Attracting Beneficial Insects to the Garden
Control Pests in the Vegetable Garden with Natural Predators
Nov 5, 2009
There are two classes of what are considered to be beneficial insects. The first class is the pollinators which make it possible for the garden to produce vegetables and flowers. These include butterflies, bees, black soldier flies, and Blue Mason bees.
The second class is comprised of predators which are those insects that consume destructive plant pests. These include ladybugs, soldier flies, and lacewings. Ideally, the gardener wants to invite both insect types into the vegetable garden.
Some insects that are considered plant pests in the garden include slugs, snails, aphids, and Colorado potato beetle. These plant enemies wreak havoc on vegetables, fruits, and flowers. The beneficial insect's job is to consume the bad bugs and balance out the potential garden damage.
Learn to Recognize Beneficial Insects
It's important that gardeners learn to recognize the cavalry when they see it so that the good bugs aren't inadvertently destroyed. Many of these insects don't look like the friendly type at all. Ladybug larva, for example, look nothing like their cheerful-colored parents and are especially off-putting with their prehistoric form.
With very little research, beneficial insect images can be found online and in organic gardening books. Field guides are another excellent insect photo source. Mac's Field Guide Bug Identification Page available at Amazon.com is one of the handiest references for gardeners to keep around the garden. This laminated sheet has pictures of beneficial insects on one side and garden pests on the other.
It's highly recommended if the gardener doesn't recognize an insect, to catch it in a jar and bring it down to a local nursery for proper identification. If the species can't be identified, the local Cooperative Extension Office can help.
Predatory Insect List
- Spider - People are often repelled by these eight-legged creatures, but spiders are a friend to the garden. They eat more insects in the garden than birds.
- Green Lacewing - Also called the "Aphid Lion", it's the green lacewing larva that eat 60 aphids per hour. They also eat other soft-bodied insects such as mites, mealybugs, spider mites, whiteflies, scale, and thrips. The adult lacewing is a pollinator.
- Ladybug - Adult ladybugs will eat 5,000 aphids by the time they die. Other ladybug prey includes bean thrips, mites, chinch bugs, Colorado potato beetle, asparagus beetles.
- Ladybug Larva - While these spiny little creatures aren't much to look at, they can eat 50-70 aphids per day. Have a prehistoric alligator look to them; black and orange - he has a bad guy appearance but gardeners can rest assured he's one of the good ones.
- Hoverfly - Also called "Syrphid Flies" the larva also feeds on soft-bodied pest insects.
- Praying Mantid - While mantids certainly eat garden pests, they aren't big consumers and sometimes grab a good guy or two in the process.
- Minute Pirate Bug - These tiny predators control small caterpillars, aphids, mites, and thrips. They are especially handy in the greenhouse as they like high humidity.
- Spined Soldier Bug - Potato beetles, tomato hornworms, cabbage worms end up getting "harpooned" by this predator.
- Trichogramma Wasp - This wasp is one in a group of parasitic wasps that lay their eggs inside the larva of garden pests such as cabbage worms, cutworms, and borers.
- Assassin Bug - These predators don't have much in the looks department but do have a voracious appetite for plant pests.
Plants that Attract Beneficial Insects
Some plants and flowers are especially gifted in the art of seducing beneficial insects. The list below is in no way an exhaustive one. For more information on plants grown to attract beneficials in specific areas, contact a local Cooperative Extension Office.
- Feverfew (Chrysanthemum parthenium)
- Marigold (Tagates spp.)
- Tansy (Tanacetum vulgare)
- Queen Anne’s Lace (Ammi majus)
- Stonecrop (Sedum 'Autumn Joy')
- Lavender (Lavendula augustifolia)
- Thyme (Thymus spp.)
- Summer Savory (Satureja hortensis)
- Floss Flower (Ageratum houstonianum)
- Alyssum (Lobularia spp.)
- Red Clover (Trifolium pratense)
- Lovage (Levisticum officinale)
- Rudbekia (Rudbeckia spp.)
- Bee Balm (Monarda spp.)
- Cosmos (Cosmos spp.)
- Sedum (Sedum spp.)
- Yarrow (Acheillea filipendulina)
- Goldenrod (Solidao californica)
By drawing predatory insects into the vegetable garden, potentially harmful inorganic control methods are avoided. Gardeners not only incorporate healthy food practices, but encourage sustainability in their natural environment.
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