NATURAL PEST CONTROL
(OTHER THAN CALLER ID)
Attracting Beneficial Insects to Your Garden

In previous Eco-Logicals, we've talked about the problem of chemical pesticides around the house and yard. We don't want our kids and pets being exposed to these toxic substances. We've also talked about "adaptive pesticides," otherwise known as beneficial insects that prey on pest insects. This approach helps reduce or eliminate the need for toxic pesticides by providing natural pest control for your garden. Doing this also avoids the issue of pests developing resistance to pesticides since the beneficial insects evolve right along with the garden pests.

Today's article will further explore the topic of natural pest control using beneficial insects and give specific tips about how you can add certain plants to your yard to create a haven for the good little buggers that can help you fight the bad little buggers. The information comes to us from the good folks at Eartheasy.com, a site that is chock-full of handy tips about how to live naturally and sustainably.

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Garden Insectary — Natural Pest Control
by Eartheasy.com

Creating A Home Base for Beneficial Insects

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, shelter, and alternative food sources (such as pollen and nectar), something many predators need as part of their diet.

Here's an example. You can control aphids with an aphid predator like aphidius, and you can encourage aphidius to set up shop by planting sunflowers or lupin. Of course, the aphid predators need the pests to be present in order to eat, thrive, and reproduce—that is, they need aphids to be found in and around the general area you're trying to protect from the aphids. But that's where stocking your insectary with the appropriate plants comes in.

The idea of inviting the pests in to munch on plants in your insectary may seem alarming, until you understand that you are doing so to encourage host-specific pests. The pests remain on the desired plant in your insectary yet provide an ideal breeding ground for the associated predators and parasites.

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 Species

Use Table A to figure out which beneficial insects you want to attract, based on your particular pest problems. Then use Table B to see what you should plant to attract the beneficial insects (predator insects). Note that in Table A, pest species may occur in more than one row. Similarly, in Table B, predator species may be listed in more than one row. Find the combination of predators and insectary plants that maximizes the benefit to your particular pest problem.

Table A.
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
From left to right: ichneumon wasp, lacewing, pirate bug, hoverfly, damsel bug

Table B.
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
From left to right: Statice, Lupin, Tansy, Queen Anne's Lace, Sunflower

Get these two tables as a 1-page PDF file

Tips and Suggestions for Your Garden Insectary

1. 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.

2. Allow some of your salad and cabbage crops to bloom.   Brassica flowers (cabbage, broccoli, Brussels sprouts, bok choy) are also appreciated.

3. 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.

4. 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.

5. 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.

6. Composite flowers (daisy and chamomile) and mints (spearmint, peppermint, or catnip) will attract predatory wasps, hover flies, and robber flies.

Wrap-Up

A garden insectary should be thought of as a long-term permanent component of your garden. Results are not instant and conclusive; rather, the benefits to your garden are cumulative. As your plantings mature and resident populations of beneficial insects are established, the need for chemical pesticides and other aggressive insect control techniques will diminish. Your garden will become a more natural and balanced environment for the healthy production of vegetables and flowers.

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Publish date: 26-APR-2005

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