A surprisingly wide range of animals feed on plant roots, from tiny worm-like nematodes invisible to the naked eye to wild boar tearing up entire hillsides. Underground root systems are rich in stored energy, and dozens of species across multiple animal groups have evolved to exploit them. The list includes burrowing rodents, beetle larvae, cicada nymphs, microscopic roundworms, and even aquatic grazers like swans. Some of these root feeders are so effective that they rank among the most economically damaging agricultural pests on Earth.
Burrowing Rodents That Live on Roots
The most specialized root-eating mammals are the subterranean rodents. Roughly 250 species of rodents spend most of their lives underground in burrows, foraging and breeding in dark, oxygen-poor tunnels.1Springer. Subterranean Rodents: News from Underground Among the best studied are the African mole-rats (family Bathyergidae), which dig extensive tunnel networks specifically to find bulbs, corms, tubers, and other underground storage organs of plants. These starchy plant parts are calorie-dense and highly digestible. Research on four species of bathyergid mole-rats found that bulbs and corms had digestibility coefficients above 95%, with low fiber and high energy content around 15 to 16 kilojoules per gram. On this diet, mole-rats easily maintained their body mass.2Journal of Zoology. Coefficients of digestibility and nutritional values of geophytes and tubers eaten by southern African mole‐rats (Rodentia: Bathyergidae) One species, the Cape dune mole-rat, thrives on a diet that is over 80% grass, including grass roots, and still achieves high digestibility.
Pocket gophers in North and Central America operate similarly, tunneling through soil and clipping roots they encounter along the way. They eat a mix of roots, tubers, and above-ground vegetation pulled down into their burrows. Gardeners and farmers in the western United States know pocket gophers well: a single animal can damage the root systems of young trees, vegetable crops, and ornamental plants across a large area.
Voles are another rodent group notorious for root and bark feeding. Voles of the genus Microtus are considered the most damaging mammalian pest of tree fruit crops in both North America and Europe. During winter, when other food is scarce, they feed on bark, vascular tissues, and sometimes roots of trees.3Crop Protection. Influence of living mulches on vole populations and feeding damage to apple trees Apple orchards are particularly vulnerable. Vole damage to the base of a tree can girdle it, cutting off the flow of water and nutrients and killing the tree outright. Because voles are small and travel beneath snow or mulch cover, the damage often goes unnoticed until spring.
Wild Boar and Surface Rooters
Wild boar do not live underground, but their foraging behavior is one of the most dramatic forms of root disturbance on the planet. Rooting, the behavior in which wild boar overturn leaf litter, vegetation, and soil with their snouts and tusks, is a major disturbance in forest ecosystems. This activity can alter soil properties, reshape biotic communities, and disrupt ecosystem processes.4Forest Ecology and Management. Ecological impacts and management of wild boar rooting in forest ecosystems Wild boar are looking for a variety of foods when they root, including bulbs, tubers, rhizomes, insect larvae, and earthworms. The root material they consume is often a secondary target alongside invertebrate prey, but in some habitats, underground plant parts make up a large share of their diet.
The ecological footprint of boar rooting extends well beyond the roots they eat. Overturning the soil accelerates nutrient cycling, exposes seeds, and creates bare patches that change which plant species can establish. In forests where wild boar populations have exploded due to lack of predators or supplemental feeding, the cumulative rooting can reshape the understory plant community over time. This makes wild boar both a root consumer and a broader agent of below-ground ecosystem change.
Insect Larvae That Feed on Roots
Some of the most economically significant root feeders are not mammals at all but the larval stages of beetles. Two groups stand out: white grubs and corn rootworms.
White grubs are the larvae of scarab beetles, including Japanese beetles and June bugs. They live in the soil and feed on grass roots, sometimes devastating lawns, pastures, and golf courses. In turf grass, their feeding severs the root system so completely that the grass can be peeled back from the soil like a carpet. Research on tall fescue and bermudagrass confirmed that root-feeding white grubs cause severe damage, significantly reducing root mass in untreated grass compared to grass given root-stimulating treatments.5Wiley Online Library / Pest Management Science. Rhizobacterial treatments of tall fescue and bermudagrass increases tolerance to damage from white grubs Homeowners often discover a grub problem only when brown patches appear and the turf lifts easily, because the roots connecting it to the soil are gone.
Corn rootworms (Diabrotica species) are among the most serious pests of corn in the United States.6Crop Science. A Method of Controlling Corn Rootworm Feeding Using a Bacillus thuringiensis Protein Expressed in Transgenic Maize The adult beetles lay eggs in the soil near corn plants, and the larvae hatch and immediately begin feeding on the root system. Western corn rootworm larvae tend to concentrate their damage on specific root nodes.7Crop Science. Rootworm and Mechanical Damage Effects on Root Morphology and Water Relations in Maize This root pruning reduces the plant’s ability to take up water and nutrients, and in severe infestations, plants lodge, meaning they fall over because the damaged roots can no longer anchor them. Research has shown that plants with severe larval feeding damage had less total leaf area and lower rates of photosynthesis than plants with moderate or no damage, confirming that what happens below ground directly limits growth above ground.8Crop Science. Maize Morphology and Shoot CO2 Assimilation after Root Damage by Western Corn Rootworm Larvae Rootworm larvae also reduce the uptake of iron, potassium, calcium, and other nutrients in maize.9Agronomy Journal. Root Damage by Western Corn Rootworm and Nutrient Content in Maize
Beyond grubs and rootworms, many other insect larvae feed on roots. Root maggots (the larvae of certain flies) attack brassica crops like cabbage and turnips. Wireworms, the larval stage of click beetles, bore into the roots and tubers of potatoes, carrots, and cereal crops. Weevil larvae are another major group: the larvae of vine weevils, for example, are a persistent problem in container-grown ornamental plants, where they quietly eat through root systems until the plant wilts and dies.
Cicada Nymphs and the Long Underground Wait
Periodical cicadas offer one of the strangest root-feeding stories in the animal kingdom. After hatching from eggs laid in tree branches, the tiny nymphs drop to the ground, burrow into the soil, and attach themselves to tree roots. They stay there for either 13 or 17 years, depending on the species, feeding the entire time. Histological studies of tree roots where cicada nymphs had been feeding revealed that the nymphs tap into xylem vessels, the water-conducting tissue of the root, to suck up xylem fluid. No feeding was found in phloem cells, confirming that these nymphs are exclusively xylem feeders throughout their entire development.10Ecological Entomology. Xylem feeding by periodical cicada nymphs on tree roots
Xylem fluid is extremely dilute, essentially water with small amounts of dissolved minerals. This nutritional poverty is thought to explain why periodical cicadas need over a decade to mature. They are getting so little energy per sip that the growth process is extraordinarily slow. Despite this, cicada nymphs can occur in huge densities. A single large tree can host thousands of nymphs on its root system simultaneously. Whether this collective drain meaningfully harms the tree is still debated. Healthy mature trees seem to tolerate it, but young or stressed trees in areas with especially dense cicada populations may show reduced growth.
Root-Knot Nematodes
Moving to an even smaller scale, root-knot nematodes (Meloidogyne species) are among the most damaging root feeders worldwide. These microscopic roundworms, typically less than a millimeter long, invade plant roots and hijack the plant’s own cellular machinery. During infection, they create specialized feeding structures composed of enlarged, multinucleate “giant cells” that form from redifferentiated vascular root cells. These giant cells become the nematode’s sole source of nutrients and are essential for its growth and reproduction.11Journal of Insect Physiology. Gall-forming root-knot nematodes hijack key plant cellular functions to induce multinucleate and hypertrophied feeding cells The overgrowth of surrounding root cells produces the characteristic swollen galls, or “knots,” visible on infected roots.
The damage is more than cosmetic. The galls disorganize the vascular system of the root, impairing the plant’s ability to transport water and nutrients.12PubMed. Galls induced by a root-knot nematode in Petroselinum crispum (Mill.): impacts on host development, histology, and cell wall dynamics Infected plants often show stunting, yellowing, and wilting that mimics drought stress, because the root system can no longer do its job efficiently. Root-knot nematodes attack an enormous range of crops, including tomatoes, peppers, lettuce, carrots, and many ornamentals. In warm climates with sandy soils, they can be the single biggest biological constraint on crop production, causing billions of dollars in losses globally each year.
Aquatic and Wetland Root Grazers
Root feeding is not limited to terrestrial environments. In freshwater and marine ecosystems, several large herbivores target the below-ground parts of aquatic plants. Swans and certain fully aquatic species have some of the strongest impacts on submerged plant abundance and species composition. Because they sometimes target below-ground parts, digging into sediment to pull up roots and rhizomes, their activity can result in the local collapse of entire plant beds.13Ecography. Assessing the role of large herbivores in the structuring and functioning of freshwater and marine angiosperm ecosystems
Tundra swans, for instance, are well known for uprooting wild celery and other submerged aquatic vegetation in shallow lakes and estuaries. They use their long necks to reach the sediment and pull out the energy-rich rhizomes and tubers. In some wintering and staging areas, large flocks of swans can strip entire sections of a lake bottom bare, leaving behind “grazing lawns” of short, cropped vegetation. Manatees, dugongs, and green sea turtles also graze on seagrass beds and sometimes uproot below-ground tissue, particularly in areas where grazing pressure is concentrated. The ecological consequences ripple outward: when root and rhizome networks are destroyed, the sediment they held in place can erode, and the habitat that sheltered fish and invertebrates disappears along with the plants.
How Plants Defend Their Roots
Given the sheer diversity of organisms trying to eat them, plants have not remained passive. Root defense strategies range from physical barriers to sophisticated chemical signaling. Many plants produce toxic or deterrent compounds in their roots, including alkaloids, terpenoids, and cyanogenic glycosides, that discourage feeding or slow the growth of herbivores. Others toughen their root tissues with lignin and silica deposits that make the roots harder to chew through.
One of the more remarkable defense strategies is indirect: plants under root attack can release volatile chemical signals into the soil that recruit natural enemies of the attacking herbivore. When western corn rootworm larvae begin feeding on maize roots, many maize varieties release a compound called (E)-β-caryophyllene. This chemical attracts entomopathogenic nematodes, tiny predatory roundworms that seek out and kill the rootworm larvae.14PubMed Central. Restoring a maize root signal that attracts insect-killing nematodes to control a major pest The plant essentially calls in reinforcements. Interestingly, many North American maize varieties have lost the ability to produce this signal through selective breeding, which may partly explain why rootworm pressure is so severe in commercial corn.
This kind of three-way interaction, where the plant, the herbivore, and a natural enemy of the herbivore all influence each other, is common underground. Research has confirmed that root-feeding insects interact with a complex web of other soil organisms, including mycorrhizal fungi, bacterial pathogens, arthropod predators, and entomopathogenic fungi.15PubMed. Root-feeding insects and their interactions with organisms in the rhizosphere Mycorrhizal fungi, the beneficial fungi that colonize plant roots and help with nutrient uptake, tend to have negative effects on root herbivores. This raises the possibility of managing root-feeding pests by encouraging healthy fungal communities in the soil rather than relying solely on pesticides.
When Root Defenses Are Disrupted
These underground alliances are not invincible. When a plant is simultaneously dealing with root herbivores and a pathogenic infection, the defense signals can get scrambled. Research on citrus rootstock showed that a bacterial pathogen disrupted the plant’s ability to attract beneficial entomopathogenic nematodes to the site of root-feeding insect larvae.16PubMed Central. Bacterial phytopathogen infection disrupts belowground plant indirect defense mediated by tritrophic cascade In other words, a sick plant may lose the ability to call for help, leaving it more vulnerable to root feeders. This kind of defense disruption is a growing concern in agriculture, where crops often face multiple stressors simultaneously.
The interaction between root herbivores and mycorrhizal fungi adds another layer of complexity. In one study on clover, weevil larvae feeding on roots actually changed the pattern of fungal colonization. Herbivory increased one type of fungal structure (arbuscules, involved in nutrient exchange) while decreasing another (vesicles, involved in fungal energy storage), and altered hyphal density.17Applied Soil Ecology. Is a specialist root-feeding insect affected by arbuscular mycorrhizal fungi? So the herbivore does not just damage the plant; it reshapes the microbial community living on the roots, which in turn affects how well the plant can recover.
Practical Concerns for Gardeners and Farmers
If you are dealing with root damage in a garden, lawn, or farm field, identifying which animal is responsible matters for choosing the right response. The symptoms often look similar at the surface, wilting, stunting, yellowing, or outright plant death, but the culprits and solutions differ.
- Grubs in lawns: Brown patches of turf that peel up easily suggest white grub feeding. Timing insecticide applications to target young larvae in late summer is more effective than treating mature grubs in spring.
- Rootworms in corn: Crop rotation remains one of the most reliable strategies, since rootworm larvae hatch in cornfields and need corn roots to survive. Transgenic maize varieties that express a protein toxic to rootworm larvae have also been developed.6Crop Science. A Method of Controlling Corn Rootworm Feeding Using a Bacillus thuringiensis Protein Expressed in Transgenic Maize
- Voles in orchards: Keeping grass and mulch trimmed short around tree bases reduces vole cover and discourages feeding. Hardware cloth guards around the trunk base provide a physical barrier.
- Root-knot nematodes: Soil solarization, resistant crop varieties, and crop rotation with non-host plants are the main management tools. Chemical nematicides exist but are increasingly restricted due to environmental concerns.
- Mole-rats and gophers: Trapping is generally the most effective option. Raised beds lined with hardware cloth can protect high-value garden plants.
For all of these pests, encouraging a healthy soil ecosystem, with diverse microbial communities and beneficial fungi, provides a baseline of natural suppression. Plants growing in biologically active soils tend to have more robust root systems and better access to the indirect chemical defenses described above. This does not eliminate the need for targeted management, but it can reduce the severity of damage and help plants recover faster when root feeding does occur.
Why Root Herbivory Gets Overlooked
Root feeding is one of the least visible forms of herbivory, and that invisibility has historically led researchers and growers to underestimate it. When a caterpillar eats a leaf, you see the holes. When a rootworm larva prunes away half a plant’s root system, the only visible sign might be a plant that looks slightly off. By the time symptoms are obvious above ground, the damage below ground may be severe. This disconnect means that root herbivory has received far less scientific attention than above-ground herbivory for most of the history of ecology and agriculture.
That gap is closing. Advances in soil imaging, molecular tools for identifying organisms from soil DNA samples, and a growing awareness of below-ground ecological interactions have pushed root herbivory toward the center of soil ecology research. The finding that plants actively recruit predators to defend their roots, and that these defenses can be disrupted by disease, reflects a level of biological sophistication that was barely imagined a few decades ago. For the gardener pulling up a wilted tomato plant and finding swollen, knotted roots, or the homeowner watching a raccoon dig up a lawn to get at grubs, the organisms responsible are just pests. But from an ecological perspective, root-feeding animals are key players in a complex underground economy that shapes how nutrients cycle, which plants thrive, and how ecosystems function from the ground up.