Mechanistic modeling of pesticide uptake with a 3D plant architecture model

Meaningful assessment of pesticide fate in soils and plants is based on fate models that represent all relevant processes. With mechanistic models, these processes can be simulated based on soil, substance, and plant properties. We present a mechanistic model that simulates pesticide uptake from soil and investigate how it is influenced, depending on the governing uptake process, by root and substance properties and by distributions of the substance and water in the soil profile. A new root solute uptake model based on a lumped version of the Trapp model (Trapp, 2000) was implemented in a coupled version of R-SWMS-ParTrace models for 3-D water flow and solute transport in soil and root systems. Solute uptake was modeled as two individual processes: advection with the transpiration stream and diffusion through the root membrane. We set up the model for a FOCUS scenario used in the European Union (EU) for pesticide registration. Considering a single vertical root and advective uptake only, the root hydraulic properties could be defined so that water and substance uptake and substance fate in soil showed a good agreement with the results of the 1D PEARL model, one of the reference models used in the EU for pesticide registration. Simulations with a complex root system and using root hydraulic parameters reported in the literature predicted larger water uptake from the upper root zone, leading to larger pesticide uptake when pesticides are concentrated in the upper root zone. Dilution of root water concentrations at the top root zone with water with low pesticide concentration taken up from the bottom of the root zone leads to larger uptake of solute when uptake was simulated as a diffusive process. This illustrates the importance of modeling uptake mechanistically and considering root and solute physical and chemical properties, especially when root-zone pesticide concentrations are non-uniform.

Pesticide Usage Is Compromising People’s Health in the United States: Ideas for Reducing Damages

The development of synthetic pesticides has provided new tools for addressing troublesome pests. A review of parts of the registration process for pesticides in the United States identifies an outdated evaluation system that undervalues health damages. Registration fails to adequately consider co‑formulants and effects of exposure to multiple chemicals. Frustration with failures to protect people and property from damages accompanying pesticide usage has led injured plaintiffs to resort to tort lawsuits to secure relief. However, litigation involves compensating injured persons after they are injured rather than preventing injury. A more proactive approach would be to prevent situations that injure people. This paper offers four ideas to reduce health damages accompanying pesticide usage. Slight adjustments to pesticide registration requirements can offer greater protection for people’s health.

The Application of PRIMET For Pesticide Registration and Monitoring in Ethiopia

Pesticide registration is an activity often not supported with proper risk assessment procedures in developing countries like Ethiopia. In this study, we tried the PRIMET (Pesticide Risks in the Tropics for Man, Environment and Trade), a tool developed to assess the risks to non-target protection goals believed to assist the pesticide registration and monitoring activities in Ethiopia. For this study, seven pesticides (imdacloprid, difenoconazole, metalaxyl, dimethoate, thiamethoxam, nicosulfuron and bupirimate) were selected randomly and their data of physico-chemical characteristics, toxicological information and pesticide use were mined from either the information given on the dossier or PPDB (Pesticides Properties Database). Results indicated that imidacloprid, dimethoate and thiamethoxam are highly risky to bees when bee hives are present inside the field of the sprayed crop, while Thiamethoxam is highly risky at when hives are present in and off field crop situation. Another outcome was that imidacloprid and dimethoate are expected to have high acute risk for birds, while difenoconazole, metalaxyl, dimethoate showed high acute and chronic risks to the aquatic ecosystem, respectively. Future studies should give emphasis on how the results of risk assessment can be practical to help the registration processes and how the results are compared with actual measurement values.

Control of pesticides in Ecuador: An underrated problem?

Pesticides have become necessary control agents to guarantee food sovereignty and strengthen development in Ecuador. Nevertheless, the current management practices of pesticides in Ecuador restrain the progress of agriculture in this region. There is evidence of a knowledge gap regarding the correct handling of pesticides and the possible health impacts they generate, especially in small producers and surrounding communities. Furthermore, a lack of updated information on pesticide registration difficult their control and distribution. Given this, there is a need to implement new public policies that promote relations between science and technology, not only with the industry but also with local producers, to promote the growth of agriculture, minimizing risks to health and the environment in the sectors involved. The purpose of this review is to exhibit the most updated panorama regarding the management of pesticides in Ecuador.

Special Local Need Pesticide Registrations--24(c)

This document describes a unique type of pesticide registration – Special Local Need, also known as a 24(c) registration, and examples of situations where it is warranted. This document is PI-95, one of a series of the Agronomy Department, UF/IFAS Extension. Original publication date January 2006. PI-95/PI132: Special Local Needs Pesticide Registrations—24(c) (ufl.edu)