Pollinator stewardship during fruit crop bloom
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EmailAs bees come into fruit farms during bloom, growers can protect pollinators and minimize pesticide exposure.
Bees and other pollinators will soon emerge or arrive on farms as the warming weather continues to push fruit crops closer to bloom. Whether you are a fruit grower who rents honey bee hives from a beekeeper or depend on wild bees for crop pollination, you can protect these vital insects so they can provide pollination and contribute to high quality and abundant yields.
A primary concern for pollinator health during bloom is pesticide exposure. Although pesticides are important tools for managing crop pests in fruit plantings, they can also pose many health risks for bees. Always make sure you are following the pesticide’s label. The Protect Pollinators: Read Pesticide Labels card describes where to find pollinator protection language on a pesticide label.
Insecticides tend to be the most acutely toxic to bees, which is one of the reasons insecticide applications are often restricted during crop bloom. Fungicides are generally considered less acutely toxic to bees; however, studies show they can have chronic and sublethal effects on bee foraging behavior, development and longevity. Herbicides tend to have little direct toxicity to bees, however aggressive removal of all flowering plants around a farm can reduce bee access to alternative food sources throughout the season and therefore indirectly harm bee health.
Additionally, tank mixing different pesticides may cause an increased risk to bees, as some pesticide combinations have synergistic effects (become more toxic to bees when mixed). Bees can encounter pesticides through many different routes of exposure, such as direct spray, contact with treated plants, drift, through contaminated surface water or when contaminated pollen or nectar is brought back to the nest.
The best way to protect pollinators from pesticide exposure is to avoid sprays while crop flowers are open. However, pest and disease pressure may warrant applications during bloom. Follow these guidelines whenever possible to protect pollinators:
- Use pest scouting, weather tracking, development models, etc. to determine if/when sprays are necessary and reduce unnecessary applications.
- Where possible, use integrated pest management strategies such as biological, cultural or mechanical control in place of pesticide applications.
- Make applications when bees are not flying (after sunset or before sunrise, when air temperature is below 50 degrees Fahrenheit).
- Consider using liquid formulations when available, as powders and encapsulated pesticides are more likely to be picked up by foraging bees.
- Use drift reduction practices such as nozzle calibration, targeted spraying and monitoring wind speeds.
- Remove flowering weeds from within crop rows if the flowers are likely to be exposed to pesticide drift (e.g., dandelions and clovers).
- Maintain good communication with your beekeeper if renting hives and consider developing a pollination contract.
Michigan State University Extension has many resources available to help protect pollinators during bloom, such as Minimizing Pesticide Risks to Bees in Fruit Crops. You can also use the Bee Precaution Pesticide Ratings online search tool developed by the University of California to understand the effects of particular pesticides on bees and get guidance on reducing bee poisoning while using different products. More crop-specific resources are available at the Michigan Pollinator Initiative resources for growers page and Michigan State University Extension’s Pollinator Protection Plan page. Growers can enroll in the free Pollinator Protection for Pesticide Applicators online course to learn more.
You can also promote bee health on your farm by providing non-crop flowering plants in areas that are protected from spray drift. Planting wildflowers is a great way to support bees in any environment. These non-sprayed floral resources provide refuges for bees by providing abundant chemical-free food and nesting habitat for wild bees. Providing wildflower habitat for bees may also help increase pollinator abundance during crop bloom, with potential yield or fruit quality benefits.
Acknowledgments
This work is supported by the Crop Protection and Pest Management Program [grant no 2021-70006-35450] from the USDA National Institute of Food and Agriculture.
This work is supported by the USDA National Institute of Food and Agriculture, Crop Protection and Pest Management Program through the North Central IPM Center (2018-70006-28883).
Thank you to the Michigan Department of Agriculture and Rural Development for securing funding from the U.S. Environmental Protection Agency for Michigan State University to implement strategies in the Michigan Pollinator Protection Plan.
