4 Beneficial Bugs That Eat Grubs—and Naturally Promote a Healthier Garden

Not all insects are pests—many species can improve the health and vitality of your plants. One way these beneficial insects do this is by eating grubs, the larvae of beetles that feed on roots and cause damage to edible and ornamental plants. By enticing good bugs to your garden, you can help eliminate harmful grubs. Ahead, a gardening expert and a pest professional share what organisms eat grubs and how to welcome these beneficial helpers into your garden.

Beneficial Nematodes

Beneficial nematodes can help control unwanted caterpillars or grubs that dine on plant roots. "This microscopic worm burrows into the ground and will find the grubs with great accuracy," says Tammy Sons, master gardener and founder of TN Nursery. You can buy beneficial nematodes from a reputable supplier and add them to your garden, or introduce them by applying biologically active compost, compost extract, or vermicompost to your soil. Just remember that nematodes need moist soil and the right temperature to survive.

Parasitic Wasps

Hornworm wasps and chalcid wasps are just a few parasitic wasps that will parasitize—and thereby remove—garden pests such as cutworms, corn earworm, white grubs, and caterpillars. Parasitic wasps will also go after fly larvae, another benefit of having them around. According to Nicole Carpenter, pest control expert and president of Black Pest Prevention, these wasps help reduce grub numbers because they lay their eggs inside them. To welcome wasps to your garden, plant flowers like yarrow, fennel, and dill near the garden beds where you have grubs, she adds.

Ladybugs

Ladybugs love to eat grubs. "But the nice thing about these helpers is they’re not one-trick ponies," says Carpenter. They will also eat other unwanted garden pests, including fire ants, fleas, and white grub worms, making ladybugs a great addition to your garden. In spring, many garden stores and plant nurseries sell bags of ladybugs you can purchase and release into your garden, but it’s better to attract them naturally with their favorite plants and by maintaining an organic garden. "I have discovered if I keep my soil healthy and avoid synthetic pesticides, it will encourage these good guys to stick around," says Sons.

Ground Beetles

Ground beetles, like Scarb and June beetles, produce larvae that consume slugs, grubs, caterpillars, Japanese beetles, and other pests that eat garden vegetables. "Ground beetles are the best—they feed on soft-bodied pests like grubs and significantly reduce their numbers," says Carpenter. "They stick around if you avoid heavy pesticides and keep some low mulch or leaf cover."