Underground Garden Pest Insects

Gardening can be an incredibly rewarding experience, but it’s not without its challenges. One of the most frustrating aspects of gardening is dealing with pests, particularly those that lurk beneath the soil. In this article, we’ll take a closer look at 11 garden pest insects that live below the ground and provide tips on how to prevent and control them. Let’s get started!

Carrot Rust Fly

The carrot rust fly is a small, dark-colored fly that lays its eggs in the soil near carrot plants. The larvae feed on the roots, causing rust-colored tunnels and stunted growth. To prevent carrot rust fly infestations, rotate your crops, use floating row covers, and plant carrot varieties resistant to the pest.

Celery Leaftier

Celery leaftier is a small moth whose larvae feed on the leaves and stems of celery, causing the leaves to fold and stick together. While the larvae may not directly attack the roots, they can weaken the plant and make it more susceptible to other pests and diseases. Control measures include hand-picking the larvae, using biological controls like parasitic wasps, and applying Bacillus thuringiensis (Bt) as a safe and effective pesticide.


Cutworms are the larvae of several species of moths. These pests feed on the stems and roots of a wide range of plants, often cutting them off at the soil line. To prevent cutworm damage, use collars made from paper or plastic around the base of your plants, handpick the larvae at night, and cultivate the soil to expose and kill any overwintering pupae.


Earwigs are nocturnal insects with a pair of pincer-like appendages at the end of their abdomen. They feed on decaying organic matter but can also attack seedlings, roots, and tubers. To control earwigs, reduce hiding places by removing debris, set up traps using rolled-up newspapers or shallow containers filled with vegetable oil, and encourage natural predators like birds and toads.

Fire Ant

Fire ants are aggressive, stinging insects that can be a major nuisance in the garden. They build large mounds and tunnel through the soil, which can damage plant roots. To control fire ants, use a combination of baits, mound treatments, and barrier treatments, and consider introducing beneficial nematodes to help reduce their populations.


Nematodes are microscopic roundworms that can be both beneficial and harmful to plants. Plant-parasitic nematodes feed on plant roots, causing stunted growth, yellowing leaves, and reduced yields. To manage nematodes, practice crop rotation, use resistant plant varieties, and incorporate organic matter into the soil to encourage beneficial nematodes.

Root Maggot

Root maggots are the larvae of various species of flies that feed on the roots of

plants such as cabbage, radish, and onion. They cause stunted growth and may lead to the plant’s death. To prevent root maggot infestations, practice crop rotation, use floating row covers, and avoid overwatering your plants. Additionally, you can introduce beneficial insects like rove beetles that prey on root maggots.

Root Weevil

Root weevils are small beetles whose larvae feed on the roots of various plants, including strawberries, rhododendrons, and azaleas. Damage from root weevil larvae can cause wilting, yellowing leaves, and reduced growth. Control methods include applying beneficial nematodes, using insecticidal soap on adult weevils, and maintaining proper soil moisture levels to discourage egg-laying.


Slugs are slimy, soft-bodied mollusks that feed on plant leaves, stems, and roots. They can cause significant damage to seedlings and young plants. To control slugs, use barriers like copper tape or diatomaceous earth, set up beer traps, and encourage natural predators like ground beetles, frogs, and toads.


Snails, like slugs, are mollusks that can damage plants by feeding on leaves, stems, and roots. To prevent snail infestations, use similar control methods as for slugs, such as barriers, traps, and encouraging natural predators. Additionally, hand-picking snails during evening hours can help reduce their population.

Wire Worm

Wire worms are the larvae of click beetles and can be a major problem in vegetable gardens. They feed on the roots and tubers of plants, causing stunted growth and reduced yields. To manage wire worms, rotate your crops, use trap crops like potatoes to lure them away from your main plants, and encourage natural predators like birds and beneficial insects.

Preventing and Controlling Soil-Borne Pests

There are several key steps to preventing and controlling soil-borne pests in your garden:

  1. Practice crop rotation to reduce the buildup of pests and diseases.
  2. Use resistant plant varieties and maintain healthy soil with proper nutrient levels.
  3. Encourage natural predators and beneficial insects.
  4. Employ physical barriers and traps.
  5. Apply organic or chemical pesticides as a last resort, following label instructions carefully.


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