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Attracting Beneficial Insects

By Kimberly Christensen

Everyone's favorite beneficial insect, the ladybug, makes herself at home on a borage bloom. Kimberly Christensen photol.

Jun 06, 2002 -- Few things are as distressing as walking among your prized plants and realizing that they are suffering as thousands of insects munch away at the foliage. Naturally, you want to get rid of those destructive little beasts as soon as possible. However, before you break out the pesticide, consider the long-term repercussions of smiting bugs with chemicals. Not only are pesticides dangerous to the environment and your health, but by applying pesticides to your garden, you will destroy the beneficial bug population along with the destructive bugs.

Beneficial insects (and arachnids) prey on foliage-eating pests. Ladybugs, green lace wings, ground beetles, spiders and many other garden residents should be counted as every gardener's friend because they eat several times their weight in harmful bugs each day. These beneficial bugs are often the most voracious in their immature forms. Therefore, it behooves the gardener to create a pleasing environment in which these creatures can reproduce.

Most beneficial bugs have pinchers or prominent jaws that allow them to catch and devour aphids, caterpillars, flies and other garden pests. However, when these meaty dishes are scarce, beneficial insects subsist by eating pollen and nectar. Since they have jaws, not long tube-like snouts for dipping into flowers, they need plants that produce small, plentiful flowers with pollen and nectar that can easily be reached, like daisies, borage, or yarrow. Growing flowering plants in your garden from early spring through fall will help sustain beneficial bugs, and attract them to your yard especially when other forms of food are scarce.

Resources:

King County's Local Hazardous Waste Management Program maintains a website (http://www.metrokc.gov/hazwaste/house/garden/goodbugs.html) that includes color photos of local beneficial insects, a list of flowing plants that support them and a bibliography for further reading. They can also be reached at (206) 263-3051.

Buglogical Control Systems (http://www.gardeninsects.com/products.asp) maintains a database that includes color photos of beneficial insects and a "Pest Problems and Biological Solutions" lists. You can choose the type of garden pest that is plagueing you, and they will tell you which kind of beneficial insects will help. They also sell beneficial insects. They can also be contacted at (520) 298-4400.

Some plants the attract and nurture beneficial insects:
Angelica * Anise * Aster * Bee balm * Borage * Calendula * Coriander * Dill * Evening Primrose * Fennel * Goldenrod * Snowberry * Sunflower * Sweet Alyssum * Thyme * Wild carrot * Yarrow * Zinnia

Bushes, cover crops, flower beds, rocks and compost piles can help shelter beneficial insects and spiders from disturbances like mowing, tilling and excess water runoff. Since beneficial bugs include flying and crawling insects, having plants of different heights will allow you to shelter a variety of bugs. Taller plants will help create shady spots, in which insects like green lacewings can lay their eggs. Ground cover, stones, and mulch will provide places for ground-dwellers to hide, lay eggs, and over-winter.

By providing food and shelter, you will not only attract beneficial bugs, but you will encourage them to reproduce in your garden. Sometimes gardeners panic when it appears that there are no beneficials in their yards. Keep in mind that the adult insects may fly or crawl off in search of more plentiful pest populations. Since pests tend to reproduce quickly, by the time your garden is in need of pest control, the next generation of beneficial insects will have hatched and be ready to devour your problem bugs. Also remember that beneficial bugs in their immature forms usually eat the most pests. Many people forget to look for larvae and nymphs when surveying their resident beneficials.

If you feel that your resident population of beneficials is too small to be of much help, you can purchase insects like praying mantises, ladybugs and green lacewings at garden and hardware stores. Before you do this, take steps to make your yard an attractive place for them to stay, at least long enough to lay eggs. Introduce beneficial insects into your garden at night, when they are least likely to fly away. The adults may leave your yard more quickly than you would like. However, if you have encouraged them to hang around for a few days, then they should leave you with a hungry juvenile bug population that is ready to attack your garden pests.

Feverfew provides shelter and food for beneficial insects. Kimberly Christensen photo.

Beneficial bugs will never eat all of your garden pests. Since beneficials rely on garden pests as their major food source, it would not be smart to eat them all. However, they will keep the pest population at a manageable level. If you are promoting plant health by building healthy soil, growing plants that are right for our climate and growing plants at the appropriate time of year, then your plants should be able to tolerate a certain amount of pest damage. Your garden is an ecosystem, and as such, it needs to have predators and prey in order to stay healthy.

Using chemical pesticides destroys your garden ecosystem by killing both insect pests and beneficial bugs. Unfortunately, the pests usually recover first, which can lead to an even greater infestation. Many people treat each subsequent infestation with yet more pesticide, which never allows the beneficial insects to repopulate the garden. Additionally, some harmful insects are starting to develop resistance to pesticides. There are many alternatives to chemical pesticides that can be used in the home garden, including: hand picking the pests, spraying foliage with soapy water or garlic-pepper oil, directing blasts of water at the foliage to dislodge the pests, and growing smelly plants like mints and marigolds to deter bugs from your garden. However, cultivating a garden that attracts beneficial insects will be your best line of defense against problem bugs.

Kimberly Christensen lives and gardens in Wallingford.

Reader Comments

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Lina Hanson	May 19, 2004	Kirkland, Wa	court clerk
I am looking for the location of the "ladybug man" on 15th ave w near the Magnolia bridge. Do you have an address and phone?

Notes From the Garden

Attracting Beneficial Insects

By Kimberly Christensen

Reader Comments