Vigilant homeowners in Minnesota discovered two new invasive insect species in August through the state’s Report a Pest service, demonstrating how citizen detection serves as the critical first line of defense against ecological and economic damage.
The emerald ash borer has now spread to 44 Minnesota counties, Japanese beetles cost $460 million annually to control nationwide, and brown marmorated stink bugs threaten important regional crops including corn, soybeans, apples, and grapes worth billions to Minnesota’s agricultural economy.
Early identification of new invasive insect occurrences enables rapid response that can prevent widespread establishment and devastating losses. You don’t need specialized training to protect Minnesota’s forests, farms, and gardens—just the ability to recognize these damaging insects and report them promptly to the Minnesota Department of Agriculture’s Report a Pest hotline at 1-888-545-6684.
1. Emerald Ash Borer
The emerald ash borer (Agrilus planipennis) has become the poster child for invasive insects in Minnesota, confirmed in 44 counties as of recent surveys with continuing spread into central Minnesota. This small Asian beetle threatens to replicate the devastation Minnesota experienced from Dutch elm disease, which decimated the state’s elm population after introduction in 1968 via bark beetle-infested wood products on Mississippi River shipments.
You’ll recognize adult emerald ash borers by their distinctive metallic emerald green color, measuring about half an inch long with an elongated, narrow body. The insects emerge from ash trees during summer months, leaving behind the most telling evidence of infestation—D-shaped exit holes in bark, roughly one-eighth inch in diameter. These uniquely shaped holes, flatter on one side and rounder on the other, distinguish emerald ash borer from native wood-boring insects.
The larvae cause the actual tree damage by tunneling beneath bark to feed on the phloem layer that transports water and nutrients throughout the tree. This feeding creates distinctive serpentine galleries visible when bark is removed. Infested trees display crown dieback starting at the top, with branches becoming progressively thinner and more sparse. You’ll notice vertical bark splits, increased sprout growth from the trunk base, and sometimes extensive woodpecker damage as birds feed on larvae beneath bark.
Pro Tip: If you live in the southern half of Minnesota, emerald ash borers are likely already in your area. Check the interactive map provided by state authorities to see whether borers have been confirmed in your county. If they’re nearby and you have healthy ash trees you truly value, consider getting them inoculated by a local tree care company—this must be done before infestation occurs, so don’t delay.
Firewood-moving restrictions now apply to multiple Minnesota counties where emerald ash borer has been confirmed. These quarantines prevent transporting ash material and firewood that could carry larvae to new areas. The primary spread mechanism remains human transportation of infested wood products, not natural insect dispersal.
What should ash tree owners do? Take stock of your ash trees now. Trees valued for their location, size, or aesthetic contribution warrant proactive protection through professional inoculation treatments. Trees of marginal value should be considered for removal and replacement with diverse species less vulnerable to single-pest devastation. Delaying decisions until infestation occurs eliminates treatment options.
Monitor ash trees for the earliest signs of infestation, including unusual amounts of woodpecker activity, thinning canopy, epicormic sprouting, and D-shaped exit holes. Report suspected new infestations to the Minnesota Department of Agriculture immediately with clear photographs and exact location information. Early detection in previously unaffected areas enables rapid response efforts.
2. Gypsy Moth
Gypsy moth (Lymantria dispar)—also called spongy moth following the 2021 name change—represents one of the most serious forest pest threats, capable of devouring leaves from more than 500 tree and shrub species. While Minnesota has avoided the severe outbreaks experienced by eastern states, ongoing detection and eradication efforts prevent this devastating defoliator from establishing permanent populations.
Male spongy moths appear brownish-gray with darker wavy bands across their wings, measuring about one and a half inches across when wings are spread. They’re strong fliers that actively search for females during summer. Female moths are larger with white to cream-colored wings, but they cannot fly and remain near where they emerge to lay egg masses.
The caterpillars cause extensive defoliation damage. You’ll recognize them immediately by the distinctive paired dots along their backs—five pairs of blue dots near the head followed by six pairs of red dots toward the rear. The entire body is covered with long hairs that give caterpillars a fuzzy appearance. Mature larvae reach two inches long and consume enormous quantities of foliage daily during late spring and early summer.
Key Insight: Spongy moths arrive in Minnesota through people moving infested materials—outdoor furniture, vehicles, recreational equipment, and especially firewood from outbreak areas. Inspect items carefully before transporting them into Minnesota, and check your property for egg masses in fall and winter when they’re most visible against bare bark and surfaces.
Egg masses appear as tan or buff-colored fuzzy patches about one to two inches long. Each mass contains 500 to 1,000 eggs protected by a covering of hairs from the female’s abdomen. Females lay these masses on tree trunks, but they also attach them to outdoor furniture, vehicles, trailers, firewood, and any protected surface near where they emerge.
Find and destroy egg masses before spring hatching. Scrape them into containers of soapy water using a putty knife or similar tool, ensuring you collect all eggs. The fuzzy covering protects eggs through winter, so complete removal is essential. Check stored outdoor items, recreational vehicles, and firewood stacks thoroughly.
During outbreak years in other states, heavy defoliation strips entire forests bare, creating significant ecological and economic damage. The sound of caterpillar frass (droppings) falling from trees becomes audible, and accumulations of frass beneath trees create nuisance problems. Trees weakened by complete defoliation become vulnerable to other pests and diseases.
Minnesota’s ongoing surveillance and rapid response program has successfully prevented spongy moth establishment despite regular introductions. Your reports of suspected sightings contribute directly to this success. If you notice distinctive blue and red-dotted caterpillars, unusual defoliation patterns, or tan fuzzy egg masses, photograph them and report immediately through Report a Pest.
3. Japanese Beetle
Japanese beetles (Popillia japonica) have been reported in at least 21 southern Minnesota counties, attacking everything from crabapple trees to roses to turfgrass. These invasive beetles cost $460 million per year to control nationwide, with both adult beetles and larvae causing significant damage to landscapes, gardens, and agricultural crops across their established range.
Adult Japanese beetles measure about half an inch long with distinctive metallic green bodies and copper-colored wing covers. Five small patches of white hair appear along each side of the abdomen where it extends beyond wing covers, with two larger white hair patches on the rear end. These white tufts provide the most reliable identification feature and distinguish Japanese beetles from similar-looking native species.
The beetles emerge from soil in late June through July and remain active into August, feeding on plant foliage during warm daylight hours. They consume leaf tissue between veins, leaving behind a lacy, skeletonized appearance. Heavy infestations can completely defoliate plants, with roses, grapes, raspberries, and numerous landscape ornamentals suffering particularly severe damage.
Important Note: Parasitic winsome flies are starting to make a difference in the Twin Cities area. If you see a Japanese beetle with a white dot or dots near its head, that’s a winsome fly egg. The fly larvae develop inside the beetle and eventually kill it, providing natural biological control. This represents exactly the type of solution scientists hope to establish more widely across Minnesota.
Japanese beetles aggregate while feeding, releasing pheromones that attract more beetles to the same plants. Finding one beetle often means finding dozens within hours as chemical signals draw them from surrounding areas. This aggregation behavior makes management particularly challenging and explains why beetle populations can explode seemingly overnight.
The larvae—white C-shaped grubs measuring up to one inch long—feed on grass roots from late summer through the following spring. Lawn damage appears as brown, dead patches that pull up easily like carpet since roots have been consumed. Birds, skunks, and raccoons often dig up infested lawns searching for grubs, creating additional damage beyond what the larvae cause directly.
Remove prematurely ripening or diseased fruit from trees and the ground promptly. Japanese beetles show extreme attraction to compromised fruit, so eliminating these attractants helps prevent beetles from discovering your trees. This simple sanitation practice significantly reduces beetle pressure in home orchards and fruit gardens.
Common Mistake: Avoid Japanese beetle traps that use pheromone lures. While these traps do catch beetles as advertised, research consistently shows they attract more beetles to your property than they capture. You’ll end up with increased feeding damage on nearby plants as beetles swarm toward the trap but land on your landscape plants along the way.
Handpick beetles early in the morning when cooler temperatures make them sluggish and less likely to fly away. Drop collected beetles into soapy water to kill them. Focus removal efforts on new arrivals before aggregation pheromones attract large populations that become overwhelming to manage manually.
4. Brown Marmorated Stink Bug
Brown marmorated stink bugs (Halyomorpha halys) have been reported in 25 Minnesota counties to date, posing serious threats to important regional crops including corn, soybeans, apples, and grapes. This invasive insect from Asia can also become a significant household pest, sheltering indoors in large numbers similar to Asian lady beetles when cold weather arrives.
You’ll identify adult brown marmorated stink bugs by their shield-shaped bodies measuring about three-quarters of an inch long. They display mottled brown coloring on top with a marble-like pattern that provides excellent camouflage on tree bark and brown vegetation. The smooth shoulder edge when viewed from above distinguishes them from native stink bug species. Look for alternating light and dark bands on the antennae and along the edges of the abdomen.
These insects pierce plant tissue with needle-like mouthparts to suck out juices, leaving behind damaged produce. On fruits and vegetables, feeding creates dimpled, corky areas that extend beneath the surface, causing internal breakdown and rendering produce unmarketable. Sweet corn, tomatoes, peppers, apples, grapes, and soybeans all suffer damage when stink bugs feed during crop development.
Research funded by the Minnesota Invasive Terrestrial Plants and Pests Center focuses on understanding how brown marmorated stink bugs are spreading across the state. Computer simulation models are helping predict future movement patterns with precision, identifying which Minnesota resources face greatest economic risk from potential invasion. Other research has determined that population growth is very likely to occur at the northern edge of the insect’s range in the Midwest, where climate conditions increasingly favor establishment.
Pro Tip: Download the Midwest Stink Bug Assistant app to help identify and report brown marmorated stink bugs. This tool was specifically built for Minnesota and surrounding states, with features designed to distinguish this invasive species from native stink bugs that pose no threat. Consistent early detection through reporting slows spread and contributes to management solutions.
Brown marmorated stink bugs seek shelter inside buildings during fall when temperatures drop. They enter through any available gaps around windows, doors, vents, and utility penetrations, congregating in attics, wall voids, and other protected spaces. Unlike some insects that reproduce indoors, stink bugs only overwinter inside—they remain dormant until spring temperatures trigger their return outdoors.
Seal entry points before fall temperatures trigger the bugs’ search for winter shelter. Check window and door screens for tears, apply weatherstripping to doors, and caulk gaps around utility lines, vents, and other penetrations. Once inside, vacuum up stink bugs rather than crushing them to avoid releasing the characteristic pungent odor that gives them their common name.
Monitor crops and gardens regularly during growing season. The bugs feed preferentially on developing fruits and seeds, making mid to late summer the critical damage period. Surrounding vegetation can harbor populations that move into crops, so managing weeds and volunteer plants around garden edges reduces nearby stink bug numbers available to colonize your plants.
5. Spotted Lanternfly
Spotted lanternfly (Lycorma delicatula) is designated as an early detection species by the Minnesota DNR, meaning it hasn’t yet been confirmed in the state but poses significant threat if introduced. This piercing-sucking insect from Asia has established in Pennsylvania and surrounding states, causing severe damage to vineyards, orchards, and hardwood forests while creating major nuisance problems.
Adult spotted lanternflies display striking coloration that makes them unmistakable once you know what to look for. The forewings appear grayish with black spots, while the hindwings are bright red with black spots and white bands. When wings are spread during flight or at rest, the red hindwings create a flashy appearance. Adults measure about one inch long with distinctive spotted patterns.
Nymphs progress through four stages before reaching adulthood, with early instars appearing black with white spots. Late-stage nymphs develop red patches along with the black and white spotting, providing a preview of adult coloration. Both nymphs and adults feed by piercing plant tissue to suck out sap, causing wilting, dieback, and oozing wounds that attract secondary pests.
One of the insect’s favorite hosts is tree-of-heaven (Ailanthus altissima), a fast-growing invasive tree that has established in some Minnesota locations. Spotted lanternflies are also known to feed on grapevines, which has proven devastating for vineyards in Pennsylvania. Apple, cherry, walnut, and many other economically important trees serve as hosts, along with numerous hardwood forest species.
Key Insight: Spotted lanternflies lay distinctive egg masses that resemble mud smeared on surfaces—tree trunks, outdoor furniture, vehicles, trailers, and stone surfaces. Each mass contains 30 to 50 eggs covered with a gray waxy coating. Finding and destroying these egg masses before spring hatch prevents establishment, making fall and winter inspection critically important.
The insects excrete large amounts of honeydew (sugary liquid waste) that coats plants and surfaces below where they feed. This sticky honeydew attracts wasps, flies, and other insects while promoting growth of black sooty mold that covers leaves and reduces photosynthesis. The accumulation of honeydew on outdoor furniture, vehicles, and patios creates significant nuisance problems in heavily infested areas.
Minnesota’s location and agricultural profile put the state at high risk if spotted lanternflies establish. Vigilant monitoring for this species is essential, particularly around known tree-of-heaven locations and along transportation corridors where the insects might arrive on vehicles or cargo from infested states. If you see any insect matching the description—especially the distinctive red and black spotted wings—photograph it immediately and report through the Report a Pest hotline.
Check vehicles, trailers, and outdoor equipment carefully when traveling from Pennsylvania, New York, New Jersey, Delaware, Maryland, Virginia, West Virginia, Ohio, and Indiana where spotted lanternflies are established. The insects and their egg masses hitchhike on these items, making human transportation the primary long-distance spread mechanism.
6. European Pine Shoot Moth
European pine shoot moth (Rhyacionia buoliana) attacks various pine species throughout Minnesota, with particular damage to red pine and Scots pine plantations and ornamental trees. While not as destructive as some other invasive insects, the cumulative effects of repeated annual infestations can significantly reduce tree growth, deform trees, and make them less valuable for timber or landscaping purposes.
The adult moths appear small and inconspicuous, measuring about half an inch across with reddish-brown to orange-brown wings marked with silver-gray bands. Adults emerge in late June through July, flying during evening hours to mate and lay eggs on pine shoots and needles. The moths themselves cause no damage—all harm results from larval feeding inside shoots.
Larvae bore into terminal and lateral buds and new shoots during late summer and early fall. You’ll notice infested shoots that fail to grow properly in spring, appearing stunted with needles turning brown or red. The shoot tips often bend into distinctive “shepherd’s crook” shapes as larvae tunnel inside, killing the growing tissue. Heavy infestations create a bushy, deformed appearance as lateral shoots attempt to compensate for damaged terminals.
Pro Tip: Look for masses of resin (pitch) at the base of buds and on damaged shoots—this is the tree’s response to larval feeding and provides a clear sign of European pine shoot moth activity. The resin appears as yellowish or white crusty deposits that accumulate around feeding sites and entry holes.
The larvae overwinter inside buds and infested shoots, resuming feeding briefly in spring before pupating. This overwintering strategy allows European pine shoot moth to survive Minnesota’s harsh winters and complete one generation per year. The moths have become well established throughout much of the state, particularly in areas with red pine and Scots pine plantations.
Christmas tree growers and pine plantation managers face economic losses from European pine shoot moth damage. Repeated attacks reduce tree height growth, create multiple leaders where single leaders should dominate, and decrease overall tree quality. Ornamental pines in landscapes suffer aesthetic damage that reduces their appeal and value.
Management focuses on timing insecticide applications to kill young larvae before they bore into shoots, typically in late summer. Natural enemies including parasitic wasps and predatory insects provide some biological control, but rarely sufficient to prevent economic damage in high-value plantations. Proper pine species selection for specific sites can also reduce problems, as some pine species show greater tolerance to shoot moth damage than others.
Monitor red pine and Scots pine trees in June through August for signs of larval feeding. If you notice bent shoots, browning needles on new growth, or masses of resin on buds, examine the affected shoots more closely for larvae or their damage. While European pine shoot moth is established in Minnesota, reporting significant outbreaks helps authorities track population dynamics and provide management guidance.
7. Larch Casebearer
Larch casebearer (Coleophora laricella) is a small moth whose larvae feed on larch (tamarack) needles, causing browning and defoliation that weakens trees. While this European native has been present in North America for decades, it continues causing periodic damage to larch stands throughout Minnesota, particularly during outbreak years when populations build to damaging levels.
You’ll recognize larch casebearer damage first rather than seeing the insects themselves. Infested larches display browning needles in late spring and early summer, often creating a scorched appearance across entire trees. The larvae mine inside needles while protected in small cases they construct from hollowed needle sections and silk, carrying these cases as they move and feed.
The cases appear as small hollow tubes about one-quarter inch long, slightly curved, and brownish in color. Larvae attach cases to branches when not feeding, with heavy infestations showing numerous cases clustered together. Each larva feeds by cutting into a needle, consuming the interior, then moving to the next needle while remaining protected inside its portable case.
Adult moths emerge in June and July, appearing small and grayish-brown with narrow wings held folded along their bodies at rest. The moths lay eggs on larch twigs, with larvae hatching and immediately constructing their protective cases from needle material. The larvae feed through summer, then overwinter in their cases attached to twigs.
Important Note: Larch is the only conifer in Minnesota that drops its needles each fall, making larch casebea
rer damage easy to confuse with natural needle senescence. Check trees in late spring and early summer when healthy larches should display full green foliage. If needles appear brown or sparse during the growing season, examine branches closely for the telltale cases that indicate larch casebearer feeding.
Native to Europe, larch casebearer has spread throughout much of North America’s larch range. Natural enemies including parasitic wasps have been introduced as biological control agents, with varying success in different regions. These parasitoids attack larch casebearer larvae inside their cases, providing some population suppression but not complete control.
Damage typically affects tree appearance and vigor rather than causing direct mortality. However, repeated severe defoliation over multiple years can weaken larches, making them vulnerable to other pests and environmental stresses. Young trees and trees already stressed by poor site conditions or other factors face greatest risk from larch casebearer damage.
Monitor tamarack trees on your property during the growing season. If you notice unusual browning of needles or see the distinctive small cases attached to branches, note the extent of damage and consider reporting heavy infestations. While larch casebearer is established in Minnesota, tracking population levels helps forest health specialists provide management recommendations and predict outbreak patterns.
8. Asian Lady Beetle
Asian lady beetle (Harmonia axyridis) was intentionally introduced to North America as a biological control agent for aphids and scale insects but has become a nuisance pest when thousands of beetles invade homes seeking winter shelter. While beneficial in gardens where they consume pest insects, their tendency to aggregate in buildings during fall creates significant problems for homeowners.
You’ll recognize Asian lady beetles by their dome-shaped bodies measuring about one-quarter inch long. They range in color from pale orange to deep red, with variable numbers of black spots—some individuals have many spots while others have few or none. The most reliable identification feature is a distinctive M or W-shaped black marking behind the head on the pronotum (section between head and wings).
Asian lady beetles gather on the sunny sides of buildings during fall, seeking entry points to overwinter indoors. They squeeze through tiny gaps around windows, doors, vents, utility lines, and siding, sometimes accumulating in walls and attics by the thousands. The beetles don’t reproduce or feed indoors—they simply seek protected spaces to survive winter—but their numbers and the staining they cause create major nuisance problems.
When disturbed or crushed, Asian lady beetles release a yellowish defensive fluid from their leg joints that has an unpleasant odor and can stain walls, curtains, and furnishings. This reflex bleeding (called reflex hemorrhaging) serves as a predator deterrent but creates additional problems when beetles invade homes in large numbers.
Common Mistake: Don’t confuse Asian lady beetles with native lady beetles that provide similar aphid control benefits. Native species typically show fewer spots with more consistent patterns, lack the distinctive M marking, and rarely invade homes in massive numbers. Asian lady beetles aggregate much more extensively and show greater color variation within populations.
Seal entry points before fall temperatures trigger the beetles’ search for winter shelter. Focus on the sunny sides of buildings where beetles preferentially congregate. Install tight-fitting screens on vents, apply weatherstripping to doors and windows, and caulk gaps around utility penetrations and siding. Prevention through exclusion is far more effective than trying to remove thousands of beetles once they’re inside.
Vacuum beetles that enter your home rather than crushing them. Empty the vacuum bag or canister promptly and dispose of contents in sealed bags to prevent beetles from escaping back indoors. Avoid crushing beetles on walls and surfaces where their defensive fluid will create stains that are difficult to remove.
Despite their nuisance behavior, Asian lady beetles do provide valuable pest control in gardens and agricultural settings. The beetles and their larvae consume enormous numbers of aphids, scale insects, and other soft-bodied pests. The same characteristics that make them effective biological control agents—high reproductive rates, voracious appetite, and cold tolerance—contribute to their success as an invasive species.
9. Soybean Aphid
Soybean aphid (Aphis glycines) represents a serious threat to Minnesota’s soybean production, with the potential to cause significant yield losses when populations reach economic thresholds. This tiny Asian aphid first detected in North America in 2000 has become one of the most important pests of soybeans throughout the upper Midwest, requiring ongoing monitoring and management.
You’ll find soybean aphids as small, soft-bodied insects about one-sixteenth inch long with pale yellow to light green coloring. Both winged and wingless forms occur, with wingless individuals dominating most of the growing season. The aphids cluster on the undersides of soybean leaves and on stems, with heavy infestations causing leaves to appear coated with moving masses of insects.
The aphids feed by piercing plant tissue with needle-like mouthparts and sucking out phloem sap. This feeding removes nutrients the plant needs for growth and seed production. Infested plants show yellowing leaves, stunted growth, and reduced pod and seed development. The aphids also excrete honeydew that coats leaves and promotes sooty mold growth, further reducing photosynthesis.
Soybean aphids reproduce rapidly during summer, with females giving birth to live young without mating (parthenogenesis). Under favorable conditions, populations can explode from low levels to damaging densities within weeks. A single female can produce 50 to 100 offspring during her lifetime, with each generation maturing in just one to two weeks during warm weather.
Pro Tip: Scout soybean fields regularly from July through August when aphid populations typically peak. Check at least 20 plants across multiple field locations, counting aphids on randomly selected leaves. Economic threshold guidelines recommend treatment when fields average 250 or more aphids per plant during vegetative stages or the early reproductive period, before populations cause irreversible damage.
Natural enemies including lady beetles, lacewings, parasitic wasps, and fungal pathogens provide biological control that often keeps soybean aphid populations below economic thresholds. Weather conditions strongly influence both aphid reproduction and natural enemy effectiveness, with hot, dry conditions generally favoring aphids while cool, humid weather promotes fungal diseases that kill aphids.
Winged aphids colonize soybean fields in early summer, flying from buckthorn (their alternate host) where they spent winter as eggs. The aphids produce multiple generations on soybeans through summer, then produce winged forms in fall that return to buckthorn to mate and lay overwintering eggs. This host alternation between buckthorn and soybeans is essential to the aphid’s life cycle.
Management combines monitoring, biological control conservation, and insecticide applications when populations exceed economic thresholds. Avoid prophylactic insecticide applications that kill natural enemies and can lead to aphid resurgence. Time treatments based on actual field populations reaching threshold levels, typically during late July through August.
10. Zebra Swallowtail Leafhopper
Zebra swallowtail leafhoppers (various Erythroneura species) represent a complex of small insects that feed on grape leaves, causing stippling damage and reducing vine vigor. While native leafhoppers are present in Minnesota, some species within this complex have expanded their ranges or increased in abundance, creating management challenges for vineyard operators and home grape growers.
These tiny leafhoppers measure about one-eighth inch long with wedge-shaped bodies. They display distinctive zigzag or banded patterns on their wings, typically in combinations of yellow, white, and darker markings. The insects are very active, jumping quickly when disturbed, which makes close observation challenging but provides a useful identification behavior.
Leafhoppers feed by piercing leaf tissue and sucking out cell contents, leaving behind white or yellow stippling that gives leaves a bleached, mottled appearance. Heavy feeding causes leaves to appear bronzed or scorched, with significant infestations leading to premature leaf drop. This defoliation reduces photosynthesis and carbohydrate production, weakening vines and reducing fruit quality and quantity.
Multiple generations per year allow leafhopper populations to build through the growing season, with peak numbers typically occurring in late summer. Both adults and nymphs feed on grape leaves, with nymphs appearing as smaller, paler versions of adults without fully developed wings. The insects overwinter as adults in protected areas, emerging in spring to colonize grape vines as new growth begins.
Key Insight: Monitor grape leaves from June through harvest for early signs of stippling damage and leafhopper presence. Check the undersides of leaves where leafhoppers prefer to feed and rest. Catching infestations early, before populations build to damaging levels, enables more effective management with less intensive interventions.
Natural enemies including parasitic wasps, predatory bugs, spiders, and general predators provide some biological control of leafhopper populations. However, these natural enemies rarely prevent economic damage in commercial vineyards where quality standards are high and even moderate feeding damage reduces marketability.
Vineyard operators use various management strategies including insecticide applications timed to target early-season populations before they build, canopy management to reduce favorable microclimate conditions, and monitoring to determine when populations reach economic thresholds. Home grape growers can often tolerate higher leafhopper densities than commercial operations, relying more on natural control and accepting some cosmetic leaf damage.
The presence of grape leafhoppers in Minnesota vineyards highlights the ongoing challenge of managing both native and potentially expanding pest species. Report unusually severe leafhopper damage or populations that don’t respond to typical management approaches, as this may indicate range expansion by more aggressive species or resistance to commonly used control methods.
Conclusion
Your observations and reports serve as Minnesota’s early warning system against invasive insect establishment and spread. The Minnesota Department of Agriculture’s Report a Pest service depends on citizen reports, with recent discoveries of elm seed bugs and Asiatic garden beetles demonstrating how homeowner vigilance enables rapid response before widespread establishment occurs.
When you find a suspected invasive insect, take clear, in-focus photographs from multiple angles showing distinctive features. Note your exact location using physical address or GPS coordinates, record the date of observation, and describe what the insect was doing or what damage you observed. If safe to do so, collect a specimen by placing it in a sealed plastic bag or container—freezing kills insects while preserving them for identification.
Submit reports through the online Report a Pest system or call 1-888-545-6684 to speak with specialists who can guide you through the reporting process. Include your contact information so experts can follow up with questions or request additional specimens if initial photographs don’t allow confident identification. Even if you’re uncertain whether an insect is invasive, submit the report—specialists review all submissions and appreciate thoroughness over hesitation.
For invasive aquatic plants or wild animals, contact the DNR Invasive Species Program at 651-259-5100 (metro area) or 1-888-646-6367. The division of regulatory authority between the Minnesota Department of Agriculture (terrestrial insects and plants) and Department of Natural Resources (aquatic species and wild animals) ensures specialized expertise handles each report appropriately.
Never move firewood between Minnesota locations or transport wood products from other states without verification they’re pest-free. The most visible example in Minnesota remains Dutch elm disease introduction via Mississippi River shipments in 1968, but emerald ash borer continues spreading primarily through human transport of infested firewood. Buy firewood where you’ll burn it, or gather on-site when camping in state forests and parks.
Inspect outdoor items carefully when traveling from states with known invasive insect infestations. Spotted lanternflies, Asian longhorned beetles, and other serious pests hitchhike on vehicles, trailers, outdoor furniture, and equipment. A few minutes checking and cleaning these items before returning to Minnesota can prevent introducing devastating invasive species to new areas.
The Minnesota Invasive Terrestrial Plants and Pests Center conducts research on priority invasive species, developing management strategies and expanding control options. Research projects focus on biological control, genetic control methods, population modeling to predict spread, and understanding how invasive insects interact with Minnesota’s climate and agricultural systems.
Early detection remains the single most important factor in preventing widespread establishment and minimizing economic and ecological damage. Your vigilance today protects Minnesota’s forests, agricultural industries, and natural landscapes for future generations. Report suspected invasive insects promptly—your observation could be the critical detection that enables successful management before a pest becomes permanently established.
