The stories you’ve heard and how people condition us to see worms as slimy, dirty animals crawling in the soil. However, if you see worms in your indoor or outdoor garden, don’t panic, don’t be disgusted – be informed.
What looks like worms in the soil can be 1) wireworms, 2) pseudocentipedes, 3) centipedes, 4) millipedes, 5) flatworms, or 6) earthworms. Some can be harmful to plants or humans. Some can also help and enrich the soil or kill pests. It’s important to know which is which.
To help you know the good ones that you should keep and to be aware of the harmful ones, this article summarizes six creatures that may look like worms in your garden.
TIP:In this detailed guide I also dug to find the scientific name of each worm. This is very useful as you can check for more images on the web using the scientific name as it is way easier.
Wireworms are not worms. They’re the larva (worm-like form) of beetles. They live and mature in the soil, so you’ll see them when you dig in.
Wireworms are up to about 1¼ inches long, slender, shiny, and smooth. Some are white or yellow, while others are brown. Wireworms are no more than 30 to 35 millimeters long.
FACTOID: The false wireworm is only about 15 millimeters long.
Unless you look closely, it’s difficult to differentiate between the larvae of false and true wireworms. Often, they’re also confused with the larvae of the bronzed field beetle, the vegetable beetle (photo), and the carabid beetle (photo).
PRO TIP: False wireworms have longer antennae and legs compared to true wireworms.
True wireworm: True wireworms are the larvae of clickbeetles (Coleoptera: Elateridae).
- A true wireworm has a wirelike, soft body, a flattened head, as well as a flattened and serrated tail.
- They are about half the size of a false wireworm.
FACTOID: When placed on their backs, clickbeetles can jump into the air with a click.
False wireworm (Gonocephalum spp.): False wireworms (also called mealworms) are the larvae of darkling beetles (family Tenebrionidae).
- A false wireworm has a wirelike, hard body that is cylindrical instead of flattened, and a head that is rounded and segmented.
- They are about double the length of a true wireworm.
FREE PDF: Characteristic ye-spot differences between click beetles and wireworms illustrated in this research paper (page 27).
While false wireworms live for about one generation per year, true wireworms usually live for 1 to 3 years with overlapping generations. Species such as the Ctenicera glauca can live up to 10 years even in the most unfavorable conditions.
FACTOID: The false wireworm (Eleodes hisperlabrus) matures into a black beetle (Eleodes tenebrionidae) that is frequently seen crossing the roads between crop fields.
Adult beetles and their larvae can chew on softer plant parts near the ground. As a result, plants can wither while still standing, or fall over.
- They feed on germinating seeds and plant roots of crops and vegetables such as barley, potato, corn, sorghum, wheat, and cotton.
- They hollow out seeds, emerging seedlings, stems, and fruits near the ground, but also consume dead organisms.
- Wireworm larvae do the most damage to seeds during the colder days of spring.
There are more than 9,000 species of wireworms around the world, but only some of them have been examined or described. Here are some examples where you can find the common name but also the scientific one.
|Common Click Beetle (T)
|Eastern False Wireworm (F)
|Flat Wireworm (T)
|Garden Wireworm (T)
|Grey/Small False Wireworm (F)
|Great Basin Wireworm (T)
|Gulf Wireworm (T)
|Oregon Wireworm (T)
|Melanotus longulus oregonensis
|Pacific Coast Wireworm (T)
|Beetle p 27, Larva
|Puget Sound Wireworm (T)
|Ctenicera aeripennis aeripennis
|Sand Wireworm (T)
|Larva, Beetle p 5
|Small False Wireworm (F)
|Striate False Wireworm (F)
|True Wireworm (T)
|Western Field Wireworm (T)
At least 200 species of symphylans have been recorded around the world. Researchers say that these pseudocentipedes are so fast that they can go from about 1/4 inch to 1.5 inches per second
Symphyla stay away from the light, so they have soft, unpigmented, translucent bodies that are between 2 to 10 millimetres (0.08 to 0.4 in) long.
PRO TIP: The longest pseudocentipede is the Hanseniella magna measured at 1 to 1.2 inches (25 to 30 millimeters).
Symphylans usually live six to 12 months, but some may live four years or more. You’ll find them in soil, but also under decaying wood as well as beneath damp rocks and other microhabitats in gardens, farmlands, forests, and caves.
Males deposit sperm packets on the ground, which the females pick up in their mouths. In about 40 days, the eggs hatch and go through six instars (growth stages) from six to nine weeks. See how they look like here, and here.
Because symphylans eat plants, fungi, and decaying plants, they help new plant growth access nutrients in the soil. In breaking down soil components, they help redistribute nutrients and chemicals essential to plant growth.
Symphylans can harm seeds, roots, and root hairs in cultivated soil. They can destroy crops such as pineapple or sugarcane. For instance, the garden centipede (Scutigerella immaculata) consume seeds, seedlings and fine roots thus destroying garden vegetables, flowers, and seedlings.
We know that centipedes are named for having 100 legs, but that’s not true. Some adult centipedes have 15 pairs of feet while others have more.
FACTOID: The Gonibregmatus plurimipes has at least 382 feet. That’s 191 pairs of legs!
Of course they’re fast. For instance, the 15-legged house centipede can travel up to 1.3 feet in one second.
Centipedes (or chilopods) are active when it’s dark. They’re found even in the Arctic Circle and deserts. However, most blend in drab backgrounds of dark and moist gardens, basements, or in potted soil.
Although they’re blind, centipedes use their long antennae to move around. Many consume plants but larger species are carnivorous and feed on small birds, toads, mice, and snakes.
FACTOID: One of the world’s largest centipedes is the Scolopendra gigantea L. (photo here).
In the USA, the largest centipede is the Scolopendra heros Girard at about 6 inches (153 millimeters) long. It is found in Central Arizona, Arkansas, and Missouri. However, most centipedes are only from 10 to 270 millimeters (or 0.05 to 10.5 inches) long.
Some centipedes can live a long time, even up to six years. A few centipede species don’t lay eggs but instead give birth to young.
FACTOID: Centipedes have existed on Earth since 400 million years ago.
House centipedes are known to kill termites, cockroaches, moths, silverfish, spiders, earwigs, and flies. In fields and gardens, centipedes consume spiders, snails, grubs, earthworms, and soft-bodied insects. Some people have pet centipedes.
Centipedes have prehensors (poison claws) that release venom to kill prey as well as bite humans. Usually, human reaction to the poison reaction is similar to a bee sting: a few hours of moderate to severe pain with some localized numbness, discoloration, and swelling.
Centipedes produce the cardio-depressant toxin-S, serotonin, and histamine. If you are allergic to insect venom and other toxins, you may experience a severe reaction to centipede venom.
FACTOID: According to a source, there is only one recorded human fatality from a centipede. This happened in the Philippines when a centipede bit a child on the head.
When there’s a high population of centipedes and food supplies become scarce, some centipedes may will eat plant leaves, stems, and roots.
There are about 8,000 species of centipedes on Earth but only about 3,000 have been described by researchers. Reports indicate that there are only four or even up to six types in North America, but here’s a list of 17 known types.
|Blue ring centipede
|Eastern Bark Centipede
|Giant Red-headed Centipede
|Peruvian giant centipede
Also known as rainworms or 1,000-legged worms, they do crawl out on rainy days. However, they don’t have a thousand legs. The name is simply a figurative expression for an animal with a tremendous number of legs, up to 750 in fact.
When you see millipedes moving about, it’s one of the sure signs of oncoming cold weather or imminent rainfall.
Millipede bodies are worm-like, ranging from light brown to black, and can easily crawl through cracks and up on walls, but they’re not worms. They have very limited movements, and travel rather slowly.
Millipedes were already on earth at least 425 million years ago and are some of the oldest known land animals. There are at least 12,000 species around the world, with about 1,400 species in Canada and the United States.
Most are less than 1 inch long, but some can grow up to 10.5 inches. The longest millipede is the Archispirostreptus gigas in Africa. In North America, the longest millipede is the Paeromopus paniculus at about 16 centimeters (about 6. inches) long.
Millipedes rarely get out of the soil, where they lay up to 300 eggs every springtime. The eggs hatch after a few weeks. Young millipedes molt about seven times until they mature in about two to five years, depending on the species.
Millipedes do help by breaking down the contents of compost, but can also destroy gardens when there’s a lot of them and there’s too little food. Some species of millipedes feed on the roots of plants.
All millipedes shred leaf litter and consume decayed plants and contribute to soil nutrient cycles. Burrowing millipedes promote microbial decomposition. In fact, some millipedes create soil and reduce debris in forest habitats.
Millipedes don’t sting or bite. When threatened, most millipedes curl into a ball. Some emit a foul and irritating liquid. The larger species can squirt chemicals up to 3 feet (half meter) and blind pets or predators.
They also produce hydrochloric acid, hydrogen cyanide (HCN by polydesmids), hydroquinones or benzoquinones, as well as mandelonitrile benzoate and benzoyl cyanide (by Harpaphe haydeniana). These can burn eyes and even kill pigeons.
There are three groups of millipedes: 500 species of spirobolids, 3,500 species of polydesmids, and 750 species of julids. Here are some examples.
These are 500 species of these round-backed millipedes, all of which carry a “suture” in front of their heads. See photo.
|American Giant Millipede
|Wandering Leg Sausage
There are about 3,500 species of polydesmid millipedes worldwide. Adults can produce formic acid, hydrogen cyanide, etc. for defense. Many species are known to feed on the leaves and shoots of cultivated vegetables as well as those of ornamental plants.
|Flat-backed / Tractor Millipede
|Gippsland / Trafalgar Flat Millipede
|High Knob mimic millipede
|Hothouse / Greenhouse Millipede
|Kentucky Flat Millipede
|Pennington Gap Mimic Millipede
|Red-Sided Flat Millipede
Julid millipedes (Cylindroiulus caeruleocinctus) generally have 50-segment, shiny bodies ranging from dark grey to black that can discharge a red or yellow fluid when feeling threatened. They are mostly found in garden mulch, compost, and damp soil.
There are about 750 species of julid millipedes in Asia, North America, and Europe. Some have eyes but many others are eyeless and brightly colored. Some are as short as 10 millimeters (0.39 inches) while others are as long as 120 millimetres (4.72 in).
|Black Portuguese Millipede
|White-legged Snake Millipede
Although flatworms have very limited mobility, they are now all over the world because of the export of potted plants to nurseries and garden centres in Belgium, France, Italy, Spain, Portugal, and the United Kingdom.
FACTOID: Flatworms are hermaphrodites (with male and female sex organs). Some reproduce by laying eggs while others do so by splitting themselves (fission).
When gardeners buy potted plants, they may be unaware that the soil contains egg cocoons or mature specimens. Thus, flatworms can proliferate in gardens and invade neighbouring gardens or farmlands as well.
Land flatworms (planarians) are mucus-covered animals. Their unsegmented, flat, soft bodies look like ribbons. Although some species are more than 30 centimeters (about 1 foot) long, most are only between 3 and 15 millimeters (0.1 and 0.6 inch) long.
FACTOID: The three types of flatworms are planarians, flukes, and tapeworms.
Flatworms usually prefer shady, wet soil such as under containers, pots, leaf litter, and the like, but they can also stick to gardening tools or plastic sheets. Since their two eye spots are sensitive to light, these planarians are very active only in the dark.
FACTOID: When cut into two, a flatworm can regenerate and you get two complete flatworms.
These land planarians feed mainly on invertebrates (e.g., snails, slugs, earthworms, woodlice, millipedes, spiders, and insects).
According to research, healthy planaria can survive up to three months without food. According to a source, planarians can live indefinitely.
At the same time, scientists observing the planaria’s ability to regenerate consider this animal as “immortal”. For instance, planarian worm fragments can regenerate completely within two weeks (P. gracilis needs more than a month to regenerate completely).
Planarians often are used to do research on developmental biology, to study regeneration, and in neurological research to find treatments for brain damage and various neurological disorders.
Land planarians are known to host the rat lungworm parasite that can cause meningitis. These flatworms can also cause paragonimiasis infection of the lungs. Flatworms can also produce toxic chemicals that can cause allergies in some people.
There are at least 910 species of terrestrial (land-based) flatworms, a group that survives only in moist soil. Here are some examples.
|Black Kontikia Flatworm
|Brown Kontikia Flatworm
|New Guinea Flatworm
|New Zealand Flatworm
|Wandering Broadhead Worm
Earthworms (anglers call them angleworms) have no antennae, bones, carapaces, fins, arms, or legs. There are black, red, and brown earthworms, but many are pale or translucent.
They are so named for being soil-dwelling animals. In fact, earthworms can be categorized according to where you can find them.
Epigeic worms: The term “epigeic” comes from the Greek for “on the earth”. Some examples are: D. attemsi, L. castaneus, L. festivus, L. friendi, D. octaedra, D. rubidus, E. tetraedra, H. oculatus, L. rubellus, and S. mammalis.
- You’ll find these dark-colored worms on topsoil (surface dwellers).
- They reproduce very quickly. They don’t burrow but live on topsoil and under loose organic matter.
- They vary in length, from less than an inch up to seven inches.
Endogeic worms: The term “endogeic” comes from the Greek for “in the earth”. Some examples are: O. lacteum, A. chlorotica, A. icterica, A. caliginosa, A. rosea, M. muldali, and O. cyaneum.
- You’ll find these subsoil dwellers burrowing below ground. They burrow in the upper soil layers or under logs, rocks, or detritus.
- They appear on the ground surface after heavy rain, since they depend on water to keep their bodies moist.
- They are lighter colored – from pale to translucent – and move slower than epigeic worms. They range from one to 12 inches in length.
Anecic worms: The term “anecic” comes from the Greek for “out of the earth”. Some examples are L. terrestris, A. nocturna, L. friendi and A. longa.
- You’ll find these worms living below topsoil but search for food on the soil surface.
- They create permanent burrows as deep as six feet below the ground.
- They are often milky in color and can be as small as an inch or as long as 60 inches.
- Some earthworms can grow up to 14 inches while giant earthworms can grow up to 22 feet.
Each year, you can expect earthworms, which are hermaphrodites (have male and female sex organs), to reproduce up to 80 times.
According to researchers, earthworms can live from four to eight years on average.
Earthworms don’t bite or sting. They aerate, drain, and fertilize the soil as well as serve as food to other animals.
Earthworms feed on soil, decaying organic matter, but not on living plants, so they pose no danger to plants. Soil rich with earthworm casts has 1000 times more beneficial bacteria than soil with no earthworms.
Compost earthworms such as Dendrobaena veneta and Eisenia fetida eat the soil and, in the process, aerate it. Their excretions (cast) enrich the soil with nutrients such as nitrogen, ammonia and phosphorus that plants, bacteria, and fungi can consume.
However, like other soil-dwelling worms, earthworms can carry pathogens such as salmonella and E. coli, which are common in soil and can cause severe gastrointestinal infections. They can also be invasive and threaten hardwood forests.
There are at least 182 known species of earthworms in North America alone. Around the world, however, there are more than 2,700 kinds of earthworms. Here are some examples.
|Blue Worm, Composting Worm, or Spike Tails
|Carpenterworm (Moth Larva)
|Nightcrawler, Dew Worm, Lob Worm
|European Nightcrawler, Greenhouse Worm, or Compost Worm
|Giant Gippsland Earthworm
|Gray Worm, Tasmanian Earthworm
|Oregon Giant Earthworm
|Giant Washington / Palouse Earthworm
Other types of worm-like creatures in your garden soil can be grubs, maggots, pot worms or fungus gnats (Engchyraeids), root rot nematodes, leeches, tiger worms (Eisenia fetida). You can find more information about these soil dwellers on the internet.
Congratulations! You’ve just reviewed 6 different types of worm-like organisms that live in indoor or outdoor garden soil. To summarize:
- Wireworms: Whether they’re the true or the false types of wireworms, they’re not actually worms (they’re beetle larvae) and they don’t harm humans or animals. However, they harm plants, which is one of their major food sources.
- Symphylans: Although they’re known as garden centipedes, they’re not centipedes. They’re not venomous. They enrich the soil but can also harm plants, particularly seeds and other soft plant parts near the soil.
- Centipedes: House and garden centipedes are known to eat pests and other nuisance insects. They can also bite and inject venom.
- Millipedes: Some millipedes can feed on plant roots but most feed on decaying organic matter. They don’t cause harm, but when they feel threatened, they emit chemicals in self-defense.
- Terrestrial flatworms: These land planarians eat snails, slugs, earthworms, woodlice, millipedes, spiders, and insects. They don’t destroy plants.
- Earthworms: Earthworms don’t bite, sting, or kill plants. Instead, they aerate, drain, and enrich the soil with essential nutrients that plants need.
If this article helped you identify different types of worm-like creatures in your garden, please use the comment section below.
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