By Lynn Byczynski
Beneficial insects need food and shelter if they are to control pests of vegetable, flower, or herb crops. An insectary planting of flowering plants will greatly increase the likelihood that predators and parasitoids will hang around and help with pest management. An insectary planting can be reserved entirely for beneficials, or it can be small, unharvested areas of valuable crops such as flowers and herbs. Here are some of the plants that can be used:
Cover crops. Many plants grown to improve soil fertility and tilth are also attractive to beneficial insects when they are allowed to flower. Buckwheat is one of the best, especially because it flowers over a long period. Other cover crops that provide food and shelter for beneficials include the clovers, hairy vetch, cowpeas, and alfalfa. Growing cover crops in numerous small sections throughout a field keeps the beneficials close to the cash crops.
Grasses and grains. Often grown in strips among cash crops, grasses and grains provide refuge for ground beetles and spiders and a shady place to lay eggs for other beneficial species.
Flowers and herbs. Several families of flowers are particularly attractive to beneficials. The Apiaceae family has umbels of tiny flowers that are a good source of nectar. It includes angelica, Ammi majus, anise, carraway, carrot, cilantro, dill, fennel, parsley, Queen Anne’s lace, tansy, and yarrow. The Asteraceae family provides abundant and easily accessible pollen. Many cut flowers are in this family, including sunflowers, blanket flower, coneflower, cosmos, and goldenrod.
Vegetables. Mustard-family vegetables, including many Asian greens, broccoli, cabbage, kale, mustard, and turnips, can be left to flower for beneficials.
Trees and shrubs. Permanent hedgerows provide refuge for many types of beneficials and will be especially attractive if they include black locust, elderberry, euonymus, and Prunus species.
A helpful resource is the publication Practical Guidelines for Establishing, Maintaining, and Assessing the Usefulness of Insectary Plantings On Your Farm..
Lynn Byczynski is the editor of Growing for Market and the publisher of The Hoophouse Handbook.