Comparing the Acute Toxicity of Imidacloprid with Alternative Systemic Insecticides in the Aquatic Insect Chironomus...

Area of Science:

• Environmental toxicology
• Aquatic entomology
• Insecticide ecotoxicology

Background:

• Neonicotinoids are widely used systemic insecticides with known aquatic toxicity.
• Emerging insecticides, including ryanodine receptor agonists, require ecotoxicological assessment.
• Chironomus dilutus is a standard test organism for aquatic toxicity evaluations.

Purpose of the Study:

• To compare the acute toxicity of five systemic insecticides (chlorantraniliprole, cyantraniliprole, flupyradifurone, flubendiamide, sulfoxaflor) to larval Chironomus dilutus.
• To evaluate the relative risk of these insecticides compared to imidacloprid, a common neonicotinoid.

Main Methods:

• Acute 96-hour toxicity tests were conducted on larval Chironomus dilutus.
• Concentration-response data were analyzed to determine toxicity endpoints.
• Results were compared statistically to establish relative toxicity.

Main Results:

• Three tested insecticides were 2.5 to 25 times less acutely toxic than imidacloprid.
• Chlorantraniliprole and cyantraniliprole were 1.5 to 1.8 times more toxic to C. dilutus than imidacloprid.
• Significant variation in toxicity was observed among the tested insecticides.

Conclusions:

• Chlorantraniliprole and cyantraniliprole pose a potentially higher risk to aquatic insects like C. dilutus compared to imidacloprid.
• Ryanodine receptor agonists may present greater ecological risks than neonicotinoids in aquatic environments.
• Further research is warranted to fully assess the environmental impact of these newer insecticides.