By Carla Throckmorton, Piedmont Master Gardener Intern
Question: I have been told to avoid the use of “neonicotinoids”. How can I tell if my rose care product has this pesticide? How long does the effect last if the plant was treated?
Neonicotinoids, often called “neonics”, are a group of insecticides that affect the nervous system of insects. They are chemically similar to nicotine, behave in a similar manner and are toxic to insects. Today they are the most widely used insecticides on earth. They are used on agricultural crops, residential and commercial landscapes, turf and ornamentals.
Neonics became popular in the mid-1990s because insect pests were becoming immune to older insecticides and they are effective in lower doses and less toxic to humans and other mammals. However, they can be very harmful to beneficial insects, including honey, bumble and solitary bees, as well as insect pests. They also impact the environment in other ways.
How Neonics Work
Neonics are systemic insecticides that are absorbed by the plant and transported to all parts of the plant. When sprayed on plant leaves and seeds, neonics can accumulate in the pollen, nectar and other plant tissue. As insects feed on the plant, they can take in enough neonics to affect insect behavior, growth and reproduction and contribute to the decline and death of bees and other pollinators.
Neonics have been used to control a wide variety of insect pests in the soil or on plants and the effects of neonics can be long lasting. After only one application (spray, seed coating or soil drench), neonicotinoids can stay in the soil for months or years and remain in woody plants for up to six years. In addition, water contaminated with neonics can pollute waterways, and harm new soil, new plants and aquatic life. Studies have also linked neonics to losses of birds, collapse of fisheries and birth defects in white tailed deer and neurological disorders in humans.
Given their negative impact on pollinators, other beneficial insects and the environment, home gardeners should avoid the neonics and consider other options to control the sap sucking and leaf chewing insects (aphids, beetles, thrips, rose leaf hoppers) that typically attack roses.
How To Identify Neonics in Pesticide Products
The home gardener’s best resource to identify the neonics in insecticides is the label on the product. The labels must also describe how, when and where to use, what pests are controlled, and the pre-harvest interval (when it is safe to harvest after applying the product). Instructions on storage and disposal are also included. One of three signal words on the label report the level of toxicity. “Caution” is the least toxic; “Warning” is moderately toxic and “Danger/Poison” or “Poison” is highly toxic and not usually sold in lawn and garden stores. Regulated by the Environmental Protection Agency and state agencies, pesticide users are legally required to follow all label directions. The label is the law!
Insecticide products may contain any of these chemicals in the neonic group: Acetamiprid, Clothianidin, Dinotefuran,Imidacloprid or Thiamethoxam. This list from the Center for Food Safety includes some examples of the most commonly used neonic products. Look for label information on environmental hazards or “Bee Advisory” boxes for information on harmful impacts and ways to limit exposure. As the Xerces Society reports, neonics can be applied in much higher doses in home gardens than in agricultural settings and pose more risk to pollinators.
Alternative Methods to Control Insect Pests
Often home gardeners use pesticides, including insecticides, without consideration of the alternatives and best practices for pest management. Integrated pest management (IPM) offers many strategies for pest control to reduce or avoid use of chemicals in the garden.
Prevent problems. Prevention strategies can go a long way to mitigate insect pest impact.
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- Start by choosing roses that are disease resistant, particularly to black spot and powdery mildew.
- Before you buy roses, ask if plants were treated with neonics. If so, don’t buy them.
- Keeping roses healthy makes them less susceptible to insect and mite pests. Roses need 6 to 8 hours of direct sunlight, and well drained and nutrient-rich soil. Follow recommended guidance on soil pH, watering and pruning. Clean up dead, dying, diseased plants or parts from the area.
Monitor your plants. Know which insects are harmful to your roses, and check for these insects regularly. How many pests are there? Are there enough to warrant action? If treatment is needed, try cultural, physical or biological options first. Avoid use of pesticides if possible.
Use pesticides with extreme care. Ask questions before making a decision on using pesticides. (See Table 1 of this Virginia Cooperative Extension publication). Then use the least toxic insecticide that targets the specific insect pest. Select products listed by the Organic Manufacturers Research Institute (OMRI) or EPA’s Reduced Risk Listwhen possible. Follow application instructions and recommended best management practices. For example, don’t apply them when pollinator plants are in bloom or when bees are foraging.
Help pollinators thrive. Learn which insects are beneficial and how to attract them to your garden. Check out the Virginia Native Plant Finder and select native plants suitable for your garden to help feed birds, pollinators and other wildlife and provide healthy habitat. Interested in visiting a Central Virginia rose and pollinator garden that demonstrates best practices? Visit the demonstration garden, located at The Center at Belvedere in Charlottesville, VA, and maintained organically by the Piedmont Master Gardeners and The Center’s Horticulture Club. It includes a rose garden and pollinator garden filled with native plants. It has successfully helped to attract pollinators and beneficial insects and control unwanted pests. Drop by anytime or join Master Gardeners in the garden on Tuesday mornings.
Image source: Olena Bohovyk, Unsplash
References
“Chemicals Implicated”, Beyond Pesticides.
“Growing Roses”, Russ, Karen, Former HGIC Horticulture Specialist & Polomski, Robert F, PHD, Associate Extension Specialist, Clemson University, Clemson Cooperative Extension, Home and Garden Information Center, Factsheet, 19 Sep 1999.
“Help The Honey Bees”, Center for Food Safety.
“How Neonicotinoids Can Kill Bees”, Hopwood, Jennifer et. al, Xerces Society for Invertebrate Conservation, 2ndedition; Revised & Expanded.
“Integrated Pest Management”, United States Environmental Agency, 3 Jun 2024.
“Neonicotinoids In Your Garden”, Hopwood, Jennifer and Shepherd, Matthew, Xerces Society for Invertebrate Conservation.
“Pesticide Fact Sheets”, National Pesticide Information Center, 18, Jan 2019.
“Pollinators and Pesticides”, University of Maryland, University of Maryland Extension.
“Protecting Bees from Neonicotinoids in Your Garden”, Xerces Society for Invertebrate Conservation.
“Rose Insects and Related Pests”, Scott, Janet McLeod, Former Horticulture Information Specialist and Williamson, Joey, HGIC Horticulture Extension Agent, Clemson University, Clemson Cooperative Extension, Home and Garden Information Center, Factsheet, 30 Jul 2021.
“Stewardship Guidelines and Best Management Practices for Home and Residential Use of Neonicotinoid Insecticides”, University of Minnesota, May 2019.
