15 Destructive Invasive Insects You Must Eliminate Immediately!
This post may contain affiliate links.
Rob Morrison, Ph.D., states, “Admittedly, it’s hard to narrow the worst invasive insect species to just four…because there are so many in the U.S., and each decade seems to bring increasingly damaging species from exotic locales.” It’s estimated that at least 20% to 40% of the total crop output worldwide is affected by pests every year.
And they EAT. I mean, it’s greens, but I still wish some bougie insects got the memo on dieting—but oh well. The Food and Agriculture Organization of the United Nations has estimated that invasive insects impact the global economy by approximately $70 billion each year. These fifteen sneaky critters can convert your beautiful garden area into an ugly, dried, sandy wasteland within the blink of an eye.
Asian Longhorned Beetle
These beetles are approximately 1.5 inches long, white-spotted, and have red antennae longer than their body and striped like candy canes. They feed on maples, elms, birches, and willows.
Based on USDA research, the ALB can potentially wipe out 30% of the trees that grow in urban settings, hence the whopping $669 billion price tag. It is already rearing its ugly head in places like Massachusetts, New York, and Ohio. Some of the signs you may notice include round holes on tree trunks or branches or branches with chewing marks.
Systemic insecticides applied to trees have been somewhat effective in controlling the insects. Sometimes, the only way out is to cut down and destroy infected trees where possible.
Emerald Ash Borer
Everyone has a type, and so does the Agrilus planipennis. It is fond of ash trees. The EAB is native to Asia but has rapidly spread through North America following its discovery in Michigan in 2002. It is now established in more than 35 states in the United States.
First, search for the occurrence and the D-shaped exit holes in the bark and the serpentine galleries below it. Its larvae live under the surface and feed by girdling the tree, interrupting the water and sap conduction system. Other indications include the death of the canopy and higher-than-usual termite activity because they love the EAB larvae.
Try using systemic insecticides or professional control insecticides, such as Imidacloprid. Insect rearing, such as Tetrastichus planipennisi, is also being embraced as a biological control technique for controlling the pest.
Spotted Lanternfly
Originally from China, it sneaked into the U.S. around 2014 and has been on the rampage recently. Lanternfly prefers trees like the Tree of Heaven and Ailanthus altissima, but they can be found on any tree.
It will gladly frolic around your fruit trees, vineyards, or any ornamentals you can think of while costing agriculture $324 million annually! An adult spotted lanternfly is approximately one inch long and has black spots on the forewings. If you are an absolute devotee, try to locate the putty-like, grayish-brown masses on trees and flat surfaces, which are the next generation eggs waiting to hatch.
First, remove all the droppings that contain the egg masses by scraping the tree trunks and dipping them in alcohol or 10% bleach solution. Tree banding with adhesive is also necessary to get those tricky nymphs.
Brown Marmorated Stink Bug
These pests arrived from Asia and started performing grandly in the United States in the late nineties. They have been doing great damage since then. They can eat as much as a teenage football team.
These bugs bite more than 100 plant species, including apples, peaches, and soybeans. They are distinctively shaped like shields with varied brown markings, measuring a little over ½ an inch in length, and marked white lines on their antennae.
You might find them chillaxing on your fruit trees, soaking up some heat, or invading your warm house once it starts getting colder. And they have a stinky surprise when threatened! Pick them off plants (always use gloves), or use bait crops such as sunflowers or mustard to divert them from your plants.
Japanese Beetle
Originally introduced to the United States in 1916, the Japanese Beetle is now among the most destructive pests in North America. It devours leaves and damages flowers and fruits. The United States Department of Agriculture reveals that these beetles cause Americans about $460 million in yearly losses and eradication expenses!
They are reported to consume more than 300 different types of plants, including roses, grapes, and, yes, your nice-looking lawn. They were also reported to feed on grassroots as grubs.
Adult Japanese beetles are approximately 1/2 inch long, bronze/metallic greenish in color, and have coppery-brown wings. To control your lawn’s grub phase, you may want to apply parasitic nematodes or milky spores.
Gypsy Moth
This species of Lepidopteran pest is native to Europe and Asia. It accidentally flew into North America in the late 19th century and has since toured 20 states. According to the U.S. Forest Service records, it literally strips about a million acres of forests every year.
Large moving masses of slowly crawling caterpillars are rare, so look for their colorful, fuzzy, light brown, coin-sized eggs. Once these critters hatch, the caterpillars are perhaps more easily identified by their five pairs of blue dots followed by six pairs of red dots along their backs.
Well, scrape them off in soapy water, and there you have it! For the few caterpillars that may escape into the tree, burlap barrier bands around tree trunks act as a trapping tool. It is also possible to control the population with a naturally occurring bacterium called Bacillus thuringiensis, or Bt, for short.
Red Imported Fire Ant
These pests are originally from South America but have traveled to more than 13 southeastern United States states and beyond, creating a storm. Their painful sting can cause some people to experience allergies.
Their aggressiveness further endangers some forms of wildlife, such as ground-nesting birds and tiny mammals. The Texas A&M AgriLife Extension reports that they are responsible for more than $147 million in electrical equipment damages annually.
They build enormous mounds with heights of up to 18 inches, usually mounted in sunny areas, fields, or yards. Your best weapon here is bait products specifically created to attract fire ants. Scatter them around the mound so that the workers can take the poison to their hive.
Kudzu Bug
The Kudzu Bug was first detected in the United States in the state of Georgia in 2009. This tiny but invasive pest, native to Asia, threatens soybean crops and results in yield losses of up to 19%.
They are as small as a ladybug and olive green in color, with flattened oblong bodies. When threatened, they move close to windows and doors—something they learned from their relative, the stink bug—releasing a particular smell.
The use of pesticides is effective but must be exercised cautiously due to the environmental side effects. One can introduce parasitic wasps that feed on pests as a friendly approach.
Formosan Subterranean Termite
Though hailing from East Asia, these creatures have smoothened their stay in the United States, more fondly in the warmer and humid area of the South particularly. The American National Pest Management Association further estimates that termites result in more than $ 5 billion in property damages annually in the United States.
Look for signs like mud tubes or tunnels on your foundation, winged termites during the spring, and wooden structures that have been infested and sound like a drum when banged on.
They can be seen easily because they possess a pale and translucent body structure. Elimination strategies entail using professionally applied barrier treatments, bait systems, or liquid soil treatments that contain termiticides.
Asian Citrus Psyllid
It’s all about its ability to sneak through Huanglongbing (HLB), or citrus greening disease in simple terms, which is as nasty as it sounds. Trees infected with HLB become nonproductive within 2 to 5 years of showing disease symptoms. Young trees that are affected by the disease hardly survive to fruition age.
These pests have long, slender bodies and mottled brown wings. The ACPs are fond of citrus trees; most can be found on the underside of the leaves. It’s also evident by honeydew, a sticky substance they eject on the leaves and stems, and sooty mold.
Predaceous insects such as ladybugs are beneficial to your garden since they prey on the ACPs. You can also use eco-friendly insecticides where possible. Apply a systemic insecticide (every 7-15 days) to kill the psyllid to avoid massive reproduction.
Woolly Adelgid
Native to Asia, the woolly adelgid became a guest of North America in the fifties and soon announced that it was here to stay. The woolly adelgid has continued to devastate hemlock trees, leaving behind trails of gray and brittle trees.
According to the University of Florida, hemlock forests in areas like the Blue Ridge Parkway and Shenandoah National Park have suffered up to 80% mortality rates. These slimy creatures curl up in tiny white, cotton-like structures on the underside of hemlock branches—they look like snow or little marshmallows.
Unfortunately, there are few chemical controls for these pests, but if utilized well, horticultural oil or insecticidal soap could suffocate them. A systemic insecticide known as Imidacloprid has surprisingly great efficacy for a more significant outbreak.
European Gypsy Moth
This persistent plant pest, native to Europe, can munch through a square foot of leaves in a single day. These corpulent fellas, with masses of hair and characterized by well-glimpsed blue and red blotches, can breed quickly and lay up to 1000 eggs at once. As stated by the USDA, the invasion has occurred across the country, covering over 75 million acres since 1970.
Such activities result in deforestation, which leads to the development of diseases and other pests that affect trees. Look for small beige tufted masses like a quarter; they are often found on tree trunks, outdoor furniture, or your house’s outside walls.
Remove and thoroughly eradicate those egg masses during the fall and winter. During the summer, they can be restricted from accessing trees by using sticky traps or burlap bands. In severe cases of invasion, use Bacillus thuringiensis (Bt), a naturally occurring bacteria.
Argentine Ant
Their number makes them potential food competitors, while some are known to guard such crop-damaging insects as aphids. Argentine ants are tiny, measuring 1/8 inch long, typically dull brown, and move in lines or columns.
Unlike standard ant colonies, these may live in nearly any site, from beneath the stones to the walls of your house. Do not leave gaps in doors and windows; remove sources of food, such as crumbs, on the floor, and put all food items in airtight containers.
You can bring in products such as fipronil and bifenthrin for a more active approach for a perimeter spray.
Light Brown Apple Moth
Coming from Australia, LBAM is not very selective. The voracious beetle has damaging potential on over 200 plant species, many of which are highly prized fruits and ornamental plants. This moth is a little more minor, approximately half an inch long, and possesses V-shaped markings on the wings.
The real nuisance is the caterpillars, which are green in color and crawl through leaves and buds with great joy. Their sign is rolled leaves bound with silk very tightly.
Begin with planned, systematic plant inspection and installation of pheromone traps to check the number of moths. If you notice them, you can combat them with primary predators like Trichogramma wasps or employ Bacillus thuringiensis (Bt).
Mediterranean Fruit Fly
It is a small insect about 3 to 5 millimeters in size and is commonly called the Med fly. It is famed for attacking over 260 kinds of fruits, nuts, and vegetables, devastating crops and causing significant losses.
It has a bright yellow and brown color with banded wings, which, in my opinion, just scream, ‘SPOT ME!’ Their females go on to lay eggs beneath the husk of mature fruits and out emerge larvae, which feed on fruits and make them unfit for human consumption due to rotting.
Parasitic wasps can be an environmentally friendly way of controlling the situation. A more direct approach can be institutionalized by using insecticidal sprays to tame the menace.
Disclaimer – This list is solely the author’s opinion based on research and publicly available information.
13 Worst Garden Pests and How to Get Rid of Them
13 Worst Garden Pests and How to Get Rid of Them
9 Best Humidifiers for Plants: Top Picks and Expert Tips For 2024
9 Best Humidifiers for Plants: Top Picks and Expert Tips For 2024