Invasive insects can wreak havoc on your garden, damage your home’s structure, or even pose serious health risks to you and your family. While many pests are native, others hail from distant lands, sneaking into the United States via shipping containers, plants, or cargo planes. Some are even introduced by well-meaning folks unaware of the chaos they can unleash. Knowing how to spot these invaders and what to do about them is key to protecting your home and yard.
1. Japanese Beetle (Popillia japonica)
These insects actually aren’t pests in their native home of Japan, where natural predators keep their population in check. Unfortunately, those predators don’t exist here, which is why these green metallic bugs can gather en masse uncontested in early summer to wreak havoc on the foliage of vegetables, fruit trees, flowers, and other plants located east of the Mississippi River, though they’re sometimes found farther west. You can combat these pests by shaking them off of plants daily, covering smaller plants, or setting out baited traps about 30 feet away from your garden or trees.
I’ve seen these shiny little devils munch through rose bushes like they’re at an all-you-can-eat buffet. One summer, I noticed my garden looking like Swiss cheese and realized it was these beetles. Shaking them off early in the morning when they’re sluggish worked wonders, but you’ve got to be consistent. According to the USDA, Japanese beetles cause about $460 million in crop damage annually in the U.S., targeting over 300 plant species. For long-term control, consider introducing parasitic nematodes to your soil—they’re a natural enemy that can reduce beetle larvae without chemicals. Just make sure to apply them in late summer when the grubs are active. Baited traps are tempting, but studies from the University of Kentucky suggest they can sometimes attract more beetles than they catch, so place them far from your prized plants.
2. Brown Marmorated Stink Bug (Halyomorpha halys)
This relatively newer invasive species arrived in Allentown, Pennsylvania, from East Asia sometime in the mid to late ’90s. By the early aughts, they were eating their way through the Mid-Atlantic’s fruit trees. Today, they’ve spread to most of the country. Most homeowners are familiar with these bugs as nuisance insects that take refuge from the cold during winter months inside their homes. The stink bug gets its colorful name from the unpleasant odor it releases if squashed. To keep these pests out of your house, caulk your windows, add weatherstripping to your entry doors, and insulate gaps around plumbing.
These stinkers are no joke—I once found a dozen crawling around my window sills in late fall, and that smell when you accidentally squash one is unforgettable. Research from Penn State shows they’ve caused millions in losses for fruit growers, especially apple and peach farmers. Beyond sealing entry points, you can try vacuuming them up (use a dedicated shop vac, or you’ll regret it). For outdoor control, planting trap crops like sunflowers or sorghum can lure them away from your fruit trees. Just don’t expect a quick fix; these bugs are tough, and a single female can lay up to 400 eggs in her lifetime. Regular checks and early action are your best bet.
3. European Spongy Moth (Lymantria dispar)
This invader from the Old World, named for its sponge-like egg masses, made its way to the United States way back in the 1860s. Upon arriving, it set upon the country’s trees and shrubs with an unquenchable appetite. The caterpillar form of this species, identifiable by its fuzzy yellow hair, has the ability to cause widespread deforestation in the Mid-Atlantic and parts of the Midwest. The nests, which consist of dense white web-like masses in tree branches, are easy to spot. Should you discover these tree killers on your property, contact a professional to remove them right away before it’s too late.
Those fuzzy caterpillars might look harmless, but I’ve seen entire oak groves stripped bare in a matter of weeks. The USDA estimates that spongy moths defoliate millions of acres annually, with significant outbreaks in states like Pennsylvania and Michigan. If you spot those creepy white nests, don’t try to burn them off yourself—caterpillar hairs can cause skin irritation, and you might make things worse. A pro can use targeted sprays like Bacillus thuringiensis (Bt), a natural bacteria that’s safe for most other wildlife. Wrapping tree trunks with burlap bands can also trap caterpillars for easy removal. Act fast, as a single egg mass can contain up to 1,000 caterpillars!
4. Termite (Isoptera)
There are some 28 termite species that are considered to be invasive. The mere mention of their name strikes fear into the heart of any homeowner, and for good reason. Their destructive appetite for wood can cause structural damage to a home’s framing. Since a single colony of termites can contain up to 1 million specimens, it’s little wonder they pose such a grave threat. You can reduce the risk of termites, which are found mainly in the warmer southern half of the country, by storing wood materials, such as firewood, as far from your home as possible. You can also install termite baits around your home’s perimeter or hire one of the best pest control companies, like Orkin or Terminix, to perform annual inspections and termite treatments.
Termites are every homeowner’s nightmare—I had a neighbor who ignored a small mud tube on their foundation, and it cost them thousands in repairs. The National Pest Management Association reports that termites cause over $5 billion in property damage yearly in the U.S. To stay ahead, check your home’s foundation for those telltale mud tubes, and keep an eye on any wood that feels soft or hollow. Bait stations can be a game-changer, but they’re not cheap—expect to spend $1,000-$3,000 for professional installation and monitoring. If you’re in a high-risk area, investing in a termite bond with a pest control company can save you from major headaches down the road.
5. Spotted Lanternfly (Lycorma delicatula)
With its bright-red coloring and black spots, the spotted lanternfly may be pretty to look at, but you should still squash it if you happen to find one. These pests, which arrived in the United States via a shipping container in 2014, inhabit Oregon, Wyoming, Texas, and Hawaii, where they feast on grapes, fruits, and roses. Then they release excrement on trees and shrubs, eventually poisoning and killing the plants. After slaying the lanternfly, call your local ag extension office to report it, and then purchase a trap to catch its companions.
These flashy bugs caught my eye in a vineyard once, but their sticky “honeydew” mess is a real plant killer—it promotes mold growth that chokes trees. The USDA notes they’ve hit grape industries hard, with losses in Pennsylvania alone reaching $50 million annually. Sticky traps work well, but avoid placing them where birds might get caught. Another trick is to wrap tree trunks with double-sided tape to snag nymphs before they climb. Reporting sightings is critical since these pests spread fast—check with your state’s agriculture department for local guidelines. And don’t be fooled by their beauty; they’re a serious threat.
6. Asian Longhorned Beetle (Anoplophora glabripennis)
That treasured oak or elm tree that’s been growing for decades in your backyard may be at risk of this pest if you happen to live in the Northeast. The Asian longhorned beetle, identifiable by its long, striped antenna and shiny black color, feasts on hardwood trees. This insect’s attack is so potent that it causes more damage to hardwoods than Dutch elm disease, chestnut blight, and spongy moths combined. Telltale signs of a tree being eaten by these pests include sawdust around the base of the trunk, pencil-sized holes in the tree, and yellowing leaves. If you spot these pests, report your finding immediately to the USDA.
I’ve walked past trees in my area with those eerie pencil-sized holes, and it’s a sinking feeling knowing what’s at stake. These beetles have destroyed millions of trees since arriving in the 1990s, with eradication efforts costing the U.S. over $700 million, per USDA reports. If you’re in a quarantine zone, avoid moving firewood, as it can spread the beetles. Look for exit holes about the size of a dime on tree trunks, and if you see them, don’t wait—call the USDA hotline. Early reporting can save entire forests, and trust me, you don’t want to lose that shade tree you’ve loved for years.
7. Red Imported Fire Ants (Solenopsis invicta)
Considered to be one of the most aggressive species of fire ant, red imported fire ants are an invasive species from Brazil. They can form colonies around homes in the southern and western parts of the country, building their nests in soil or near home foundations, often near HVAC units and electrical boxes. Their stingers, which are loaded with venom, can deliver a very painful sting and even cause life-threatening anaphylaxis. Since these ants band together, you’re likely to receive several stings if you happen to stumble upon a nest. You can call in a professional if you find one on your property, or you can pour boiling water over fire ants’ telltale hills.
I stepped on a fire ant mound once, and let me tell you, those stings burn like crazy—I had welts for days. The CDC estimates that fire ant stings cause dozens of deaths annually due to allergic reactions. Boiling water can work for small mounds, but larger colonies need professional-grade baits, which can cost $50-$200 depending on the size of the infestation. Keep your yard free of debris and standing water to discourage nests, and wear closed-toe shoes when walking in infested areas. If you’re allergic to stings, keep an epinephrine auto-injector handy, just in case.
8. Asian Tiger Mosquitoes (Aedes albopictus)
This invasive species made its way to the United States by stowing away in shipments of used tires from Asia sometime in the 1980s. Since then, they have spread rapidly across the country. While Asian tiger mosquitoes can deliver a painful and itchy bite, they also present a serious health hazard due to their ability to transmit life-threatening diseases such as West Nile virus. The best way to avoid the bite of one of these mosquitoes is to defend yourself with a good DEET-based bug spray. Although DEET is the most effective chemical ingredient available, it isn’t advisable for children and can even be harmful to adults. Always follow the manufacturer’s instructions for use and application to avoid harmful effects from ingestion, absorption, or inhalation.
These mosquitoes are relentless—I’ve been bitten in broad daylight while gardening, unlike most mosquitoes that come out at dusk. The CDC reports they’ve spread diseases like Zika and dengue in warmer states, with thousands of cases annually. To keep them at bay, empty any standing water from pots, buckets, or even bottle caps, as they breed in tiny amounts of water. Natural repellents like citronella candles can help, but they’re less effective than DEET. If you’re worried about chemicals, try long sleeves and pants during peak mosquito hours. It’s a hassle, but it beats scratching bites all week.
9. Northern Giant Hornet (Vespa mandarinia)
These headline-grabbing invasive pests, formerly known as murder hornets, are some of the newest invaders to the United States, having arrived in the country at the start of the coronavirus pandemic in 2020. These massive hornets, which can be found in Washington State, are immediately noticeable by their size; they can grow to a whopping 2 inches long with a wingspan of 2.75 inches. Their large bodies can carry enough venom to be lethal to humans, especially if a person is stung multiple times. In their native Japan, they’re responsible for around 50 deaths each year. They also pose a huge threat to honey bees, as a single hornet can wipe out an entire colony in hours. If you spot a northern giant hornet nest, contact your state department of agriculture ASAP.
Seeing one of these giant hornets is like something out of a sci-fi movie—I haven’t spotted one myself, but the photos are terrifying. A single hornet can kill up to 40 bees per minute, decimating hives and threatening pollination, which impacts about $15 billion in U.S. crops annually, per the USDA. If you’re in the Pacific Northwest, keep an eye out for their football-shaped nests in trees or underground. Don’t try to remove them yourself; professionals use protective suits and specialized traps. Reporting sightings quickly can help contain their spread before they become a bigger problem.
10. Africanized Honey Bees (Apis mellifera scutellata)
This dangerous breed of honey bee came into being in the 1950s when southern African bees mated with European honey bees. Often called killer bees, Africanized honey bees are dangerous because they’re extremely aggressive and attack in much greater numbers than the European honey bees found in the United States. Killer bees are responsible for the deaths of thousands of people around the world. Since these bees, which are found in southern California, Texas, Arizona, southern Nevada, New Mexico, Oklahoma, and Louisiana, look virtually identical to European honey bees, you should call an expert for help if you believe you’ve discovered a hive of killer bees.
I’ve heard stories from friends in Texas about stumbling onto these hives, and it’s no picnic—they swarm fast and don’t let up. Reports suggest they’ve caused over 1,000 human deaths globally since their spread began. If you notice a hive, stay calm and back away slowly; sudden movements can trigger an attack. Professional removal can cost $100-$1,000 depending on the hive’s size and location. To avoid attracting them, keep sugary drinks and food covered outdoors, as they’re drawn to sweets. If you’re in a high-risk area, it’s worth investing in a beekeeper’s consultation to assess your property.
11. Camel Crickets (Rhaphidophoridae)
These odd-looking alien-like crickets, which originate from Asia, like to invade homes across the eastern United States, where they make a meal out of wood, cupboards, boxes, and fabrics. They’re particularly attracted to damp places, such as basements. Discourage these invaders from entering your home by keeping the humidity and moisture level in basements low with a dehumidifier and sealing any cracks in the basement walls that might allow rainwater to enter.
These creepy critters gave me a jump scare in my basement last year—they look like spiders on steroids! They don’t bite, but their munching can ruin stored clothes or cardboard. A good dehumidifier, costing around $100-$200, can make your basement less inviting, as they thrive in humidity above 60%. I also sprinkle diatomaceous earth in corners; it’s a natural powder that dehydrates them without chemicals. Check your basement regularly for leaks, as even a small drip can draw them in. It’s not glamorous work, but it keeps these weirdos out.
12. Mexican Bean Beetle (Epilachna varivestis Mulsant)
Though the Mexican bean beetle may resemble its garden-friendly cousin the ladybug at only 0.25 inch long, these spotted insects are a bane to any gardener who happens to be a bean lover. In keeping with their name, they chow down on bush beans, snap beans, lima beans, and soybeans throughout the eastern half of the United States, along with western states such as Colorado, Nebraska, and Texas. To keep these pests off your beans, you can hand-pick them off, add lures to attract the bean beetle’s natural predator, the spined soldier bug, or spray them with a neem oil that suffocates them.
My bean patch took a hit from these imposters one season, and it was frustrating to see those chewed-up leaves. They can reduce crop yields by up to 20%, according to agricultural studies, which is a big deal for small gardeners. Hand-picking is tedious but effective if you catch them early—drop them into soapy water to finish them off. Neem oil is great, but it needs reapplying after rain, and a bottle costs about $10-$20. I’ve also had luck planting marigolds nearby; their scent seems to deter the beetles a bit. Stay vigilant, and your beans will thank you.
