Many different creatures consume plant roots as a food source, directly impacting plant health and growth. These root-eating animals range from tiny, microscopic organisms to larger mammals. Their activities below ground can significantly affect ecosystems by altering plant populations and soil structure. Understanding which animals feed on roots helps in identifying the cause of plant damage and managing affected areas.
Mammals That Eat Roots
Several mammalian species are known for consuming plant roots, often causing considerable damage in gardens and agricultural settings. Gophers, such as those from the Thomomys genus, are common examples. These rodents create extensive tunnel systems and pull entire plants, including their roots, into their burrows to feed. Their activity often leaves fan-shaped soil mounds near tunnel entrances.
Voles, belonging to the Microtus genus, are also significant root eaters. These small rodents, sometimes called meadow mice, have stout bodies and short tails and primarily feed on grasses, seeds, tubers, and roots. They can cause severe damage to root systems, and their presence is often indicated by shallow, grassless surface runways about 1 to 2 inches wide, which connect small burrow openings.
Groundhogs (Marmota monax), while primarily consuming above-ground plant material like grasses, herbs, and vegetables, may occasionally dig for and eat tubers and roots. Groundhogs are opportunistic eaters and their diet includes a wide range of plant parts.
Moles (Talpidae family) are frequently blamed for root damage, but they primarily consume insects such as grubs and earthworms, not plant roots. Their extensive tunneling, however, can indirectly harm plants by disturbing root systems and causing them to dry out. These tunnels can also be utilized by other rodents, like voles, which then access and consume plant roots.
Insects and Larvae That Eat Roots
Numerous insect species and their larval stages are prolific root feeders, often inflicting more widespread damage than larger animals. Grubs, the C-shaped larvae of various scarab beetles like the Japanese beetle (Popillia japonica), are a common concern. These grubs feed on plant roots from fall through spring or summer, with Japanese beetle larvae specifically targeting grass roots. High populations of grubs can significantly weaken plants by compromising their root systems.
Wireworms, which are the larvae of click beetles (Agriotes genus), also feed on plant roots and underground stems. These slender, hard-bodied larvae can persist in the soil for several years before maturing, causing continuous damage. Root maggots, the larvae of certain flies such as the cabbage maggot (Delia radicum) and onion maggot (Delia antiqua), are another group of destructive root feeders. These small, white larvae burrow into plant roots, especially those of brassicas and alliums, leading to stunted growth and wilting as the plant’s ability to absorb water and nutrients is impaired.
Nematodes, microscopic roundworms, include many plant-parasitic species like root-knot nematodes (Meloidogyne species). These nematodes infect plant roots, causing distinctive swellings or galls that interfere with the roots’ ability to transport water and nutrients. Their damage can lead to symptoms resembling nutrient deficiencies or drought, and heavily infested plants may experience reduced yields or even death.
Visible Signs of Root Damage
Recognizing the above-ground symptoms of root damage is often the first step in identifying an issue below the soil surface. One common indicator is wilting, even when plants receive adequate water. This occurs because damaged roots cannot efficiently absorb and transport moisture to the rest of the plant.
Stunted growth is another frequent sign, as compromised roots cannot supply the necessary nutrients for healthy development. Leaves may also exhibit yellowing or discoloration, a condition known as chlorosis, due to nutrient deficiencies caused by impaired root function. In severe cases, plants may be easily pulled from the ground because their root systems have been significantly consumed or damaged. Sudden plant death, particularly without obvious disease or pest issues above ground, can also point to extensive root damage.
Pinpointing the Culprit
Identifying the specific animal responsible for root damage requires observing additional evidence beyond general plant symptoms. The presence of tunnels or mounds on the soil surface can provide important clues, such as the distinct fan-shaped mounds of gophers, the shallow runways of voles, or the volcano-shaped mounds and ridges created by moles, whose damage is indirect.
Close inspection of the roots themselves can reveal direct evidence. Chewed roots, especially those with gnaw marks, often indicate feeding by larger rodents like gophers or voles. If a plant pulls up easily and its roots appear chewed or missing, voles are often the cause. Digging carefully around affected plants might expose the culprits directly, such as the C-shaped grubs of beetles or the small, white larvae of root maggots in the soil.
For microscopic pests like nematodes, physical examination of roots is necessary to find distinctive galls or knots, which are swellings on the roots where these parasites feed. Observing the specific type of damage, coupled with other signs like tunneling patterns or the presence of larvae, helps narrow down the list of potential root-eating animals.