Garden Insects: Friend or Foe?

Many gardeners are tested by annoying garden insects, chewing and damaging, or even killing, our treasured trees, shrubs, flowers, and vegetables. We bemoan those pesky vermin eliminating our well-deserved blue ribbon in horticulture and design exhibits with every bite they take, despite our toil in the garden all season long. Yet some garden insects are also important friends.

To help club members sort out insect friends or foes, Nicholas St. Sauveur, Arborist, Cortese Tree Specialists, provided a highly entertaining and interactive program entitled “Harmful and Helpful Insects” at the September meeting of the Tuckaleechee Garden Club (District IV).

Nicholas tested our knowledge of common harmful insects. As gardeners, our “most despised insects list” often includes the southern pine bark beetle and aphids. The bark beetle can kill a tree in as little as two weeks. Aphids (plant lice) can cause damaged leaves, stunted growth, yellowing or browning, and reduced yields. Aphids are prolific: they give birth to live young, who are born pregnant, and can give birth up to 10 times per day. No wonder we fear them!

Nicholas educated club members on the insects that are helpful in our gardens, including lady bugs, assassin bugs, and lacewings. Many of these helpful insects eat the harmful ones. For example, one adult lady bug can eat 50 aphids per day, or about 5,000 aphids in a lifetime. Lacewings also eat aphids and spider mites.

One of our gardening challenges is to reduce the harmful insects and increase the number of helpful ones. Nicholas offered the following guidance to reduce harmful insects:

  • Increase biodiversity in our gardens
  • Plant trees with narrow families ( e.g., ginkgo)
  • Reduce stress on our plants
  • Promote predatory insects in our gardens
  • Use select chemical controls carefully, and generally avoid soil injections that kill everything

Submitted by Allison Pearson