Praying Mantis with a grasshopper lunch. Photo by Chris Horne, bugwood.org
Were you aware that many beetles, flies, and “true bugs” actually attack, lay eggs in, and sometimes eat harmful pests that farmers and gardeners often control with pesticides? These beneficial insects work in relative silence, often keeping the harmful insect population below bothersome levels.
Farmers Give it a Try
As farmers learn more about the advantages of employing beneficial insects to control pests, they are also learning how to protect and increase the good insect populations by adjusting farming practices. This is an approach to biological control called conservation biocontrol. The practice includes providing food and shelter for beneficial insects in non-cropped areas so when a pest arrives, there is a population of beneficial insects to attack the pest. Think of it as marrying natural habitats with farm fields.
Why is this evolving method of insect control so exciting? Because it provides an effective alternative to using insecticides. While conservation biocontrol may not completely eliminate the need for chemical applications, it may reduce the chemical use to the minimum amount that is absolutely necessary to sell a crop. Moreover, a targeted insecticide may be used, thus avoiding harm to other creatures.
Investment and Return
Providing food and shelter may come in the form of planting cover crops in field margins, building beetle banks (mounded strips covered with native grasses and wildflowers), planting strips of native plants around field edges, installing hedgerows of native trees and shrubs, and leaving brush piles in small areas around the farm. Other practices include providing clean sources of water, reduced till or no-till planting of fields, using insecticides that are selective or have low toxicity (when necessary), and not spraying toward insect habitat areas, especially when flowers are in bloom.
Pollinator visiting camas photo by Jason Faucera
While this may not sound like a big deal, it translates into millions of dollars of savings for food producers, nursery and flower growers, and Christmas tree producers. According to the Xerces Society’s newest guide, Farming with Native Beneficial Insects: Ecological Pest Control Solutions, Professor Doug Landis from Michigan State University and his colleagues estimated that the suppression of soybean aphid using beneficial insects was worth $239 million dollars a year in Iowa, Michigan, Minnesota, and Wisconsin (based on 2008 soybean prices).
Scaling Down
Gardeners take note! You can scale-down all of these practices to encourage beneficial insects to fit your home landscape. When you notice aphids on your favorite cut flowers, check for beneficial insects that may already be on the job!
One last note before you are off to install your own hedgerow. All of the practices that provide food and shelter for beneficial insects also provide food and shelter for our struggling pollinators! Wow, two good things for the price of one!
To learn more about conservation biocontrol, check out:
- Farming with Native Beneficial Insects by The Xerces Society, published by Storey Publishing.
- The Integrated Plant Protection Center
