Natural Pest Control: Attracting Beneficial Insects

By Jeanne Hepler

If you want to protect your garden plants from destructive insects without resorting to toxic sprays or pesticides, there’s a simple and effective solution: attract beneficial insects. These helpful creatures can do all the work for you, eliminating harmful pests and maintaining a balanced ecosystem in your garden.

I first discovered the concept of beneficial insects while studying Permaculture, a design system that mimics nature’s processes to create sustainable and self-sufficient gardens. Permaculture advocates for natural pest control methods, relying on the power of beneficial insects rather than relying on chemical sprays. By encouraging a diverse ecosystem in your garden, you can harness the natural systems of nature to your advantage. Integrated Pest Management (IPM) is a key principle of Permaculture and is crucial for maintaining a healthy garden. If you want to learn more about IPM, check out last month’s article, “Integrated Pest Management,” in The Garden Shed.

The first step in attracting beneficial insects is to stop using chemical pesticides immediately. These chemicals harm both harmful and beneficial bugs, disrupting the delicate balance of your garden’s ecosystem. Instead, focus on creating the ideal environment for beneficial insects to thrive.

To attract beneficial insects, start by planting flowers. These flowers will serve as nectar and pollen sources, drawing beneficial insects towards your garden. It’s important to choose flowers that specifically attract these insects and plant them near the plants you want to protect. Aim for a variety of flowers that bloom throughout the gardening season to ensure a continuous presence of beneficial insects.

Beneficial insects have specific preferences when it comes to flowers. They typically have short mouthparts, making it difficult for them to access nectar from deep or tubular flowers. Instead, they prefer small flowers with shallow, exposed nectaries. Flowers from the Umbelliferae family, such as fennel, dill, cilantro, parsley, and carrot, are great options. The Asteraceae or Compositae family also offers small and flat flowering varieties like yarrow, chamomile, daisy, feverfew, and aster. The Brassicaceae family, which includes sweet alyssum, basket-of-gold, and candytuft, along with certain garden vegetables like broccoli and mustard, are also excellent choices. The Mint family, with plants like spearmint, peppermint, lemon balm, and mountain mint, are also attractive to beneficial insects.

The practice of interplanting flowers to attract beneficial insects is commonly used in commercial agriculture and is known as farmscaping. If you’re interested in expanding your knowledge, Virginia Tech and the Natural Resources Council of Maine have compiled useful lists of plants that attract beneficial insects.

If you’re looking for a shortcut and want to skip the research, I’ve compiled a shortlist of plants that attract a wide variety of beneficial insects. Sweet alyssum, with its long bloom season and ease of growing, should be at the top of your list. Yarrow, both common and fern-leaf varieties, are also excellent choices. Dill, coriander, and fennel, when in bloom, attract many beneficial species as well. Lastly, cosmos, marigold, and zinnia are colorful annuals that are easy to grow and will attract beneficial insects.

Now that you know how to attract beneficial insects, it’s important to recognize them when they arrive. Here are some widely known species that are useful for pest control:

  1. Ladybugs or Lady Beetles: Ladybugs are easily recognizable with their red bodies and black polka-dots. The adults feed on pollen, but it’s the larvae that are voracious consumers of aphids and other soft-bodied pests. Ladybugs lay up to 1,000 eggs during their 3 to 6-week lifespan and can eat as many as 5,000 aphids in their lifetime.

  2. Lacewings: Lacewing larvae prey on harmful pests like aphids, caterpillars, mealybugs, and leafhoppers. The adults feed on flower nectar.

  3. Hoverflies or Syrphid Flies: Hoverflies resemble bees but do not sting. The adults feed on pollen and nectar, while their larvae consume aphids, mealybugs, and other soft-bodied insects.

  4. Parasitic Mini-Wasps: These tiny wasps lay their eggs inside the eggs of pests like moths and butterflies. When their eggs hatch, the larvae consume the pest eggs.

  5. Tachinid Flies: Tachinid flies are beneficial parasites that target damaging caterpillars and bugs. The adults lay their eggs on the host’s body, and the larvae feed on the host, eventually killing it.

  6. Praying Mantis: While praying mantises are known insect eaters, they can also consume beneficial insects. However, their overall usefulness in pest control outweighs this drawback.

These are just a few examples of beneficial predators. To learn more about beneficial insects, the University of California Agriculture & Natural Resources and the Virginia Cooperative Extension have compiled useful resources and lists.

In addition to attracting beneficial insects, you can consider planting native species in your garden. Since beneficial insects are often native species themselves, they are naturally inclined to prefer native flowers as food sources.

Don’t forget to think big when it comes to attracting beneficial insects. Blooming shrubs and trees also attract these helpful creatures. Consider planting redbud, serviceberry, elderberry, American holly, and other native shrubs and trees to extend the bloom season and provide additional food sources for beneficial insects.

Embrace strategic neglect in your garden. Allow vegetables to go to flower, as these flowers attract beneficial insects. Clover, violets, and dandelions in your grass are also loved by beneficials and pollinators, so let them bloom. Avoid spraying the undersides of leaves to remove aphids manually, as you may also be removing the eggs of future aphid-eating insects.

To wrap it up, attracting beneficial insects requires patience and a willingness to let some damage occur in your garden as you wait for these helpful allies to arrive. However, the long-term benefits of a balanced ecosystem and reduced reliance on harmful pesticides make it all worthwhile. So make your garden a magnet for beneficial insects, and they will happily battle your garden pests while you enjoy the beauty of your thriving garden.

Sources:

  • Attracting Beneficial Insects, PennState Extension
  • Attracting Beneficial Insects with Native Flowering Plants, Anna Fiedler, Michigan State University MSU Extension
  • The Virginia Gardener Guide to Pest Management for Water Quality, Virginia Cooperative Extension
  • Permaculture Design, North Carolina Extension Gardener Handbook
  • Beneficial Insects, University of Florida IFAS Extension
  • Encouraging Beneficial Insects in Your Garden, Oregon State Extension Service

Featured Photo: Steven Ash, courtesy of the Univ. of Delaware Cooperative Extension, “The ‘New’ Companion Planting: Adding Diversity to the Garden”

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