree mortality and spread to several neighboring counties. Walnut trees are highly valued for their nut production and their wood, which is prized for lumber and veneer. While recent years have seen fewer detections of the disease, the following information details TCD, its impact in Tennessee, and the recent lifting of the state quarantine for TCD.
TCD is a progressive disease known to kill walnut trees within two to three years of initial infection. However, some trees with milder infections have shown the ability to recover. The walnut twig beetle (WTB), Pityophthorus juglandis, carries the spores of G. morbida and tunnels into the trunks or branches of black walnuts. The combined activity of the fungus and beetle results in the development of cankers, and repeated attacks can eventually lead to tree mortality. The walnut twig beetle is native to Arizona, California, and New Mexico and has more recently been detected in Colorado, Oregon, Idaho, and Washington. While the native origin of TCD is unknown, the disease has been present in the western states since the late 1990s.
Photo courtesy of Whitney Cranshaw, Colorado State University, Bugwood.org