Five considerations on Neonicitinoid use
/
Stock photo
Article by, Nicole Sanchez,
Horticulture, OSU Extension Service, Klamath County
Neonicitinoids, or Neonics for short, are a group of pesticides commonly used worldwide. The group gained popularity in the 1990’s as substitutes for the organophosphate pesticides, which are highly toxic to mammals. At first, Neonics were celebrated for lower risk to people and pets, but mounting evidence demonstrates that Neonic use is problematic for bees, especially bumblebees, and other pollinators. This has led to restrictions on Neonic use in some countries.
Neonics are systemic pesticides: A small amount, taken up through the plant, is highly effective in controlling pests like aphids and whitefly that feed on the plants. Early in the trajectory of Neonic use, it was thought that the chemicals would only contact, and therefore impact, insects feeding on the plants. However, we now know these pesticides are also expressed in plant pollen. Problems arise when pollinators collect pollen with pesticide residues.
At present, Neonics remain available in the US for both homeowners and for commercial use. They remain highly effective for controlling some pest types, but information about unintended effects on pollinators has many people questioning whether continued Neonic use makes sense in any situation. Answers are more complicated than a simple yes or no, as illustrated in the five examples below.
Multiple Chemistries.
Neonics is a group of pesticide active ingredients, not one single compound. Pesticide compounds included in the Neonic group include acetamiprid, clothianidin, imidacloprid, nitenpyram, nithiazine, thiacloprid, and thiamethoxam. Each of these is available in multiple formulations, with different methods of application and length of persistence in the plant. Slight differences in chemistry divide those active ingredients into two groups, the “Cyano” group and the “Nitro” group. The Nitro group includes imidacloprid, one of the active ingredients most commonly available to homeowners. The nitro group is considered more toxic to pollinators than the cyano group, and the cyano group is more toxic to birds further along the food web.
Sub- lethal doses.
Applying a Neonic pesticide to a plant in bloom can result in dramatic bee deaths very quickly: many Neonic labels expressly mention that the product should not be applied while plants are in bloom or while pollinators are foraging. Less easy to measure are the sub- lethal effects of lots of tiny micro-doses of pesticide delivered via pollen and visits to numerous flowers. While these micro-doses are not strong enough to kill the pollinator, they can affect things like motor function, ability to find the nest, and pollinating efficiency. Sub lethal doses of pesticides are thought to be one of the contributors to the decline of honeybee populations known as “colony collapse disorder”.
Changes to seed treatments.
One commercial use of some Neonics has been as a seed coating, used against pests like cutworms that attack plants early in development. When mechanical planting of these coated seeds results in a dust cloud of pesticide that drifts to nearby plants, pollinators can be exposed to pesticide. Newer, “dustless” formulations in development are intended to allow farmers to continue using seed coating as a tool without unintended consequences to pollinators.
No new outdoor uses.
Until more data has been collected, EPA has halted the addition of outdoor uses to the labels of Neonic pesticides. Most data about bee toxicity based on lab or “semi-field” conditions. More data collection is underway, and for now EPA doesn’t anticipate allowing additional uses of Neonics outdoors that are not already allowed. This means that additional products for homeownesr are less likely. It’s also worth noting that while Neonics are still legally available for homeowners to use, EPA is no longer recommending their use in home gardens.
Risks vary with plant and treatment.
When using Neonics, treatment when a plant is blooming or about to bloom represents the most risk to pollinators. Some formulations are intended to remain in the plant for as long as a year, while others break down more quickly. Neonic use may be appropriate for indoor plants, where there are no pollinators that might be accidentally impacted. And in woody plant material that rarely blooms, pollinator risk is lower than in herbaceous plants that bloom all season long- if application to the woody plant is timed correctly.
Like many horticultural issues, there are numerous factors to consider. Reducing pesticide use, whenever possible, is always going to be more favorable for our environment. Practices like regularly inspecting for pests, choosing plants that are less prone to pest and disease problems, appropriate water delivery, and good garden sanitation (removal of decaying plant matter and debris) all contribute to reduced pesticide use. Neonicitinoids, or Neonics for short, are a group of pesticides commonly used worldwide. The group gained popularity in the 1990’s as substitutes for the organophosphate pesticides, which are highly toxic to mammals. At first, Neonics were celebrated for lower risk to people and pets, but mounting evidence demonstrates that Neonic use is problematic for bees, especially bumblebees, and other pollinators. This has led to restrictions on Neonic use in some countries.
Neonics are systemic pesticides: A small amount, taken up through the plant, is highly effective in controlling pests like aphids and whitefly that feed on the plants. Early in the trajectory of Neonic use, it was thought that the chemicals would only contact, and therefore impact, insects feeding on the plants. However, we now know these pesticides are also expressed in plant pollen. Problems arise when pollinators collect pollen with pesticide residues.
At present, Neonics remain available in the US for both homeowners and for commercial use. They remain highly effective for controlling some pest types, but information about unintended effects on pollinators has many people questioning whether continued Neonic use makes sense in any situation. Answers are more complicated than a simple yes or no, as illustrated in the five examples below.
Multiple Chemistries.
Neonics is a group of pesticide active ingredients, not one single compound. Pesticide compounds included in the Neonic group include acetamiprid, clothianidin, imidacloprid, nitenpyram, nithiazine, thiacloprid, and thiamethoxam. Each of these is available in multiple formulations, with different methods of application and length of persistence in the plant. Slight differences in chemistry divide those active ingredients into two groups, the “Cyano” group and the “Nitro” group. The Nitro group includes imidacloprid, one of the active ingredients most commonly available to homeowners. The nitro group is considered more toxic to pollinators than the cyano group, and the cyano group is more toxic to birds further along the food web.
Sub- lethal doses.
Applying a Neonic pesticide to a plant in bloom can result in dramatic bee deaths very quickly: many Neonic labels expressly mention that the product should not be applied while plants are in bloom or while pollinators are foraging. Less easy to measure are the sub- lethal effects of lots of tiny micro-doses of pesticide delivered via pollen and visits to numerous flowers. While these micro-doses are not strong enough to kill the pollinator, they can affect things like motor function, ability to find the nest, and pollinating efficiency. Sub lethal doses of pesticides are thought to be one of the contributors to the decline of honeybee populations known as “colony collapse disorder”.
Changes to seed treatments.
One commercial use of some Neonics has been as a seed coating, used against pests like cutworms that attack plants early in development. When mechanical planting of these coated seeds results in a dust cloud of pesticide that drifts to nearby plants, pollinators can be exposed to pesticide. Newer, “dustless” formulations in development are intended to allow farmers to continue using seed coating as a tool without unintended consequences to pollinators.
No new outdoor uses.
Until more data has been collected, EPA has halted the addition of outdoor uses to the labels of Neonic pesticides. Most data about bee toxicity based on lab or “semi-field” conditions. More data collection is underway, and for now EPA doesn’t anticipate allowing additional uses of Neonics outdoors that are not already allowed. This means that additional products for homeownesr are less likely. It’s also worth noting that while Neonics are still legally available for homeowners to use, EPA is no longer recommending their use in home gardens.
Risks vary with plant and treatment.
When using Neonics, treatment when a plant is blooming or about to bloom represents the most risk to pollinators. Some formulations are intended to remain in the plant for as long as a year, while others break down more quickly. Neonic use may be appropriate for indoor plants, where there are no pollinators that might be accidentally impacted. And in woody plant material that rarely blooms, pollinator risk is lower than in herbaceous plants that bloom all season long- if application to the woody plant is timed correctly.
Like many horticultural issues, there are numerous factors to consider. Reducing pesticide use, whenever possible, is always going to be more favorable for our environment. Practices like regularly inspecting for pests, choosing plants that are less prone to pest and disease problems, appropriate water delivery, and good garden sanitation (removal of decaying plant matter and debris) all contribute to reduced pesticide use.