Plants That Attract Beneficial Insects

by Fred Hoffman

Nature wants to make your job as a gardener as easy as possible; but you have to help. So, let’s talk about putting in plants that attract the "good bugs", the crawling and flying creatures whose diet includes pests that are ravaging your garden plants. These beneficial predatory insects do not live on aphid steaks alone. They need other natural sources of food and shelter for their entire life cycle before they call your backyard a permanent home.

What are these "Welcome Mat" plants and the beneficial insects they attract?

Here is a list of those good bugs and the plants that they like to visit for shelter and as another source of food for their diet, the sugar from flowers. For some beneficials, especially syrphid flies, this nectar is necessary in order to mature their eggs. Intersperse these plants among the “problem pest areas” in your yard to attract the garden good guys.

Lacewings (Chrysopa spp.)


Individual white eggs are found laid on the
ends of inch-long stiff threads.

Beautiful, little (3/4”) green or brown insects
with large lacy wings.

 

It is the larvae (which look like little alligators) that destroy most of the pests. They are sometimes called aphid lions for their habit of dining on aphids. They also feed on mites, other small insects and insect eggs. On spring and summer evenings, lacewings can sometimes be seen clinging to porch lights and screens or windows.


Green lacewing larva

Plants that attract lacewings:

  • Achillea filipendulina — Fern-leaf yarrow
  • Anethum graveolens — Dill
  • Angelica gigas — Angelica
  • Anthemis tinctoria — Golden marguerite
  • Atriplex canescens — Four-wing saltbush
  • Callirhoe involucrata — Purple poppy mallow
  • Carum carvi — Caraway
  • Coriandrum sativum — Coriander
  • Cosmos bipinnatus — Cosmos white sensation
  • Daucus carota — Queen Anne’s lace
  • Foeniculum vulgare — Fennel
  • Helianthus maximilianii — Prairie sunflower
  • Tanacetum vulgare — Tansy
  • Taraxacum officinale — Dandelion

Ladybugs

Easily recognized when they are adults by most gardeners. However, the young larvae, black with orange markings, eat more pests than the adults, and they can’t fly. Yellowish eggs are laid in clusters usually on the undersides of leaves.

Plants that attract ladybugs:

  • Achillea filipendulina — Fern-leaf yarrow
  • Achillea millefolium — Common yarrow
  • Ajuga reptans — Carpet bugleweed
  • Alyssum saxatilis — Basket of Gold

  • Ladybug larva

    Anethum graveolens — Dill

  • Anthemis tinctoria — Golden marguerite
  • Asclepias tuberosa — Butterfly weed
  • Atriplex canescens — Four-wing saltbush
  • Coriandrum sativum — Coriander
  • Daucus carota — Queen Anne’s lace
  • Eriogonum fasciculatum — CA Buckwheat
  • Foeniculum vulgare — Fennel
  • Helianthus maximilianii — Prairie sunflower
  • Penstemon strictus — Rocky Mt. penstemon
  • Potentilla recta ‘warrenii’ — Sulfur cinquefoil
  • Potentilla villosa — Alpine cinquefoil
  • Tagetes tenuifolia — Marigold “lemon gem”
  • Tanacetum vulgare — Tansy
  • Taraxacum officinale — Dandelion
  • Veronica spicata — Spike speedwell
  • Vicia villosa — Hairy vetch

Hoverflies

Also known as syrphid fly, predatory aphid fly or flower fly. Adults look like little bees that hover and dart quickly away. They don’t sting! They lay eggs (white, oval, laid singly or in groups on leaves) which hatch into green, yellow, brown, orange, or white half-inch maggots that look like caterpillars.

They raise up on their hind legs to catch and feed on aphids, mealybugs and others.

Plants that attract hoverflies:

  • Achillea filipendulina — Fern-leaf yarrow
  • Achillea millefolium — Common yarrow
  • Ajuga reptans — Carpet bugleweed
  • Allium tanguticum — Lavender globe lily
  • Alyssum saxatilis — Basket of Gold
  • Anethum graveolens — Dill

  • Hoverfly larva

    Anthemis tinctoria — Golden marguerite

  • Aster alpinus — Dwarf alpine aster
  • Astrantia major — Masterwort
  • Atriplex canescens — Four-wing saltbush
  • Callirhoe involucrata — Purple poppy mallow
  • Carum carvi — Caraway
  • Chrysanthemum parthenium — Feverfew
  • Coriandrum sativum — Coriander
  • Cosmos bipinnatus — Cosmos white sensation
  • Daucus carota — Queen Anne’s lace
  • Eriogonum fasciculatum CA — Buckwheat
  • Foeniculum vulgare — Fennel
  • Lavandula angustifolia — English lavender
  • Limnanthes douglasii — Poached egg plant
  • Limonium latifolium — Statice
  • Linaria vulgaris — Butter and eggs
  • Lobelia erinus — Edging lobelia
  • Lobularia maritima — Sweet alyssum white
  • Melissa officinalis — Lemon balm
  • Mentha pulegium — Pennyroyal
  • Mentha spicata — Spearmint
  • Monarda fistulosa — Wild bergamot
  • Penstemon strictus — Rocky Mt. penstemon
  • Petroselinum crispum — Parsley

  • Rudbeckia

    Potentilla recta ‘warrenii’ — Sulfur cinquefoil

  • Potentilla villosa — Alpine cinquefoil
  • Rudbeckia fulgida — Gloriosa daisy
  • Sedum kamtschaticum — Orange stonecrop
  • Sedum spurium — Stonecrops
  • Solidago virgaurea — Peter Pan goldenrod
  • Stachys officinalis — Wood betony
  • Tagetes tenuifolia — Marigold “lemon gem”
  • Thymus serpylum coccineus — Crimson thyme
  • Veronica spicata — Spike speedwell
  • Zinnia elegans — Zinnia "liliput"

Parasitic mini-wasps

Parasites of a variety of insects. They do not sting! The stingers have been adapted to allow the females to lay their eggs in the bodies of insect pests. The eggs then hatch, and the young feed on the pests from the inside, killing them. After they have killed the pests, they leave hollow “mummies.”

Braconid wasps (right)

These feed on moth, beetle and fly larvae, moth eggs, various insect pupae and adults.

If you see lots of white capsules on the backs of a caterpillar (below), these are the braconid cocoons. Leave the dying caterpillar alone!

Ichneumonid wasps

These control moth, butterfly, beetle and fly larvae and pupae.

Trichogramma wasps

These lay their eggs in the eggs of moths (hungry caterpillars-to-be), killing them and turning them black.

Plants that attract parasitic mini-wasps:

  • Achillea filipendulina — Fern-leaf yarrow
  • Achillea millefolium — Common yarrow
  • Allium tanguticum — Lavender globe lily
  • Anethum graveolens — Dill
  • Anthemis tinctoria— Golden marguerite
  • Astrantia major — Masterwort
  • Callirhoe involucrata — Purple poppy mallow
  • Carum carvi — Caraway
  • Coriandrum sativum — Coriander
  • Cosmos bipinnatus — Cosmos white sensation
  • Daucus carota — Queen Anne’s lace
  • Foeniculum vulgare — Fennel
  • Limonium latifolium — Statice
  • Linaria vulgaris — Butter and eggs
  • Lobelia erinus — Edging lobelia
  • Lobularia maritima — Sweet alyssum – white
  • Melissa officinalis — Lemon balm
  • Mentha pulegium — Pennyroyal
  • Petroselinum crispum — Parsley
  • Potentilla recta ‘warrenii’ — Sulfur cinquefoil
  • Potentilla villosa — Alpine cinquefoil
  • Sedum kamtschaticum — Orange stonecrop
  • Tagetes tenuifolia — Marigold – lemon gem
  • Tanacetum vulgare — Tansy
  • Thymus serpylum coccineus — Crimson thyme
  • Zinnia elegans — Zinnia – ‘liliput’

Tachinid flies

Parasites of caterpillars (corn earworm, imported cabbage worm, cabbage loopers, cutworms, army worms), stink bugs, squash bug nymphs, beetle and fly larvae, some true bugs, and beetles. Adults are 1/3 to 1/2 inch long. White eggs are deposited on foliage or on the body of the host. Larvae are internal parasites, feeding within the body of the host, sucking its body fluids to the point that the pest dies.

Plants that attract tachinid flies:

  • Anthemis tinctoria — Golden marguerite
  • Eriogonum fasciculatum CA — Buckwheat
  • Melissa officinalis — Lemon balm
  • Mentha pulegium — Pennyroyal
  • Petroselinum crispum — Parsley
  • Phacelia tanacetifolia — Phacelia
  • Tanacetum vulgare — Tansy
  • Thymus serpyllum coccineus — Crimson thyme

Minute pirate bugs (Orius spp.)

Tiny (1/20 inch long) bugs that feed on almost any small insect or mite, including thrips, aphids, mites, scales, whiteflies and soft-bodied arthropods, but are particularly attracted to thrips in spring.

Damsel bugs (Nabis spp.)

Feed on aphids, leafhoppers, plant bugs, and small caterpillars. They are usually dull brown and resemble other plant bugs that are pests. Their heads are usually longer and narrower then most plant feeding species (the better to eat with!).

Big eyed bugs (Geocoris spp.)

Small (1/4 inch long), grayish-beige, oval shaped) bugs with large eyes that feed on many small insects (e.g., leaf hoppers, spider mites), insect eggs, and mites, as both nymphs and adults. Eggs are football shaped, whitish-gray with red spots.

Plants that attract minute pirate bugs, damsel bugs and big eyed bugs:

  • Carum carvi — Caraway
  • Cosmos bipinnatus — Cosmos “white sensation”
  • Foeniculum vulgare — Fennel
  • Medicago sativa — Alfalfa
  • Mentha spicata — Spearmint
  • Solidago virgaurea — Peter Pan goldenrod
  • Tagetes tenuifolia — Marigold “lemon gem”

More tips to Keep beneficial insects working in your yard

  • Use a wide variety of attractive plants. Plants that flower at different times of the year can provide beneficials with nectar and pollen when they need it.
  • Plantings that are at least 4′ by 4′ (1.2m x 1.2m) of each variety work best at attracting beneficials.
  • A bird bath or backyard water feature not only attracts birds (another predator of insects), but also attracts beneficials.
  • Tolerate minor pest infestations. The beneficial insects will get the memo before you do. This will provide another food source for the beneficials and help keep them in your yard.
  • More information about beneficial predatory insects: "The Natural Enemies Handbook", from the University of California Division of Agriculture and Natural Resources.

Editor’s addition:

  • Don’t use pesticides — these kills beneficials too, which usually have a slower reproductive cycle than your pests, so the pests will quickly bounce back into a beneficial-insect-free environment….

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