Robinson et al., 2020
Robinson, Claire, Portier, Christopher J., ČAvoŠKi, Aleksandra, Mesnage, Robin, Roger, Apolline, Clausing, Peter, Whaley, Paul, Muilerman, Hans, & Lyssimachou, Angeliki; “Achieving a High Level of Protection from Pesticides in Europe: Problems with the Current Risk Assessment Procedure and Solutions;” European Journal of Risk Regulation, 2020, 11(3), 450-480; DOI: 10.1017/err.2020.18.
ABSTRACT:
The regulation of pesticides in the European Union (EU) relies on a network of hard law (legislation and implementing acts) and soft law (non-legally binding guidance documents and administrative and scientific practices). Both hard and soft laws govern how risk assessments are conducted, but a significant role is left to the latter. Europe’s pesticide regulation is one of the most stringent in the world. Its stated objectives are to ensure an independent, objective and transparent assessment of pesticides and achieve a high level of protection for health and environment. However, a growing body of evidence shows that pesticides that have passed through this process and are authorised for use may harm humans, animals and the environment. The authors of the current paper – experts in toxicology, law and policy – identified shortcomings in the authorisation process, focusing on the EU assessment of the pesticide active substance glyphosate. The shortcomings mostly consist of failures to implement the hard or soft laws. But in some instances the law itself is responsible, as some provisions can only fail to achieve its objectives. Ways to improve the system are proposed, requiring changes in hard and soft laws as well as in administrative and scientific practices. FULL TEXT
Powles and Gaines, 2017
Powles, Stephen B., & Gaines, Todd A.; “Exploring the Potential for a Regulatory Change to Encourage Diversity in Herbicide Use;” Weed Science, 2017, 64(SP1), 649-654; DOI: 10.1614/ws-d-15-00070.1.
ABSTRACT:
An overreliance on herbicides in several important grain- and cotton-producing regions of the world has led to the widespread evolution of herbicide-resistant weed populations. Of particular concern are weed populations that exhibit simultaneous resistance to multiple herbicides (MHR). Too often, herbicides are the only tool used for weed control. We use the term herbicide-only syndrome (HOS) for this quasi-addiction to herbicides. Growers and their advisers focus on herbicide technology, unaware of or ignoring basic evolutionary principles or the necessary diversity provided by other methods of weed control. Diversity in weed control practices disrupts resistance evolution. Significant challenges exist to implementing diversity, including how to address information so that producers choose to alter existing behaviors (HOS) and take calculated risks by attempting new and more complex strategies. Herbicide resistance management in the long term will require creativity in many sectors, including roles for growers, industry, researchers, consultants, retailers, and regulators. There can be creativity in herbicide registration and regulation, as exemplified by the recent U.S. Environmental Protection Agency program that encourages herbicide registrants to register products in minor crops. We propose one idea for a regulatory incentive to enable herbicide registrants in jurisdictions such as the United States to receive an extended data exclusivity period in exchange for not developing one new herbicide in multiple crops used together in rotation, or for implementing stewardship practices such as robust mixtures or limitations on application frequency. This incentive would provide a mechanism to register herbicides in ways that help to ensure herbicide longevity. Approaches based only on market or financial incentives have contributed to the current situation of widespread MHR. Our suggestion for regulatory creativity is one way to provide both financial and biological benefits to the registering company and to the overall stakeholder community by incentivizing good resistance management. FULL TEXT
Osteen and Fernandez-Cornejo, 2016
Osteen, Craig D., & Fernandez-Cornejo, Jorge; “Herbicide Use Trends: A Backgrounder;” Choices, 2016, 31(4th Quarter 2016).
ABSTRACT:
None Available
Ruden and Grandjean, 2018
Mie, A., Ruden, C., & Grandjean, P.; “Safety of Safety Evaluation of Pesticides: developmental neurotoxicity of chlorpyrifos and chlorpyrifos-methyl;” Environmental Health, 2018, 17(1), 77; DOI: 10.1186/s12940-018-0421-y.
ABSTRACT:
Authorization of pesticides for market release requires toxicity testing on animals, typically performed by test laboratories on contract with the pesticide producer. The latter provides the results and summary to the regulatory authorities. For the commonly used pesticide chlorpyrifos, an industry-funded toxicity study concludes that no selective effects on neurodevelopment occur even at high exposures. In contrast, the evidence from independent studies points to adverse effects of current exposures on cognitive development in children. We reviewed the industry-funded developmental neurotoxicity test data on chlorpyrifos and the related substance chlorpyrifos-methyl. We noted treatment-related changes in a brain dimension measure for chlorpyrifos at all dose levels tested, although not been reported in the original test summary. We further found issues which inappropriately decrease the ability of the studies to reveal true effects, including a dosage regimen that resulted in too low exposure of the nursing pups for chlorpyrifos and possibly for chlorpyrifos-methyl, and a failure to detect any neurobehavioral effects of lead nitrate used as positive control in the chlorpyrifos study. Our observations thus suggest that conclusions in test reports submitted by the producer may be misleading. This discrepancy affects the ability of regulatory authorities to perform a valid and safe evaluation of these pesticides. The difference between raw data and conclusions in the test reports indicates a potential existence of bias that would require regulatory attention and possible resolution. FULL TEXT
Manalil et al, 2017
Manalil, Sudheesh, Busi, Roberto, Renton, Michael, & Powles, Stephen B.; “Rapid Evolution of Herbicide Resistance by Low Herbicide Dosages;” Weed Science, 2017, 59(2), 210-217; DOI: 10.1614/ws-d-10-00111.1.
ABSTRACT:
Herbicide rate cutting is an example of poor use of agrochemicals that can have potential adverse implications due to rapid herbicide resistance evolution. Recent laboratory-level studies have revealed that herbicides at lower-than-recommended rates can result in rapid herbicide resistance evolution in rigid ryegrass populations. However, crop-field-level studies have until now been lacking. In this study, we examined the impact of low rates of diclofop on the evolution of herbicide resistance in a herbicide-susceptible rigid ryegrass population grown either in a field wheat crop or in potted plants maintained in the field. Subsequent dose–response profiles indicated rapid evolution of diclofop resistance in the selected rigid ryegrass lines from both the crop-field and field pot studies. In addition, there was moderate level of resistance in the selected lines against other tested herbicides to which the population has never been exposed. This resistance evolution was possible because low rates of diclofop allowed substantial rigid ryegrass survivors due to the potential in this crosspollinated species to accumulate all minor herbicide resistance traits present in the population. The practical lesson from this research is that herbicides should be used at the recommended rates that ensure high weed mortality to minimize the likelihood of minor herbicide resistance traits leading to rapid herbicide resistance evolution. FULL TEXT
Malone and Foster, 2019
Malone, M., & Foster, E.; “A mixed-methods approach to determine how conservation management programs and techniques have affected herbicide use and distribution in the environment over time;” Science of The Total Environment, 2019, 660, 145-157; DOI: 10.1016/j.scitotenv.2018.12.266.
ABSTRACT:
No-till agriculture has the ability to reduce fuel consumption, increase soil moisture, reduce soil erosion and increase organic matter. However, it remains unclear whether it increases herbicide use overall in the long term for communities that use no-till as their primary source of conservation agriculture. The preponderance of literature suggests that no-till has increased herbicide use, but it is difficult to quantify how much herbicide has increased in a given location and to directly correlate changes in herbicide use to changes in soil and water quality. This paper provides several methods to determine how herbicide use has changed over time in an agricultural community in Oregon that switched over to no-till in the late 1990s and early 2000s. These methods include: spatial analysis of remote sensing satellite imagery of vegetation health along streams; use of a drone fitted with an agricultural camera to detect vegetation health; and soil, sediment, and water sampling for the most commonly used herbicides in the study area. By using these methods, this study shows where stream vegetation health continues to be an issue in the agricultural community, and where concentrations of a commonly used herbicide in the community may be impacting human and ecological health. This study has important implications for impacts to soil and water quality over time in agricultural communities, as many researchers have noted the need to determine the long term effects of conversion to no-till and other forms of conservation agriculture. By providing these methods, communities heavily engaged in multiple forms of conservation agriculture may be able to track herbicide use changes in real time and on shorter decadal time spans in places where conservation agriculture is practiced. FULL TEXT
Givens et al., 2017
Givens, Wade A., Shaw, David R., Johnson, William G., Weller, Stephen C., Young, Bryan G., Wilson, Robert G., Owen, Micheal D. K., & Jordan, David; “A Grower Survey of Herbicide Use Patterns in Glyphosate-Resistant Cropping Systems;” Weed Technology, 2017, 23(1), 156-161; DOI: 10.1614/wt-08-039.1.
ABSTRACT:
A telephone survey was conducted with growers in Iowa, Illinois, Indiana, Nebraska, Mississippi, and North Carolina to discern the utilization of the glyphosate-resistant (GR) trait in crop rotations, weed pressure, tillage practices, herbicide use, and perception of GR weeds. This paper focuses on survey results regarding herbicide decisions made during the 2005 cropping season. Less than 20% of the respondents made fall herbicide applications. The most frequently used herbicides for fall applications were 2,4-D and glyphosate, and these herbicides were also the most frequently used for preplant burndown weed control in the spring. Atrazine and acetochlor were frequently used in rotations containing GR corn. As expected, crop rotations using a GR crop had a high percentage of respondents that made one to three POST applications of glyphosate per year. GR corn, GR cotton, and non-GR crops had the highest percentage of growers applying nonglyphosate herbicides during the 2005 growing season. A crop rotation containing GR soybean had the greatest negative impact on non-glyphosate use. Overall, glyphosate use has continued to increase, with concomitant decreases in utilization of other herbicides. FULL TEXT
Dean et al., 1995
Dean, E. Riechers, Loyd, M. Wax, Rex, A. Liebl, & Don, G. Bullock; “Surfactant Effects on Glyphosate Efficacy;” Weed Technology, 1995, 9(2), 281-285.
ABSTRACT:
Field and greenhouse studies were performed to examine the influence of various surfactants with glyphosate on whole plant efficacy. Relationships were examined between glyphosate phytotoxicity and surfactant properties, including ionic form, degree of ethoxylation, and hydrophobe composition. Cationic tertiary amine surfactants enhanced glyphosate performance in both field and greenhouse studies. Nonionic allinol and octoxynol surfactants were not effective in combination with glyphosate. In field studies, glyphosate efficacy increased with increasing surfactant ethylene oxide (EO) content. Soybean and velvetleaf responded similarly to glyphosate-surfactant spray applications, as both demonstrated significant linear and quadratic relationships between increasing surfactant ethoxylation and phytotoxicity, while common lambsquarters showed a significant linear relationship only. Cationic surfactants were evaluated in the greenhouse and a significant quadratic regression of glyphosate phytotoxicity to common lambsquarters on increasing surfactant ethoxylation indicated an optimum surfactant EO content of about 10 moles. Both tertiary and quaternary ethoxylated fatty amines were effective with glyphosate in decreasing common lambsquarters’ fresh weight. Fatty amine hydrophobe composition did not correlate with glyphosate phytotoxicity to common lambsquarters. FULL TEXT
Boone et al., 2014
Boone, Michelle D., Bishop, Christine A., Boswell, Leigh A., Brodman, Robert D., Burger, Joanna, Davidson, Carlos, Gochfeld, Michael, Hoverman, Jason T., Neuman-Lee, Lorin A., Relyea, Rick A., Rohr, Jason R., Salice, Christopher, Semlitsch, Raymond D., Sparling, Donald, & Weir, Scott; “Pesticide Regulation amid the Influence of Industry;” BioScience, 2014, 64(10), 917-922; DOI: 10.1093/biosci/biu138.
ABSTRACT:
Pesticide use results in the widespread distribution of chemical contaminants, which necessites regulatory agencies to assess the risks to environmental and human health. However, risk assessment is compromised when relatively few studies are used to determine impacts, particularly if most of the data used in an assessment are produced by a pesticide’s manufacturer, which constitutes a conflict of interest. Here, we present the shortcomings of the US Environmental Protection Agency’s pesticide risk assessment process, using the recent reassessment of atrazine’s impacts on amphibians as an example. We then offer solutions to improve the risk assessment process, which would reduce the potential for and perception of bias in a process that is crucial for environmental and human health. FULL TEXT
Bonny, 2011
Bonny, Sylvie; “Herbicide-tolerant Transgenic Soybean over 15 Years of Cultivation: Pesticide Use, Weed Resistance, and Some Economic Issues. The Case of the USA;” Sustainability, 2011, 3(9), 1302-1322; DOI: 10.3390/su3091302.
ABSTRACT:
Genetically modified (GM) herbicide-tolerant (HT) crops have been largely adopted where they have been authorized. Nevertheless, they are fiercely criticized by some, notably because of the herbicide use associated with them. However, how much herbicide is applied to GMHT crops compared to conventional crops, and what impacts does the use of herbicide have? The paper first presents some factors explaining the predominance of GMHT crops. Then, trends in the use of herbicide for GM crops are studied in the case of the most widespread HT crop: HT soybean in the USA. The trends in the toxicity of herbicides applied to HT soybean are also addressed, as well as the appearance of glyphosate-resistant (GR) weeds. Lastly, the paper examines the spread of GR weeds and its impact. How are farmers, weed scientists, and the industry coping with this development, and what are the prospects of glyphosate-tolerant crops given weed resistance? In conclusion, some issues of sustainability and innovation governance raised by genetically modified herbicide-tolerant crops are discussed. FULL TEXT