EPA Proposes Neonic Mitigations
After a thorough review involving industry insights along the way, EPA finally released proposed use changes to five common neonicotinoids: acetamiprid, clothianidin, dinotefuran, imidacloprid, and thiamethoxam.
All five reviews were released at the same time. None of the active ingredients were cited as having significant human dietary risks, but all were found to have potential ecological risks to aquatic and terrestrial invertebrates (including honeybees) in some form or another. The proposed label changes are meant to minimize these risks.
EPA’s proposals impact several industries, including both food crops and ornamentals. However, the following uses not impacted (and relevant to environmental horticulture) include:
- Indoor nurseries
- Christmas tree production
- Forestry uses
- USDA quarantine uses, including but not limited to imported fire ants, Asian citrus psyllid, and spotted lanternfly.
Noteworthy changes that will impact environmental horticulture include reductions in the total application amounts (on a per-year basis), loss of one use pattern, increased personal protective equipment (PPE) requirements, an advisory statement directed at homeowner use, and enhanced measures to reduce spray drift and runoff. Proposed mitigations vary greatly among the active ingredients and are summarized in Table 1.
These five neonicotinoids fall into two separate groups based on their chemical composition, chloropyridinyls (acetamiprid) and nitroguanidines (clothianidin, dinotefuran, imidacloprid, and thiamethoxam). Chloropyridinyls (such as acetamiprid) are documented as being less toxic to honeybees—so much less so that the acetamiprid label isn’t required to have the warning ‘bee box’ found on the other neonicotinoids. However, the proposed changes indicate that EPA is calling the level of toxicity into question with the addition of required advisory language indicating moderate toxicity to bees. The bee box, however, is still not required.
EPA has recommended measures across the board to reduce spray drift and runoff (to minimize off-target impacts). Specifics related to droplet size, wind speed, distance to bodies of water, vegetated filter strips, and more are all detailed.
In each product’s decision, EPA recommends that individual industries work to develop and implement stewardship and best management practices (BMPs). The Horticultural Research Institute (HRI) and AmericanHort released Best Management Practices (BMPs) for Bee Health in the Horticultural Industry in 2017. A revision is currently underway to reflect the latest research updates. EPA has been asked to review the amended document.
These proposed changes only relate to outdoor use. One of the greatest impacts to environmental horticulture is the proposed rate reduction for clothianidin, dinotefuran, and imidacloprid. Potential exists that these proposed reduced rates may not provide full protection against certain pests. Landscape management will face significant impacts from the loss of imidacloprid foliar sprays to turf (primarily) for grub control, but granular applications look to remain the same.
Comments will be accepted through April 3, 2020.
Table 1. Summary of proposed changes with potential impact on outdoor environmental horticulture (nursery production and landscape management) industries.