Plan the perfect garden with our interactive tool →

Insects That Eat Plant Roots

Cicada
Lightwriter1949/iStock/Getty Images

It’s hard to know if your browning lawn or drooping flowers are suffering from disease, lack of water, poor nutrition or something else entirely. The symptoms of root-eating insects, including loss of plant vigor, stunted growth, wilting and discoloration, often resemble plant diseases or deficiencies. If you suspect root-feeding insects are damaging your plant, dig the soil around the plant and sift through it for insects. You may have to dig up the entire plant to fully inspect its roots and properly identify the pest.

Beetle Grubs

Macro shot with worm
sakdinon/iStock/Getty Images

Immature beetles, called grubs, are lightly colored with dark, hard heads. Most have six legs, grow up to 1 inch long and typically lie in a “C” shape. Japanese and June beetle grubs, along with the legless grubs of long-nosed beetles, called weevils, are common root-feeding pests of vegetables, turfgrasses and ornamental plants. The presence of adult beetles and evidence of digging by raccoons and skunks are indicators of root-eating grubs. Pick adult beetles off plants and drop them in a bucket of soapy water. Treat larvae underground with the parasitic nematode Heterorhabditis bacteriophora, available from garden suppliers in granule or other forms. Mix 1 teaspoon of the nematodes, which come packaged in inert powder, in 1 gallon of water. Spray during overcast conditions onto moist soil or turf. Keep the area moist for the next seven days.

  • It’s hard to know if your browning lawn or drooping flowers are suffering from disease, lack of water, poor nutrition or something else entirely.
  • The symptoms of root-eating insects, including loss of plant vigor, stunted growth, wilting and discoloration, often resemble plant diseases or deficiencies.

Fly Maggots

Maggot of fly for sport fisherman.
fiulo/iStock/Getty Images

Root-feeding fly larvae, or maggots, are pale, legless, tube-shaped creatures measuring approximately 1/4-inch long. Common pests of root vegetables and other plants, root maggots cause wilting, yellowing and stunted growth in host plants. Young plants are most vulnerable to root maggots in cool, wet springs. No effective treatment exists for these pests once they are established in your plants. Cultivate the soil well in the fall to remove all plant debris, including roots, where root maggot pupae hide for the winter.

Moth Caterpillars

Hawk moth caterpillar
VitaSerendipity/iStock/Getty Images

With their clear wings and striped markings, adult Sesiidae, or clearwing moths look similar to wasps and bees. Caterpillars of these moths are frequent feeders on the roots of trees, shrubs and vines. Keep roots healthy with loosely packed soil for oxygen and proper irrigation for the particular plant. When cultural methods fail and plants show serious signs of distress, apply parasitic nematodes to kill pest caterpillars.

  • Root-feeding fly larvae, or maggots, are pale, legless, tube-shaped creatures measuring approximately 1/4-inch long.
  • Young plants are most vulnerable to root maggots in cool, wet springs.

Cicadas and Aphids

Aphids
Michael Pettigrew/iStock/Getty Images

Large, noisy cicadas lay eggs in twigs, which then die and fall to the ground. The eggs hatch, and nymphs burrow into the soil where they feed on roots for several years. The feeding inflicts only minor damage and is rarely a cause for concern. Aphids are tiny, pear-shaped insects that suck the sap out of plants. While most species favor leaves and stems, some aphids attack fruit tree and vegetable roots. Aphid treatments usually work on contact with the pest. No current treatments are available for underground aphids, but these pests rarely cause significant damage. Rotate vegetable crops to avoid increasing populations of root aphids.

  • Large, noisy cicadas lay eggs in twigs, which then die and fall to the ground.
  • No current treatments are available for underground aphids, but these pests rarely cause significant damage.

Related Articles

Pest Control for Radishes
Pest Control for Radishes
Planting Iris Bulbs in Spring
Planting Iris Bulbs in Spring
Brown Spots on the Leaves of Green Beans
Brown Spots on the Leaves of Green Beans
Zucchini Root Rot Prevention
Zucchini Root Rot Prevention
What Insects Kill Grass?
What Insects Kill Grass?
Magnolia Tree Root Damage
Magnolia Tree Root Damage
Harmful Bugs for Zucchini Plants
Harmful Bugs for Zucchini Plants
Tree Roots Facts
Tree Roots Facts
Burrowing Yard Pests
Burrowing Yard Pests
Yellow Leaves & Brown Spots on Gardenias
Yellow Leaves & Brown Spots on Gardenias
Low-Flying Lawn Insects
Low-Flying Lawn Insects
Pests on Laurel Shrubs
Pests on Laurel Shrubs
Shallow Root Perennials
Shallow Root Perennials
Garden Guides
×