Beneficial Insects
From Antivist
A garden insectary is a small garden plot of flowering plants designed to attract and harbor beneficial insects. These "good insects" prey on many common garden insect pests and offer the gardener a safer, natural alternative to pesticides.
The garden insectary is a form of "companion planting," based on the positive attributes plants can share in deterring pests, acquiring nutrients, or attracting natural predators. By becoming more diverse with your plantings, you're providing habitat, picture of predatory wasp shelter, and alternative food sources (such as pollen and nectar), something many predators need as part of their diet.
Your insectary plot does not have to be large, just big enough to hold six to seven varieties of plants that attract insects. Once the garden has matured, you can watch your personal security force of beneficial insects do the work for you.
Natural Pest Control by Insect Species
| Pest Insect | Predator Insect |
| Aphids | Aphidius |
| Aphids | Aphidoletes |
| Thrips, spidermites, fungus gnats | Beneficial mites |
| Eggs of many pest insects | Damsel bugs (Nabidae) |
| Whiteflies, aphids, thrip, spider mites | Dicyphus |
| Slugs, small caterpillars and grubs | Ground beetles |
| Grubs | Spring Tiphia wasp |
| Aphids, mealybugs and others | Hoverflies |
| Scale, aphids, mites, soft-bodied insects | Lacewings |
| Aphids, mites | Ladybugs |
| Thrips, aphids, mites, scales, whiteflies | Pirate bugs |
| Caterpillars; beetle and fly larvae | Tachinid flies |
| Whiteflies; moth, beetle and fly larvae | Parasitic wasps |
What to Plant to Attract Beneficial Insects (Predator Insects)
| Predator Insect | What to Plant (Insectary Plant) |
| Lacewings, aphidius, ladybugs | Achillea filipendulina |
| Hoverflies | Alyssum |
| Ground beetles | Amaranthus |
| Spring Tiphia wasp | Peonies, firethorn, forsythia |
| Ichneumon wasp, ladybugs, lacewings | Anethum graveolens (dill) |
| Lacewings | Angelica gigas |
| Ladybugs, hoverflies | Convolvulus minor |
| Hoverflies, parasitic wasps, lacewings | Cosmos bipinnatus |
| Dicyphus | Digitalis |
| Lacewings, ladybugs, hoverflies | Daucus carota (Queen Anne's lace) |
| Damsel bugs, ladybugs, lacewings | Foeniculum vulgare (fennel) |
| Pirate bugs, beneficial mites | Helianthus annulus |
| Hoverflies | Iberis umbellata |
| Hoverflies, parasitic wasps | Limonium latifolium (Statice) |
| Aphidius, aphidoletes, hoverflies | Lupin |
| Parasitic wasps, tachinid flies | Melissa officinalis (lemon balm) |
| Parasitic wasps, hoverflies, tachinid flies | Petroselinum crispum (parsley) |
| Pirate bugs, beneficial mites | Shasta daisy |
| Pirate bugs, aphidius | Sunflowers |
| Ladybugs, lacewings | Tanacetum vulgare (tansy) |
| Dicyphus | Verbascum thaspus |
Tips and Suggestions for Your Garden Insectary
- Intersperse vegetable beds with rows or islands of insectary annuals. This will add decorative elements to your vegetable beds while luring beneficial insects toward prey.
- Allow some of your salad and cabbage crops to bloom. Brassica flowers (cabbage, broccoli, Brussels sprouts, bok choy) are also appreciated.
- Include plants of different heights in your insectary. Ground beetles require the cover provided by low-growing plants such as thyme, rosemary, or mint. Lacewings lay their eggs in shady, protected areas, so providing such places near crop plants is a good idea.
- Tiny flowers produced in large quantity are much more valuable than a single, large bloom. Large, nectar-filled blooms actually can drown tiny parasitoid wasps.
- Members of the Umbelliferae family are excellent insectary plants. Fennel, angelica, coriander, dill, and wild carrot all produce the tiny flowers required by parasitoid wasps.
- Composite flowers (daisy and chamomile) and mints (spearmint, peppermint, or catnip) will attract predatory wasps, hover flies, and robber flies.
