07
May
Study Quantifies Cost of Pesticide Resistance, while Advocates Chart a Course Beyond Pesticides
(Beyond Pesticides, May 7, 2024) The marginal user costs (MUC) of pesticide resistance for chemical-intensive farmers and the pest management industry are significantly affected by pesticide costs, density dependence (growth rate of a pest population impacted by its density), and dominant genetic mutations that cause resistance, according to a novel study published in Journal of the Agricultural and Applied Economics Association. Although the authors believe that integrated pest management (IPM) can be fine-tuned based on these findings, many advocates believe that these findings in fact underscore the importance of eliminating toxic pesticide use amidst compounding climate, biodiversity, and public health crises—which many IPM strategies do not adequately address.
As the costs of petrochemical-based pesticides increase, organisms identified as pests continue to increase in population density as global and regional temperatures dually increase. Organic agriculture, and organic land management principles more broadly, are an economically and ecologically advantageous leap ahead in transitioning to a food system that moves beyond the status quo that poisons people and the planet.
“This paper seeks to develop a better understanding of how the user costs of resistance are potentially determined by the interactions of heterogeneous bioeconomic factors that vary by context,†say the study authors. “We provide the first systematic numerical analysis of model-based user costs of pesticide susceptibility, that is, the price of resistance, and their variation across different bioeconomic contexts.†This study builds on an existing model focused on measuring Bacillus thuringiensis (Bt) species of bacteria in European corn borer. In this most recent study’s methodology, the authors expand the existing model through the implementation of stochastic dynamic programming and sensitivity analysis. Stochastic dynamic programming allows for the inclusion of unexpected variables such as weather fluctuations and the opportunity to “examine…user costs not just as calendar-based schedules…but in terms of how these quantities depend on the current state of pest population and resistance.†Meanwhile, authors indicate that sensitivity assessment is important because the findings can be “more broadly relevant for the economics of resistance management in general†rather than in just specific geographies or specific combinations of pesticides and crops.
“We adopt a two-state, discrete-time model of resistance to a single crop and single pesticide, in which resistance is generated from a single gene mutation R relative to the original wild-type gene S that left the pest susceptible to the pesticide,†according to further reporting by the authors on their methodology. “In our model, we define the net MUCs of resistance as the net adjustment factor to the marginal cost of the pesticide that would induce a self-interested farmer ignoring pest population dynamics and evolution to make a decision in the collective interest of farmers as a whole (see detailed rationale for this definition in Supporting Information).†Net MUCs of resistance is an important measurement to consider given the compounding factors (economic, socio-cultural, and philosophical) that impact the adoption of pesticide use by agricultural communities within and outside the United States. IPM claims a pesticide reduction strategy, meaning product substitution rather than the approach of organic land management principles that serves as a transformative alternative to rethink systems in alignment with the health of soil, water, ecosystems, wildlife, and humans.
Pest resistance to pesticides manifests for various pests and pesticides as documented over the years through numerous studies in the scientific literature. For example, a 2023 study published in Pest Management Science finds resistance to insecticides, like pyrethroids, is jeopardizing attempts to control the mosquito Aedes aegypti, the primary vector of dengue fever. Prevention of disease outbreaks is threatened by pesticide reliance to which pathogens and their vectors develop resistance.
A 2022 study published in Scientific Reports documents wholesale toxic pesticide use (deltamethrin, permethrin, lambda-cyhalothrin, propoxur, and malathion) for mosquito control, allowing genetic mutations to persist among mosquito populations and causing subsequent resistance to future exposure. In this study, two common species of female mosquitoes (Aedes aegypti and Culex quinquefasciastus) learned to evade pesticides following non-fatal exposure through smell. More concerning is the survival rate of these pre-exposed mosquitoes, as it is more than double that of unexposed mosquitoes. A 2021 study in Journal of Medical Entomology determined black-legged ticks (Ixodes scapulari) in the state of New York are developing potential resistance to the pyrethroid insecticide, permethrin. Regarding the resilience of cockroaches, a 2019 study in Scientific Reports found that many develop cross-resistance to insecticides to which they have never been directly exposed; additionally, pre-treatment application of synthetic pyrethroids revealed an 80% survival rate of these pesky insects. See more on pesticide resistance in the Daily News.
Antibiotic resistance is a compounding implication of relying on toxic chemical inputs in agriculture and broader land management strategies. Agricultural and veterinary uses of antibiotics significantly contribute to the resistance of certain bacteria or fungi to antibiotics that have historically knocked down such infections in humans, as mentioned in a 2017 Pesticides and You article written by Terry Shistar, Ph.D and Carla Curle, “Agricultural Uses of Antibiotics Escalate Bacterial Resistance.“ The authors note, “In addition to the promotion of weed resistance by widespread application of glyphosate and use of glyphosate-resistant genes in agriculture, there is evidence that glyphosate at environmentally relevant levels increases bacterial resistance to antibiotics important in fighting human pathogens and bacterial infections.†There are alternative models being developed in real time. For example, after successful challenges in federal court regarding synthetic antibiotic use for citrus orchards, the conventional citrus industry has been under pressure to find alternative strategies to lure pest insects such as the Asian citrus psyllid (citrus greening) away from trees through an agroecological method called “push-pull†pest management. See more on antibiotic resistance in the Daily News.
Beyond Pesticides collaborates with scientists, advocates, physicians, and local communities to pressure elected officials and regulators to reimagine pesticide regulation through a holistic, systematic approach. Through advocacy with frontline communities, farmers, farmworkers, immunocompromised individuals, and people of color, we enable advocates who believe that organic land management principles are a critical approach to eliminating toxic pesticide exposure to loved ones. See Keeping Organic Strong to see our proposed changes and opportunities to engage in strengthening federal organic standards and policy. See Eating With A Conscience to learn which pesticides are sprayed on conventionally grown fruits and vegetables to better inform your next grocery store run. See Mosquito Management and Insect-Borne Diseases to learn about the ineffectiveness of pesticide spraying and alternatives for ecologically based management strategies. See Action of the Week Archive to see how to stay engaged and get involved in advocacy each week.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: Journal of the Agricultural and Applied Economics Association
