When gardeners think about insects in their gardens, they often focus on pests that damage ornamental and edible plants. However, most insects are harmless, and many play crucial roles in supporting plant health through pollination and natural pest control.
Diverse Insect Population
Having a diverse insect population, including beneficial insects, is essential for maintaining a balanced ecosystem. Attracting these helpful creatures is one of the safest and most effective methods of natural pest control. While insect pests may not be entirely eradicated, their damage can be reduced and better managed through biological control methods. Learn how to recognize beneficial insects and how to attract and retain them in your garden.
Types of Beneficial Insects
There are three primary types of beneficial insects:
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Pollinating Insects: These insects, such as bees, butterflies, and beetles, move from plant to plant, transmitting pollen and performing essential fertilization. Without them, plant diversity and crop yields suffer significantly.
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Predatory Insects: These insects, including ladybugs and lacewings, feed on other insects in either adult or larval form. They help control a wide range of insect pests.
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Parasitoid Insects: These tiny insects lay eggs on or inside a host insect, where their larvae feed on the host, ultimately killing it. Most parasitoids are small, stingless wasps or flies.
Many predators and parasitoids also serve as pollinators, primarily in their adult stages.
12 Common Beneficial Insects
1. Assassin Bug
- Description: Ranging from 2/5 to 4/5 inch long, assassin bugs can be black, brown, or brightly colored. They consume a variety of pests, including aphids and caterpillars.
- Attract: Include daisies, marigolds, and herbs like dill.
- Keep: Provide hiding places like wood piles and leaf debris.
2. Bees
- Description: Essential pollinators, including honeybees and bumblebees, contribute to plant reproduction and crop yields.
- Attract: Plant a variety of flowering plants, such as asters and sunflowers.
- Keep: Provide bee houses and shallow water dishes.
3. Damsel Bug
- Description: These slender, brown insects grow up to ½ inch long and are active in summer. They feed on soft-shelled insects.
- Attract: Plant caraway, fennel, and alfalfa.
- Keep: Leave garden beds undisturbed for overwintering.
4. Garden Spider
- Description: These arachnids build webs to trap pests and inject venom to immobilize them.
- Attract: Allow spaces for web spinning.
- Keep: Provide shelter with mulch or protected areas.
5. Green Lacewing
- Description: Reaching 1/2 to 3/4 inch long, they are valuable for both pollination and predation.
- Attract: Plant angelica, dill, and cosmos.
- Keep: Tolerate some pests for a consistent food source.
6. Ground Beetle
- Description: With over 2,500 species, these nocturnal predators feed on a variety of garden pests.
- Attract: Keep a compost pile and plant a perennial border.
- Keep: Delay garden cleanup until spring.
7. Hoverfly
- Description: Resembling bees, hoverflies are effective pollinators and predators of pests like aphids.
- Attract: Grow alyssum, chives, and zinnias.
- Keep: Provide early blooming plants and avoid spring cleanup.
8. Ladybug
- Description: Known for their orange-red shells with black spots, ladybugs eat a wide variety of pests.
- Attract: Plant angelica, calendula, and yarrow.
- Keep: Provide water sources and shelter.
9. Parasitic Wasp
- Description: These small insects lay eggs on various host insects, helping control pests like aphids.
- Attract: Include plants from the carrot family.
- Keep: Provide a consistent source of food and water.
10. Praying Mantis
- Description: Easily recognizable, these predators eat a range of pests, including moths and crickets.
- Attract: Grow dill and marigolds.
- Keep: Provide dense shrubbery for shelter.
11. Soldier Beetle
- Description: Related to fireflies, soldier beetles feed on nectar and prey on soft-shelled insects.
- Attract: Plant catnip, goldenrod, and Queen Anne’s lace.
- Keep: Leave leaf piles for overwintering larvae.
12. Tachinid Fly
- Description: These parasitoids help control many pests, including armyworms and Japanese beetles.
- Attract: Grow flat-topped flowers like buckwheat and cilantro.
- Keep: Delay garden cleanup until spring.
6 Ways to Support Beneficial Insects
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Grow a Diversity of Plants: Include a mix of trees, shrubs, and flowering plants, particularly native varieties. Early and late bloomers provide a consistent food source.
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Keep Plants Healthy: Ensure plants receive adequate water, light, and nutrients to be resilient against pests.
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Include Water Sources: Set out shallow saucers with water and pebbles for insects to rest while drinking.
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Provide Protection: Non-flying insects need shelter. Incorporate ground cover plants and coarse mulches.
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Delay Fall Cleanup: Allow beneficial insects to overwinter in plant debris and soil by postponing garden cleanup until spring.
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Eliminate Chemical Pesticides: Avoid chemical pest controls that can harm beneficial insects.
