Assessing the fate and effects of an insecticidal formulation

Abstract

A 3-yr study was conducted on a corn field in central Illinois, USA, to understand the fate and effects of an insecticidal formulation containing the active ingredients phostebupirim and cyfluthrin. The objectives were to determine the best tillage practice (conventional vs conservation tillage) in terms of grain yields and potential environmental risk, to assess insecticidal exposure using concentrations measured in soil and runoff water and sediments, to compare measured insecticidal concentrations with predicted concentrations from selected risk assessment exposure models, and to calculate toxicity benchmarks from laboratory bioassays performed on reference aquatic and terrestrial nontarget organisms, using individual active ingredients and the formulation. Corn grain yields were not significantly different based on tillage treatment. Similarly, field concentrations of insecticides were not significantly (p > 0.05) different in strip tillage versus conventional tillage, suggesting that neither of the tillage systems would enable greater environmental risk from the insecticidal formulation. Risk quotients were calculated from field concentrations and toxicity data to determine potential risk to nontarget species. The insecticidal formulation used at the recommended rate resulted in soil, sediment, and water concentrations that were potentially harmful to aquatic and terrestrial invertebrates, if exposure occurred, with risk quotients up to 34.

Mixture toxicity of phostebupirim and cyfluthrin: Species‐specific responses

“…Method detection limits in water samples were 4.0 ng/L and 3.2 ng/L, for phostebupirim and cyfluthrin, respectively .…”

Kinetics of Lipophilic Pesticide Uptake by Living Maize

“…Understanding the uptake of lipophilic pesticides into the cuticles of agronomically significant plant species is of vital importance from the perspectives of agrochemical efficiency, − environmentalism, − and toxicology, − including risk assessment and food quality. The lipidic cuticle is the plant’s primary barrier against the uptake of potentially hazardous material, including pesticides. ,,, Not only does it sequester lipophilic material and thus can reduce uptake into the underlying tissue, but it also acts as a diffusional barrier, slowing the mass transport.…”

“…Generally, rapid and effective uptake into the cuticle is preferred, either as a precursor to transport into the plant tissue (e.g., systemic herbicides) or to enhance the pest resistance of the cuticle itself (e.g., certain fungicides and insecticides). Rapid uptake from the leaf surface may also help to mitigate loss processes from the leaf surface, such as washing off by rain, which also adds to the environmentally damaging effects of pesticide runoff. , Additionally, cuticular uptake is vital for modeling the movement and accumulation of pesticides and other pollutants in the biosphere − ,,− and thus assessing their threat to humans − or to the environment, such as through crop consumption.…”

“…Rapid uptake from the leaf surface may also help to mitigate loss processes from the leaf surface, such as washing off by rain, which also adds to the environmentally damaging effects of pesticide runoff. 7 , 15 Additionally, cuticular uptake is vital for modeling the movement and accumulation of pesticides and other pollutants in the biosphere 8 − 10 , 13 , 16 − 19 and thus assessing their threat to humans 8 − 10 or to the environment, 13 such as through crop consumption.…”