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Pyrethrum

Pyrethrum is the powdered or extracted form of the dried flower heads from Tanacetum cinerariifolium (synonym Chrysanthemum cinerariifolium), a perennial herbaceous plant in the Asteraceae family native to the Balkan Peninsula and Caucasus region, valued primarily for its natural insecticidal properties derived from pyrethrins.^[1]^[2] These pyrethrins consist of six closely related esters—pyrethrin I and II, cinerin I and II, and jasmolin I and II—that occur in the glandular trichomes of the plant's inflorescences and function as neurotoxins, rapidly paralyzing and killing insects by prolonging sodium channel opening in their nerve cells while exhibiting low toxicity to mammals due to differences in body temperature and detoxification enzymes.^[1]^[3]^[2] Historically, pyrethrum's insect-repellent qualities were recognized in the Middle East as early as the 17th century, with trade reaching Europe by the 18th century; commercial extraction began in the 19th century in regions like Dalmatia (modern-day Croatia), and production surged during World War I to meet demand for delousing agents, leading to widespread cultivation in Kenya starting in the 1920s.^[1]^[4] As of 2024, global pyrethrum production of dried flowers is dominated by East African countries, with Tanzania, Rwanda, and Kenya together supplying over 80% of the world's pyrethrins (derived at 1–2% content from the flowers)—approximately 8,000 metric tons from Tanzania, 3,500 from Rwanda, and 1,000 from Kenya—as well as output from Australia (particularly Tasmania) and Ecuador, where the crop is grown at high altitudes (1,800–3,000 meters) for optimal pyrethrin content.^[5]^[6]^[7] As a key component in organic pest management, pyrethrum is formulated into over 2,000 registered products worldwide, including agricultural sprays for crops like fruits and vegetables, household aerosols against flies and ants, pet shampoos for fleas, and public health tools such as insecticide-treated bed nets for malaria control, prized for its broad-spectrum efficacy, quick degradation in sunlight (half-life of about 12 hours), and minimal environmental persistence compared to synthetic alternatives.^[2]^[3]^[1] Despite its safety profile—classified by the EPA as low acute toxicity to humans, with primary effects limited to skin irritation or respiratory symptoms from high exposure—pyrethrum remains highly toxic to beneficial insects like bees and aquatic organisms like fish, necessitating careful application to avoid non-target impacts.^[2]^[3]

Botanical Overview

Description and Morphology

Pyrethrum (Tanacetum cinerariifolium) is a herbaceous perennial plant in the Asteraceae family, characterized by its tufted growth habit and slender, erect stems that reach heights of 50–80 cm. The leaves are alternate, pinnately divided into fern-like segments, gray-green in color, and densely covered with white tomentum on both surfaces. This woolly covering gives the foliage a distinctive silvery appearance.^[8]^[9] The plant produces daisy-like flower heads (capitula) measuring 2–3 cm in diameter, borne singly on rigid stems. Each capitulum features 18–22 white ray florets surrounding 40–100 yellow disc florets, arranged on a convex receptacle within an involucre of 12–18 mm diameter. Flowering typically occurs in summer, with the plant exhibiting a short-lived perennial life cycle, though it can be managed as an annual in cultivation. Native to the Balkan Peninsula, particularly the Dalmatia region along the eastern Adriatic coast, from sea level to elevations up to about 1,300 m, it forms shallow fibrous roots.^[9]^[10]^[8] Pyrethrum prefers temperate climates and well-drained, fertile soils rich in phosphorus, calcium, and magnesium, with a neutral to slightly alkaline pH of 6.0–7.5. It thrives at elevations of 1500–2500 m in commercial settings, where cooler temperatures enhance growth. Key cultivars, such as those selected in Kenya, are prized for their elevated pyrethrin content (up to 2.0%) while maintaining the standard flower morphology of ray and disc florets.^[11]^[12]^[13]^[14]

Taxonomy and Species

Pyrethrum is scientifically classified under the binomial nomenclature Tanacetum cinerariifolium (Trevir.) Sch. Bip., with notable synonyms including Chrysanthemum cinerariifolium (Trevir.) Vis. and Pyrethrum cinerariifolium Trevir..^[15]^[16] The species belongs to the genus Tanacetum within the Asteraceae family, a diverse group of flowering plants in the order Asterales, where pyrethrins—its key secondary metabolites—have evolved primarily as a chemical defense mechanism against herbivorous insects and pathogens.^[17]^[18] Within the Tanacetum genus, which encompasses around 160 species of mostly perennial herbs, T. cinerariifolium stands out for its high-yield production of pyrethrins, rendering it the only commercially viable species for insecticide extraction.^[19] Related species include Tanacetum coccineum, known as the painted daisy and primarily cultivated as an ornamental for its vibrant flowers, which produces only trace amounts of pyrethrins insufficient for commercial use; and Tanacetum parthenium, or feverfew, valued for its medicinal properties due to sesquiterpene lactones like parthenolide but lacking significant pyrethrin content.^[17]^[20] These distinctions highlight T. cinerariifolium's specialized biochemical adaptations within the genus. The common name "pyrethrum" derives from the Greek word pyretos, meaning "fever," reflecting the plant's historical application in traditional medicine to treat febrile conditions, though its insecticidal properties later became the focus of its nomenclature.^[21]

Historical Development

Traditional Uses

Pyrethrum has been valued for its insecticidal properties since ancient times. The earliest recorded use dates to around 400 BC in Persia, where dried flower powder was used to delouse children during the reign of King Xerxes.^[22] Indigenous communities in the Balkans, particularly in Croatia's Dalmatian region, have long employed ground dried pyrethrum flowers as a household insecticide to protect stored grains from insect infestation and as a natural repellent in agricultural settings.^[10] Following its introduction in the 1920s, small-scale farmers in Kenya and Tanzania have applied pyrethrum dust or infusions for fumigation to safeguard stored grains and repel pests in subsistence farming.^[23]

Modern Commercialization

Commercial extraction of pyrethrum began in the 1820s in Dalmatia (modern-day Croatia), where dried flowers of Tanacetum cinerariifolium (synonym Chrysanthemum cinerariifolium) were processed into insecticidal powders. These powders were exported to France, where they were commercialized for use in early insecticide formulations targeting household pests.^[24] In the 20th century, British colonial authorities introduced pyrethrum cultivation to Kenya in the late 1920s, initially by European settlers in high-altitude regions suitable for the crop, marking the start of organized production in Africa. By the 1930s, expansion efforts supported by colonial agricultural services transformed it into a key cash crop, with Kenya emerging as the world's largest producer by the 1950s, accounting for over 70% of global supply through exports of dried flowers. The surge in demand during World War II, driven by military needs for effective, low-toxicity insecticides amid shortages from Japanese sources, further boosted Kenyan output as a preferred alternative to emerging synthetics like DDT.^[25]^[26]^[27] Post-war, pyrethrum's dominance waned in the 1950s and 1960s due to the development of cheaper, more stable synthetic pyrethroids, such as allethrin in 1949, which offered greater persistence and scalability for agricultural use. Global production shifted toward these analogs, leading to a sharp decline in natural pyrethrum demand and reduced cultivation in traditional areas. A revival began in the 1990s, fueled by growing interest in organic farming and restrictions on synthetic pesticides, repositioning pyrethrum as an eco-friendly option and restoring its role in integrated pest management.^[28]^[19]^[29] Today, pyrethrum production centers on Kenya, Tanzania, and Ecuador, where smallholder farmers predominate and the crop supports rural livelihoods through stable income from biweekly harvests. In Kenya, ongoing revival initiatives since 2017 have distributed millions of seedlings to over 15,000 households, benefiting more than 100,000 farmers economically by funding education, local businesses, and food security. Typical yields range from 500-800 kg/ha of dry flowers, contributing to global organic insecticide supply amid rising demand for sustainable alternatives.^[30]^[31]

Chemical Properties

Active Compounds: Pyrethrins

Pyrethrins are the principal insecticidal constituents extracted from the dried flowers of Tanacetum cinerariifolium, comprising a mixture of six structurally similar esters that account for the plant's natural pesticidal properties. These compounds are biosynthesized in the glandular trichomes of the flower heads and serve as a defense mechanism against herbivorous insects.^[1] The six pyrethrins are classified into two groups based on their acid components: pyrethrin I, cinerin I, and jasmolin I, which are esters of chrysanthemic acid (a cyclopropanecarboxylic acid); and pyrethrin II, cinerin II, and jasmolin II, which are esters of pyrethric acid (a related acid with an additional carboxyl group). Each is formed by esterification with one of three alcohol moieties (pyrethrolone, cinerolone, or jasmololone), resulting in the following molecular formulas: pyrethrin I (C₂₁H₂₈O₃), cinerin I (C₂₀H₂₈O₃), jasmolin I (C₂₁H₃₀O₃), pyrethrin II (C₂₂H₂₈O₅), cinerin II (C₂₁H₂₈O₅), and jasmolin II (C₂₂H₃₀O₅).^[32]^[1] The insecticidal potency of pyrethrins is critically dependent on their stereochemistry, particularly the (1R,3R)-trans configuration of the cyclopropane ring in the acid moiety and specific configurations in the alcohol portion, with only certain stereoisomers exhibiting significant bioactivity. Pyrethrins typically represent 1–2% of the dry weight of pyrethrum flowers, with concentrations varying by cultivar and environmental factors; the highest levels are concentrated in the achenes (seed-like structures) of the flower heads.^[1]^[32] Pyrethrins act primarily by binding to a distinct site on voltage-gated sodium channels in insect nerve membranes, slowing channel activation and inactivation while prolonging the open state, which causes repetitive spontaneous firing of action potentials. This disruption leads to hyperexcitation, uncoordinated tremors, paralysis, and rapid knockdown of target insects, often within minutes of exposure. Their short residual activity stems from instability in environmental conditions, as pyrethrins degrade quickly via photolysis and oxidation when exposed to sunlight and air.^[33]^[1]

Extraction and Formulation

The extraction of pyrethrins from pyrethrum flowers primarily involves solvent-based methods to isolate these active esters from the dried flower heads of Tanacetum cinerariifolium. Traditional solvent extraction uses non-polar solvents such as hexane, which is applied to ground flowers in a percolation or immersion process, yielding a crude oleoresin containing 20-50% total pyrethrins by weight.^[34] This oleoresin represents a concentrated form of the natural insecticidal compounds, with the solvent recovered through evaporation to minimize losses. Alternatively, supercritical carbon dioxide (CO₂) extraction has gained prominence as an environmentally friendly method, operating at pressures of 100-300 bar and temperatures around 40-60°C to selectively extract pyrethrins while avoiding residual solvents; yields from this process typically achieve 1-2% extraction efficiency from dry flower material, producing an oleoresin of comparable pyrethrin content to solvent methods.^[35]^[36] Following initial extraction, purification steps remove impurities like waxes, pigments, and plant debris to enhance the purity and stability of the pyrethrin concentrate. Filtration through celite or similar media separates solid residues, followed by distillation—often under vacuum to prevent thermal degradation—to eliminate residual solvents and volatile impurities, achieving a refined extract with 45-60% pyrethrin concentration.^[37] Recovery efficiencies in these purification processes generally range from 70-100%, depending on the scale and conditions, with supercritical methods often attaining higher selectivity and near-complete pyrethrin recovery.^[38]^[39] Commercial formulations of pyrethrum extracts are developed to suit various application needs, incorporating the purified pyrethrins into stable delivery systems. Common types include emulsifiable concentrates (ECs), which mix pyrethrins with surfactants and solvents for dilution in water; dusts, blending the extract with inert carriers like talc for direct application; and aerosols, where pyrethrins are suspended in propellants for fogging.^[40] To counter the rapid degradation of pyrethrins by oxidation and UV light, synergists such as piperonyl butoxide are added at ratios of 2-10:1, inhibiting insect detoxifying enzymes and extending efficacy without altering the natural profile.^[41] Quality control in pyrethrum processing ensures consistent potency through standardization of the final extract to 25-50% total pyrethrins, verified by high-performance liquid chromatography (HPLC) analysis of the six key components (pyrethrin I and II, cinerin I and II, jasmolin I and II).^[41] This standardization aligns with regulatory requirements, such as those in the United States specifying 45-55% w/w pyrethrins for technical-grade products, facilitating reliable performance in end-use insecticides.^[41]

Agricultural Production

Cultivation Practices

Pyrethrum cultivation requires careful site selection to optimize growth and pyrethrin content. In high-altitude East African regions like Kenya and Tanzania, which dominate global production, cool conditions between 1,500 and 2,500 meters above sea level are favored, with temperatures ranging from 15°C to 20°C and a period below 18°C for at least six weeks to initiate flowering.^[11]^[42] In contrast, in Tasmania (Australia), cultivation occurs at lower altitudes (typically 100–500 m) in cool temperate climates, relying on supplementary irrigation to mimic highland conditions. Ecuadorian production emphasizes altitudes up to 3,000 m for optimal pyrethrin levels.^[43]^[44] Annual rainfall of 800 to 1,200 mm, well-distributed throughout the year, is essential in East Africa, though a minimum of 750 mm suffices in areas with lower evaporation; semi-arid conditions with cool winters enhance productivity.^[11]^[42] Soils should be well-drained sandy loams or loamy volcanic types rich in organic matter, with a pH of 5.5 to 7.0 to prevent nutrient deficiencies or toxicity; waterlogging must be avoided to reduce disease risk.^[11]^[42] The perennial herbaceous morphology of pyrethrum, with its shallow root system, aligns well with these fertile yet non-excessively rich soils.^[45] Planting typically involves seed propagation, where seedlings are raised for 5 to 8 months and transplanted before the rainy season to establish roots in East African systems, though vegetative cuttings from healthy clones can be used for uniformity in commercial fields. In Tasmania, direct seeding in late winter is common, with a longer establishment phase.^[11]^[42]^[46] Optimal spacing is 30 to 60 cm between plants within rows spaced 60 to 70 cm apart, allowing approximately 21,000 plants per acre to balance airflow and light exposure.^[11]^[42] Crop rotation with legumes, such as beans or clover, every 3 to 4 years is recommended to restore soil nitrogen and mitigate depletion from the nutrient-demanding perennial growth cycle.^[11] Fertilization focuses on phosphorus and nitrogen to support root development and foliage, with applications of 50 to 100 kg per hectare of phosphorus (e.g., triple superphosphate at 50-60 kg per acre) and complementary nitrogen sources, alongside 4 tonnes per acre of farmyard manure incorporated three months prior to planting.^[11]^[42] In acidic soils (pH below 5.6), lime or gypsum is added to adjust pH, while balanced NPK fertilizers ensure steady nutrient supply without excess that could dilute pyrethrins.^[42] Irrigation, particularly drip systems, is employed in drier regions like parts of East Africa or Tasmania to supplement rainfall during establishment and dry spells, maintaining consistent moisture without overhead wetting that promotes foliar diseases.^[11]^[43] Pest and disease control relies on integrated management practices to maintain organic certification, avoiding synthetic chemicals that could contaminate pyrethrins.^[11] Common pests include aphids, thrips (such as flower and leaf thrips), whiteflies, and root-knot nematodes, managed through biological agents like predatory insects, resistant varieties, and cultural methods such as annual cut-back and burning of stalks to disrupt life cycles.^[45]^[47] Diseases like root rot, caused by fungal pathogens in poorly drained soils, are prevented by site preparation, rotation, and avoiding overhead irrigation; organic biopesticides derived from neem or other botanicals supplement monitoring and rogueing of infected plants.^[11]^[45]

Harvesting and Yield

In East African cultivation, harvesting of pyrethrum flowers begins approximately four months after transplanting, with subsequent picks occurring every two weeks during the flowering season, which typically spans 3 to 5 cycles over 4 to 6 months depending on the cultivar and environmental conditions. In Tasmania, the first harvest occurs 14–18 months after seeding. Flowers are selectively picked by hand when about 50% are open, with ray florets horizontal and 3 to 4 outer disc florets visible, to maximize pyrethrin content while minimizing contamination from leaves or immature buds.^[42]^[46] The preferred hand-picking technique involves holding the flower head between the first and second fingers and jerking it free with the thumb, ensuring only clean capitula are collected and avoiding rainy conditions that could lead to fermentation.^[42] Following harvest, flowers must be dried promptly to preserve pyrethrins, the active insecticidal compounds, which are sensitive to light, heat, and moisture. Traditional sun drying reduces moisture content to around 10%, but controlled methods such as oven drying at 50°C for 21 hours or using solar dryers yield higher pyrethrin retention, achieving up to 1.44% extractable content compared to 1.02% in direct sunlight.^[48] Dried flowers are then stored in cool, dark, well-ventilated containers like baskets to prevent degradation from oxidation or microbial activity, maintaining potency for extraction.^[42] Yields of dry pyrethrum flowers typically range from 250 to 1,200 kg per hectare, with lower outputs (around 250 kg/ha) in the first year increasing to 1,000–1,200 kg/ha in subsequent years under optimal conditions. Pyrethrin yields vary from 8 to 20 kg per hectare, influenced by cultivar, altitude, and soil; for instance, production in the Kenyan highlands often reaches 700–1,000 kg/ha of dry flowers due to cooler temperatures that enhance pyrethrin concentration (1.8–2.2%), while Tasmanian yields can average around 1,700 kg/ha.^[49]^[42]^[50] Improper post-harvest handling, such as exposure to sunlight during drying or temperatures exceeding 50°C, can cause significant pyrethrin degradation, with losses of 20–30% reported from isomerization to inactive forms or hydrolysis at moisture levels above 10%. These factors underscore the importance of timely drying and protected storage to minimize economic losses for producers.^[48]

Insecticidal Applications

As Natural Insecticide

Pyrethrum extracts, rich in pyrethrins, serve as a broad-spectrum natural insecticide effective against a wide range of pests, including flying insects such as mosquitoes and flies, crawling insects like cockroaches and ants, and agricultural pests including aphids and beetles.^[2]^[51] This efficacy stems from the compounds' ability to disrupt insect nervous systems, leading to rapid paralysis and death, while their biodegradable nature minimizes long-term environmental residue.^[2] Pyrethrum is particularly valued in integrated pest management for its low toxicity to mammals and quick degradation in sunlight and air, making it suitable for both household and field applications.^[51] Common application forms include liquid sprays at concentrations of 1-2%, dust formulations at 0.5-1%, and aerosol fogging systems for broader coverage.^[2] Sprays are typically diluted in water or oil for direct application on plants or surfaces, targeting pests like aphids on crops or ants in homes.^[52] Dusts provide residual control in soil or storage areas, while fogging—often using ultra-low volume techniques—is employed in public health efforts, such as mosquito control to combat malaria transmission.^[2]^[53] Pyrethrum's efficacy is characterized by rapid knockdown, often within 5-15 minutes of exposure, due to immediate neurotoxic effects on insects. However, its short persistence—typically 1-2 days in the environment—necessitates reapplication for sustained control, with half-lives of about 12 hours on surfaces exposed to sunlight, but 2-10 days in soil under aerobic conditions.^[2]^[54] This transience aligns well with organic farming practices, where pyrethrum is applied to over 100 crops to manage pests without violating certification standards.^[51] Regulatory bodies have approved pyrethrum for organic use, with the U.S. EPA registering pyrethrins since the 1950s and listing them as compliant for organic production on more than 200 fruits and vegetables.^[2]^[55] In the EU, pyrethrins are authorized under Regulation (EC) No 1107/2009 for plant protection and organic farming, subject to national conditions.^[56] Examples include household aerosol products for indoor pest control and crop protectants like EverGreen Pyrethrum Concentrate for agricultural use.^[57]^[58]

Companion Planting and Organic Gardening

Pyrethrum (Tanacetum cinerariifolium), a perennial daisy known for its insect-repelling qualities, plays a key role in companion planting strategies within organic gardening. While pyrethrins provide insecticidal properties, the plant is traditionally used in companion planting for potential repellency, possibly due to volatile compounds, though scientific evidence for strong protective effects is limited. It is intercropped with crops such as roses, tomatoes, and cabbage to deter pests like aphids and whiteflies. Recent genetic studies (2024) have uncovered mechanisms enhancing pyrethrum's potential as a companion plant in eco-friendly pest management.^[59]^[60]^[61]^[62] In permaculture and biodynamic systems, pyrethrum contributes to holistic pest management by fostering biodiversity in mixed plantings, where it integrates seamlessly with other species to suppress insect populations naturally. Practical examples include using it in mixed borders alongside vegetables, which can significantly decrease the overall need for external pesticides while enhancing ecosystem resilience. Its compatibility with organic standards stems from the eco-friendly degradation of pyrethrins, making it a preferred choice for certified organic operations.^[63]^[64] For home gardeners, pyrethrum excels as a border plant around vegetable patches or as a companion to fruit trees, where it provides ongoing protection against aerial pests like thrips and beetles. Propagation is simple and accessible: sow seeds on the soil surface in spring under light exposure for germination, or divide established clumps every 2-3 years in early spring or fall to propagate new plants and prevent overcrowding. Well-drained soil and full sun ensure vigorous growth, allowing gardeners to establish colonies that offer season-long benefits.^[65]^[66] Despite its advantages, pyrethrum's efficacy in companion planting has limitations; it primarily targets above-ground, soft-bodied insects and offers minimal control over soil-dwelling pests due to the localized action of its compounds. Achieving optimal repulsion often necessitates dense plantings to create an effective perimeter, as sparse arrangements may allow pests to bypass the barrier.^[61]

Toxicity and Environmental Impact

Mammalian Toxicity

Pyrethrins, the active compounds in pyrethrum, exhibit low acute toxicity to mammals, with oral LD50 values in rats ranging from 1,030 mg/kg in females to 2,370 mg/kg in males, classifying them as slightly toxic under EPA Toxicity Category III for acute oral exposure.^[67] This low toxicity profile stems from their rapid detoxification in mammalian systems, in contrast to the prolonged action on insect sodium channels.^[68] Exposure to pyrethrum concentrates can cause mild skin irritation, including paresthesia (tingling or numbness) and contact dermatitis, particularly in occupational settings or with direct handling.^[67] Eye contact may result in mild irritation and excessive lacrimation, while inhalation of aerosols or dusts can lead to respiratory tract irritation, such as nasal or throat discomfort and, in rare cases, labored breathing.^[68] Allergic reactions, known as pyrethrum dermatitis, are uncommon but can manifest as skin rashes, urticaria, or hypersensitivity responses like respiratory distress in sensitized individuals.^[69] In mammals, pyrethrins undergo rapid metabolism primarily through hydrolysis of the ester bond by carboxylesterases in the liver, followed by oxidation via cytochrome P450 enzymes, resulting in nontoxic metabolites excreted mainly in urine.^[67] The elimination half-life is short, typically ranging from 6 to 12 hours in blood and tissues, preventing significant bioaccumulation even with repeated low-level exposures.^[68] Safety guidelines recommend using personal protective equipment (PPE), such as gloves, long sleeves, eye protection, and respirators, during handling or application of pyrethrum formulations to minimize dermal, ocular, and inhalation risks. At recommended low doses, pyrethrins are generally safe for mammalian pets like dogs, but they pose a higher toxicity risk to cats due to their inefficient glucuronidation pathway, which impairs detoxification and can lead to severe neurological symptoms like tremors and seizures even from spot-on products intended for other animals.^[70]

Effects on Non-Target Organisms

Pyrethrins, the active compounds in pyrethrum, exhibit high toxicity to beneficial insects, including pollinators and predators essential for ecosystem balance. Honey bees (Apis mellifera) are particularly vulnerable, with an acute contact LD50 of 0.022 μg per bee, classifying pyrethrins as highly toxic and capable of causing rapid paralysis and death upon exposure.^[71] Predatory insects such as wasps also face significant risks, as pyrethrins disrupt sodium channels in their nervous systems, leading to mortality rates exceeding 80% in direct contact scenarios similar to those observed in field applications.^[72] To mitigate these impacts, applications are recommended in the late evening or early morning when foraging activity is minimal, allowing partial degradation before peak insect activity resumes.^[73] Among wildlife, birds experience moderate risk due to low oral toxicity, with acute LD50 values exceeding 2000 mg/kg body weight in species like the bobwhite quail, indicating practical non-toxicity under typical exposure levels. In contrast, fish and amphibians face higher threats, as pyrethrins are extremely toxic to aquatic vertebrates; for instance, the 96-hour LC50 for rainbow trout is 5.1 μg/L, and for sheepshead minnows it is 16 μg/L, with amphibians showing comparable sensitivity due to shared ectothermic physiology.^[74] In aquatic environments, pyrethrins pose risks to non-target invertebrates despite their relatively short persistence. They strongly bind to sediments, with an adsorption coefficient (Kd) of approximately 302 L/kg, reducing bioavailability in water columns but concentrating exposure for benthic organisms. Species like the water flea (Daphnia magna) are highly susceptible, exhibiting an EC50 of 11.6 μg/L for immobilization, which disrupts populations of grazers and prey in freshwater systems. Photodegradation accelerates breakdown under sunlight, with a half-life of 11.8 hours in water, or up to 14-17 days in darkness, prolonging potential harm during low-light periods.^[75] Field trials underscore these effects, revealing approximately 10-fold higher mortality in non-target arthropods following pyrethrin applications compared to control areas, particularly among small-bodied species in sprayed areas, though larger arthropods often recover due to the compounds' rapid dissipation.^[76] These impacts highlight the need for targeted use to preserve biodiversity, contrasting with lower risks to mammals where safety margins are broader.

Ecological Considerations

Pyrethrins, the active compounds in pyrethrum, exhibit rapid environmental degradation primarily through photolysis upon exposure to sunlight and hydrolysis in aqueous environments, with additional breakdown via microbial activity in soil. These processes result in low persistence, with half-lives (DT50) in soil typically ranging from 2.2 to 9.5 days under aerobic conditions, contrasting with the longer persistence of many synthetic alternatives.^[2] In terms of sustainability, pyrethrum production aligns with organic farming principles by minimizing chemical inputs and reducing runoff into waterways, thereby supporting soil health in regions like Kenya where it is predominantly grown. However, reliance on monoculture practices in these highland areas can lead to biodiversity erosion, as intensive cultivation diminishes habitat diversity and increases vulnerability to pests and diseases, prompting recommendations for crop rotation and intercropping to mitigate these effects.^[11]^[77] Pyrethrum cultivation demands well-distributed annual rainfall of 800 to 1,200 mm, often supplemented by irrigation in drier seasons, which can elevate local water consumption to significant levels depending on soil and climate conditions in production zones. Additionally, the carbon footprint of pyrethrum is influenced by the transportation of dried flowers from remote farms in Kenya to processing facilities, contributing an estimated 7.74 kg CO₂e per kg of product at the farm gate, though overall emissions remain lower than those of persistent synthetic pesticides due to its biodegradable nature.^[11]^[78] Conservation efforts surrounding pyrethrum emphasize its integration into agroecological systems through integrated pest management (IPM), where it serves as a targeted, low-residue option that preserves beneficial insects and soil ecosystems. By prioritizing biological and cultural controls alongside selective pyrethrum applications, IPM frameworks enhance biodiversity in treated fields and position pyrethrum as a viable green alternative in sustainable agriculture, reducing reliance on broad-spectrum chemicals that harm non-target species.^[79]^[80]

Synthetic Pyrethroids

Synthetic pyrethroids are man-made insecticides chemically derived from the natural pyrethrins found in pyrethrum flowers, with modifications to enhance stability and efficacy. The development of these compounds began in the late 1940s when the first synthetic analog, allethrin, was created at the United States Department of Agriculture (USDA) in 1949 through structural modifications of pyrethrin esters to improve insecticidal activity while addressing the natural compounds' rapid degradation.^[28] Subsequent advancements in the 1960s and 1970s at Rothamsted Research in the UK led to more stable variants, including resmethrin in 1967 and permethrin, which was synthesized and patented in 1973, marking a breakthrough in photostable pyrethroids suitable for outdoor use.^[4] Synthetic pyrethroids are classified into two main types based on their chemical structure and toxicological effects. Type I pyrethroids, lacking an α-cyano group, include compounds like allethrin, permethrin, and resmethrin; these exhibit rapid knockdown of insects by disrupting sodium channels in nerve cells, leading to quick paralysis and death.^[1] Type II pyrethroids, which contain the α-cyano group, such as cypermethrin and deltamethrin, are generally more potent and provide longer residual activity due to slower metabolism in target pests, often causing convulsions in addition to knockdown.^[1] Structural alterations, particularly in the alcohol and acid moieties of the pyrethrin backbone, were key to achieving this stability against light, heat, and oxidation.^[81] Compared to natural pyrethrins, synthetic pyrethroids offer significant advantages, including enhanced photostability that prevents rapid breakdown under sunlight, allowing efficacy to last weeks rather than hours or days.^[1] They are also more cost-effective to produce at scale and require lower application rates for equivalent control, making them economical for large-scale use.^[82] These properties have enabled widespread adoption in agriculture for crop protection against pests like aphids and bollworms, as well as in veterinary applications such as flea and tick collars for pets.^[83]^[84] By the 2020s, synthetic pyrethroids dominated the insecticide market, accounting for over 90% of pyrethroid-based products due to their superior performance and reduced reliance on natural pyrethrum extraction, which has consequently seen declining demand.^[85]^[86]

Current Research and Alternatives

Recent research on pyrethrum focuses on genetic enhancements to boost pyrethrin yields, addressing limitations in natural extraction efficiency. A 2024 study elucidated the biosynthetic pathways of pyrethrins in Tanacetum cinerariifolium, identifying key genes such as those involved in sesquiterpene lactone and (E)-β-farnesene production, which could enable targeted breeding for higher pyrethrin content.^[87] In Australia, 2020s breeding trials in Tasmania have explored marker-assisted selection and genetic variation analysis to develop cultivars with elevated pyrethrin levels, leveraging global germplasm diversity through selection for high-yielding traits.^[88] Overexpression of genes like TcCHS in transgenic approaches has demonstrated increases in pyrethrin accumulation, supporting genotype-independent transformation systems for commercial improvement.^[89] Insect resistance to pyrethrins is an emerging challenge, particularly in mosquito vectors, prompting studies on integrated management strategies. Research from the 2020s indicates widespread resistance in Anopheles gambiae to pyrethrins and related pyrethroids, driven by metabolic detoxification and target-site mutations, which reduces efficacy in malaria control.^[90] To counter this, investigations have explored insecticide rotation, including alternation with neonicotinoids like imidacloprid, which target distinct biochemical pathways and show promise in restoring susceptibility in resistant populations.^[91] Experimental evolution studies confirm that neonicotinoids can manage pyrethroid resistance without cross-selection, offering a viable rotation option for vector control programs.^[92] Alternatives to pyrethrum emphasize sustainable, low-toxicity options, including plant-derived essential oils and biological agents. Neem oil (Azadirachta indica) extracts, rich in azadirachtin, provide effective insecticidal activity against pests like beetles and mosquitoes, serving as a biopesticide in integrated pest management with minimal environmental persistence.^[93] Citronella oil (Cymbopogon nardus) acts as a repellent and contact toxicant, particularly in nanoemulsion formulations that enhance stability and efficacy against vectors without synthetic additives.^[94] Biological controls such as Bacillus thuringiensis (Bt) toxins target specific lepidopteran pests via gut disruption, offering a selective alternative in organic systems.^[95] Nanotechnology advancements include nanoencapsulated pyrethrins and essential oils, improving delivery, bioavailability, and resistance to degradation for prolonged pest control.^[96] Future trends in pyrethrum research prioritize climate-resilient cultivars and regulatory shifts toward natural insecticides. Studies on local genetic adaptation reveal that environmental factors influence pyrethrin composition, guiding breeding for cultivars tolerant to heat and drought stresses prevalent in production regions like Australia and Kenya.^[44] Regulatory pressures, including EU reforms post-2020 bans on hazardous synthetics like chlorpyrifos, are accelerating approvals for biopesticides, with proposed amendments to Regulation 1107/2009 in 2025 aiming to fast-track natural alternatives like pyrethrum to reduce synthetic reliance.^[97] These efforts underscore a shift toward sustainable, eco-friendly pest management amid global calls for biopesticide integration.^[98]

References

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Pyrethrins and Pyrethroids: A Comprehensive Review of Natural ...
This comprehensive scientific review provides an in-depth analysis of both the natural compounds, pyrethrins, and their synthetic derivatives, pyrethroids ...
[2]
Pyrethrins General Fact Sheet - National Pesticide Information Center
Pyrethrins are pesticides found naturally in some chrysanthemum flowers. They are a mixture of six chemicals that are toxic to insects.
[3]
Public Health Statement for Pyrethrins and Pyrethroids - CDC
Pyrethrum is a naturally occurring mixture of chemicals found in certain chrysanthemum flowers. Pyrethrum was first recognized as having insecticidal properties ...
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Discovery and development of pyrethroid insecticides - PMC - NIH
In Japan, pyrethrum seeds were independently introduced by Tamari and Ueyama in the 1880s. Ueyama cultivated pyrethrum flowers in the Wakayama prefecture and ...
[5]
Pyrethrum Industry Statistics in Africa - SME Blue Pages
Feb 8, 2024 · Kenya and Tanzania are the main producers, with Kenya producing around 500 metric tons annually and Tanzania about 200. Kenya has a dominant ...
[6]
Pyrethrum Profile - AFA
Pyrethrum is a natural insecticide. Kenya was a major producer, with Nakuru, Nyandarua, West Pokot and Bomet leading. The industry has seen growing interest.<|control11|><|separator|>
[7]
https://www.tanzaniainvest.com/agriculture/pyrethrum-export-earnings-rise
[8]
[PDF] Diseases of Pyrethrum in Tasmania - USDA ARS
Pyrethrum is cultivated commercially solely for the production of six closely related esters called pyrethrins. The plant is tufted, slender, and herba- ceous, ...
[9]
Genetic Diversity and Structure of Dalmatian Pyrethrum (Tanacetum ...
Dalmatian pyrethrum (Tanacetum cinerariifolium Trevir. /Sch./ Bip.) is an outcrossing, perennial insecticidal plant, restricted to the eastern Adriatic coast ( ...Missing: growth | Show results with:growth
[10]
Pyrethrum Farming in Kenya - Safi Sarvi Organic Fertilizer
Jul 31, 2024 · ... High-altitude areas, ranging from 1,500 to 2,500 meters above sea level. In Kenya, some of the most suitable regions for pyrethrum farming are:.
[11]
Pyrethrum / Tanacetum Plant Growing & Care Guide for Gardeners
Nov 7, 2023 · Pyrethrum plants prefer to grow in full sun or light shade, and well-drained soil. They can be planted in the spring or fall.
[12]
[PDF] Review Article Pyrethrum an Organic and Natural Pesticide
Jun 25, 2020 · Pyrethrum requires rich soils in phosphorous, calcium and magnesium with a minimum soil pH of 5.6. The appropriate situation is fertile and ...
[13]
Growing Pyrethrum - Richters Herbs
Jan 26, 2025 · Pyrethrum was first established as a bedding plant because we wanted to work with a special cultivar from Kenya which yielded up to 2.0% pyrethrins.
[14]
Tanacetum cinerariifolium (Trevir.) Sch.Bip. | Plants of the World ...
Tanacetum cinerariifolium (Trevir.) Sch.Bip. ; Subclass Magnoliidae ; Order. Asterales ; Family. Asteraceae ; Genus. Tanacetum ; Species. Tanacetum cinerariifolium ...
[15]
Taxon: Tanacetum cinerariifolium - USDA
Taxonomic Classification Level. Kingdom: Phylum: Class: Order: Plantae; Tracheophyta; Magnoliopsida; Asterales. Family: Genus: Species: Sub-Species: Variety ...
[16]
Pyrethrins in Tanacetum cinerariifolium biosynthesis, regulation, and ...
Jun 3, 2024 · This review provides a comprehensive overview of pyrethrum cultivation history and its essential biological characteristics, particularly ...
[17]
Understanding pyrethrin biosynthesis: toward and beyond natural ...
Aug 13, 2024 · Plants use pyrethrins as a defence against herbivores, but pyrethrin biosynthesis pathways are shared with plant hormones and signal molecules.
[18]
[PDF] Pyrethrins in Tanacetum cinerariifolium - Maximum Academic Press
The Tanacetum genus, part of the Asteraceae family, comprises approximately 160 species of perennial plants, recognized for their daisy-like flowers, these ...Missing: synonyms | Show results with:synonyms<|control11|><|separator|>
[19]
(A) Flowers of Tanacetum cinerariifolium and Tanacetum coccineum ...
However, T. cinerariifolium produces large amounts of pyrethrins, a class of natural insecticides, whereas T. coccineum produces much smaller amounts of these ...Missing: parthenium | Show results with:parthenium
[20]
PYRETHRUM definition and meaning | Collins English Dictionary
Word origin. C18: from New Latin pyreticus, from Greek puretos fever, from pur fire. COBUILD frequency band. pyretic in American English. (paɪˈrɛtɪk ).Missing: etymology name
[21]
Feverfew (Tanacetum parthenium L.): A systematic review - PMC
The first-century Greek physician Dioscorides used feverfew as an antipyretic. Feverfew also was known as “medieval aspirin” or the “aspirin” of the 18th ...
[22]
Pyrethrum - an overview | ScienceDirect Topics
It produces a natural insecticide, pyrethrum, that has been used for thousands of years as a mosquito repellent and as a remedy for lice in ancient Persia and ...
[23]
From Chrysanthemum to Control: The Journey of Pyrethrin
The earliest documented uses of ground chrysanthemum flowers as an insecticide date back to ancient China, Greece, and Persia. The dried flowers were pulverized ...
[24]
The use of indigenous ecological resources for pest control in Africa
Nov 26, 2013 · Nonetheless, as pyrethrum is grown as an export cash crop, few Kenyan farmers actually use it for pest control on their own crops.<|control11|><|separator|>
[25]
Feverfew Uses, Benefits & Dosage - Drugs.com
Aug 22, 2025 · The first century Greek physician Dioscorides used feverfew as an antipyretic. Feverfew also was known as "medieval aspirin" or the "aspirin" of ...
[26]
[PDF] Review Article Pyrethrum an Organic and Natural Pesticide
Jun 25, 2020 · powders that were processed and commercialized in Europe in the 1820s were most likely prepared from a mixture of C. roseum and C. corneum ...
[27]
Historical Journey of Pyrethrum & its benefits in Kenya
Nov 14, 2024 · The cultivation of pyrethrum, a perennial daisy-like plant, began in Kenya in the early 1920s, introduced by European settlers.
[28]
Pyrethrum: History of a Bio-Insecticide – Part 3 - ChemistryViews
Dec 4, 2018 · Dried, pulverized flower heads of two chrysanthemum species (also known as “pyrethrum”) contain insecticides with nearly perfect toxicity profiles.<|control11|><|separator|>
[29]
[PDF] GAIN Report - USDA Foreign Agricultural Service
May 29, 2007 · Pyrethrum production in Kenya dates back to 1928. Presently Kenya is the leading producer of pyrethrum extract producing about 70 % of the ...Missing: share | Show results with:share
[30]
The history of extensive structural modifications of pyrethroids - PMC
Nov 20, 2019 · The first synthetic pyrethroid, allethrin, was invented at the United States Department of Agriculture (USDA) in 1949, and its patent was opened ...
[31]
US commits US$12M towards reviving pyrethrum sector in Kenya
Jul 20, 2023 · In the 1990s, pyrethrum was the 3rd largest Kenyan export crop, providing an income for over 200,000 smallholder farmers. Kenya was controlling ...
[32]
The deadliest flower in the insect world is a lifeline to farmers—and ...
Aug 4, 2021 · This flower, the pyrethrum plant, contains a potent chemical that is made into an effective, and environmentally friendly, insecticide.
[33]
Pyrethrum Comeback Afoot in East Africa - AgriBusiness Global
Jul 31, 2018 · Concrete pyrethrum revival programs have been launched in Kenya and Tanzania while plans are underway to reform the regulatory regime to ...
[34]
https://www.inchem.org/documents/pims/chemical/pimg026.htm
[35]
Molecular Mechanisms of Pyrethroid Insecticide Neurotoxicity
The insecticidal actions of pyrethroids depend on their ability to bind to and disrupt voltage-gated sodium channels of insect nerves.Missing: sources: | Show results with:sources:
[36]
PYRETHROID (Group PIM G026) - INCHEM
Pyrethrins are extracts of the pyrethrum flower, largely Chrysanthemum cinerariaefolium. Extracts contain 20-50% total pyrethrins, the main active constituents ...
[37]
Supercritical fluid extraction of pyrethrins from pyrethrum flowers ...
Therefore, the oleoresin can be obtained with a good yield directly from the flowers of pyrethrum using SFE. Direct extraction from pyrethrum flowers with ...Missing: CO2 | Show results with:CO2
[38]
Supercritical carbon dioxide processing of pyrethrum oleoresin and ...
To understand the dynamics of pyrethrin extraction, CHE was extracted in a single step; pyrethrin concentration was found to be improved from 0.16 to 0.50 g/g.Missing: solvent yield
[39]
US3952047A - Method of purifying pyrethrum extract - Google Patents
The recovered extract was analyzed for pyrethrin content and the results showed a complete recovery of pyrethrins (100.2% yield) in the extraction process.
[40]
(PDF) Comparison of pyrethrins extraction methods efficiencies
Aug 6, 2025 · The present investigation was directed in identifying a simple and reliable extraction treatment using solvents with lower cost and toxicity ...Missing: distillation | Show results with:distillation
[41]
[PDF] Quantitation of Pyrethrum Residues in Brown Tree Snakes
The mean recovery for all rethrins is 70.8% with a standard deviation of 5.7%. This method is used to successfully quantitate incurred rethrin residues in ...
[42]
https://cropnuts.com/wp-content/uploads/2020/03/Pyrethrum-flyer-min.pdf
[43]
Pyrethrins | C43H56O8 | CID 60202781 - PubChem - NIH
Pyrethrins | C43H56O8 | CID 60202781 - structure, chemical names, physical and chemical properties, classification, patents, literature, ...
[44]
[PDF] Pyrethrum Growing in Kenya Suitability Factors - Cropnuts
Pyrethrum grows best at high altitudes, 1980m above sea level. However, there are varieties suitable for low-altitudes 1760-1980m. Best flowering is achieved ...Missing: elevation | Show results with:elevation
[45]
Plant extract: Pyrethrum | Infonet Biovision Home.
Pyrethrum is most productive at altitudes of above 1600 metres and ideally in semi-arid conditions where the winter is cool. On richer soils the ...Missing: elevation meters
[46]
[PDF] Tuikong - University of Nairobi
The pests that attack pyrethrum are root knot nematodes. ( He Io i dogyn e hap I a ) , flower thrips (Th rips t abac i ) , leaf thrips (Thrips neg rpp| losus) ...
[47]
(PDF) Pyrethrum (Chrysanthemum cinerariifolium) Flowers' Drying ...
May 4, 2020 · The yield of pyrethrins obtained on drying the flowers to constant weight at 40 ºC was 0.90% while drying for 18 hrs yielded 0.79%.Missing: preservation kg/
[48]
[PDF] Pyrethrins - WUR eDepot
Pyrethrins are concentrated in the flowers to a level of 1 to. 2 percent of dry weight. Pyrethrin content is larger at higher altitudes. The pyrethrum plant is ...Missing: cultivar structure
[49]
Natural Toxins for Use in Pest Management - PMC - NIH
Many of the pyrethrum-containing products are approved for use in organic agriculture operations and are approved for controlling more than 40 insects on more ...
[50]
Insecticide space spraying for preventing malaria transmission - PMC
The insecticide is dispersed using hand‐held, vehicle‐mounted or aircraft‐mounted equipment to produce a fog. Space spraying is regularly used in public health ...
[51]
[PDF] Environmental Fate and Ecological Risk Assessment Preliminary ...
Nov 30, 2011 · ... (~1-2 days). The test substance was pyrethrum extract (mixture of pyrethrins I and pyrethrins II). The results appear to confirm what would be ...<|separator|>
[52]
[PDF] Pyrethrins Proposed Interim Registration Review Decision Case ...
Jun 30, 2021 · may be niche uses in organic agricultural production systems, as pyrethrins is one of a few insecticides approved for use in organic production.
[53]
[PDF] Frequently asked questions ON ORGANIC RULES
Regulation (EU) No 540/2011 as amended by Commission. Implementing Regulation (EU) No 798/2013 of 21 August 2013 approved pyrethrins as an active substance ...Missing: pyrethrum | Show results with:pyrethrum
[54]
EverGreen® Pyrethrum Concentrate For Organic Production - MGK
EverGreen® Pyrethrum Concentrate delivers fast knockdown and kill of more than 140+ pests and is OMRI listed for use in organic production.
[55]
[PDF] Pyrethrins/pyrethrum - NationBuilder
Following indoor treatments, pyrethrins have persisted up to 2 1/2 months in carpet dust. A large family of insecticides, the synthetic pyrethroids, are ...
[56]
A dual-target molecular mechanism of pyrethrum repellency against ...
May 5, 2021 · In addition, pyrethrum-producing Chrysanthemum spp. are recommended as “companion” plants to repel pest insects. Pyrethrins and pyrethroids ...
[57]
None
### Summary on Pyrethrum in Companion Planting and Organic Gardening
[58]
Companion Planting for Pest Control | Grow To Eat
But it is certainly not a problem to complement your companion planting with organic pesticides or insect repellent sprays. ... Pyrethrum, Rue, Santolina, Winter ...
[59]
Companion Planting & Botanical Pesticides: Concepts & Resources
Companion planting can be described as establishing two or more plant species in close proximity for some cultural benefit (such as pest control or higher yield) ...
[60]
(PDF) Pyrethrum an Organic and Natural Pesticide - ResearchGate
Jun 28, 2020 · Organic farmers can use pyrethrins as an insecticide for fruit and vegetable crops. Easily degraded by oxygen, light and temperature.
[61]
Tanacetum cinerariifolium (Pyrethrum Daisy) - Gardenia.net
Soil Type, Clay, Loam, Sand. Soil pH, Acid, Alkaline, Neutral. Soil Drainage, Well-Drained. Characteristics, Cut Flowers, Fragrant, Showy. Tolerance, Drought.Missing: habitat | Show results with:habitat
[62]
[PDF] COMPANION PLANTING
Companion planting can combine beauty and purpose to give you an enjoyable, ... (i.e. pyrethrum) White flowering chrysanthemums repel Japanese beetles. To ...Missing: organic | Show results with:organic<|control11|><|separator|>
[63]
[PDF] ATSDR Pyrethrins and Pyrethroids Tox Profile
Mechanisms of toxic action and structure-activity relationships for organochlorine and synthetic pyrethroid insecticides. Environ Health Perspect 87:255-262 ...
[64]
Pyrethrin and Pyrethroid Toxicity - StatPearls - NCBI Bookshelf
Aug 11, 2024 · Patients experiencing an allergic response to pyrethroids may display respiratory distress, urticaria, hypotension, and oral swelling.
[65]
Pyrethrum allergic contact dermatitis in humans - PubMed
Pyrethrum has been reported to produce allergic contact dermatitis in humans. Moreover, it has been speculated that cross reactions occur in ragweed-sensitized ...
[66]
Pyrethrin/Pyrethroid Poisoning in Cats - VCA Animal Hospitals
The use of pyrethrins/pyrethroids is generally safe in dogs; however, cats and fish are very sensitive to these products. Fish may die from even the smallest ...Missing: PPE glutathione
[67]
Physiological selectivity and activity reduction of insecticides by ...
At the moment of application, all the insecticides were highly toxic to the wasps, causing mortality higher than 80%.
[68]
Pyrethrins - UC IPM
... evening; (Moderate) III-Apply only during late evening, night, or early morning; and (Low) IV-Apply at any time with reasonable safety to bees. For more ...Missing: mitigation | Show results with:mitigation
[69]
None
### Summary of Pyrethrins Toxicity and Environmental Effects
[70]
Mortality of nontarget arthropods from an aerial application of ...
This study supports previous work that the impact of a single ULV application of pyrethrins was limited to a variety of small-bodied arthropods.Missing: field trials pyrethrum non- target
[71]
Pyrethroid-Degrading Microorganisms and Their Potential for the ...
Sep 15, 2016 · The efficiency of the cypermethrin removal of a mixed culture significantly increased with incubation time, reaching 95.7 and 100% within 48 and ...
[72]
The impact of conventional and organic farming on soil biodiversity ...
Feb 27, 2020 · A long-term experiment at two trial sites in Kenya has been on-going since 2007 to assess the effect of organic and conventional farming systems ...
[73]
Pyrethrum, Americas · 7.74 kg CO₂e/kg | Verified by CarbonCloud
Pyrethrum from Americas has a carbon footprint of 7.74 kg CO₂e/kg at farm. Check how it compares to other ingredients or markets in ClimateHub.
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Pyrethrin Insecticide: Eco-Friendly Pest Control 2026 - Farmonaut
Oct 25, 2025 · Organic & Sustainable Farming: Pyrethrins are approved for organic agriculture in most regulatory standards globally. Their rapid ...
[75]
Integrated Pest Management: An Update on the Sustainability ... - NIH
IPM promotes biodiversity conservation by prioritizing nonchemical pest control methods and selective pesticide application, mitigating direct and indirect ...
[76]
Pyrethroid - an overview | ScienceDirect Topics
The most widely used synthetic pyrethroids includes permethrin, cypermethrin, deltamethrin, lethrin, furethrin, fenevelerate, and alphcyperamethrin. The ...
[77]
Pyrethroid pesticides: An overview on classification, toxicological ...
Pyrethroid pesticides are one of the most important groups of pesticides used to reduce the pest population that cause farmers significant economic loss.Missing: decline | Show results with:decline
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Synthetic Pyrethroids For Mosquito Control | US EPA
Mar 6, 2025 · Permethrin, resmethrin, and d-phenothrin (Sumithrin®) are synthetic pyrethroids commonly used in mosquito control programs to kill adult mosquitoes.
[79]
SYNTHETIC PYRETHROIDS for veterinary use on LIVESTOCK
Feb 13, 2022 · For use in dogs and cats pyrethroids are used in collars as well as in thousands of insecticidal shampoos, soaps, sprays, powders and the like.
[80]
Pyrethrin Market Size, Share, Trends and Industry Analysis 2033
The global pyrethrin market size was valued at USD 67.7 Million in 2024. Looking forward, IMARC Group estimates the market to reach USD 120.7 Million by 2033.Missing: pyrethroids 2020s
[81]
Pyrethroids Market Size, Share & Forecast Report, 2024 – 2032
Type I segment stands out in the pyrethroids industry with a market of USD 2.6 billion in 2023 and is expected to hold a market size of USD 4.1 billion by 2032.Missing: pyrethrum 2020s
[82]
https://www.sciencedirect.com/science/article/pii/S2772416623000554
[83]
Implications of genetic variation within pyrethrum (Chrysanthemum ...
Apr 27, 2025 · This research determined genetic variation within and among populations of C. cinerariifolium and C. coccineum from seed lots from around the globe, a wild ...
[84]
Overexpression of TcCHS Increases Pyrethrin Content When Using ...
Jun 15, 2022 · Overexpression of TcCHS increases pyrethrin content when using a genotype-independent transformation system in pyrethrum (Tanacetum cinerariifolium).
[85]
Cross-Resistance to Pyrethroids and Neonicotinoids in Malaria ...
Dec 12, 2024 · This work aims to raise awareness of the widespread resistance of An. gambiae s.l. to pyrethroid and organochlorine insecticides and demonstrate ...
[86]
Experimental evolution supports the potential of neonicotinoid ...
Sep 30, 2021 · The introduction of neonicotinoids for managing insecticide resistance in mosquitoes is of high interest as they interact with a biochemical ...
[87]
Experimental evolution supports the potential of neonicotinoid ...
The introduction of neonicotinoids for managing insecticide resistance in mosquitoes is of high interest as they interact with a biochemical target not ...Missing: pyrethrum emerging research rotation
[88]
Nano-Agrochemicals as Substitutes for Pesticides - NIH
Dec 29, 2023 · Neem oil-containing nanoemulsions have proven effective against two economically significant agricultural pests: the red flour beetle (Tribolium ...
[89]
Green Micro- and Nanoemulsions for Managing Parasites, Vectors ...
The oldest and most widely used biopesticide is pyrethrum ... Antifungal activity of nano emulsions of neem and citronella oils against phytopathogenic fungi, ...
[90]
Biopesticides as a promising alternative to synthetic pesticides - NIH
Feb 16, 2023 · Biological pesticides (biopesticides) are substances produced from biological agents that manage pests in agriculture to enhance crop production ...
[91]
Nanomaterials for Postharvest Management of Insect Pests - Frontiers
In this article, we reviewed the nanoformulations that are developed and have proved effective against the insect pests under postharvest storage of grains.
[92]
Local adaptation to the native environment affects pyrethrin ...
Jun 21, 2024 · Recent studies (Grdiša et al., 2013; Varga et al., 2021), have shown high variability in pyrethrin content and composition in natural Dalmatian ...
[93]
Ban of Chlorpyrifos and Chlorpyrifos-methyl in EU and USA
The insecticides chlorpyrifos/-methyl are no longer authorised for food production in the EU. The USA have also withdrawn their tolerance levels.<|control11|><|separator|>
[94]
Why EU Biopesticide Reform Is Urgent for Sustainable Agriculture
Oct 20, 2025 · The EU is striving for more sustainable farming, but outdated pesticide regulations are hindering the adoption of biocontrol technologies by ...