(Beyond Pesticides, October 25, 2024) To better understand synergistic interactions between multiple stressors, researchers from the Helmholtz Centre for Environmental Research in Leipzig, Germany, analyze exposure to the pyrethroid insecticide esfenvalerate with two nonchemical environmental factors: elevated temperature and food limitation. In their recent publication in Environmental Pollution, the authors find the greatest synergistic effects when Daphnia magna (D. magna) are subjected to esfenvalerate under conditions experienced with climate change including lower food availability and increased temperature. D. magna, also known as daphnids or water fleas, are small planktonic crustaceans that represent an essential part of the food web in lakes and ponds. Impacts on populations of daphnids can lead to effects throughout multiple trophic levels that impact overall biodiversity. As the researchers state, “Global biodiversity is declining at an unprecedented rate in response to multiple environmental stressors… A key challenge is understanding synergistic interactions between multiple stressors and predicting their combined effects.” To study this, a Stress Addition Model (SAM), which predicts the cumulative effects of interacting stressors, was utilized and compared to laboratory data using 24-hour-old neonates of D. magna. The organisms were subjected to various conditions, singularly and in combination, including increased temperature, lower quantities of food, […]

(Beyond Pesticides, August 21, 2024) A literature review, published this month in the Journal of Agricultural and Food Chemistry, explores levels of pesticide residues found in samples of human urine with environmental exposure and dietary intake and confirms prior findings about the benefits of an organic diet. Similar to past findings, lower concentrations of chemicals are detected in the urine of participants who report eating an organic diet. By analyzing 72 scientific research studies published between 2001 to 2023, the review assesses routes of exposure and “explores urinary concentrations and detection frequency of metabolites of organophosphates and pyrethroids, as well as herbicides such as 2,4-D and glyphosate,” the authors say. While “exposure to pesticide residues is influenced by a variety of demographic factors, including occupation, agricultural practices, seasonal variations, residence, diet, age, and gender,” the authors say, the concentrations of pesticides and their metabolites in human urine highlights the disproportionate risk to certain groups as well as the overall threat to the health of humans and the environment. Pesticide exposure can occur from dermal/skin contact or inhalation, through residence or work, and with dietary intake. “Pesticides in urine can be detected as parent compounds, specific metabolites corresponding to a specific […]

(Beyond Pesticides, March 11, 2024) Inside a recent disagreement between the Office of the Inspector (OIG) and the U.S. Environmental Protection Agency’s (EPA) Office of Pesticide Programs (OPP) on the agency’s review of pet flea and tick collars—leading to thousands of deaths and poisonings—is a basic question of the adequacy of pesticide regulation. The disagreement is over the cause of 105,354 incident reports, including 3,000 pet deaths and nearly 900 reports of human injury, and the February 2025 OIG report’s conclusion that “[EPA] has not provided assurance that they can be used without posing unreasonable adverse effects to the environment, including pets.” While the disagreement focuses on a number of EPA process failures, Beyond Pesticides urges that the findings advance the need for the agency to address a key element of chemical mixtures in pesticide products not currently evaluated, potential synergistic effects—the increased toxic potency created by pesticide and chemical combinations not captured by assessing product ingredients individually.  Key to the dispute is what many see as a foundational failure of EPA to evaluate the effect of pesticide mixtures and full formulations of pesticide end products, a longstanding criticism of the agency’s pesticide registration process, which focuses on pesticide products’ active […]

(Beyond Pesticides, March 6, 2024) With over 2,500 pet deaths and 900 reports of adverse effects to people, an Office of Inspector General (OIG) report, published on February 29, 2024, reveals multiple systemic failures by the U.S. Environmental Protection Agency’s (EPA) Office of Pesticide Programs (OPP), citing inadequate safety reviews of Seresto pet collars. The report, The EPA Needs to Determine Whether Seresto Pet Collars Pose an Unreasonable Risk to Pet Health, concludes, “The EPA’s response to reported pesticide incidents involving Seresto pet collars has not provided assurance that they can be used without posing unreasonable adverse effects to the environment, including pets.” At the time the animal effects made headlines in 2021, the agency defended the product’s registration, telling the media that, despite these incidents, EPA deemed Seresto collars “‘eligible for continued registration’ based on best available science, including incident data… No pesticide is completely without harm, but EPA ensures that there are measures on the product label that reduce risk.” Despite the scathing criticism, EPA maintains the position that it conducted an adequate review of the two active insecticide ingredients in the pet collars—the neurotoxic insecticide flumethrin, and the notorious neonicotinoid imidacloprid—proven to have adverse effects on the endocrine system as […]

(Beyond Pesticides, October 17, 2023) In the past month, Paris, France has witnessed a surge in bed bug populations. From public transportation to hotels, hostels, and movie theatres, bed bugs are posing a threat to the city’s two million residents and potentially a broader global population as the infestation spreads.   This resurgence of bed bugs in Paris is not unique. For centuries, these pests have been both adaptable and persistent, presenting an enduring challenge to pest control. However, the current surge in bed bug infestations is not merely a revival of a longstanding problem; it is a complex issue intertwined with the development of resistance to insecticides, mainly through a mechanism known as knockdown resistance. This mechanism, along with three other main resistance mechanisms, has enabled these insects to defy chemical-intensive control methods  Knockdown resistance is a significant factor contributing to the resistance exhibited by bed bugs to insecticides, especially pyrethroids. The mechanism plays a central role in countering the action of these insecticides, which target the nervous system of bed bugs, causing paralysis and eventual death. Knockdown resistance provides the genetic adaptation that provides bed bug populations with resistance to insecticides. It inhibits the effectiveness of certain insecticides. Bed […]

(Beyond Pesticides, October 10, 2023) In recent years, the effects of climate change have become more frequent and more severe, from extreme weather events to rising sea levels. But perhaps one of the most insidious consequences of a warming planet is the way it influences the spread of diseases, often hitting marginalized communities the hardest. This is no more evident than in the case of malaria, where the disease transmission through the Anopheles stephensi mosquito serves as a dire warning of the challenges caused by a changing climate. As this deadly vector of disease expands its territory, it is clear that pesticide-intensive approaches are poorly equipped to cope with the threat as insect resistance to chemical controls steadily grows.  Native to South Asia, the Anopheles stephensi mosquito has been on a relentless journey, crossing continents from the Arabian Peninsula to East Africa and deeper into the African continent. The mosquito’s ability to quickly adapt to new environments, bolstered by shifting climate patterns, illustrates how global warming affects disease vectors. Matthew Thomas, PhD, emphasizes, “Anopheles stephensi has higher thermal tolerance and a capacity to transmit at higher temperatures than Anopheles gambiae [another malaria-spreading mosquito]. This is significant when considering climate change […]

(Beyond Pesticides, August 30, 2023) Invasive yellow-legged hornets have been spotted near Savannah, Georgia, causing concern among agriculture officials. These hornets are known for their ability to prey on honeybees and other pollinators, and their presence in the United States is a cause for alarm. This is the first time a live specimen of this species has been detected in the open United States, according to the Georgia Department of Agriculture. The hornets, which are native to Southeast Asia, have been spotted in other parts of the world, including Europe, where they have caused significant damage to bee populations. They are considered “invasive,” which means the hornet is not native and officials expect their introduction to result in economic, environmental, or health-related damage to humans, animals, plants, or the environment. In response to the sighting in Georgia, officials are taking action to eradicate the hornets before they can cause any harm to US agriculture. One of the methods being used to eradicate the hornets is the localized use of the highly toxic insecticide cypermethrin on nests. The pesticide has been registered for use in agriculture and residential pest control since the 1970s. It kills insects such as mosquitoes, flies, ticks, […]

(Beyond Pesticides, October 7, 2022) Pyrethroid insecticides are associated with the growing worldwide epidemic of non-alcoholic fatty liver disease (NAFLD), a condition that causes swelling of the liver and can eventually lead to cirrhosis, cancer, or liver failure. According to research published in Environmental Science and Ecotechnology, exposure to pyrethroids like bifenthrin can induce gut microbiota dysbiosis (an imbalance in microorganisms in the intestines). This dysbiosis results in abnormal lipid (fat) metabolism and subsequent accumulation of lipids in liver cells, contributing to NAFLD development. Gut microbiota plays a crucial role in lifelong digestion, immune and central nervous system regulation, as well as other bodily functions. Through the gut biome, pesticide exposure can enhance or exacerbate the adverse effects of additional environmental toxicants on the body. Since the gut microbiome shapes metabolism, it can mediate some toxic effects of environmental chemicals. However, with prolonged exposure to various environmental contaminants, critical chemical-induced changes may occur in the gut microbes, influencing adverse health outcomes. Considering NAFLD is becoming the most prevalent form of liver disease, impacting at least 25 percent of the globe, and a growing body of evidence demonstrates the significance gut microbiota play in overall health, safety analyses that currently do not consider the […]

(Beyond Pesticides, October 4, 2022) A study published in Environmental Pollution finds pyrethroid insecticides contribute to a secondary source of contamination in water resources. Various pyrethroids, including bifenthrin, are detectable in urban catch basins (storm drains) that collect runoff water before draining into the open environment. There is a lack of information regarding the pesticides’ presence in urban catch basins. However, pesticide contamination in water resources is historically commonplace and widespread throughout U.S. rivers and streams, with at least five different pesticides present in 90 percent of water samples. Moreover, thousands of tons of pesticides not only enter waterways (e.g., rivers, streams, lakes, oceans) around the U.S. through urban catch basins but agricultural and nonagricultural sources as well, contaminating essential drinking water sources, such as surface water and groundwater. Reports like these are essential for determining appropriate regulatory action to protect the human, animal, and environmental health from chemical toxicant contamination, especially if chemical contamination is highly detectable. The study notes, “The high detection frequency of bifenthrin and overall pyrethroid concentrations, especially for particle-bound residues, suggest that underground urban catch basins constitute an important secondary source for extended and widespread contamination of downstream surface waters by pesticides such as pyrethroids in urban […]

(Beyond Pesticides, May 12, 2022) A report published in Environmental Health finds that exposure to environmentally relevant concentrations of pesticides can alter gut microbial communities, as demonstrated through fecal samples. Over 300 environmental contaminants and their byproducts, including pesticides, are chemicals commonly present in human blood and urine samples. Ample evidence demonstrates that environmental contaminants, including pesticides, negatively affect the human mouth and gut microbes. However, fecal samples provide an accurate representation of the microbial community existing in the gut. These toxicants can alter hormone metabolism, which adversely affects health outcomes. Adverse health effects of environmental contaminants include reproductive and developmental defects, diabetes, cardiovascular disease, liver disease, obesity, thyroid disorders, and improper immune operation. Although studies show how chemical exposures affect human health, more research is now questioning how these toxic chemicals influence gut health. Therefore, studies like these highlight the importance of evaluating how chemical contaminants deregulate normal bodily function through microbiome changes. The report notes, “Our results highlight the need for future dietary intervention studies to understand effects of pesticide exposure on the gut microbiome and possible health consequences.” Researchers examined dietary exposure to 186 common pesticide residues in the fecal excrement to determine impacts on the microbiome among 65 twins in the United Kingdom. […]

(Beyond Pesticides, July 22, 2021) A new study published in the Journal of Medical Entomology finds black-legged ticks (Ixodes scapulari) in New York are developing potential resistance to widely used tick-control pyrethroid insecticide, permethrin. The study suggests continuous use of area-wide, 4-poster devices (devices that attract deer and then apply pesticide to their head, ears, and neck) to apply insecticide treatments on deer to control tick populations promotes resistance. Resistance is an ever-present issue among chemical compounds (i.e., antibiotics, antimicrobials, pesticides) used in medicine and agriculture, and threatening the ability to prevent disease outbreaks, such as Lyme disease. Furthermore, increasing populations of rodent and mammalian hosts, in addition to warmer temperatures prompted by the climate crisis, allows for disease-carrying ticks to flourish. Lyme disease is the most common vector disease and a primary concern for the general population. Therefore, studies like this highlight the need to assess resistance among disease-vector pest populations regardless of pesticide application methods. The researchers note, “Permethrin susceptibility of tick populations should be monitored from other 4-poster control areas so that guidelines for managing pesticide resistance in the field can be developed.” Four-poster devices impart selective pressure on tick populations influencing reproduction and natural extinction of species. However, like mosquitoes, a subpopulation of ticks […]

(Beyond Pesticides, July 1, 2021) Yellow fever mosquitoes (Aedes aegypti) are evolving resistance to the pyrethroid insecticide permethrin, according to a study published by Colorado State University, highlighting the need to adopt ecologically-based mosquito management. Widespread, intensive use of the pesticide in mosquito control has allowed genetic mutations to persist among these mosquito populations, causing subsequent resistance to permethrin. Pyrethroids are one of the few remaining classes of insecticides available to control yellow fever mosquitos, and resistance threatens the ability to prevent disease outbreaks with chemical-intensive methods. Yellow fever mosquitoes are a vector for numerous untreatable diseases in humans, including dengue, chikungunya fever, and Zika viruses. Hence, this study highlights the significance of addressing pest resistance to pesticide control, particularly to mitigate disease exposure and effects. The researchers note, “This knowledge can help scientists understand how mosquitoes have evolved resistance and when a population can no longer be controlled with permethrin. This understanding will be necessary to develop tools to support future insecticide management strategies.” Researchers sequenced the genome of resistant and knockdown (either recovered or dead) mosquitoes after permethrin exposure using a bottle bioassay. The aim was to identify genomic variants/biomarkers associated with specific resistance mechanisms. Two common pyrethroid resistance mechanisms occur among […]

(Beyond Pesticides, April 8, 2021) Pesticide use threatens aquatic and terrestrial invertebrates and plants more than ever, despite declining chemical use and implementation of genetically engineered (GE) crops in the U.S., according to a University Koblenz-Landau, Germany study. Since the publication of Rachel Carson’s Silent Spring (1962), many environmental agencies have banned the use of pesticides like organochlorines, organophosphates, and carbamates for their devastating toxic—sometimes lethal—effects, particularly on vertebrates, including humans. However, this ban created a pathway for a new generation of pesticides (e.g., neonicotinoids, pyrethroids) to take hold. Although these pesticides are more target-specific, requiring lower chemical concentrations for effectiveness, they have over double the toxic effects on invertebrates, like pollinators.  Invertebrates and plants are vital for ecosystem function, offering various services, from decomposition to supporting the food web. Furthermore, invertebrates and plants can act as indicator species (bioindicators) that scientists can observe for the presence and impact of environmental changes and stressors. Therefore, reductions in invertebrate and plant life have implications for ecosystem health that can put human well-being at risk. Study lead author Ralf Schulz, PH.D., notes, “[This study] challenge[s] the claims of decreasing environmental impact of chemical pesticides in both conventional and GM [genetically modified or genetically engineered (GE)] crops and […]

(Beyond Pesticides, March 5, 2021) Pet owners will be alarmed to read the report, by USA Today, that a popular flea and tick collar — Seresto, developed by Bayer and sold by Elanco — has been linked to nearly 1,700 pet deaths, injuries to tens of thousands of animals, and harm to hundreds of people. At the time of publication, the U.S. Environmental Protection Agency (EPA), which regulates pesticides, had issued no informational alert to let the public know about these risks to pets — despite many hundreds of incident reports in its Office of Pesticide Programs Incident Report database. Beyond Pesticides and other advocates have warned of the toxicity of pet pesticide treatments, not only to the animals themselves, but also, to children and other household members. There are nontoxic ways to protect pets from fleas and other pests, and to protect human family members at the same time. Beyond Pesticides is calling on EPA to recognize, finally, that the label on flea collars is not adequately protective, as evidenced by the number of deaths and 75,000 incidents. “EPA has the authority to act now, and it should use its powers to protect the health and lives of pets,” […]

(Beyond Pesticides, July 10, 2020) A study published in June 2020 in Environmental Health journal is especially concerning for people who become, or plan to become, pregnant. It concludes that personal, agricultural, and household exposures to pesticides may increase the risk of a relatively rare fetal disorder called “holoprosencephaly.” The study finds that pre-conception and the first few weeks of pregnancy are the most vulnerable periods during which exposure can increase risk of this disorder, in which the embryo’s forebrain fails to develop into two distinct hemispheres. The study’s results reinforce Beyond Pesticide’s long-standing warnings of the dangers of pesticides to children and the necessity of shifting to a precautionary approach to the introduction and use of synthetic pesticides (and other chemicals) across all sectors. The importance of this shift is perhaps no more poignantly illustrated than in the impacts that pesticide exposure can have on new life. The study, conducted from 2016 through 2019 by researchers from NIH (the U.S. National Institutes of Health) and the University of Wisconsin–Madison, is a case-control study — one that compares subjects who have a disease or disorder with “controls” who do not have the disorder, comparing the frequency of exposure to a particular risk […]

(Beyond Pesticides, July 8, 2020) Efforts to control the transmission of malaria are encountering a big, though predictable, problem: the mosquitoes that transmit malaria are developing resistance to at least five of the insecticides that have been central to limiting transmission of the disease. A study released in late June reveals a dramatic increase in resistance to pyrethroid insecticides and DDT across sub-Saharan Africa. This signals the failure of a mainstay chemical approach to the spread of malarial mosquitoes; this same problem — resistance — is happening with chemical management of agricultural pests and weeds, and with antibiotics to treat human bacterial infections. This study underscores a point Beyond Pesticides has made repeatedly: resistance to pesticides (whether insecticides, herbicides, biocides, fungicides, or medical antibiotics) is nearly inevitable. The solution to containing the spread of malaria lies not in the use of more and different chemicals, but in nontoxic approaches that respect nature and ecological balance. Malaria is a sometimes deadly disease caused by female Anopheles mosquitoes infected with any of four varieties of the Plasmodium parasite. The disease kills roughly 400,000 people annually, with half that mortality in sub-Saharan Africa. The U.S. sees approximately 2,000 cases of malaria annually, primarily in […]

(Beyond Pesticides, March 27, 2019) Exposure to commonly used pesticides in the womb and during the first year of life is linked to a higher risk of developing autism, according to the study, “Prenatal and infant exposure to ambient pesticides and autism spectrum disorder in children: population based case-control study,” published in the journal BMJ last week. Although the study does not reveal a causal link, it adds to previous literature highlighting autism risks from pesticide exposure, and reinforces calls to limit pesticide exposure during early life critical windows of vulnerability. The authors note their findings “support the need to avoid prenatal and infant exposure to pesticides to protect the developing child’s brain.” Researchers used data from California’s records of autism disorder diagnosis and birth rates from 1998 to 2010. Roughly thirty-five thousand healthy patients acted as a control, while scientists identified nearly three thousand patients with an autism diagnosis, of which 445 also displayed a co-occurring intellectual disability. Data was then drawn from California’s pesticide use recording database, and eleven pesticides (glyphosate, chlorpyrifos, diazinon, acephate, malathion, permethrin, bifenthrin, methyl bromide, imidacloprid, avermectin, and myclobutanil) were analyzed for their use within 2000 meters (1.25 miles) of the homes of those […]

(Beyond Pesticides, February 14, 2018) Total release foggers, otherwise known as bug bombs, received updated labels from the U.S. Environmental Protection Agency (EPA) in 2011 as part of efforts to reduce accidental poisonings, but a new report from the U.S. Centers for Disease Control and Prevention (CDC) finds that EPA restrictions are a public health failure. Bug bombs pose a significant risk of acute illness to individuals even when attempting to follow new label instructions. Beyond Pesticides has long called for bug bombs to be banned, as there are a myriad of non-toxic alternative strategies to successfully manage household pests. CDC’s report, Acute Illnesses and Injuries Related to Total Release Foggers, updates a previous study released in 2008 which found significant safety concerns about bug bombs and ultimately prompted EPA to revise the labels of these products. At the time, CDC found a total of 466 illnesses or injuries associated with the use of total release foggers between 2001-2006. Incidents ranged from failing to leave an area after releasing the bug bomb, reentering the premises too early, use of too many products for the space provided, and even explosions related to the ignition of aerosols released from the product. Bug […]