Integrated Pest Management · Agriculture and Natural Resources
University of California
Protecting natural enemies and pollinators
Adult, female Aphytis melinus parasitoid laying her egg in a California red scale, Aonidiella aurantii. Photo by Jack Kelly Clark.
Natural enemies are parasitoids (parasites), pathogens, and predators that can reduce pest numbers and the damage that pests cause to crops, gardens, and landscapes. Pollinators are essential for the production of many crops and the reproduction of plants. Among the important pollinators are domesticated honey bees, wild bees, and various other insects, such as flower flies, or syrphids.
Application of certain pesticides can kill natural enemies and pollinators or otherwise disrupt their beneficial activities. Natural enemies and pollinators can be more adversely affected by pesticides than the targeted pests; they spend much of their time moving and can be exposed to a higher total dose and more types of pesticides in comparison with plant pests that are relatively stationary.
To maintain healthy populations of natural enemies and pollinators that improve plant growth, productivity, and quality use integrated pest management (IPM) and follow these guidelines:
Use pesticides sparingly and wisely.
- Consult the University of California (UC) IPM website to help you identify pests and their damage and determine which methods can provide control.
- Control pests using methods compatible with the conservation of natural enemies and pollinators when feasible.
- Do not apply certain pesticides or allow them to drift to plants that are flowering, including weeds.
- Read and follow all directions on product labels before applying any pesticide.
- Target applications to specific problem areas (make spot applications) to limit the harm to natural enemies and pollinators.
Choose nonpersistent and selective pesticides.
- Avoid applying nonselective (broad-spectrum), persistent (residual) insecticides. When they are needed, limit the number of their applications. Carbamates (e.g., carbaryl), organophosphates (e.g., malathion), and pyrethroids (e.g., bifenthrin, cypermethrin, permethrin) kill many different invertebrates and leave persistent residues that kill natural enemies and pollinators that migrate in after the application. Neonicotinoids (e.g., acetamiprid, dinotefuran, and imidacloprid) and other systemic insecticides (e.g., acephate, an organophosphate) move (translocate) within plants and can poison bees and natural enemies that feed on nectar, pollen, and liquids that plants ooze (guttation).
- Avoid spraying tank mixes of insecticide(s) combined with fungicide(s).
- Choose effective pesticides with the least adverse effect on natural enemies and pollinators.
- Grow insectary plants that attract, feed, and shelter natural enemies and pollinators. Be aware that broad-spectrum herbicides and herbicides selective for broadleaf weeds reduce the abundance of flowering plants that attract and feed pollinators and natural enemies.
Follow the guidelines in Best Management Practices to Protect Bees from Pesticides. Use the UC IPM Pest Management Guidelines to look up the impact of specific pesticides on bees and important parasitoids and predators of the problematic pest(s). Each crop has a table of Relative Toxicities of Insecticides and Miticides to Natural Enemies and Honey Bees. Use this information to make informed decisions about how to protect bees and natural enemies when choosing or applying pesticides.
Other resources for agriculture
- Bee Precaution Pesticide Ratings, UC IPM
- Farmscaping to Enhance Biological Control, National Sustainable Agriculture Information Center
- Farmscaping: Making Use of Nature’s Pest Management Services, Clemson University and eXtension
- Flower Flies (Syrphidae) and Other Biological Control Agents for Aphids in Vegetable Crops , UC Agriculture and Natural Resources
- Honey Bee Best Management Practices for California Almonds , Almond Board of California
- How to Reduce Bee Poisoning from Pesticides , Pacific Northwest Extension
- Pesticide Applicator Best Management Practices, Pesticide Environmental Stewardship
- Pollination Basics: pollinators of specific crops and factors affecting pollinators, Ontario and the University of Guelph
- Pollinator Conservation Resource Center, Xerces Society for Invertebrate Conservation
- Protecting Bees and Other Pollinators from Pesticides, U.S. Environmental Protection Agency
- UC IPM Pest Management Guidelines: natural enemies of specific pests, by commercial crop
Gardens and landscapes
Learn which pesticides to avoid by reviewing the active ingredients (common names) on the labels of products you are considering for use and contemplating the characteristics of those compounds as presented in the Bee Precaution Pesticide Ratings for commercial agriculture and Pesticide Active Ingredients Database for gardens and landscapes. Consult Pest Notes: Biological Control and Natural Enemies of Invertebrates to learn which parasitoids and predators are important for managing the problematic pest(s). Guides for identifying the bee species present include those from the UC Berkeley Urban Bee Lab, UC Davis Häagen-Dazs Honey Bee Haven, and Xerces Society Pollinator Conservation Resource Center California website. Determine target plants' attractiveness to bees and other pollinating insects to help inform your pest management decision-making.
- Avoid applying any miticide (acaricide) or insecticide to plants when they are flowering. Exceptions include products colored green in the Relative Toxicity of Insecticides to Natural Enemies table in Conservation: Protect Natural Enemies.
- Avoid applying systemic insecticides (such as neonicotinoids) to shrubs and trees that attract bees. Even if these perennials are not flowering at the time of pesticide application, the toxins can persist in the plant till the next growing season and contaminate the nectar and pollen of flowers on which adult natural enemies and pollinators feed.
- Do not apply pesticides toxic to bees on lawns with flowering clover, dandelions, or other weeds with blossoms that attract bees. Mow prior to the application of insecticide to remove flowerheads. Mow regularly after pesticide application to prevent flowerheads, especially if applying a systemic insecticide.
Other resources on pollinators for gardens and landscapes
- 10 Ways to Protect Bees from Pesticides , Washington State
- How to Attract and Maintain Pollinators in Your Garden, UC Agriculture and Natural Resources
- Insectary Plants, UC IPM
- IPM & Beneficial Insects, UC IPM
- What Can Gardeners do to Help Honey Bees?, UC Davis
Other resources on natural enemies for gardens and landscapes from UC
- Beneficial Predators
- Natural Enemies Gallery
- Natural Enemies Handbook or its eBook
- Parasites of Insect Pests
- Pest Notes: Biological Control and Natural Enemies of Invertebrates
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