Grow Your Garden with Beneficial Insects
"All these sounds, the crowing of cocks, the baying of dogs, and the hum of insects at noon, are the evidence of nature's health or sound state." - Henry David Thoreau
As a gardener, there's nothing more frustrating than finding a prized vegetable crop being devoured by insect pests. A couple of hornworms can level a row of tomatoes overnight. Fortunately, every pest has a predator, and we can use that natural food chain to our advantage. A sufficient number of beneficial insects will keep garden pests to manageable numbers.
Yet more than one organic gardener has opened a box of ladybugs to employ as natural garden pest control, only to watch a bright red-orange cloud fly away into the neighbor's garden! Beneficial insects are the most environmentally-friendly way to prevent slugs, bugs, and caterpillars from destroying the garden, but first you have to get them to hang around.
When you begin to encourage beneficial insects there may be a brief surge in the plant eaters, but the predator populations will expand to control them. Be patient. You have to give the good bugs time to find the smorgasbord. Rinse off early infestations off with a strong spray of water, or pick them off by hand. For Japanese beetles hold a bucket of soapy water and in the early part of the day the beetles can be knocked off plants into the bucket where they will drown.
Remember, pesticides can't distinguish the good guys from the bad guys and kills them all. Then you have eliminated nature’s defenses and a garden without natural predators means a world of insects gone wild.
Years ago when I bought my first home I stock piled a wide selection of insecticides… malathion, Bug-B Gon, Home Defense, Sevin, Flying Insect Killer, etc. I thought (and was told) that they were just part of the must-haves for a home-owner. Then some years ago one fine October day I took them all to Wilton’s Household Hazardous Waste collection and surrendered them to the poisons section. I quickly realized that I have no insect problem and that I never had an insect problem.
So, choose to work with nature, not poison it. Plant an Insectary in the spring to invite insects to your garden. An insectary is just an area dedicated to growing plants these bugs love. The right variety of plants will attract beneficial bugs to the neighborhood. It can be a separate landscape bed right near your garden, or several small plantings interspersed among the veggies.
Plant some early bloomers to attract beneficial insects early in the season, even before your gardens are full of pests. Many of the important beneficial insects, like hover flies and lacewings, feed on pollen and nectar as adults. By providing flowers early in the season, you will invite these insects into your garden in time to unleash their predatory offspring on your aphids and mites.
To further speed the process along you can order beneficials from companies such as Gardens Alive or GreenMethods.com. Handle and release them according to the directions provided by the source.
The insectary should include plants of varied heights. Low growing herbs like thyme and oregano give ground beetles a place to hide. Taller flowers, like daisies or cosmos, beckon to hover flies and parasitic wasps looking for nectar. Praying mantids will hide between the plants in a well-planted insectary.
Umbels and composite flowers provide the most attractive sources of food to most beneficial insects. The tiny, clustered flowers of umbels offer exposed nectar and pollen to smaller pollinators like parasitic wasps. This group includes yarrow, dill, fennel, and wild carrots. Composites attract the larger pollinators, like robber flies and predatory wasps. Composite flowers include many garden favorites, like zinnias, and sunflowers.
A shout out to our favorite beneficial insects: Green lacewing, lady bugs, hoverflies, tachnid flies, hunting and parasitic wasps, ground beetles, dragon flies, honey bees, and spiders.
There are many plants to include in your insectary, including: Queen Anne’s lace, fennel, yarrow, coreopsis, parsley, sunflowers, tansy, alyssum, dill, cosmos, and pincushion. 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 (they do not sting), hover flies, and robber flies.
Finally, some tips to remember: Tiny flowers produced in large quantity are much more valuable than a single, large bloom. Provide water for insects. Like all animals, insects need water to live.
