12 Harmful Insects You Should Squash Immediately

If you love your garden, you know the damage invasive insects can do—wreaking havoc on plants and upsetting local ecosystems. It’s a real problem, costing the U.S. around $21 billion a year in damages.

As gardeners, we’re on the front lines in the fight against these pests. Knowing which bugs to target can save your garden and help keep the environment balanced.

Let’s look at 12 invasive insects you should squash immediately to protect your green space.

Tomato Hornworm

Got tomatoes? Then you might meet the tomato hornworm, a massive caterpillar that could be munching on your plants right now! Native to North America, these green giants can grow up to 4 inches long and sport a quirky horn-like spike on their tail.

They blend in well with the greenery, feasting on the leaves, stems, and even the fruits of tomato plants, leading to serious defoliation and a drop in your tomato yield. Spotting them can be a challenge, but if you do, handpicking them off your plants is a surprisingly effective control method.

You can also try introducing parasitic wasps. They sound bad, but they actually help keep hornworm populations in check without your having to use harsh chemicals.

The Tiger Mosquito

Watch out for the Tiger Mosquito, an invader with a striped body that’s more than just a nuisance at your backyard barbecue. These mosquitoes are potential carriers of serious diseases like West Nile virus and dengue fever, making them a public health hazard everywhere they go.

They’re now buzzing around most states in the U.S., so staying vigilant is key. If you see one, don’t hesitate to swat it.

Beyond your swift justice with a shoe, consider reducing standing water in your area to cut down on their breeding spots, and maybe invest in some mosquito repellent to keep them away from your skin.

Japanese Beetle

Ever come across a shiny, metallic green and copper-colored beetle? That’s the Japanese Beetle, and trust me, it’s not as pretty as it looks when it comes to your garden.

This bug is a nightmare for over 300 plant species, including favorites like roses, grapes, and turfgrass. The adults chew through leaves, leaving them looking like skeletons, while the larvae get busy wrecking the roots, ruining lawns and pastures.

To tackle these tough critters, the USDA suggests a few tactics: you can pick them off plants by hand, use insecticides where they feed, or even introduce natural enemies like parasitic wasps to keep their numbers in check.

European Corn Borer

This moth might hail from Europe, but it’s made itself quite at home devastating corn crops across other regions. The larvae burrow right into the stems and ears of corn, blocking nutrients and weakening the plants. This leads to not just less corn at harvest but also plants that are more vulnerable to diseases and other pests.

To keep your crops healthy and your yields high, the USDA advises rotating your crops, planting varieties that are resistant to borers, and employing biological controls. Using parasitic wasps or the bacterium Bacillus thuringiensis (Bt) can specifically target and manage these destructive larvae.

Kudzu Bug

Have you heard of the Kudzu Bug? This small, brownish-green pest from Asia has a particular taste for legumes, like soybeans, and its relentless feeding can seriously hurt crop yields and quality.

Beyond farms, kudzu bugs can swarm homes in large numbers, turning into a real headache for homeowners. The cost of calling in professionals to manage these infestations can add up fast.

To keep them at bay, seal any cracks and entryways to stop them from coming indoors, apply insecticides to affected plants, and clear out any kudzu vines around your property.

Asian Citrus Psyllid

The Asian Citrus Psyllid might be tiny, but it packs a devastating punch to citrus groves as the main spreader of citrus greening disease, or Huanglongbing (HLB).

This disease cripples citrus trees, slashing fruit production and eventually killing the trees. The impact on citrus industries worldwide has been catastrophic, with significant economic losses not just in farming but also in food processing sectors.

Stopping this pest is key to saving our citrus. Monitor your citrus trees regularly, use insecticides to manage psyllid numbers, and implement quarantine measures to halt the movement of infected plants and pests.

Red Imported Fire Ant

If you’ve ever stepped near a fire ant mound, you know to give these feisty critters a wide berth! Native to South America, red imported fire ants are notorious for their aggressive behavior and painful stings.

These ants can take over agricultural fields, wreaking havoc on crops and even damaging machinery with their extensive mounding activities. They reproduce rapidly and pose serious health risks, especially since their stings can trigger allergic reactions.

Gypsy Moth

The Gypsy Moth, originally from Europe, is like the unwelcome guest who eats you out of house and home—except it’s the trees and shrubs that suffer. These moths have larvae that are incredibly hungry, capable of devouring the leaves of over 300 types of trees and shrubs.

During severe infestations, they can strip entire forests bare, disrupting ecosystems and hurting the timber industry. What’s more, the females lay eggs on almost any outdoor surface, spreading the nuisance far and wide.

To fight these pests, consider using pheromone traps to mess with their mating or applying natural pesticides like Bacillus thuringiensis to keep their populations under control.

Emerald Ash Borer

Watch out for the Emerald Ash Borer, a shiny green beetle that’s not as pretty as it sounds, especially if you love your ash trees. Hailing from northeastern Asia, this beetle’s larvae have a nasty habit of munching on the inner bark of ash trees, effectively choking off the trees’ ability to shuttle water and nutrients upwards.

The result? A devastating impact across North America with hundreds of millions of ash trees dead, leading to serious ecological and economic fallout.

If you spot these metallic invaders, swift action is crucial. Removing them helps curb their spread and preserves the biodiversity that keeps our environment balanced and soils fertile.

Brown Marmorated Stink Bug

Then there’s the Brown Marmorated Stink Bug, an unwelcome visitor from East Asia that’s as annoying as its name suggests. This bug doesn’t discriminate -it attacks a broad range of plants from fruits to ornamentals, leaving a trail of damaged crops and garden nightmares in its wake.

Beyond the garden, these pests seek refuge in homes when the weather cools, becoming a major indoor annoyance. To fend off these shield-shaped intruders, seal up cracks and gaps in your home or consider setting up pyramid traps.

Spotted Lanternfly

If you’ve ever stumbled upon the Spotted Lanternfly, you’ll recognize its distinctive polka-dotted wings right away. Originally from Asia, this pest has become a real headache in the U.S., especially for those in farming.

They feast on the sap from various plants, including grapevines and maples, and this munching habit doesn’t just stress the plants—it also attracts molds due to the sticky honeydew they leave behind. This combo can devastate crops, turning lush greenery into moldy messes.

So, if you see one of these bugs, do your garden a favor and squash it! Their rapid spread threatens not just local flora but major industries like wine-making and orcharding too.

Asian Longhorned Beetle

Meet the Asian Longhorned Beetle, a striking bug with its stark black and white contrast and long antennae. This invader targets precious hardwood trees—maples, birches, you name it—drilling into them and laying larvae that interrupt the tree’s ability to transport nutrients.

The damage? It’s not just a tree here and there; this beetle can lead to widespread forest destruction, transforming vibrant ecosystems into ghost towns of dead wood.

Spotted in North America since the 1990s, it’s been on the radar for serious eradication efforts. If you come across this beetle, removing it helps protect our tree populations and maintain our ecosystems’ health.