Enlist Beneficial Insects for Natural Pest Control

Grow the right flowers to attract these Top 10 beneficial insects to your garden to minimize damage from aphids, caterpillars, flea beetles and other pests.


| April/May 2012



Braconid Wasp

North America is home to nearly 2,000 species of braconid wasps.


ILLUSTRATION: KEITH WARD

Day and night, pesticide-free organic gardens are abuzz with activity, much of it a life-and-death struggle between predators and prey. We seldom see much of this natural pest control, in which tiny assassins, soldiers and lions — aka “beneficial insects” (the bugs that eat other bugs) — patrol their surroundings in pursuit of their next meal. Assassin bugs aren’t picky: They will stab, poison and devour a wide range of garden pests, including caterpillars, leafhoppers and bean beetles. Soldier and carabid beetles work the night shift, emerging after dark from beneath rocks, mulch and other daytime hiding places to feast upon soft-bodied insects and the eggs of Colorado potato beetles. Aphid lions (the larvae of the lacewing) have a hooked jaw that helps them dispatch huge numbers of aphids, caterpillars, mites and other pests.

These and many other beneficial insects (find profiles of our Top 10 later in this article and pictures of each in the Image Gallery) are well-equipped to see, smell and/or taste a potential meal. Sometimes they’re alerted by the plants themselves, as some emit a chemical alarm signal when pest insects begin feeding on them, and nearby beneficial insects are quick to respond. If your garden is teeming with beneficials, these bugs may often thwart budding pest infestations before you’ve even noticed the threat. It’s nature’s way of managing pests — no pesticides required.

Judging from reports from MOTHER EARTH NEWS readers across the continent, tapping the support of beneficial garden insects is one of our best tools for natural pest control. By providing a welcoming habitat — shelter, water and alternate food — you’ll encourage these insect helpers to maintain year-round residence in your garden. You can then kick back and enjoy the natural pest control provided by the diverse and amazingly complex balance among what we humans see as the “good bugs” and the “bad bugs.”

Habitats for beneficial bugs go by several names, such as “farmscape,” “eco-scape” and, in Europe, “beetle banks.” The concept of “farmscaping” to promote natural pest control isn’t new, but designing studies to confirm exactly what works best for a given crop in various regions is challenging. An increasing number of researchers has been exploring these complex interactions between insects and plants to find new ways gardeners and farmers can grow food without resorting to toxic pesticides. The information here will equip you to put this growing body of knowledge to work in your garden.

7 Ways to Welcome Beneficial Insects

1. Plant a Nectary Smorgasbord of Flowers. When they can’t feed on insect pests in your garden, beneficial insects need other food to survive and reproduce. Having certain flowering plants in or near your garden supplies that food in the form of nectar and pollen. Beneficials use the sugar in nectar as fuel when searching for prey and reproducing, and the protein in pollen helps support the development of their eggs.

Which plants are easiest for them to tap? Researchers have identified the following groups whose flowers provide easily accessible nectar and pollen: 1) plants in the daisy family, such as aster, cosmos and yarrow; 2) plants in the carrot family, such as cilantro, dill, fennel, parsley and wild carrot; 3) alyssum and other members of the mustard family; 4) mints; and 5) buckwheats. 

ann pulley
3/21/2012 2:35:15 PM

Interesting, but there are no praying mantises mentioned in the photo gallery. THEY are very beneficial in the garden. Thankfully, I have them in my yard.






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