Attracting Beneficial Insects
Promoting beneficial insects is an important strategy in ecological management of insect pests. Attract these “good bugs” by increasing the diversity of plants in or near the garden. Select plants they prefer including those in the parsley or carrot family (Apiaceae formerly Umbelliferae) and the aster, sunflower or daisy family (Asteraceae formerly Compositae). There are lots to chose among. Aim to vary color, scents, textures and plant height.
You can spot members of the parsley or carrot family by their umbrella-shaped clusters of small 5-petaled flowers. The overall appearance is often a large flat head of white or yellow flowers. Think Queen Anne’s Lace. The flower head provides a place to land for many insects, especially beneficial wasps. Using a variety of plants from this family that bloom at different times can provide season long food and habitat for beneficial insects as well as an attractive garden landscape.
A number of culinary herbs are also in parsley or carrot family including parsley, dill, caraway, cilantro or coriander, and fennel. These plants will spread quickly if left to go to seed. Remove flower heads after they stop producing nectar, but before seeds mature. Some are also biennials which means you won’t see flowers until the second year of growth.
The aster, sunflower or daisy family is characterized by flower heads that are actually made up of numerous small flowers growing together. Many have flowers composed of rays around a disk-like center. This is a large family of plants including many popular ornamentals like marigolds, dahlias, daisies, asters, cosmos, calendula, coreopsis, tansy, yarrow, zinnia, and sunflowers are. These plants usually produce more than one flower per plant with a long bloom time so provide season long food and habitat for beneficial insects.
Cover crops offer protection to beneficial insects when annual garden plants are not actively growing. Buckwheat is a cover crop that provides shelter and flowers to attract beneficial insect. It does self-seed readily so can become a weed. Consider a small permanent planting of buckwheat near the garden verses in the garden.
Biological Control: A Guide to Natural Enemies in North America.
Natural Enemies of Vegetable Insect Pests. Michael P. Hoffmann and A. C. Frodsham. Cornell Cooperative Extension Publication. 48pp.
Fatal Attraction by Roger Bossley in National Gardening, May 1989. pp 34-37.
Beneficial Borders by Joanna Poncavage in Organic Gardening May/June 1991. PP 42-45
Flower Power by Robert Kourik in Garbage, May/June 1992. pp 26-31.
Carolyn Klass and Michael. P. Hoffmann, Department of Entomology, 11/95, Ecogardening Factsheet #14, Spring 1996
Updated by Steve Gabriel 11/2011