Master Gardener: Attracting beneficial bugs to the home garden

Most of the time, people think of insects as pests. What most folks don’t know is that only about 1 percent of the millions of insects on Earth are considered “pests.”

Beneficial insects not only pollinate our flowers and our fruit and nut trees, but also can be used to reduce the population of those we consider pests. For example, in an aphid-infested flower or vegetable garden, assassin bugs, flower flies, lacewings and lady beetles can significantly reduce the infestation, eliminating the need for chemicals.

Of course, the effectiveness of control with beneficial insects can vary with the level of pests present. When infestation levels are high, and there is enough other food and proper habitat to support beneficial insects, pests will feed and reproduce more, thus having a greater negative impact on the health and well being of your garden. On the other hand, if pest infestation levels are low, the beneficials will have less to eat; and unless alternate sources of food are provided, they will leave to search elsewhere for food.

Let’s consider ways to attract beneficials to the home garden by providing shelter, alternate food sources and water. When pest populations are low, beneficial insects will feed on pollen, nectar or plant juices to supplement their insect diet.

• Shelter: All living things need a stable habitat to stay healthy. Care should be taken to provide protection from habitat disturbances, so the beneficials will stay in your garden. Plots of cover crops, perennial flower beds, hedges near flower beds and vegetable gardens all provide excellent shelter. Mulch used under and around trees and flower beds creates shelter for predacious ground beetles, as do small piles of limbs

• Alternate food sources: This is where choosing plants with pollen and nectar comes into play. Pollen-producing plants such as crocus, snowdrops, maple, dandelion, fruit trees, coltsfoot, grape hyacinth, mustard and many berry plants will act as food sources. Some good choices for nectar-producing plants include clover, alfalfa, Queen Anne’s lace, members of the squash family and the pollen-producing plants listed above.

• Water: Like all living things, insects require water to survive. Any small shallow container will work, as will birdbaths and fountains. To discourage mosquitos, all water containers must be kept clean by changing the water every two to three days. Small sticks or rocks placed in the water will give insects a place to perch.

To sustain pests as a food source, beneficials must allow some of their prey to feed and reproduce. As a result, they will not always be able to resolve all your pest problems. This is where tolerance and other pest management strategies come into play. Choosing plants that are alternative food for beneficial insects may not be enough. One may need to choose plants that are resistant to pests as well. The use of some pesticides may also be necessary.

Linda Lee, of Cosmopolis, was a Master Gardener for 17 years.