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PubMed2005

Effect of temperature on toxicity of a natural pyrethrin pesticide to green anole lizards (Anolis carolinensis).

Metabolic rates of reptiles vary with body temperature; therefore, the sensitivity of reptiles to a particular dose level of a pesticide might be expected to vary as well. The purpose of the present study was twofold: To evaluate the effects of temperature on the toxicity to green anole lizards (Anolis carolinensis) of a single concentration of a natural pyrethrin pesticide via percutaneous exposure, and to compare the effects of temperature (20 vs 35 degrees C) on the toxicity of different concentrations of pyrethrins to green anoles. When lizards were exposed to a solution that contained 300 mg/L of pyrethrins, the mortality of lizards maintained at 15 and 20 degrees C was significantly higher (p < 0.01) than the mortality of lizards maintained at 35 and 38 degrees C. In addition, the median lethal concentrations of pyrethrins for lizards maintained at 20 and 35 degrees C were 77.6 and greater than 300 mg/L, respectively. Therefore, temperature clearly influenced the sensitivity of lizards to pyrethrin pesticides.

Animals↗

PubMedDate not supplied

Determination of pyrethrin and pyrethroid pesticides in urine and water matrixes by liquid chromatography with diode array detection.

The following pyrethrin and pyrethroid pesticides were determined in urine and water matrixes by liquid chromatography with diode array detection (LC-DAD): pyrethrin I, pyrethrin II, tetramethrin, baythroid, bifenthrin, fenvalerate, phenothrin, allethrin, resmethrin, cis-permethrin, and trans-permethrin. In addition, 3-phenoxybenzyl alcohol, a metabolite of various pyrethroids, was also successfully determined by the analytical method. The matrix extraction was simple, inexpensive, and fast, using only sodium chloride and acetonitrile. The acetonitrile extract was filtered and analyzed by LC-DAD. The method detection limits for the pyrethrin pesticides in 5 mL urine were determined to range from 0.002 to 0.04 microg/mL, depending on the individual pyrethrin. Recoveries from spiked tap water ranged from 77 to 96%; recoveries from urine ranged from 80 to 117%. This method is especially well-suited to clinical investigations, in which rapid analysis of forensic samples is often required.

Calibration↗

PubMed1998

Efficacy of mosquito coils containing 0.3% and 0.4% pyrethrins against An.gambiae sensu lato mosquitoes.

OBJECTIVE: To investigate the efficacy of a formulation containing 0.4% pyrethrins against registered mosquito coil containing 0.3% pyrethrins. DESIGN: Non intervention analytical study. SETTING: Four villages in Mashonaland East province, Mumurwi, Chitengu, Katiyo and Nyagande. SUBJECTS: Biological efficacy of Doom and IT mosquito coils. MAIN OUTCOME MEASURES: To measure insecticidal, knock down and inhibition of biting activities of the coils in the presence of mosquitoes. RESULTS: A two hour exposure of mosquitoes to both coils results in a 99% and 98.5% mortality rate for a 0.4% and a 0.3% formulation respectively. The KT50 and KT90 of a formulation containing 0.4% pyrethrins were half those of a 0.3% formulation, suggesting that a 0.4% formulation has a rapid knock down effect. A formulation containing 0.4% pyrethrins inhibited 92.5% from biting as compared to a 0.3% formulation (80%). CONCLUSION: A formulation containing 0.4% pyrethrins is more effective in repelling mosquitoes than a 0.3% formulation.

Animals↗

PubMed1976

Toxicity of natural pyrethrins and five pyrethroids to fish.

The toxicity of natural pyrethrins and five pyrethroids was determined with coho salmon (Oncorhynchus kisutch), steelhead trout (Salmo gairdneri), fathead minnow (Pimephales promelas), channel catfish (Icatlurus punctatus), bluegill (Lepomis macrochirus), and yellow perch (Perca flavescens). The 96-hour LC50's in static tests at 12 degrees C ranged from 24.6 to 114 mug/l of natural pyrethrins and from 0.110 to 1,140 mug/l of pyrethroids. Two pyrethroids, RU-11679 and SBP-1382 (R), were over 10 times more toxic than pyrethrum extract in the flow-through tests. Coldwater species of fish were more sensitive than warmwater species to all the compunds. Temperature (12-22 degrees C) influences the toxicity of natural pyrethrin and the pyrethroids. The natural pyrethrin was more toxic to fish in pH 6.5 than in pH 9.5 water, but the toxicity of pyrethroids was not influenced in the pH range. The two most toxic pyrethroids, RU-11679 and SBP-1382, Were deactivated more rapidly in water solutions than natural pyrethrins, S-bioallethrin, dimethrin, and d-trans allethrin.

Animals↗

PubMed1997

Lethality of pyrethrins to larvae and postlarvae of the American lobster (Homarus americanus).

Pesticide formulations containing pyrethrins are being used to treat salmonids for infestations of the copepod parasites Lepeophtherius salmonis and Caligus elongatus (sea lice). The acute lethality of one such formulation to four larval stages of the American lobster (Homarus americanus), a species of significant economic importance in eastern Canada, was determined. The formulation tested contained 0.06% pyrethrins and 0.6% piperonyl butoxide (a synergist). Stage I larvae (48-h LC50 = 4.42 microg/liter) were significantly less sensitive than stage II, III, or IV larvae. Stage II larvae (48-h LC50 = 2.72 microg/liter) were significantly less sensitive than Stage III or IV larvae. Stage III and IV larvae were not significantly different in their response to the pyrethrins formulation (48-h LC50 = 1.39 and 0.73 microg/liter, respectively). Most published studies using lobster larvae have reported that the earliest larval stage was the most sensitive to chemicals. The results described here indicate that the earliest larval stage is the least sensitive to the pyrethrins formulation.

Animals↗

PubMed2006

Pyrethroids, pyrethrins, and piperonyl butoxide in sediments by high-resolution gas chromatography/high-resolution mass spectrometry.

A new method for determination of pyrethroids, pyrethrins, and piperonyl butoxide (PBO) by high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) was developed for aquatic sediments. The method detection limits for pyrethroids (15 compounds), pyrethrins, and PBO ranged from 0.16 to 1.50 ng/g sediment, which was suitable for detecting these chemicals at environmentally relevant concentrations (low ng/L range) that are toxicologically significant to benthic organisms. Recovery of the analytes from a low level spiked sediment ranged from 89.7% to 135%. Resmethrin showed the lowest recovery at 23.5% and pyrethrins showed the highest recovery at 154%. To confirm the utility of this new method for environmental applications, sediment samples collected from five tributaries of the San Francisco Bay, California were analyzed. Individual pyrethroids were detected in concentrations of up to 17.6 ng/g, while PBO was detected in all sediment samples in concentrations of 0.010-0.215 ng/g. Pyrethrins were not found in the sediment samples.

California↗

PubMed2001

Separation of the insecticidal pyrethrin esters by capillary electrochromatography.

A simple, rapid technique for the direct separation and quantification of the six insecticidally active pyrethrin esters in typical extracts and commercial formulations by capillary electrochromatography (CEC) has been described. The separation of the pyrethrin esters was achieved by optimizing several parameters including the length of stationary phase, the mobile phase composition and column temperature. The mobile phase composition had the most pronounced effect toward resolving these structurally similar compounds. A ternary mobile phase composed of acetonitrile-aqueous buffer-tetrahydrofuran (55:35:10) provided the elutropic solvent strength needed to resolve the six esters from an extract mixture in under 16 min. A 25 cm packed bed of Hypersil 3 microm C18 stationary phase was used with the ternary mobile phase at 25 degrees C and 30 kV voltage. These conditions also yielded excellent separation of the pyrethrin esters in two different commercially available insecticidal formulations. In addition, the developed CEC method was shown to be a fast and easy way of quantifying the amount of these esters in typical pyrethrin formulations.

Chromatography, Micellar Electrokinetic Capillary↗

PubMed2005

Residues and half-life times of pyrethrins on peaches after field treatments.

The behavior of pyrethrins and piperonyl butoxide (PB) on peaches has been studied after field treatment. Three experiments were carried out at 1, 5, and 10x the concentration recommended by the manufacturer. In all experiments, the initial deposition was below the maximum residue level (MRL), and the half-life time calculated in the 10x experiment for total pyrethrins within 2.3 days was in agreement with the preharvest interval (PHI) recommended. In a model system, the photodegradation rates of the pyrethrins in three commercial products were compared with pyrethrum pale (PP), with and without the presence of peach waxes. The pyrethrins in formulations containing PB showed higher half-life times but were not influenced by the presence of waxes, whereas in the case of PP that does not contain any PB, photodegradation was significantly affected by the presence of waxes.

Chromatography, High Pressure Liquid↗

PubMed2005

Effect of sunscreen and antioxidant on the stability of pyrethrin formulations.

The stability of pyrethrins in formulations containing different combinations of antioxidant and sunscreen was studied with model system experiments. The mechanism of disappearance of pyrethrins was mainly due to photodegradation, but some loss by codistillation can occur. In formulations, the presence of mineral oil and emulsifiers determined a decrease on codistillation losses. The presence of the antioxidant in formulations even at high concentrations did not affect pyrethrin photodegradation rates, but rising amounts of sunscreen determined a progressive increase on half-life times of pyrethrins. A combination of sunscreen and antioxidant at low concentrations provided an effective protection against sunlight similar to that obtained by high amounts of sunscreen alone.

Antioxidants↗

PubMed2001

Pyrethrins and piperonyl butoxide residues on potato leaves and in soil under field conditions.

Residues of pyrethrin-I (Py-I) and pyrethrin-II (Py-II), the major insecticidal components of the pyrethrum daisy (Tanacetum cinerariifolium) as well as residues of piperonyl butoxide (PBO, a pyrethrum synergist) were determined in soil and on potato foliage grown under field conditions. A pyrethrum formulation (Multi-Purpose Insecticide) containing the three active ingredients was sprayed twice at the rate of 6 lbs of formulated product.acre(-1) ( 5.4 and 27.2 g A.I. of pyrethrin and PBO, respectively) on potato foliage during the growing season. In soil, three management practices (yard waste compost, grass filter strips, and a no mulch treatment) were used to study the impact of surface soil characteristics on the amount of pyrethrins (Pys) and PBO retained in soil. Soil samples and potato leaves were collected at different time intervals after spraying. Samples were purified and concentrated using solid-phase extraction columns containing C18-Octadecyl bonded silica. Residues were quantified by high-performance liquid chromatograph equipped with a UV detector. The first spray resulted in mean initial deposits of 0.18, 0.40, and 0.99 microg.g(-1) potato leaves for Py-I, Py-II, and PBO, respectively. Residues in soil were higher in compost treatments compared to no mulch treatments.

Agriculture↗

PubMed1999

Control of fleas on pets and in homes by use of imidacloprid or lufenuron and a pyrethrin spray.

OBJECTIVE: To evaluate imidacloprid and the combination of lufenuron and pyrethrin to control flea infestations in households with pets. ANIMALS: 37 dogs and 19 cats in 34 flea-infested households. PROCEDURE: Households were assigned randomly to 1 of 2 groups. Pets in group 1 were treated topically with imidacloprid on day 0, then once a month for 90 days. Pets in group 2 were given lufenuron orally on day 0 and at monthly intervals for 90 days and also were treated topically with a pyrethrin spray every 1 to 2 weeks throughout the study. Flea numbers in homes were assessed by use of intermittent light traps, and flea burdens on pets were assessed using visual area counts done once a week during the first month, then every other week. RESULTS: One application of imidacloprid reduced flea burdens on pets by 96 and 93.5% on days 7 and 28, respectively, compared with day-0 burdens. Following 3 applications, flea burdens on pets and in homes were reduced by 98.8 and 99.9%, respectively. Lufenuron and pyrethrin spray reduced flea numbers on pets by 48.9 and 91.1% on days 7 and 28, respectively. By the end of the study, this combination reduced flea burdens on pets and in homes by 99.2 and 99.7%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Imidacloprid applied topically or lufenuron administered orally along with a topically applied pyrethrin spray were effective in eliminating fleas on pets and in homes. Flea control can be achieved with topical application of adulticides or oral administration of insect growth regulators without concomitant treatment of the surroundings.

Administration, Oral↗

PubMed1991

Neurotoxicology of pyrethrin and the pyrethroid insecticides.

Natural pyrethrin and synthetic pyrethroid insecticides have been considered among the safest classes of insecticides available. Pyrethrins and pyrethroids are classified on the basis of their chemical structures and their toxicologic, neurophysiologic and pharmacologic effects. Cellular effects of pyrethrin and pyrethroid insecticides have been postulated to involve interactions with sodium channels, receptor-ionophore complexes, neurotransmitters, and ATPases. Toxicity is a function of chemical structure, metabolism, route of exposure, and the presence or absence of synergists. Pyrethroid insecticides are neurotoxic, and the development and severity of clinical signs is proportional to the nervous tissue pyrethroid concentration. Type I pyrethroid poisoning in mice and rats produces a syndrome characterized by tremors, prostration and altered startle reflexes. Type II pyrethroid poisoning in mice and rats causes ataxia, convulsions, hyperactivity, choreoathetosis and profuse salivation. A presumptive diagnosis of pyrethrin/pyrethroid poisoning is based upon history of exposure, development of appropriate clinical signs, and chemical analysis for insecticide residues. Treatment of pyrethrin and pyrethroid toxicosis involves basic life support, seizure control when needed, and the prevention of further insecticide absorption.

Animals↗

PubMedDate not supplied

Synergized pyrethrin mousse, a new approach to head lice eradication: efficacy in field and laboratory studies.

The purpose of this study was to evaluate the pediculicidal and ovicidal efficacy of a new, single-application formulation of synergized natural pyrethrins (presented in an aerosol mousse form) compared with an established, effective formulation based on permethrin (in a creme rinse form). The trial was a single-blind, comparative, randomized, parallel-group study. Children between the ages 7 and 15 years and adults with active head lice infections, identified by the presence of live lice, were enrolled from a school and a children's home in Dhaka, Bangladesh. Prevalence of infection ranged from 75% to 100% in the two study centers. The field study confirmed laboratory findings showing pyrethrin mousse to be effective at killing both lice and their eggs with a single 10-minute application. Of 52 patients identified with lice, 42 were treated with pyrethrin mousse and 10 with permethrin creme rinse. In each case, a sample of viable louse eggs was taken from the patients' hair before and after treatment. The eggs were then incubated to assess ovicidal activity. After treatment, the patients were examined for lice on alternate days until day 8 and then again on day 14. None of the patients in either group was found to have lice up to 2 days after treatment. One patient was found to have two moribund hatchlings on day 4. By day 6, when any eggs still present on the scalp would be expected to hatch, 19 pyrethrin mousse-treated patients were available for assessment. Two patients had been reinfected from contacts.(ABSTRACT TRUNCATED AT 250 WORDS)

Aerosols↗

PubMed2005

Management of five stored-product insects in wheat with pirimiphos-methyl and pirimiphos-methyl plus synergized pyrethrins.

Hard red winter wheat was treated with pirimiphos-methyl at 4, 6 and 8 mg kg(-1), synergized pyrethrins at 0.38, 0.75, 1.13 and 1.5 mg kg(-1), and combinations of the two insecticides, to conduct laboratory bioassays against four beetle pests of stored grain, red flour beetle Tribolium castaneum (Herbst), rusty grain beetle Cryptolestes ferrugineus (Stephens), lesser grain borer Rhyzopertha dominica (F), and rice weevil Sitophilus oryzae (L), and one moth pest, Indianmeal moth Plodia interpunctella (Hubner). Beetle adults and P interpunctella larvae survived well on control wheat, producing a large number of progeny (65-1037 insects per container). Kernel damage in control wheat among the insect species ranged from 9 to 99%. On pirimiphos-methyl-treated wheat, mortality of R dominica adults was > or =72%, but that of the other beetle species and P interpunctella larvae was 100%. Progeny were not produced on pirimiphos-methyl-treated wheat, and the kernel damage was negligible (< or =1%). Synergized pyrethrins were ineffective against the five insect pests. Pirimiphos-methyl combined with synergized pyrethrins was not superior to pirimiphos-methyl alone against the five insect pests. Pirimiphos-methyl is not registered in the USA for use on wheat, but our results suggest that it could be a viable grain protectant at rates of 4-8 mg kg(-1).

Animals↗

PubMed1986

Evaluation of the herpes simplex virus antiviral activity of pyrethrins.

Pyrethrins, complex esters extracted from Chrysanthemum cinerariaefolium, exhibit only minimal in vitro activity against herpes simplex virus (HSV). Employing a guinea pig model of HSV genital infection, no in vivo activity could be demonstrated. Although purported to be an effective remedy for the treatment of genital herpes, we were unable to demonstrate efficacy for either the oral administration of an alcoholic solution of pyrethrins or the topical application of pyrethrins in mineral oil.

Administration, Oral↗

PubMed1988

Pyrethrin poisoning from commercial-strength flea and tick spray.

A case of acute poisoning followed inhalation and cutaneous exposure to an over-the-counter flea and tick insecticide containing 0.15% pyrethrins. A self-limited syndrome of cutaneous paresthesias, upper respiratory tract irritation, dyspnea with productive cough, and repetitive vomiting and diarrhea occurred. The patient recovered uneventfully with conservative therapy. A review of the pharmacology and toxicity of pyrethrins and related products is discussed, as well as management of pyrethrin poisoning.

Acute Disease↗

PubMed2005

Biosynthesis of pyrethrin I in seedlings of Chrysanthemum cinerariaefolium.

The biosynthetic pathway to natural pyrethrins in Chrysanthemum cinerariaefolium seedlings was studied using [1-13C]d-glucose as a precursor, with pyrethrin I isolated using HPLC from a leaf extract. The 13C NMR spectrum of pyrethrin I from the precursor-administered seedlings indicated that the acid moiety was biosynthesized from d-glucose via 2-C-methyl-d-erythritol 4-phosphate, whereas the alcohol moiety was possibly biosynthesized from linolenic acid.

Biotransformation↗

PubMed1999

NMR and molecular mechanics study of pyrethrins I and II.

Bioassay-directed fractionation of the organic extract of the Kenyan pyrethrum flowers (Chrysanthemum cinerariaefolium Vissiani) resulted in the isolation of two natural pyrethrin esters, pyrethrin I (PI) and pyrethrin II (PII) as the major constituents. These esters elicited inhibition of the multiple drug resistant (MDR) Mycobacterium tuberculosis. The high-field (1)H and (13)C nuclear magnetic resonance (NMR) chemical shifts of PI and PII were unequivocally assigned using modern two-dimensional (2D) proton-detected heteronuclear multiple-quantum coherence (HMQC) and heteronuclear multiple-bond correlation (HMBC) experiments. The conformations of both esters were deduced from (1)H-(1)H vicinal coupling constants and confirmed by 2D nuclear Overhauser effect spectroscopy (NOESY). Computer molecular modeling (MM) studies revealed that PI and PII molecules adopt a "love-seat" conformation in chloroform (CDCl(3)) solution.

Chrysanthemum cinerariifolium↗