Honey bees, native bees, and other pollinators play an essential role in pollinating fruits, vegetables, flowers, and agricultural crops. In recent decades, news about bee poisonings, colony collapse disorder (CCD), and native bee species population decline has been on the rise. Although the definitive reason behind most of these mass bee deaths has not been determined, pesticides are one of many contributing factors. Pesticides, such as neonicotinoids, pose a threat to bee health and have been linked to mass bee deaths. Homeowners can reduce negative health impacts on bees by using alternative pest control methods, reading pesticide labels, and avoiding applying pesticides to plants in bloom.
How to Protect Bees from Pesticides: A Homeowners Guide
Alternative Pest Control
Many effective pest control methods do not involve the application of pesticides. These alternative methods can prevent or reduce pests without harming bee and pollinator health. Preventative measures include planting pest repellent plants or plants that attract beneficial insects, which can keep pest populations low. Many pest species are attracted to overly fertilized plants due to the increased nitrogen content. This can be avoided by using organic compost which releases nitrogen slowly. Make sure to monitor your pest infestations and determine an appropriate level to take action. Low-level infestations can be controlled using mechanical or non-chemical methods. To find more information on pest control methods visit: Washington State University Pestsense or Hortsense.
Mechanical Methods:
- Hand weeding.
- Hose down plants to remove unwanted insects.
- Prune infested portions of plants.
- Use mulch to reduce the growth of weeds.
- Encourage insect predators such as spiders, snakes, frogs, and birds.
- Encourage beneficial predatory insects including ladybugs, wasps, lacewings, hoverflies, and ground beetles.
- Nematodes can be added to soil and used to reduce soil insects.
Apply Pesticides After Flower Petals Have Fallen
The best time to apply pesticides to plants is after flower petals have fallen. This reduces the risk of bees encountering pesticides when foraging on flowers in bloom. Bees actively forage during the day when temperatures are above 55°F. Applying pesticides in the evening or when temperatures are low is another strategy used to avoid pesticide contact with bees. To prevent pesticides from drifting off the intended target, apply pesticides in dry weather with low wind.
Before applying pesticides, assess the target area and avoid contaminating any standing water. Bees and other insects rely on standing water for hydration. If you must spray ornamental plants that are in bloom, the Washington State Department of Agriculture (WSDA) recommends choosing a pesticide that is less toxic to bees or applying pesticides at a low dosage.
Before applying pesticides, assess the target area and avoid contaminating any standing water. Bees and other insects rely on standing water for hydration. If you must spray ornamental plants that are in bloom, the Washington State Department of Agriculture (WSDA) recommends choosing a pesticide that is less toxic to bees or applying pesticides at a low dosage.
Read the Pesticide Label
Carefully follow pesticide label instructions and advisories. The Environmental Protection Agency (EPA) requires all pesticides that pose a potential risk to bees or other pollinators, to display a bee advisory icon. The pesticide label will state the level of toxicity and the residual toxicity. Residual toxicity refers to the amount of time it takes for a pesticide to break down in the environment. Pesticides with residual toxicity of eight hours or longer are responsible for the majority of bee poisoning incidents. Visit the Thurston County Grow Smart Grow Safe website to find pesticide toxicity ratings. For more information on how to read a pesticide label visit: WSDA Understandings Pesticide Product Labels and WSU Learning about Labels.
Caution When Using Insecticides
Insecticides are used to control insect pests, but can also be toxic to beneficial insects such as pollinators. WSDA recommends extreme caution and to follow the label instructions when applying insecticides. Avoid application techniques such as soil drenching or tree injections to plants that attract bees. These methods can contaminate nectar and pollen for several years after the insecticide is applied. Bees collect contaminated pollen and nectar and bring it back to the hive, which can cause mass bee deaths. When buying ornamental plants that attract bees, avoid plants pre-treated with insecticides.
Neonicotinoids are a class of insecticides that are toxic to bees for several days after an application. Neonicotinoids are widely used agriculturally to grow crops, by homeowners on ornamental gardens, and on pets for flea and tick treatments. Compared to other insecticides, neonicotinoids are relatively less toxic to beneficial insects, worms, amphibians, birds, and mammals. Read the label to see if the pesticide contains neonicotinoids such as clothianidin, dinotefuran, imidacloprid, and thiamethoxam.
Neonicotinoids are a class of insecticides that are toxic to bees for several days after an application. Neonicotinoids are widely used agriculturally to grow crops, by homeowners on ornamental gardens, and on pets for flea and tick treatments. Compared to other insecticides, neonicotinoids are relatively less toxic to beneficial insects, worms, amphibians, birds, and mammals. Read the label to see if the pesticide contains neonicotinoids such as clothianidin, dinotefuran, imidacloprid, and thiamethoxam.
How to Identify and Report Bee Poisonings
Pay attention to the signs and symptoms of honey bee pesticide poisonings. The main indicator that honey bees are suffering from pesticide poisoning is a large number of dead bees outside the hive entrance. Other symptoms of bee poisonings include increased defensiveness, abnormal movements, or paralysis. Solitary bees experience many of the same symptoms but are harder to identify due to the lack of a hive. These signs will appear within 1-3 days of pesticide application. If mass bee deaths are occurring without the recent application of pesticides, it is most likely due to the presence of dehydration, starvation, extreme weather, or Varroa mites. Varroa mites are parasites that attach to honey bees and consume body fat, which weakens bees and creates vulnerabilities to contracting viruses. If you notice any bee poisoning symptoms after a pesticide application, please contact the EPA or the WSDA pesticide compliance program. To learn more visit: How to Reduce Bee Poisoning from Pesticides.
Environmental Protection Agency (EPA)
Report.Pesticide.Incident@epa.gov
National Pesticide Information Center
1-800-858-7378
WSDA Pesticide Management Division
877-301-4555
pcompliance@agr.wa.gov
Report.Pesticide.Incident@epa.gov
National Pesticide Information Center
1-800-858-7378
WSDA Pesticide Management Division
877-301-4555
pcompliance@agr.wa.gov
Additional Resources
Visit these sources for more information on bees and pesticides:
- How to Protect Bees from Pesticides: A Homeowner's Guide
- Cómo proteger a las abejas de los pesticidas: Una guía para propietarios de viviendas
- Four Bee Safe Gardener and Landscaper Tips
- Protect Pollinators Read Pesticide Labels
- Dándole duro a las Plagas Mientras Protegemos a los Polinizadores
- Washington State Becomes First To Adopt A Statewide Strategy To Protect Bumble Bees
- Bee Informed Partnership
- Pesticide Environmental Stewardship
- Pollinator Partnership
- Pesticide Information Center OnLine
- Washington State Beekeeper Association (WASBA)
- WSU Urban IPM and Pesticide Safety Education
- WSU Honey Bees and Pollinators
- Xerces Society