Identifying and Attracting Beneficial Insects
Joanna Kapke, Master Gardener
Now that the plants in our gardens are starting to bloom, we are also seeing insects on those plants. Some of those insects are certainly pests but others are actually beneficial. We know how pollinators are beneficial insects - many of the foods we enjoy rely on pollinators for fruit and seed development. But how do we identify other insects that are beneficial to our gardens and landscapes in other ways? Read this article to find out!
Now that the plants in our gardens are starting to bloom, we are also seeing insects on those plants. Some of those insects are certainly pests but others are actually beneficial. We know how pollinators are beneficial insects - many of the foods we enjoy rely on pollinators for fruit and seed development. But how do we identify other insects that are beneficial to our gardens and landscapes in other ways.
Beneficial insects (at various stages in their life cycle and using multiple methods) can help manage the populations of insect pests like aphids. Some examples of beneficial insects include ground beetles, lady beetles, lacewings, syrphid flies and a variety of solitary and parasitoid wasps.
Many of the recommendations for attracting pollinators to your garden—planting a variety of flowering plants, including native plants in your landscape or providing a water source/feature—are also true for encouraging beneficial insect visits. But beneficial insects need more than the aphids and larvae you want them to eliminate. They need pollen and nectar for energy and places to shelter and overwinter to encourage them to stay in your space. Here are several gardening strategies to attract and retain beneficial insects in your garden:
Have an array of perennial and annual plants flowering consistently throughout the growing season.
Leave some aphids on plants.
Allow some plant litter to stay on the ground over winter.
Limit or eliminate the use of pesticides.
Certain plants also attract beneficial insects. In many cases, smaller flowers will attract smaller insects like syrphid flies. Some flowers commonly listed as attracting beneficial insects that do well in Minnesota gardens are: yarrow, dill, alyssum, cosmos, gem marigolds, clover, cinquefoils, fennel, lemon balm and milkweeds. For more ideas, check the internet for lists of plants that attract beneficial insects.
Before adding any new plants to your yard in order to attract beneficial insects, check your local DNR list of invasive species to ensure there isn’t crossover. For example, common tansy and Queen Anne’s Lace are often listed as plants that will attract beneficial insects. But in Minnesota, both are considered noxious weeds and it is illegal to import, sell or transport them within the state.
You can purchase many species of beneficial insects online. Before doing so, take a few things into consideration:
Can you follow the release instructions exactly?
Will you need to repeat the process? Insects often…fly away.
Is the pest you are hoping to eliminate a serious problem?
It can often be more sustainable to make your landscape more welcoming to beneficial insects than trying to repeatedly introduce species that have been ordered from other sources.
For more information on specific beneficial insects, their life cycle and what they can do for your garden visit this U of MN Extension site.
Take some time to learn more about the insects that you want to attract to your garden. Your plants will appreciate it!
Photo Credit: Joanna Kapke (1,2,3)