Total Pyrethrins Research Articles

Local adaptation to the native environment affects pyrethrin variability in Dalmatian pyrethrum populations.

The insecticidal compound pyrethrin is synthesized in Dalmatian pyrethrum (Tanacetum cinerariifolium (Trevis.) Sch.Bip.; Asteraceae), a plant species endemic to the eastern Mediterranean. Pyrethrin is a mixture of six compounds, pyrethrin I and II, cinerin I and II, and jasmolin I and II. For this study we sampled 15 natural Dalmatian pyrethrum populations covering the entire natural distribution range of the species; Croatian coastal regions and the islands, inland Bosnia and Herzegovina and Montenegro. The plants were grown in a field experiment under uniform growing conditions to exclude a short-term response to environmental factors and instead observe variation in pyrethrin content and composition among and within populations due to genetic adaptation to the native environment. The drivers of local adaptation were explored by examining the role of bioclimatic factors as a cause of population differentiation. Pyrethrins were extracted by ultrasound-assisted extraction, and the extracts were analyzed by HPLC-UV-DAD. The populations differed significantly in the content and composition of pyrethrins. The highest levels of total pyrethrins (1.27% flower DW), were found in population P14 Budva and the significantly highest levels of pyrethrin I in population P14 Vranjske Njive, Podgorica (66.47% of total pyrethrin). Based on bioclimatic conditions of the sampling sites, populations were grouped into five bioclimatic groups (A, B, C, D, and E), which showed qualitative and quantitative variability in pyrethrin content. The most abundant bioclimatic group was bioclimatic group E, which was characterized by the highest average values for pyrethrin I (53.87% of total pyrethrin), total pyrethrin content (1.06% flower DW) and the ratio of pyrethrin I and II (1.85). The correlation analysis between the pyrethrin compounds and some of the bioclimatic variables (e. g., BIO03 Isothermality and BIO04 Temperature seasonality) showed their significant contribution in explaining the variation of pyrethrins in T. cinerariifolium. The differences in pyrethrin content and composition may be partly due to genetic adaptation to the ecological conditions of the native environment. The obtained data would enable the selection of source populations for breeding programs aimed at producing cultivars with desirable biochemical properties and adaptation to different bioclimatic conditions.

Pyrethrum (Chrysanthemum cinerariifolium) Flowers’ Drying Conditions for Optimum Extractable Pyrethrins Content

Pyrethrum flowers of the genus Chrysanthemum cinerariifolium are grown in Kenya by small scale farmers for extraction of pyrethrins, a natural insecticide’s active ingredient. Pyrethrins are classified in two groups, Pyrethrins I and II, and are degradable when exposed to air, moisture and high temperatures. The contents and ratio of Pyrethrins I:II determine the efficacy of the insecticide. Therefore, drying of the pyrethrum flowers should be optimized in order to attain maximum extractable pyrethrins content and optimum ratio. The aim of this research was to optimize the drying temperatures, time and moisture content of pyrethrum flowers. The flowers were harvested and dried at varying temperatures of 40, 50, 60 and 70 ºC to total dryness. Another set of flowers were harvested and dried in the oven at the same temperatures for a maximum period of 18 hrs. Moisture content was determined at each temperature, at intervals of one hour. The dried flowers were then ground into fine powder and extracted using Soxhlet extraction method with hexane. The extracts were refined and analyzed by Mercury reduction and High Performance Liquid Chromatographic methods. Pyrethrum flowers were found to achieve maximum moisture loss, at varying times and temperature with 70 ºC recording the shortest time of 18 hrs. 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%. Extractable Pyrethrins II were found to reduce by 8.6% when the drying temperature was raised from 50 to 60 ºC and by 11.3% from 60 to 70 ºC. Extractable Pyrethrins I were found to reduce by 6% when the drying temperature was raised from 50 to 60 ºC and by 5% from 60 to 70 ºC. The total pyrethrins obtained from the flowers dried at 50 ºC were found to be 1.37% at 18 hrs and 1.44% to constant weight drying. The pyrethrins I:II ratio was found to vary over the temperature range 40-70OC.The optimum temperature and time for drying pyrethrum flowers was found to be 50 ºC for 21 hrs.

Comparative extraction and enrichment techniques for pyrethrins from flowers of Chrysanthemum cinerariaefolium

This paper reports comparative extraction efficiencies and enrichment methods for natural insecticidal compounds pyrethrins from the dried flowers of Chrysanthemum cinerariaefolium using different techniques and solvent systems. Four different extraction techniques viz. percolation, agitation with heat, sonication and soxhlet using five different solvent systems hexane, ethyl acetate, acetone, acetonitrile and methanol were evaluated. In these studies, it was observed that maximum extract yield was obtained using methanol as extracting solvent by soxhlet technique, although the content of total pyrethrins was higher in the hexane extract than in methanol. The successive and maximum enrichment of the total pyrethrins was achieved by solid-matrix partitioning of the extract using acetonitrile as extracting solvent followed by treatment with activated charcoal, subsequent chilling and filtration by which enrichment of total pyrethrins up to 60.37% content was obtained. The quantitative analysis of the extraction and enrichment development protocol was validated by a simple, accurate, reproducible RP-HPLC-UV method using a binary gradient elution comprising of acetonitrile and water. The separation was achieved on a Waters-symmetry C18 column (150mm×3.9mm i.d., 5μm) that achieved a greater degree of linearity within an overall concentration range of 5–500μgmL−1 and higher degree of correlation (0.9842≤r2≤0.9987) for all the pyrethrin esters.

Elemental Composition and Chemometric Characterization of Pyrethrum Plant Materials and Insecticidal Flower Extracts

The elemental composition of native and cultivated pyrethrum plants (Tanacetum cinerariifolium) and their insecticidal extracts obtained from dried flower heads was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The accuracy of the analytical procedure which included pressurized digestion of plant samples in HNO3/H2O2 was tested by certified reference materials. Acceptable recoveries (90–110%) for the majority of elements were obtained measured in a simultaneous multi-element mode. The total pyrethrins content was determined by HPLC and it was 2.09% for cultivated plants and 1.58% for native species. The concentrations of 18 elements and pyrethrin content were subjected to statistical multivariate analysis which showed different patterns among plant parts. The roots were characterized by a combination of loadings of iron, aluminum, nickel, chromium, strontium, and barium, while the stems, leaves, and flowers showed more contributions from sodium, potassium, calcium, magnesium, phosphorus, sulfur, manganese, and copper. A higher loading of pyrethrins was the main characteristic of dried flower extracts. It was also observed that microelements such as copper, aluminum, and iron were more readily transferred into natural insecticide extracts.

Comparison of pyrethrins extraction methods efficiencies

Extraction efficiency of insecticidal active compounds from dried Dalmatian pyrethrum flowers (Chrysanthemum cinerariaefolium /Trevir/Vis) was tested using different techniques and solvents. The research included six treatments which are the combination of two techniques (soxtec and ultrasound) and three different solvents (hexane, ethanol and petroleum ether). Dalmatian pyrethrum is a perennial herb native to Croatia. Its powder prepared from dried flower heads has been used as natural insecticide for centuries in traditional Croatian farming systems. It has no toxicity to man and animals but possesses ecological benefits that have led to increasing worldwide production of this natural insecticide. Nowadays, it is cultivated mainly at higher altitudes in tropical countries such as Kenya, Tanzania and Rwanda. The present investigation was directed in identifying a simple and reliable extraction treatment using solvents with lower cost and toxicity and an adequate method for the identification and separation of active compounds (pyrethrins) with possible application in enterprises or industry. Best developed method was used for determination of pyrethrin content in three different natural populations of Chrysanthemum. The results revealed high content of total pyrethrins in populations grown in Croatia. Developed method and good quality product give a possibility for this culture to become again an exporting and economically valid product for Croatia.

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.

The relationship between pyrethrins and the yellow pigmentation in pyrethrum flowers

Various clones and varieties of Chrysanthemum cinerariaefolium flowers originating from various localities were used in this study to establish the link between pyrethrins and the yellow pigments in pyrethrum. Pyrethrins content was determined using spectrophotometric, AOAC and HPLC analytical techniques. Absorbances of I % (w/v) n-hexane extracts at various wavelengths in the UV and visible regions were read using a double beam spectrophotometer. This paper presents correlations between total Pyrethrins, individual ester distributions, Pyrethrins I and Pyrethrins11 ratios and specific colour absorbances (A1%1cm) in three different regions 260-300nm (1A1%cm), 300-400 nm (2A1%cm) and 400-470 nm (3A1%cm). The results depict negative colour absorbances in all the three regions. The pigments absorbing at 266-300 nm show a better correlation with the pyrethrins than pigments absorbing at 400- 470 nm. The pigments at the former region are flavonoids and the latter carotenoids from spectrophotometric scans and TLC screening. African Journal of Science and Technology Vol.4(2) 2003: 116-123

Determination of N-Octyl Bicycloheptene Dicarboximide, Pyrethrins, and Butylcarbityl 6-Propylpiperonyl Ether in Technical Materials, Concentrates, and Finished Products by Capillary Gas Chromatography: Collaborative Study

abstract Nineteen collaborating laboratories (including the authors') analyzed 6 blind, duplicate pairs of various technical materials, pyrethrum extracts, concentrates, and finished products by split injection capillary gas chromatography (GC) with flame ionization detection. This procedure simultaneously quantitates with speed, ease, accuracy, and precision all 6 insecticidal compounds in pyrethrum: pyrethrin I, jasmolin I, cinerin I, pyrethrin II, jasmolin II, and cinerin II, as well as butylcarbityl 6-propylpiperonyl ether (BPE, the predominant compound in technical piperonyl butoxide, also commonly known as piperonyl butoxide) and both the endo and exo isomers of N-octyl bicycloheptene dicarboximide (MGK 264). Repeatability ranged from 4.28 to 7.22% for total pyrethrins, from 2.41 to 7.04% for BPE, and from 2.20 to 4.91 % for total MGK 264. Reproducibility ranged from 5.22 to 9.71 % for total pyrethrins, from 4.37 to 7.04% for BPE, and from 2.66 to 6.01 % for total MGK 264. The capillary GC method for these insecticidal compounds in technical materials, concentrates, and finished products has been adopted first action by AOAC INTERNATIONAL.

EFFECT ON SOME GROWTH REGULANTS ON GROWTH AND FLOWERING BEHAVIOUR IN PYRETHRUM (Chrysanthemum cinerariaefolium Vis.)

The results of the present investigation indicate that total spread of plant was increased by Go and TIBA spross. Flowering could be adva, ced by CCC or TIBA sprays. The number and fresh and dry weights of flower were enhanced by spray of TIBA 100 ppm or CCC 250 ppm so also for total pyrethrins in flowers. On the other hand, Ethrel hed little or no effect for any of these characters.

Rapid method for the determination of ‘total pyrethrins’ by spectroscopy of their 2,4‐dinitrophenylhydrazones

AbstractA rapid method for the analysis of pyrethrum extract and pyrethrum formulations containing synergists and emulsifying agents has been developed. The pyrethrins are converted into their 2,4‐dinitrophenylhydrazones and, without chromatography, the optical density at 377 mp determined. The optical density is converted into pyrethrin concentration by using the value ϵ = 28,000 for the molecular extinction coefficient of the pyrethrin dinitrophenylhydrazones.

Pyrethrum Analysis, Rapid Colorimetric Determination of Total Pyrethrins by Reaction with Sulfur

Pyrethrum Analysis, Rapid Colorimetric Determination of Total Pyrethrins by Reaction with Sulfur

STUDIES ON THE BEAN APHID (APHIS FABAE SCOP.) AND ITS CONTROL ON FIELD BEANS

Field trials on chemical control of Aphis fabae Scop, attacking spring‐sown field beans were carried out during the years 1950–2. The insecticide sprays were applied once only, soon after primary aphid migration into the bean crop had ceased. Destruction of the few aphids present at this early date stops build‐up of the big populations that often develop later.An 0.02% (w/v) parathion spray was used in all three field trials. This gave excellent control of A. fabae as did the systemic insecticides Isopestox and Systox at 0.05% (w/v) active ingredient, and nicotine at 0.1% (w/v). Sprays containing allethrin (0.05% (w/v) pure material), pyrethrins (0.05% and 0.02% (w/v) total pyrethrins plus piperonyl butoxide) and an 0.1 (w/v) DDT emulsion gave moderate control. A. fabae was not controlled in plots treated with an 0.1% (w/v) DDT crystalline suspension, and the aphid population reached a higher peak than in the untreated plots; the suspension is not only relatively ineffective against the aphid, but is more toxic than the DDT emulsion to its Coccinellid predators.On the bean plant the 0.05% (w/v) Systox spray showed some residual toxicity to A. fabae for at least 5 days after application, but stopped causing 100% kill within 24 hr. 0.02% (w/v) parathion and 0.1 (w/v) DDT emulsion had slight, and 0.02% (w/v) pyrethrins and 0.1% (v/v) nicotine, no residual toxicity.In the year 1950, aphid attack on the field plots was slight and damage insignificant. In 1951, there was a moderate attack and the yield of bean seed was significantly increased by all insecticidal treatments; where aphid control was most efficient (parathion and Isopestox treatments) the yield (16.7–17.1 cwt./acre) was about × 2.7 that of the untreated control (6.3 cwt./acre). In 1952, there was severe aphid attack, and the mean seed yield of the untreated control plots was 1.4 cwt./acre. Plots treated with the DDT suspension yielded 1.3 cwt. seed/acre, but all other insecticides, including the DDT emulsion, increased the seed yield to 10.3–14.8 cwt./acre.All preparations used in 1952, except nicotine, were destructive to adult Coccinellid predators of A. fabae; Adalia bipunctata was more susceptible than Coccinella septempunctata. However, in 1952, predators on the experimental area were too uncommon to be economically important.

The influence of piperonyl butoxide and ddt on the determination of the pyrethrins content of commercial spray‐insecticides by the A.O.A.C. and the seil methods

AbstractThe estimation of total pyrethrins either by the A.O.A.C.* method of analysis or the Seil method yields high results in the presence of the synergist piperonyl butoxide, or DDT. Both these compounds, on hydrolysis with alcoholic potassium hydroxide, produce acidic substances which, being apparently only slightly soluble in light petroleum and non‐volatile in steam, do not affect appreciably the estimation of pyrethrins I, but, being soluble in ether, give falsely high results for pyrethrins II by either method.

The persistent Toxicity under standardised field Conditions of Pyrethrum, DDT and “Gammexane” against Pests of stored Food

The persistent toxicity of films of pyrethrum in P31 oil may endure on suitable surfaces under warehouse conditions for much longer periods than hitherto supposed, but unexplained fluctuations in toxicity may occur.Within the range 0·8 per cent. to 1·3 per cent. total pyrethrins, the pyrethrum content appears to be only a minor factor in determining the persistent toxicity of such films.The nature of the surface sprayed is of great importance in determining the persistent toxicity of pyrethrum films in P31 oil, which is negligible on concrete and increases steadily through the following list of surfaces—brick, heavy hessian, light hessian, jute, cotton, and wood; the last-mentioned two being particularly good substrates.Residual deposits of DDT or “ Gammexane ” derived from kerosene sprays are of little use on concrete, but appear otherwise little affected by the nature of the surface treated; they give a uniform degree of persistent toxicity on the various surfaces listed.

The pyrethrin contents of undried flowers, chrysanthemum cinera‐riaefolium, determined by extraction with petrol ether

AbstractA method is described of quantitatively extracting the pyrethrins from undried pyrethrum flowers, using petrol ether only as solvent. The flowers are ground in a rod mill with the solvent and then extracted in three stages. Samples of the same flowers are dried by natural and by the most favourable artificial means, and a third sample in a commercial drier. The total pyrethrins in the undried and the dried flowers are compared on a moisture‐free basis. The same procedure is applied to three strains of Kenya‐grown flowers.

The formation of insecticidal films on building materials: I. Preliminary experiments with films of pyrethrum and D.D.T. in a heavy oil

The relative toxicity to the flour beetle, Tribolium castaneum Herbst, of films of 1‐6% w/v total pyrethrins or 0.8% w/v technical D.D.T. in Shell Oil P31 sprayed on to some common building materials has been investigated. Beetles were exposed on films for 6 days, starting 24 hr. after application of the insecticide, and relatively low kills were recorded even with deposits two to three times as heavy as those normally used in practice. The materials could be placed in order, according to the toxicities of the films formed on them, as follows:1.6 % pyrethrins 0.8 % D.D.T. Rough deal, sacking Rough deal, limewashed brick Films more toxic Fletton brick Fletton brick Wallboard Cement, cement‐sand, limewashed brick ceiling board, Cement, cement‐sand Films less toxic An experiment carried out under practical conditions confirmed the low toxicities of films formed on limewash and wood.The effect has also been investigated of pretreating bricks with six substances, which might influence the rate of sorption of the oily insecticide into the substrate. Pretreatment with polyvinyl alcohol, starch paste, size, and waterglass greatly increased the toxicity of pyrethrum films on brick, but water and calcium chloride failed to do so. The toxicity of a pyrethrum film on cement‐sand blocks was also very greatly increased by a pretreatment with starch paste.

The Toxicity of DDT to the Housefly, Musca domestica, L.

DDT (p,p'-dichlordiphenyl-trichlormethyl-methane) has been shown to be very toxic to the housefly, Musca domestica, L., when applied as a spray containing 0·1 per cent, w/v or more in kerosene. DDT at 1 per cent, gives an effective spray for practical use, but at lower concentrations the speed of knock-down is too slow. This disadvantage can be overcome by the admixture of a small amount of pyrethrum. A mixture of 0·03 per cent, w/v total pyrethrins and 0·1 per cent, w/v DDT in kerosene is recommended as a suitable fly spray for practical use. This mixture can be stored in glass bottles in the dark for at least 17 months at 27·5° C. without marked deterioration. Its toxicity may be increased by the incorporation of a suitable activator, e.g., sesame oil or isobutylundecylenamide.The impurities in crude preparations of DDT appear to exert no toxic effect on houseflies.DDT acts more slowly when dissolved in industrial methylated spirit than in kerosene.Attention is drawn to the residual film effect of DDT on walls, etc., and an example is given to show how this effect was employed in the control of a fly population in a kitchen.The symptoms of poisoning of flies by DDT are compared with those caused by pyrethrum. DDT is relatively slow in action; it is a severe irritant, causing the flies to buzz violently at one stage; it induces marked tremors during the coma preceding death; and, at death, it causes the legs to be tightly flexed at the femoro-tibial joint. When the pyrethrins and DDT are mixed in a spray, these constituents, so far as can be judged from the train of toxic symptoms, act independently, so that the rapid paralytic effect of the pyrethrins keeps the insects immobile until the slow lethal effect of the DDT supervenes.This work has been carried out as part of the programme of research of the Pest Infestation Laboratory, and this account is published by permission of the Department of Scientific and Industrial Research.

The chemical evaluation of pyrethrum flowers (Chrysanthemum cinerariifolium). The extraction of the flowers for analysis and the preparation of colourless concentrates of the pyrethrins

1. Biological trials have been carried out to determine the efficacy of petroleum ether as solvent for the extraction of pyrethrum flowers for analysis. 95% of the toxic material was extracted from flowers one year old after only 3 hr. percolation. An extraction period of 8 hr. with petroleum ether is suggested.2. A method of preparing colourless extracts of pyrethrum and analytical data for such extracts are given. They are shown to be of value for the preparation of concentrates of the pyrethrins. The preparation of a colourless concentrate containing 93% of total pyrethrins, as determined by a modified Seil method, is described.

THE EFFECT OF ENVIRONMENTAL CONDITIONS UPON PYRETHRUM (CHRYSANTHEMUM CINERARIAEFOLIUM). I.

Summary.The effect of soil fertility upon the insecticidal value of the flowers has been studied in a series of pot experiments. On heavy soil the pyrethrin I content of the flowers was not increased by the application of fertilisers. The plants produced good yields of flowers, rich in pyre‐thrins, when grown in soil of low fertility.Under conditions of normal growth and vitality, the extent of production of the pyrethrins in the flowers was characteristic of the individual plant and was dependent upon some factor which appeared to be genetical in character. A plant initially producing flowers of high or low percentage poison content continued to give flowers of the corresponding degree of richness in succeeding years, independently of the application of manures, or apparently of the number of heads produced. Plants derived from rooted shoots produced flowers corresponding in quality with those initially yielded by the parent plant. The insecticidal value of pyrethrum flowers may be improved by plant selection, followed by vegetative propagation.In the fully open flowers, the complete disc florets contained 90 per cent. of the total pyrethrins present in the flowers, and of this the greater part was found to be located in the ovaries.