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Protecting Bees and Pollinators from Pesticides in Home Gardens and Landscapes

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The Importance of Bees and Pollinators
Honeybees are essential for pollination of a wide range of ornamentals and crops such as fruits & vegetables. However native pollinators, such as many other types of bees, butterflies, flies, and hummingbirds, are also significant for pollination of crops, landscape plants, native plants, and backyard vegetable and fruit gardens. Honeybee pollination services are the basis of livelihood for a number of apiculturists in New England. In addition, many more people keep bees as hobbyists, having one or two hives on their property.  County beekeeper associations exist in all Massachusetts counties and can be consulted about bee colony locations. Membership is not required of beekeepers, so County Associations will not know the locations of all hives.

Decline in Honeybee Populations
Rapid and dramatic decline of honeybee populations, have been reported by bee-keepers over the last several years. Public and private interests are currently trying to identify the mechanics of this issue, commonly referred to as honeybee decline or colony collapse disorder. Current theories on the honeybee decline include a combination of factors such as parasites, disease, low genetic diversity, poor nutrition, loss of habitat, management stress and pesticide use. The current state of honeybee health has been detailed in a joint comprehensive report released by the USDA and EPA: Report on Honey bee Health

Concerning the role of pesticides, neonicotinoid insecticides have been implicated as a potential contributing factor.

What are Neonicotinoid Insecticides?
Neonicotinoid insecticides were first registered in the United States in the mid-1990s. Neonicotinoid insecticides are insect neurotoxicants with a chemical structure similar to nicotine that are very toxic to bees. These insecticides have a relatively low mammalian toxicity and were considered a good alternative to the more toxic organophosphate and carbamate insecticides. However, unlike organophosphate and carbamate insecticides that tend to degrade relatively quickly in the environment, neonicotinoids are persistent and even as they degrade, they continue to remain toxic to bees. Neonicotinoids are usually systemic, which means that they can be absorbed by the roots and move through the entire plant into pollen nectar. While neonicotinoids have proven very effective in controlling many sucking, plant boring and turf feeding insects, these benefits also result in greater risk to pollinators. A big concern is when neonicotinoids are applied to open flowers of insect pollinated plants or move systemically into pollen nectar elevating pesticide exposure to pollinators. There is still a lot that scientists do not know about the effects of pesticides on pollinators and other beneficial insects and their movement into and residual activity in various plant parts. However, gardeners should choose and use all pesticides with care to protect bees and other pollinating insects from pesticide poisoning.

Neonicotinoid Insecticides for Home Gardeners
There are many neonicotinoid products that are currently available to home gardeners. Neonicotinoids include products with the active ingredient: acetamiprid, clothianidin, dinotefuran, imidacloprid or thiamethoxam. This would be listed on the pesticide label in small print as “active ingredients”. Neonicotinoids are the most commonly used class of insecticides in the United States. They are found in products to control bed bugs, to manage fleas and ticks on pets, to manage termites, and to manage a wide range of insects and insect relatives on fruit, vegetable, lawns, landscape, flower gardens and structural settings. Some examples of garden products that contain neonicotinoids are listed below.

Since Trade names of products frequently change, it is best to read the active ingredient on the label.

  • Products containing Imidacloprid include: Bayer Advanced 3-in-1 Insect, Disease, & Mite Control; Bayer Advanced Season-Long Grub Control; Bayer Advanced 2 in 1 Systemic Rose and Flower Care; Bayer Advanced 12 Month Tree & Shrub Insect Control; Bayer Advanced 12 Month Tree & Shrub Protect & Feed Bayer Advanced Fruit; Citrus & Vegetable Insect Control; Bayer Advanced All-in-One Rose & Flower Care; Monterey Once a Year Insect Control II; and Ortho Bug B Gon Year-Long Tree & Shrub Insect Control
  • Products containing Clothianidin include: Green Light Grub Control with Arena
  • Products Containing Thiamethoxam include: Amdro Rose & Flower Care, Maxide Dual Action Insect Killer
  • Products containing Acetamiprid include: Ortho Bug B Gon Systemic Insect Killer; Ortho Flower, Fruit and Vegetable Insect Killer; Ortho Rose and Flower Insect Killer
  • Products containing Dinotefuran include: Green Light Tree & Shrub Insect Control with Safari, Ortho Tree & Shrub Insect Control Ready to Use Granules

Users of neonicotinoid pesticides should be aware of the risks to bees. Bees can come in contact with these insecticides through direct exposure during spraying, as residuals on foliage and other surfaces, and as contaminants in nectar and pollen. 

The U.S. EPA recently introduced a label change for insecticides that contain one or more of the neonicotinoids to protect bees. The bee icon (see below) will be placed in the Environmental Hazards section of the pesticide label. There will be further instructions concerning bees in the "Directions for Use" section on the label.

Tips to Protect Bees from Pesticide Poisoning?1

  • Do not treat crops or plants in bloom.  Never spray open flowers. Do not allow sprays to drift onto adjacent plants, weeds or inter plantings that are in bloom including ground covers and trees. Be especially careful when treating a bee-pollinated crop. Home gardeners should be especially careful about using pesticides on flowering plants that are attractive to bees.
  • Use the least toxic pesticide. In addition to neonicotinoid pesticides, many other pesticides may also be harmful to bees, including organic pesticides. Also, different formulations of pesticides often vary significantly in their toxicity to bees.  Dusts are much more hazardous than sprays, and wettable powders usually provide a significantly longer toxic hazard than emulsifiable concentrates because the dry particles cling better to the body hair of foraging bees. Select pesticides that have low impact and risk to pollinators. Read and follow all directions on the pesticide label regarding toxicity to bees. EPA evaluates a pesticide for toxicity to pollinators if it is used outdoors. This information will be found in the Environmental Hazards section of the pesticide label. 
  • Adjust pesticide applications in relation to weather conditions. For example, apply pesticides when drying conditions are good to limit the length of time of direct pesticide exposure to bees. Honey bees can become active and forage at temperatures as low as 55F. If temperatures following treatment are unusually low, residues on the crop may remain toxic to bees up to twenty times as long as following normal temperatures. Conversely, if abnormally high temperatures occur during late evening or early morning, bees may forage actively on the treated crops during these times. Stop spray applications when temperatures rise and bees begin foraging.
  • Apply pesticides when bees are not actively foraging or visiting plants.  Many insecticides can be applied in late evening, night or early morning with relative safety to bees. This timing is typically from 6 p.m. to 7 a.m. in Massachusetts. 
  • Become familiar with state regulations concerning the protection of pollinators.  In Massachusetts there are additional requirements for notifying apiaries if a bee toxic pesticide is being applied to blooming fruit trees or blooming field crops (alfalfa, clover, and trefoil). The specific requirements are listed in 333 CMR 13.07(2) of the Massachusetts Pesticide Regulations.
  • Know where bee colonies are in your area.  Bees forage up to several miles searching out concentrations of flowers, plants shedding pollen and/or producing nectar. Contact beekeepers if you intend to make a pesticide application that may kill bees. Cooperation between beekeepers and pesticide applicators is essential to reduce bee kills from pesticides. Contact your area or county beekeeper association to learn if beekeepers are maintaining hives in your area.
  • Do not place unmarked honeybee colonies adjacent to fields or orchards, which are likely to be treated.  Beekeepers should put their name, address, and phone number or approved identification number on hives.  Use print large enough to be read at some distance.

Tips to Attract Bees and Pollinating Insects

  • Select plants that will provide pollen and nectar: Pollen is an essential part of the diet of young bees. It is produced in the anthers or male sexual parts of flowers and must be transferred by bees, other insects, birds, bats or wind (depending on the plant) to the female part of the flower for pollination. Nectar is the raw material used by bees to manufacture honey, and is the colony's source of energy. It is basically a solution of sucrose and water which is secreted by plants.
  • Many wildflowers and native plants will provide bees with pollen and nectar. Flowers vary in their amount of pollen and nectar. Many of our showy hybrid annual flowers have been bred for flower size and do not provide nectar or pollen. For example, male-sterile or pollenless sunflowers are grown as a cut flower because the lack of pollen helps keep the flower disk clean.
  • Select plants with colors and shapes that attract bees: Bees find blue, purple and yellow flowers most appealing. Flat or shallow blossoms, such as daisies, sunflowers, alyssum, zinnias, asters, coneflower and Queen Anne's lace, will attract the largest variety of bees because all or nearly all, the nectar is within reach of a honeybee's tongue. Very deep blossoms are better suited to bees with longer tongues such as bumblebees, and are seldom visited by honeybees. Bumblebees are also attracted to flowers with hidden nectar spurs, such as larkspur, monkshood, monarda, columbine and snapdragons.
  • Add variety: Plant a garden that has a variety of plants in bloom from early spring through late fall. Bees need diverse pollen and nectar sources for balanced diet including trees and shrubs.
  • Plant in groups:  Plant in groups so the bees can find and visit many flowers in one location. For example, Echinacea in a clump (3 ft. diameter) will attract honey bees and all types of native bees and butterflies.
  • Flowers all season long: Some kinds of bees are active all season long while others are only active in the spring. A mixture of trees, shrubs, perennials and annuals will provide blooms from spring to fall. 

Additional Information: Grub Control in Lawns: Neonicotinoids and Bees

References and Resources

1Tips to Protect Bees from Pesticide Poisoning adapted from 2014 Supplement, Core Training Manual, Pollinator Chapter by Dr. Patricia Vittum and Natalia Clifton, UMass Extension.
Tina Smith, UMass Extension, May 2014, Reviewed by Dr. Anne Averill, Department of Environmental Conservation, UMass Extension

Disclaimer -The most reliable information was included that was available at time this information was compiled. Due to constantly changing laws and regulations, UMass Extension can assume no liability for recommendations. The pesticide user is always responsible for the effects of pesticide residues on their own crops, as well as problems caused by drift from their property to other properties or crops. Always read and follow all instructions on the label.

Last Updated: 
Jun 5, 2014
Topics: 
Home Lawn & Garden
Home Lawn and Garden topics: 
Flowers
Insects