Effects of pesticides on non-target species – Pollinators

Posted on Behalf of  Andrey Massarsky, Jordan Kozal

The ecological risks of pesticides to non-target species is an ongoing topic of concern. Adverse effects to pollinators are of specific concern due to the ecosystem services that they provide. As noted by the Environmental Protection Agency (EPA), there are several insect pollinators, including bees, wasps, sawflies, butterflies, moths, beetles, and flies, as well as non-insect pollinators, including birds and bats. Pollinators contribute to healthy ecosystems by helping 90% of the world’s flowering plants reproduce. However, the most recognized pollinators, honeybees, have experienced a population decline in the U.S. and many other countries (EPA, 2019). Importantly, honeybees are used as a surrogate species for other bees and insect pollinators (EPA, 2014).

EPA has supported several efforts to minimize the adverse effects of pesticides to honeybees. For example, in 2017, EPA implemented a policy that “protects bees from agricultural pesticide spray and dust applications while the bees are under contract to provide pollination services” (EPA, 2020a). The policy also includes recommendations for states and tribes to develop pollinator protection plans and best management practices. In addition to policies, EPA has also conducted risk assessments of pesticides to non-target species, including honeybees. For example, in 2018, EPA released a Preliminary Ecological Risk Assessment for Glyphosate and Its Salts that evaluated the ecological risks of technical glyphosate and glyphosate formulations to non-target species (EPA, 2018). According to this risk evaluation, acute risk to adult bees was deemed to be low; however, it was noted that insufficient studies were available.

In January 2020, EPA followed up on the glyphosate risk assessment with an Interim Registration Review Decision to evaluate ecological risks of glyphosate and whether the pesticide continues to meet the standard for registration in the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) (EPA, 2020b). Similar to the ecological risk assessment, the interim decision concluded that the acute risk to adult honeybees was low, but that Tier 1 toxicity studies were unavailable to fully assess the potential risk to bees at the individual and/or colony level.      

More recently, EPA has launched a series of webinars dedicated to pollinator protection from pesticides. The webinars addressed several important topics, including designing and conducting risk assessment studies in bees, assessing pesticide effects and risks to bees, and developing best management practices to reduce risks to pollinators (EPA, 2020c).

· Designing and conducting bee studies (webinar date: July 21, 2020)

This webinar outlined the basic elements of studies used by EPA to assess the risk to bees to support the registration or re-evaluation of a pesticide.

· Assessing risks to bees from pesticides (webinar date: July 28, 2020)

This webinar described EPA’s tiered process for assessing risks to bees, including honeybee simulation models. Alternative approaches for risk assessment were discussed to reduce reliance on animal testing.

· Agricultural stewardship and best management practices to reduce pollinator risk (webinar date: Aug 18, 2020)

This webinar highlighted the efforts to mitigate risks of pesticides to bees, as well as initiatives to engage stakeholders on pollinator protection.

· Engaging stakeholders: development and implementation of pollinator protection plans (webinar date: Sep 15, 2020)

This webinar discussed how managed pollinator protection plans (MP3s) reduce exposure of bees to pesticides through sustainable agriculture and increased stakeholders’ engagement. It was specified that 44 states have or intend to have a plan, and 23 states have completed the plans. The webinar also addressed EPA’s plan to assess the impact of MP3s while coordinating outreach with stakeholders regarding the effectiveness of MP3 implementation. Further, it was indicated that pesticides were not the only factor affecting the health of bees and that in some cases poor management, disease/parasites, and starvation also contributed to bee deaths.

The health of pollinators is certainly an important topic that warrants additional research, toxicological evaluations, and risk assessments. Cardno ChemRisk scientists have extensive professional experience evaluating the possible hazards and risks posed by chemicals, including herbicides/pesticides; this includes the application of available models to assess pesticide risks to non-target species, including honeybees, plants, birds, and mammals. For more information on Cardno ChemRisk's capabilities, please contact Dr. Andrey Massarsky and Dr. Jordan Kozal.