Sulfoxaflor is an insecticide used in agriculture to manage specific insect populations. It protects various crops by targeting pests that cause significant damage to yields. It is a newer tool in pest management, addressing challenges from evolving pest resistance. Its usage has expanded across diverse agricultural landscapes where targeted insect control is needed to maintain crop health and productivity.
Chemical Profile and Application
Sulfoxaflor is a systemic insecticide, absorbed by plants and distributed throughout their tissues, making the entire plant toxic to feeding insects. It belongs to the sulfoximine chemical class, distinct from older insecticide groups. It acts by disrupting the central nervous system of susceptible insects, leading to paralysis and death.
It is particularly effective against sap-feeding pests resistant to other common pesticides. It is widely applied in agriculture to control pests like aphids and whiteflies, known for damaging a broad range of crops. Farmers use sulfoxaflor on various crops including soybeans, cotton, citrus, and vegetables like squash and pumpkins. Its application helps protect these crops throughout their growth cycle.
Effects on Pollinators
The impact of sulfoxaflor on pollinators, particularly bees, is a significant area of scientific investigation and public concern. Research indicates sulfoxaflor is highly toxic to honey bees across all life stages, even with short exposure. This toxicity can lead to lethal and sub-lethal effects, disrupting bee behaviors and colony survival.
Sub-lethal effects in bees include impaired foraging, navigation difficulties, and reduced reproduction. Chronic exposure to small amounts of sulfoxaflor decreased honey bee larvae emergence and survival, and adult bees consumed less food. Pollinators are exposed systemically through residues in pollen and nectar of treated plants. While it breaks down, 90 percent can take 8 to 12 days to dissipate from pollen and nectar. Sulfoxaflor shares a similar mode of action with neonicotinoid pesticides, affecting the insect nervous system, though it belongs to a distinct chemical class.
Environmental and Human Safety Profile
The environmental fate of sulfoxaflor in soil and water has been examined. The compound breaks down quickly in soil environments. However, it exhibits higher persistence in aquatic environments, with a half-life ranging from 37 days to over a year. The primary breakdown product of sulfoxaflor can persist even longer, with a half-life of up to 2.5 years in soil and potentially up to 14 years in aquatic settings.
For human safety, regulatory bodies, such as the U.S. Environmental Protection Agency (EPA), establish acceptable daily intake levels for pesticides like sulfoxaflor to ensure consumer safety. The main route of human exposure is through residues on food crops. These residues are continuously monitored to ensure they remain below established safety thresholds, protecting public health.
Regulatory Status and Controversy
Sulfoxaflor’s regulatory journey has been marked by several significant legal and policy shifts. The EPA initially approved sulfoxaflor for use in the U.S. in 2013. Shortly after its registration, beekeeping and environmental groups challenged this approval in court, citing concerns about its potential harm to bee populations.
In September 2015, a federal appeals court vacated the insecticide’s registration, ruling supporting studies were insufficient to demonstrate it would not cause environmental harm. The EPA re-approved sulfoxaflor in 2016 with stricter usage restrictions, including prohibitions on its application to blooming crops known to attract bees. The EPA expanded its approved uses in 2019, leading to further legal challenges. A December 2022 court ruling found the EPA had not adequately assessed the risks to endangered species and failed to allow public comment on its expanded approval.