Repellency Test Research Articles

Molecular characterization of lipid fractions from extremely water-repellent pine and eucalyptus forest soils

There is little information available about the molecular composition of organic fractions with a possible bearing in soil water repellency. Extremely water-repellent forest soils developed on granites or schists, under vegetation of pine or eucalyptus, were used for sequential isolation of two lipid fractions: free lipid extracted with petroleum ether and ‘bound’ lipid obtained with the same solvent after 2M H3PO4 pre-treatment. Soil water repellency tests were carried out, and lipids were analyzed by gas chromatography/mass spectrometry (GC–MS). Free lipids in soils under eucalyptus consisted mainly of sesquiterpenes (globulol, aromadendrene, eudesmol and ledene) whereas soils under pine included diterpene resin acids (mainly dehydroabietic, pimaric and seco-dehydroabietic) and phenol. Free alkanes (C15 to C37) displayed homologous series typical in epicuticular waxes, whereas free fatty acids series showed bimodal distribution.‘Bound’ lipids consisted almost exclusively of fatty acids (mainly C16 and C18 acids), and alkanes (maximum at C27 or C28 and no even-to-odd C-number preference). Major compounds related to soil water repellency are typically found in higher plants and are not synthesized by microorganisms. After removing free lipids, soil water repellency decreased slightly but remained extreme. After extraction of bound lipids, the repellency considerably decreased, but did not disappear completely. As regards the effect of the lipid fractions in soil water repellency, it was clear the dominant role of the vegetation type in the case of free lipid, whereas for bound lipid, repellency mainly represents an emergent property arising from strong interaction between organic matter and the geological material.The results suggest that soil lipids only explain a part of the soil water repellency, which also depends on surface properties of the soil matrix, i.e., not only depends on hydrophobic coatings but probably of diffusion of hydrophobic cements into micellar associations self-organized into zonal structures in humus–clay matrix.

Plasma Induced Graft Polymerization of C6 Fluorocarbons on Cotton Fabrics for Sustainable Finishing Applications

AbstractThe main objective of this research is to achieve atmospheric plasma induced graft polymerization of non‐C8 fluorocarbons onto cotton fabrics to achieve a durable nanolayer fluorocarbon coating that is water, alcohol, and oil repellent through home launderings. The influence of process parameters on the performance of polyfluorocarbon was studied using water contact angle measurements, water/alcohol, and oil repellency tests, X‐ray photoelectron spectroscopy, and scanning electron microscopy. A design of experiments for different processing conditions was used. Plasma assisted‐graft polymerization of fluorocarbon in presence of the crosslinker di(ethyleneglycol) diacrylate (10:1 molar ratio of monomer/crosslinker) resulted in a polyfluorocarbon nanolayer on cotton, which was hydrophobic and durable to five home launderings.magnified image

Acaricidal and repellent effects of myrtacean essential oils and their major constituents against Tetranychus urticae (Tetranychidae)

Nineteen plant essential oils (EOs) extracted from the family Myrtaceae growing in Australia were screened for their acaricidal and repellent activities against two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), in the laboratory by dipping method and choice- and no-choice tests. Acaricidal bioassays showed that five EOs of Callistemon viminalis, Eucalyptus bicostata, Eucalyptus maidenii, Eucalyptus sideroxylm and Eucalyptus approximans significantly increased the mortality of female adult mites and decreased the total number of eggs. In a choice test, Callistemon sieberi, E. bicostata, Eucalyptus ovata, E. sideroxylm, Eucalyptus mannifera, Eucalyptus dives, Eucalyptus elata, Eucalyptus condonocarpa, Kunzea ericoides, Melaleuca armillaris and Melaleuca fulgens demonstrated good repellency to the mite. In another test, C. sieberi, E. bicostata, E. mannifera, E. condonocarpa, K. ericoides, M. armillaris, and M. fulgens EOs decreased the egg production of the females significantly. In the acaricidal and repellent tests, E. bicostata and E. sideroxylon EOs showed both acaricidal and repellent effects (choice test) and decreased the number of eggs on treated bean leaves. The gas chromatograph/mass spectroscopy analyses revealed that the major components of E. bicostata and E. sideroxylon were 1,8-cineole, limonene, and α-pinene. The 1,8-cineole and limonene showed significant repellent effects on the mites, resulting in reduced numbers of eggs in the choice test. Hence, EOs of E. bicostata and E. sideroxylon and limonene and 1,8-cineole may be potential agents to be used in the sustainable management of T. urticae.

Novel superhydrophobic top coating on surface modified PVC-coated fabric

A superhydrophobic surface was created on poly(vinylchloride)-coated architectural fabric using spray coating method. Dispersions of nanoparticles and a flourochemical were prepared as top coating solutions. After spray-dry-cure process, contact angle, sliding (tilt) angle, 3M water repellency test and surface morphology were compared between uncoated and top coated PVC surfaces. The results indicated that a specific nano-TiO2 dispersion top coating produced a superhydrophobic layer on the top of the PVC surface with high contact angle (150°) and very low sliding angle (2°). Combination of two major requirements, the magnified of the degree of roughness and low surface energy, created self-cleaning effect on the PVC surface. Abrasion fastness of superhydrophobic top coating was improved by surface oxidation via UV–ozone surface treatments. Spectroscopic analysis demonstrated that formation of oxygenated functional groups has improved PVC wettability and adhesion. Results of artificial weathering test indicated no change in superhydrophobicity of top coated PVC.

Biofumigation of plant species onSitophilus zeamaisin stored maize

The objective of this study was to evaluate the repellent effect and toxicity of volatile substances from plant species in the form of ethereal, ethyl, aqueous extracts and powders on adults of Sitophilus zeamais. The experiments were conducted at the Laboratory of Plant Science of the Camilo Castelo Branco University, Campus Descalvado/São Paulo State. It were used the Chenopodium ambrosioides, Corymbia citriodora and Cucurbita pepo plant species. The experimental design was completely randomized with six replications. In repellency tests were used doses of 5μl, 10μl, 15μl, 20μl, and 25μl (for the ethereal, ethyl and aqueous extracts) and 0.3 g (for powder) with assessments after 24 hours. In the toxicity tests it was used the dose of 25μl (for the ethereal, ethyl and aqueous extracts) and 0.3 g (for powder) with assessments after 48 hours. Based on the obtained data it can be concluded that the ethereal (excepting C. pepo), ethyl, aqueous extracts and powders of all the tested plants showed repellent effect to adults of S. zeamais. All extracts and powders from the tested plants showed toxic effects to adults of weevil.

Composição química e atividade inseticida do extrato acetônico de Piper alatabaccum Trel & Yuncker (Piperaceae) sobre Hypothenemus hampei Ferrari

O presente trabalho teve como objetivo investigar a composição química e avaliar a atividade inseticida do extrato acetônico das raízes de Piper alatabaccum sobre Hypothenemus hampei. As raízes foram coletadas no campus da Universidade Federal de Rondônia, em Porto Velho-RO. Diluições de 100,0, 50,0, 25,0, 5,0 e 0,5 mg mL-1 foram utilizadas para exposição na superfície contaminada e aplicação tópica. No teste de repelência, utilizou-se as diluições de 25,0 e 100,0 mg mL-1. As avaliações ocorreram durante 48 horas após a exposição ao extrato. O extrato foi eficiente na mortalidade em aplicação tópica e superfície contaminada, não sendo eficiente no efeito de repelência. Estes resultados apontam para o elevado potencial inseticida do extrato de P. alatabaccum no controle de H. hampei. Identificou-se cinco compostos, sendo três amidas, dihydropiplartine piperovatina e piplartina, e duas flavona, 3',4',5,5',7 pentamethoxyflavone e 5,5',7-trimetóxi-3',4'-methylenedioxyflavone.

Multi-layered Breathable Fabric Structures with Enhanced Water Resistance

This work reports waterproof breathable layered fabrics consisting of simple fabric weave types (plain, twill) and microporous breathable films. The pretreated fabrics were treated with water-repellent finishing chemicals. Afterwards, layered structures were generated by bringing the fabrics and the microporous breathable films together. According to the results of water repellency, hydrostatic pressure (water resistancy) and water vapor permeability tests conducted on the samples with/without microporous film layers, waterproof breathable layered fabrics were able to be generated, which are supposed to be used as construction materials.

Repellent efficacy and safety evaluation of IR3535 derivative against Aedes albopictus, Culex pipiens pallens and Aedes togoi

AbstractThe IR3535 derivative (LJH158), in which the ethyl ester of IR3535 was converted to methyl ester, was synthesized and studied as a new mosquito repellent. The repellent efficacy of LJH158 was compared with that of DEET against Aedes albopictus, Culex pipiens pallens and Aedes togoi. Also, the aromatic repellent tests were conducted with mixtures of repellents and the essential oils of cinnamon, which were obtained by supercritical fluid extraction. In addition, the safety issues of LJH158 were monitored using single oral dose safety methods and eye irritation, and skin irritation tests. The results of repellent efficacy in both biting and aromatic tests and safety tests demonstrate that LJH158 has high potential to be used as a new repellent or in combination with other repellents.

Toxicity and repellency of essential oils to Zabrotes subfasciatus (Boheman) (Coleoptera, Chrysomelidae, Bruchinae) in Phaseolus vulgaris L

The effects of tangerine (Phaseolus vulgaris Blanco), lemon (Citrus medica limonum Lush), pear orange (Citrus sinensis L. Osbeck), red copaiba (Copaifera langsdorffii Desf.), rosemary (Baccharis dracunculifolia De Candole), Eucalyptus (Eucalyptus globulus Labillardière and E. citriodora Hook), lemongrass (Cymbopogon citratus Stapf.) and citronella (Cimbopogon nardus Linnaeus) oils at several concentrations on Zabrotes subfasciatus (Boheman) were studied. In toxicity tests, grains of Phaseolus vulgaris L. cv. Rajadinho were impregnated with oils and infested with adults of Z. subfasciatus up to 24 hours old. All tested oils were effective in reducing the viable egg-laying and adult emergence of this pest, in function of the concentrations used, highlighting E. citriodora and E. globulus oils which caused 100% effectiveness from 0.5 mL Kg-1 concentration. In repellency tests, two arenas consisting of plastic containers, connected symmetrically to a central box by two plastic tubes were used. In one of the boxes, untreated beans were placed and on the other ones beans treated with each oil concentration were used. In the central box, five couples of Z. subfasciatus were released. Grains of P. vulgaris treated with oils of E. citriodora, C. citratus and C. oleifera reduced the attraction percentage of Z. subfasciatus adults, while the E. globulus increased this percentage. The percentages of reduced viable eggs ranged from 17.9% (C. medica limonum) to 93.3% (C. nardus), while the reduction on the number of emerged insects was 23.9% and 95.9%, respectively for these same oils.

Studies on the properties of nonwoven surgical gowns

Polypropylene spunbond, spunbond/meltblown/spunbond, and spunlace fabrics of 35 and 50 g/m2 weight are tested for barrier properties against microorganisms and liquid or body fluids to estimate their suitability for surgical gowns. The fabrics are also treated with different levels of antibacterial and fluorochemical finishes in a single bath using pad-dry-cure method. Liquid barrier properties of samples are analyzed by water impact penetration, hydrostatic pressure test, and blood repellency test. Parallel streak method is used to measure the antibacterial activity on the fabric samples with Staphylococcus aureus. The fabric samples are also analyzed for air permeability and stiffness. It is observed that spunbond/meltblown/spunbond fabric of 35 and 50 g/m2 weight offer sufficient liquid barrier properties for level 2 protection as per the Association for the Advancement of Medical Instrumentation barrier protection classification. Spunlace and spunbond fabrics of 35 and 50 g/m2 weight offer only level 1 protection. Spunbond/meltblown/spunbond fabrics are poorest in terms of comfort, because of their higher stiffness and lower air permeability values; spunlace fabric offers the highest air permeability and lowest stiffness force. Spunbond/meltblown/spunbond fabric samples with 4% and 7% fluorochemical finish and 1.5% antibacterial finish can provide level 4 protection. Spunbond fabrics require 4% and spunbond/meltblown/spunbond fabrics require 1% fluorochemical finish to achieve level 2 protection.

Various effects of ethanolic extract of Mentha pulegium on the two-spotted spider mite, Tetranychus urticae (Tetranychidae)

Ethanolic extract of Mentha pulegium was evaluated against the adults of important arthropod pest species, the two-spotted spider mite, Tetranychus urticae. Potential acaricidal impact of plant was determined by contact application. Phytotoxicity was recorded after 24 h. The value of LC50 was 59,149 mg L−1. Also, LT50 values were 27.42, 25.56 and 19.79 h for 35,000, 50,000 and 100,000 mg L−1, respectively. Also, results showed that this ethanolic extract had impact on repellency of T. urticae. All of the tested concentrations were similar in the repellency test. On the other hand, the used concentrations (1000, 4000, 6000 and 8000 mg L−1) affected on the oviposition of mite females. These extract doses significantly decreased the egg laying on the treated surface. The current study indicated that this ethanolic extract can be used as a safe acaricide on T. urticae.

Insecticidal Effect of Fruit Extracts from Xylopia aethiopica and Dennettia tripetala (Annonaceae) against Sitophilus oryzae (Coleoptera: Curculionidae)

The insecticidal and repellent activities of fruit extracts of Xylopia aethiopica (Dunal) A. Rich. and Dennettia tripetala (Baker f.) G.E. Schatz belonging to the family Annonaceae was studied against Sitophilus oryzae (L.), an economic, primary post-harvest pest of rice, and other cereal products. Infested rice grains (100 g) treated with 1, 2, 3, 4, and 5% (w/w) powders of both plants were evaluated for toxicity against S. oryzae every 24 h for 3 d, and during F1 progeny emergence. The essential oils of both plants were also applied at 0.5, 1, 1.5 and 2 mg cm-2 filter paper in Petri dishes for toxicity bioassays at 24 h exposure. Repellence bioassay with 10 μL solution of essential oils on filter paper was performed in a Y-Tube airflow olfactometer. Results indicate that powders of both plants significantly (P < 0.001) caused adult weevil mortality and a reduction in F1 progeny emergence than the control. Essential oils were also significantly (P < 0.001) adulticidal to S. oryzae after 24 h with the highest dose (2 mg cm-2) producing 100% mortality respectively. Similarly, both male and female weevils significantly avoided the test arm compared to the control arm in the Y-Tube olfactometer repellence tests. These results suggest that X. aethiopica and D. tripetala natural extracts have potential for use as part of integrated pest management of stored product protection against S. oryzae.

Insecticidal and repellent activities of the chloroform extracts of &lt;i&gt;Urena sinuata&lt;/i&gt; L. against &lt;i&gt;Tribolium castaneum&lt;/i&gt; (Herbst) adults

The insecticidal and repellent activity tests of the chloroform extracts of fruit, leaf, root and stem of Urena sinuata L. against the red flour beetle Tribolium castaneum L. adults have been conducted. The leaf, root and stem extracts showed high toxicity by giving mortality of the beetles within 30 min. of exposure. The LD50 values for the 12, 24, 36 and 48h of exposures were 0.354, 0.262, 0.209 and 0.196mg cm2 for the fruit extract; 0.587, 0.413, 0.355 and 0.299mg cm2 for the leaf extract; 0.440, 0.389, 0.340 and 0.268mg cm2 for the root extract and 0.968, 0.661, 0.491 and 0.362mg cm2 for the stem extract. The insecticidal activity can be arranged in the order of fruit&gt; root&gt; leaf&gt; stem extracts. The root and stem showed repellent activity against T. castaneum adults at P&lt;0.01 and P&lt;0.05 levels of significance, while the fruit and the leaf extracts did not show repellency at all. DOI: http://dx.doi.org/10.3329/ujzru.v30i0.10740 Univ. j. zool. Rajshahi Univ. Vol. 30, 2011 pp. 25-28

Repellent Effect of Herb Extracts on the Population of Wingless Green Peach Aphid, Myzus persicae Sulzer (Hemiptera: Aphididae)

Investigation of the repellent and insecticidal effects of 8 kinds of herb extracts (chives, dokudami, eucalyptus, lavender, peppermint, cherry sage, sweet pepper and tansy) against wingless green peach aphids were conducted in laboratory and field test. In laboratory repellent tests, 20 aphids were placed between a radish leaf and filter paper for 16 h and aphids on radish leaf were calculated. In laboratory insecticide tests, 20 aphids were placed on a radish leaf treated with herb extract, and live aphids were counted after 16 h. In field tests, the number of aphids that propagated on radish leaves treated with each herb extract was assessed every 3 days. In the laboratory, dokudami, tansy and sweet pepper extracts repelled aphids, while chives, sweet pepper and tansy extracts killed them. In particular, sweet pepper and tansy extracts proved to be a potent insecticide against aphids. In the field test, the results found that extracts from dokudami, cherry sage and lavender had repellent effect on aphids. In particular, dokudami extract was a highly effective repellent against aphids. These findings suggest that dokudami extract can be used to control wingless green peach aphids in the field.

Repellent Effects of Volatile Extracts from Herb Plants against Larvae of Pieris rapae crucivora Boisduval

Environmental pollution and intensive use of toxic chemicals, as well as resistance to pesticides, has forced scientists to find new ways of controlling pests. Numerous substances that repel insects and inhibit eating and egg-laying have been discovered in a variety of plants. The cabbage white butterfly, Pieris rapae crucivora Boisduval, is a serious pest to Brassicaca species such as cabbage, cauliflower and broccoli, and its larvae damage the host plant leaves when feeding. In this study, to develop a botanical insecticide against P. rapae larvae, we assessed the effect of 7 kinds of herb (rosemary, spearmint, eucalyptus, sage, chili pepper, chives and tansy) extracts as feeding repellents against P. rapae larvae. Feeding repellent tests were conducted by placing two cabbage leaf disks on filter paper treated with herb extract or diethyl ether in a box; then a larva was placed between the disks and its preference was observed. The repellent rate of rosemary, spearmint, eucalyptus, sage, chili pepper, chives and tansy was 75%, 72%, 64%, 59%, 40%, 40% and 36%, respectively. These results clarified that of the tested herbs, rosemary and spearmint volatile extracts have a notable feeding repellent effect against P. rapae larvae.

Preliminary findings for the production of water repellent torrefied wood pellets with pyrolysis oil

AbstractTorrefaction of biomass has attracted considerable attention as a means to reduce biomass weight by 70% through removal of water and the hemicellulosic fractions while retaining most of the original high‐energy cellulose and lignin content. Current torrefied wood pellets or briquettes cannot be shipped in open containers exposed to precipitation because they are not highly water resistant. A highly water repellent pelletized product is required to allow bulk shipping of torrefied wood pellets or briquettes via open railcar or by barge. We have recently developed a binder produced from biomass components that imparts the water repellent quality required to produce a torrefied product that is able to be shipped in open containers. Crushing strength of the pellets produced with this binder are high at between approximately 700 and 1100 psi. Water repellency tests indicate that upon total immersion the pellets absorb water into available pores up to 2–5%. The pellets can then be dried without unacceptable loss of strength. © 2012 American Institute of Chemical Engineers Environ Prog, 2012

Repellent activities of some Labiatae plant essential oils against the saltmarsh mosquito Ochlerotatus caspius (Pallas, 1771) (Diptera: Culicidae)

The repellent activities of the essential oils of two Thymus (Thymus sipyleus Boiss. subsp. sipyleus and Thymus revolutus Celak) and two Mentha (Mentha spicata L. subsp. spicata and Mentha longifolia L.) species against Ochlerotatus caspius (Pallas, 1771) (Diptera: Culicidae) are presented. The essential oils were obtained by hydrodistillation of the aerial parts of the plants in flowering period and repellency tests were done with a Y-tube olfactometer. All essential oils showed repellency in varying degrees and exhibited no significant time-dependent repellent activities. When all test oils compared for repellent activities there was no significant activity detected within 15 min exposure period. Mentha essential oils had better activity than Thymus essential oils, producing high repellency (73.8-84.2%) at 30th min on Oc. caspius. Mentha longifolia has the best mosquito repellent activity among the plants tested at the 25th min. Th. sipyleus subsp. sipyleus essential oil produced >85% repellent activity at the 15th min, but the effect decreased noticeably to 63.1% and 68% at 25th and 30th min, respectively.

Composition and Biological Potential of Essential Oil from Thelechitonia trilobata Growing in South Africa

Thelechitonia trilobata is regarded as a troublesome weed that grows to form a dense blanket over the soil preventing the growth of other crops in farmland. Although the plant is regarded as a notorious, invasive plant, its chemical composition and biological potential have not been reported. The essential oil was isolated from the fresh leaves of T. trilobata using hydrodistillation. alpha-Pinene (21.6%), alpha-phellendrene (21.0%), limonene (12.8%) and germacrene D (7.5%) were the major constituents of the oil. The essential oil was screened against agricultural pests. The anti-tick properties were tested on Ripicephalus e. ervertsi found on sheep, while repellency, fumigation, and contact toxicity tests were carried out with maize weevils. Except for the contact toxicity test, all other bioassays gave positive results.

Host feeding responses of Aedes aegypti (L.) exposed to deltamethrin

Escape responses of mated and unmated nulliparous Aedes aegypti mosquitoes were compared using three different concentrations of deltamethrin in the presence or absence of a live animal host using an excito-repellency (ER) test system. Both insecticide contact (excitation) and non-contact (repellency) test configurations were compared. For contact trials, mated mosquitoes showed similar escape movements among the three concentrations when host stimuli were absent. Significant differences in responses were seen between the lower concentrations of (LC(50) and LC(75) ) deltamethrin with and without hosts present (P<0.05). Presence or absence of host stimuli produced no significant differences in escape response for unmated females when exposed to the highest concentration (LC(90) ) of deltamethrin. Our findings indicate that as deltamethrin concentrations decrease to sublethal levels, mating status and host cues play a more significant role in escape behavior. Therefore, insemination can influence the outcome of feeding success and flight movement of nulliparous female Ae. aegypti in contact with deltamethrin and in the presence of live host stimuli. The ER assay system serves as a useful tool for observing excitation and repellency responses of Ae. aegypti to insecticides in the presence or absence of other environmental and biological cues that can affect mosquito behavior.

TRADITIONAL USE OF MOSQUITO REPELLENT PLANTS AND TESTING THEIR REPELLENCY IN FIELD TRIALS AROUND GILGELGIBE RESEARCH CENTRE, JIMMA ZONE, SOUTHWEST ETHIOPIA

Background and Aims: Although local plants as mosquito repellents are known and used among the different cultures of Africa and beyond, little effort is done to document about the knowledge, usage pattern and their repellency potential in Ethiopia in general and specifically around Gilgelgibe Field Research Centre, Jimma Zone, Southwest Ethiopia. This study was aimed to assess the ethno botanical knowledge and usage custom of traditional mosquito repellent plants among the inhabitants of Gilgelgibe Field Research Centre, and evaluating the mean percentage repellency of candidate plants. Methods: Community based cross-sectional quantitative study and pilot field repellency test using candidate five potted mosquito repellent plants was conducted from January 19 to April 10, 2010. The total sample consisted of 417 households for quantitative study. Data were collected using a pre-tested interviewer administered structured questionnaire and by vector collectors for field test. The quantitative data were cleaned, edited and entered into SPSS version 16.0 and analyzed. Repellency of plants to mosquitoes was evaluated by using mean percentage repellency. Results: The study identified eleven species of mosquito repellent plants. Besides, 85.9% and 73.14% of the respondents had knowledge and usage practice of mosquito repellent plants, respectively. The mean percentage repellency of Lantana camara, Cymbopogen citrates, Ocimum sanctum, Chrysanthemum cinerariaefolium and Tagetes minuta to all mosquitoes were found to be 57.0%, 56.0%, 50.7%, 46.7% and 37.0%, respectively. Conclusions: Mosquito repellent plants are widely known and used among the inhabitants of the study area. Field evaluation on the repellent activity of plants showed that repellent plants reduced natural population of mosquitoes significantly as compared to the control house, showing repellency on the range of 37-57%. This study, therefore, provides valuable information to all stakeholders who are involved in mosquito born disease control, particularly for malaria vector control.