(Beyond Pesticides, November 30, 2023) Scientists at Minami Kyushu University in Japan have made a groundbreaking discovery of a new biological control for a target insect. They have identified a virus in tobacco cutworms that kills males, creating all-female generations. The discovery was described in a recent issue of the Proceedings of the National Academies of Sciences and The New York Times as evidence that multiple viruses have evolved to kill male insects. This “male-killing” virus could be added to the growing attempts to control unwanted insects with biological, as distinguished from genetically engineered (GE) solutions. Efforts range from the introduction of natural predators, to radiation-based sterilization of insects, CRISPR-based genetic mutations, and other techniques. While the GE approach has run into controversy because of unanswered questions associated with their release into natural ecosystems, some approaches have also run into resistance problems. Nearly a decade ago, researchers found armyworm resistance to Bacillus thuringiensis (Bt)-incorporated genetically engineered (GE) maize in the southeastern region of the U.S., calling this evolution of insect resistance to a naturally occurring soil bacterium engineered into crops “a serious threat to the sustainability of this technology.” The general population knows to avoid eating raw eggs because the bacteria salmonella, […]

(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 7, 2023) Why is the U.S. Environmental Protection Agency (EPA) allowing the use of pesticides under the “unreasonable adverse effects” to health or the environment standard of the federal pesticide law (Federal Insecticide, Fungicide, and Rodenticide Act [FIFRA]) if the pesticides quickly lose their efficacy? Pest resistance to pesticides is a well-known biological mechanism that becomes problematic when farmers are faced with crop failure and economic loss. It becomes especially threatening when the goal is to manage insects that are a disease vector and when the regulatory process ignores nonchemical management strategies that are efficacious and sustainable. Tell EPA, Governors, and Congress that given the certainty of pesticide resistance, ecologically-based mosquito management must replace a reliance on pesticides. Insect resistance to insecticides has been an issue since the introduction of DDT in the 1940s. Although most countries currently ban DDT use, several currently used insecticides pose the same threat. In fact, resistance is predicted by elementary population genetics, and the speed of its evolution is directly related to the toxicity—that is, strength of selection pressure—and inversely related to the generation length of the organism. When that target organism of the pesticide is a disease vector, like West […]

(Beyond Pesticides, August 2, 2023) A study published in Pest Management Science finds resistance to insecticides like pyrethroids are challenging attempts to control the mosquito Aedes aegypti (Ae. aegypti), the primary transmitter (vector) of dengue fever. While this study takes place in Bangladesh, resistance to biocides—whether to antibiotics, antimicrobials, or pesticides—is growing globally. Prevention of disease outbreaks is threatened by reliance on chemical biocides to which pathogens and their vectors develop resistance. In fact, resistance is predicted by elementary population genetics, and the speed of its evolution is directly related to the toxicity—that is, the strength of selection pressure—and inversely related to the generation length of the organism. (See PAY articles here and here, a PBS article here.) Insecticide resistance has been an issue since the introduction of DDT (dichlorodiphenyltrichloroethane) in the 1940s. Although most countries currently ban DDT use, the compound is not the only chemical pesticide promoting pest resistance. Several current-use insecticides pose the same threat. Areawide, indiscriminate spraying of insecticides is causing resistance to develop among many pests. Mosquitoes have become increasingly resistant to synthetic pyrethroids, in addition to other classes of insecticides, such as carbamates and organophosphates. Thus, this study demonstrates the need for sustainable and practical strategies […]

(Beyond Pesticides, July 3, 2023) Mosquito season is upon us, and to many that means spraying pesticides to kill them. But not only is spraying flying mosquitoes the most ineffective way to prevent mosquito problems, it is also counterproductive because it eliminates some of our most attractive and helpful allies—birds. Tell EPA to eliminate pesticides that threaten birds or their insect food supply. Tell the U.S. Fish and Wildlife Service and Department of Interior to protect birds by eliminating the use of pesticides that threaten them. Tell Congress that EPA and other agencies need to do their job and protect birds and other mosquito predators. While the appetite of purple martins for mosquitoes is well known, most songbirds eat insects at some stage of their life. Many birds who eat seeds or nectar feed insects to their young, including flying insects that may be bothersome–like mosquitoes or flies. Altogether, birds consume as many as 20 quadrillion individual insects, totaling 400-500 million metric tons, per year. Mosquito-eating birds include many well-known residents of our communities. They include, for example, wood ducks, phoebes and other flycatchers, bluebirds, cardinals, downy woodpeckers, swallows, swifts, robins, orioles, wrens, great tits, warblers, nuthatches, hummingbirds, red-winged blackbirds, […]

(Beyond Pesticides, June 13, 2023) The specific compounds that comprise one’s scent influence how attractive one is to mosquitoes finds research published in the journal Current Biology by scientists at Johns Hopkins University. Although the findings focus solely on a species of malaria mosquito primarily distributed throughout Sub-Saharan Africa, the results could provide insight into broader concerns over mosquito disease transmission and public health. As it currently stands, personal protective measures and the use of least-toxic repellents are the best methods to address most mosquito problems in the United States. Scientists utilized a mixture and semi-field trials to understand first how mosquitoes became attracted to human hosts. For the field trial, a large facility the size of a college lecture hall was utilized to mimic the sort of open space mosquitoes have available to them in the wild. Eight landing boards were placed in a ring and either heated to human temperature, “baited” with carbon dioxide, or both. Researchers then released 200 mated female mosquitoes that had been starved of food. Scientists tracked the mosquitoes through infrared cameras to determine their trajectory. Only when both heat and carbon dioxide were present did scientists witness high levels of landings on the […]

(Beyond Pesticides, May 17, 2023) British biotechnology company Oxitec is withdrawing its application to release billions of genetically engineered mosquitoes in California, according to a recent update from the California Department of Pesticide Regulation. The withdrawal is a victory for environmental and health campaigners concerned about the release of a novel mosquito that the U.S. Environmental Protection Agency (EPA) had previously authorized under an “experimental use” permit. “Genetically engineered mosquitoes are an environmental justice issue for Tulare County residents who should not be human experiments,” said Angel Garcia, codirector of the statewide coalition Californians for Pesticide Reform and Tulare County resident in a press release. “We are already impacted by some of the worst pollution problems in the state and deserve prior informed consent to being part of an open-air biopesticide experiment. Ahead of any future proposal for genetically engineered insects, DPR needs to have robust regulations in place that protect community members, and meaningful, inclusive public participation in any decision making.”     Oxitec began releasing its GE mosquitoes over a decade ago, first introducing the insects in the Brazilian town of Itaberaba. The company has made efforts to launch its mosquitoes in the United States, likely as a way […]

(Beyond Pesticides, January 5, 2022) The use of insecticidal bed nets (IBNs) to prevent mosquito bites in malaria-endemic communities can result in resistance developing in secondary pests like bed bugs, according to research published in Parasites and Vectors. Decreased efficacy against bed bugs and other non-mosquito pests may result in misuse of both mosquito adulticides and bed nets, hampering efforts to stop the spread of malaria and other insect-borne disease. With resistance following a predicable pattern in both disease-transmitting and secondary pests, there is a critical need to embrace safer, nonchemical solutions, including both ecological and structural approaches to pest management. Researchers investigated the efficacy of untreated bed nets along with those treated with the commonly used synthetic pyrethroids deltamethrin and permethrin against both a population of insecticide-susceptible and pyrethroid resistant bed bugs. Insecticidal netting was secured between two glass jars in both an aggregation and blood meal experiment. For the aggregation experiment, fully fed bed bugs were set up to cross through the bed net to reach a darker resting location. With the blood meal experiment, unfed bed bugs were set up to cross the netting to receive a blood meal. Both experiments show the bed nets carrying little […]

(Beyond Pesticides, October 5, 2022) Exposure to widely used synthetic pyrethroids, present in many mosquito adulticides and household insecticides like RAID, is associated with a diagnosis of rheumatoid arthritis, according to research published in Environmental Science and Pollution Research. This is the latest pesticide-induced disease associated with this dangerous class of chemicals – a harm to individual Americans that the U.S. Environmental Protection Agency (EPA) is not considering when it registers pesticides. To remedy the major deficiencies in EPA’s reviews, and protect residents from chronic disease, more and more communities are transitioning to safer, organic pest management practices that do not require pyrethroids and other toxic synthetic pesticides. Rheumatoid arthritis (RA) is an autoimmune disease that causes systemic inflammation throughout the body, resulting in progressive damage to an individual’s joints. In the United States, roughly 1.3 million adults suffer from RA, accounting for nearly 1% of the adult population. Health care costs associated with the disease reach nearly $20 billion annually. To better understand the etiology behind the disease, an international team of researchers from China, Illinois, and Missouri analyzed data from the 2007-2014 National Health and Nutrition Examination Survey (NHANES), a long-running program that began in the early 1960s […]

(Beyond Pesticides, March 24, 2022) A range of essential oils can provide high levels of larvicidal and adulticidal activity against a commonly found species of mosquito, according to research published last week in Scientific Reports. The use of essential oils in mosquito management has generally been limited to personal protection, with synthetic pesticides often the first choice for vector control activities. This research highlights the potential role of these natural compounds to replace hazardous synthetics in managing larval sources and killing adult mosquitoes under last-resort scenarios. The team of Egyptian-based scientists conducting the study purchased 32 different essential oils from a regional retailer in order to test them on both the larval and adult stages of Culex pipiens. C. pipiens, often referred to as the common house mosquito, is the most abundant mosquito in the Northern U.S., and is known to vector West Nile virus and Saint Louis encephalitis, among other diseases. Larval efficacy was tested on the fourth instar larvae of C. pipiens, delivered through a mixture of the essential oil, water, and the solvent Tween-20, which contains the surfactant Polysorbate-20, used to emulsify the mixture. All oils tested had some level of larvicidal activity (between 60-100%). Researchers classified […]

(Beyond Pesticides, March 16, 2022) The U.S. Environmental Protection Agency has authorized the “experimental use” and release of 2.5 billion genetically engineered (GE) mosquitoes in Florida and California by the British-based firm Oxitec. While the goal of eliminating disease carrying mosquitoes is an important public health challenge, public opinion has been consistently against the use of these animals, with nearly 240,000 individuals opposing a pilot program in the Florida Keys. Health and environmental advocates have a range of concerns with Oxitec’s approach, including the size of its latest experiment, lack of publicly verifiable efficacy data, and availability of alternative management practices not requiring GE mosquitoes. Oxitec began public releases of its GE mosquitoes at least a decade ago, when mosquito larvae were introduced in the Brazilian town of Itaberaba. The company has consistently angled to launch its mosquitoes in the United States under the claim that the animals will reduce numbers of Aedes aegypti, a highly problematic mosquito known to vector a range of diseases, including dengue, yellow fever chikungunya, and Zika. Research analyzing Oxitec’s proposals note that the risk of dengue and other disease from Aedes aegypti is low in the United States. In a recent study in Globalization […]

(Beyond Pesticides, March 3, 2022) Children’s exposure to synthetic pyrethroid insecticides, particularly during the course of mosquito control operations, is associated with increased occurrence of certain respiratory diseases and allergic outcomes, finds research published in the journal Thorax late last month. With a pandemic respiratory virus continuing to spread throughout the world, it has become increasingly important to avoid environmental exposures that can harm lung health. This research underscores the critical need for homeowners, farmers, and vector control officials to shift away from chemical use as the first line of defense against pest problems in order to safeguard children’s health. A total of 303 women and their children participated in the study, which tracked pesticide exposure during pregnancy and then at age five. All participants in the study lived within roughly three miles of a banana plantation. A structured questionnaire captured a range of variables, from socioeconomic status to medical history, local environmental conditions, occupation, and demographics. Researchers collected urine samples from pregnant mothers during the first visit, and their children during the 5-year follow-up. Urine samples were analyzed for metabolites concerning a range of pesticides, including chlorpyrifos, synthetic pyrethroids, the fungicides mancozeb, pyrimethanil, and thiabendazole, and the herbicide 2,4-D. […]

(Beyond Pesticides, February 24, 2022) Widespread, intensive pesticide use for mosquito control has allowed genetic mutations to persist among mosquito populations, causing subsequent resistance to future chemical exposure. According to a study published in Scientific Reports, two common species of female mosquitoes 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. Insects, including mosquitoes, use various sensory and cognitive abilities like vision, smell, and hearing to navigate the ecosystem for survival and reproduction. Mosquitoes associate sensory stimuli like smell to a positive or negative experience, thus facilitating a response. Considering the two species of mosquitoes in this study are a vector for numerous diseases in humans, including dengue and Zika and West Nile viruses. Hence, this study highlights the significance of addressing pest resistance in pest management strategies, particularly to mitigate disease exposure and effects. The study notes, “[The] findings highlight the importance of mosquito cognition as determinants of pesticide resistance in mosquito populations targeted by chemical control.” It is essential to understand insect behavior that propagates vector-borne disease transmission that exacerbates the widespread public health crisis. Scientists attribute memory […]

(Beyond Pesticides, February 11, 2022) A team of researchers has proffered a potential, biotechnical, way forward in the quest to reduce the scourge of malaria, which affects many people across the world. Their work uses the relatively new “Crispr” technique to address, and reverse, the growing problem of mosquito resistance to the pesticides that currently dominate control strategies for the insects that spread the disease. This innovation nevertheless raises concern about both the introduction of new, genetically altered organisms into the environment without sufficient information on the implications, and continued, intensive pesticide use. Beyond Pesticides recognizes, as do the researchers, that malaria-borne mosquitoes pose a serious public health problem; however, it advocates for alternatives to chemical approaches to managing the spread of the disease, and asserts that successful management strategies will contend with the underlying conditions that exacerbate that spread. In 2020, Executive Director Jay Feldman said, “We should focus on the deplorable living conditions, and inequitable distribution of wealth and resources worldwide that give rise to squalor, inhumane living conditions, and the poor state of development that, together, breed insect-borne diseases like malaria.”     Malaria, which is spread by female Anopheles mosquitoes infected with a Plasmodium parasite, causes illness in more than 200 million people annually, and is lethal to more than 400,000, […]

(Beyond Pesticides, November 16, 2021) Populations of disease-carrying mosquitoes are higher in urban areas of lower socioeconomic status, according to research published this year in the Journal of Urban Ecology. With insect-borne diseases on the rise due to a rapidly changing climate, it is critical to highlight disease patterns and target aid to communities at greatest risk. While pesticide use is often the knee-jerk reaction to high mosquito populations, it is critical not to compound health risks through toxic chemical use. The factors that lead to higher rates of disease-carrying mosquitoes can be remedied through considerate planning and targeted, consistent investment in sustainable infrastructure. To determine the prevalence of mosquito populations, in particular populations of disease-carrying Aedes aegypti, along a gradient of socioeconomic status, researchers began their work in San Juan, Puerto Rico. Eight neighborhoods across the region were categorized based on socioeconomic factors such as household income, population density, health coverage, unemployment level, education, and the amount of trash and abandoned homes in the area.  Mosquitoes were sampled from October 2018 to May 2019, using six mosquito traps per neighborhood. A total of over 12,000 mosquitoes were trapped over the course of the study, with nearly 90% of traps […]

(Beyond Pesticides, September 28, 2021) A widely used mosquito pesticide may exacerbate the effect of the Zika virus on fetal brain development, according to research published by an international team of scientists in the journal Environmental Pollution. Pyriproxyfen, an insect growth regulator often used as a mosquito larvicide, is registered for use in hundreds of commonly used pesticide products. But scientists have discovered that the pesticide’s mode of action has the potential to worsen the public health mosquito diseases the chemical aims to control. The research reinforces the extent of unknowns associated with synthetic pesticide exposure, underlining the need for a focus on nontoxic and ecological mosquito management. Scientists base their research on reports that in Brazil, during the 2015 Zika epidemic, certain areas of the country experienced higher rates of microcephaly. Microcephaly is a rare condition that causes pregnant women’s fetus to develop severe cranial deformities, alongside a range of other symptoms that include vision problems, hearing loss, feeding issues, developmental delays and seizures. The present study aimed to see how pyriproxyfen, used at higher rates in areas where microcephaly Zika cases were recorded, may interact with the virus. In an article published in The Conversation, researchers note that […]

(Beyond Pesticides, July 27, 2021) Researchers at North Carolina State University have developed pesticide-free clothing able to prevent 100% of mosquito bites for the wearer, and published proof of the garment’s effectiveness in a study in the journal Insects. If able to be scaled at a commercial level, the fabrics have the potential to transform personal protective measures for mosquitoes, which often includes in well-meaning consumers spraying toxic pesticides like DEET and permethrin on their body and clothing. “The fabric is proven to work – that’s the great thing we discovered,” said study co-author Andre West, associate professor of fashion and textile design at NC State and director of Zeis Textiles Extension for Economic Development in a press release. “To me, that’s revolutionary. We found we can prevent the mosquito from pushing through the fabric, while others were thick enough to prevent it from reaching the skin.” To create the mosquito-proof fabric, scientists turned to physics and mathematical models, rather than looking for new killer chemistries. “Our premise here is: why do we need an insecticide-treated textile when you can do it, now that you know a mathematical formula, without chemistry?” said Michael Roe, PhD, an N.C. State professor of entomology […]

(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, March 19, 2021) As reported by VTDigger, Vermont’s Endangered Species Committee recently took action to uphold the state’s endangered species law. The committee announced that a mosquito control program in the Champlain Valley, which uses the toxic pesticides malathion and permethrin, is threatening five species of endangered bats — all of which are on Vermont’s list of threatened and endangered species. The committee voted unanimously to recommend to the state Secretary of the Agency of Natural Resources that the spraying program in the Brandon, Leicester, Salisbury, Goshen, Pittsford Insect Control District be allowed only via special permit. Learn about safer mosquito management and insect-borne diseases at Beyond Pesticides website pages. The bats inhabit the Insect Control District’s five towns, which are host to important feeding habitat for these creatures, as well as maternal roosting colonies where baby bats are born and raised during the months when the pesticides are typically sprayed. In addition, the nighttime spraying of these compounds along 190 miles of road in these communities hangs in the air for hours, putting nocturnally active bats — who fly through the toxic mist or consume insects contaminated with the chemicals — at risk. Mason Overstreet of Vermont […]

(Beyond Pesticides, March 3, 2021) Earlier this week, pesticide regulators in the commonwealth of Massachusetts voted to restrict outdoor consumer uses of neonicotinoid insecticides. The move is the result of sustained advocacy from broad coalition of individuals and organizations focused on protecting pollinators and ecosystem health. While advocates are pleased that the Pesticide Board Subcommittee made Massachusetts the first state in the country to restrict neonicotinoids through a regulatory process, they note this is only the first step in eliminating these hazardous insecticides. “This marks an incremental victory which took us 6 years to land, and it only happened because of immense, ongoing grassroots action and legislative allies who are willing to hold state regulators accountable,” said Martin Dagoberto, Policy Director of the Northeast Organic Farming Association, Mass. Chapter in a press release. “We still have a monumental endeavor ahead if we are to reduce toxins and rein in the toxic influence of the chemical lobby,” Mr. Dagoberto added. Advocates had been pushing the legislature to pass An Act to protect Massachusetts Pollinators, sponsored by pollinator champion Representative Carolyn Dykema, since 2014. Following several failures by state lawmakers to bring the bill over the finish line, efforts in 2019 resulted […]

(Beyond Pesticides, September 16, 2020) Disease carrying mosquitoes are more likely to flourish in areas being altered by human activities, according to new research published by scientists at Oregon State University. With climate change facilitating the spread of mosquitoes into new regions throughout the world, it is critical to understand the drivers of mosquito-borne disease in order to establish effective mitigation measures. “People care a lot about what environment a lion needs to succeed in; we’ve researched that extensively. But people don’t do that with mosquitoes. We don’t understand them as a group of species and how their ecology differs between species,” said study co-author Brianna Beechler, PhD, a disease ecologist and assistant professor of research in Oregon State University’s Carlson College of Veterinary Medicine. Authors of the study note that most mosquito collection occurs opportunistically, with samples taken at known mosquito breeding sites. To better understand mosquito spatial ecology, scientists conducted paired sampling at locations inside and outside South Africa’s Kruger National Park, the largest nature preserve in the country. Each sample location inside the park was paired with another sample from a similar location (in terms of landscape and climatic conditions) in developing areas outside of the park. […]

(Beyond Pesticides, September 2, 2020) It’s being called the Monarch Massacre—hundreds of monarch butterflies found dead after the Vector Control Department of Cass County, North Dakota aerially sprayed the county for mosquito control. This incident occurred during a moment in history that is seeing monarchs at the edge of extinction, with the number of monarch butterflies overwintering in Mexico having declined 53% from last year, according to a count conducted by World Wildlife Fund (WWF) Mexico. This tragedy happened as the nation and the world are experiencing an insect apocalypse and severe biodiversity decline, threatening the web of life. (See Study Predicts Demise of Insects within Decades if Pesticide Dependence Continues.) While it is critical that steps be taken by communities nationwide to protect their local ecology, the incident generated a response from Cass County that claims that the insecticides used are “the lowest toxicity products on the market for mosquito control,” and points to the “monarch migration [that] is a sporadic event that unfortunately occurred during the latest adult mosquito control application.”  The County justifies the spraying because of nuisance mosquitoes and a finding in the “surrounding communities” of mosquitoes carrying West Nile virus (WNv). In its Facebook statement, the County […]

(Beyond Pesticides, August 4, 2020) Last month Massachusetts lawmakers finalized, and the Governor subsequently signed, emergency legislation S.2757, aimed at revamping the state’s approach to mosquito management. The final version of this mosquito reform bill continues to include certain problematic provisions, but nonetheless represents a significant shift from an initial proposal that would have allowed the blanket spraying of mosquito adulticides throughout the Commonwealth with little oversight, notification, or transparency. “Though many cooks had a hand in the process, the resulting final bill was strengthened by advocates,” said state Senator Jo Comerford, Chair of the state’s Joint Committee on Public Health, in an emailed statement to supporters. “I’m pleased that we were able to build in strong protections for both the environment and human health.” The original bill was filed by Massachusetts Governor Charlie Baker (R) under emergency legislative provisions, requiring state lawmakers to act within a set period of time. The Massachusetts Department of Public Health (DPH) had indicated that this year would bring higher risks of mosquito-borne disease, particularly Eastern Equine Encephalitis (EEE), for which outbreaks generally last two or three years. The state saw 12 human cases of EEE and four deaths from the disease in 2019; […]