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Search Results: 1 - 10 of 603 matches for " spider mites "
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Eotetranychus tremae De Leon: additional descriptions and illustrations (Acari, Tetranychidae)
Flechtmann, Carlos H.W;
Revista Brasileira de Zoologia , 1996, DOI: 10.1590/S0101-81751996000100019
Abstract: eotetranychus tremae de leon, 1957 is reported for the second time from brazil; additional descriptive characters and figures are given.
Susceptibilidad de Tetranychus urticae Koch (Acari: Tetranychidae) Colectada en Primula obconica Hance y Convolvulus arvensis L. a Acaricidas
Flores F,Alberto; Silva A,Gonzalo; Tapia V,Maritza; Casals B,Pedro;
Agricultura Técnica , 2007, DOI: 10.4067/S0365-28072007000200014
Abstract: the use of acaricides of high toxicity in the production and handling of ornamental plants should be a matter of consumer concern. the susceptibility of two populations of tetranychus urticae was assessed: one collected from primula obconica hance and the other from convolvulus arvenis l as susceptible reference strain to the acaricides dicofol, abamectin alone and mixed with the surfactant phosphatidylcholine, azadirachtin, sulfur, pyridaben and fenazaquin. the evaluated parameters were mortality, lethal concentration 50% (lc50) and 90% (lc90), lethal time 50% (lt50) and 90% (lt90), effectiveness and index of resistance (ir). the experimental design was completely at random. each treatment had ?, ?, 1, 2 and 4x of the doses indicated by the manufacturer, five replicates and were sprayed with a potter spray tower. the results showed that the lc50 for azadirachtin and sulfur was significantly high. regarding the population from p. obconica, abamectin alone and in mixture with phosphatidylcholine and fenazaquin showed the highest efficiency. azadirachtin and sulfur were the acaricides showing the slowest activity and the resistance index indicated that the population collected in p. obconica should be considered susceptible to all the evaluated acaricides
Primeiro registro no Brasil de Erythrina velutina Willd. como hospedeira de Tetranychus neocaledonicus (Acari: Tetranychidae)
Poderoso, J.C.M.;Ribeiro, G.T.;Návia, D.;Passos, E.M.;Gon?alves, G.B.;Correia-Oliveira, M.E.;Dantas, P.C.;
Revista Brasileira de Plantas Medicinais , 2010, DOI: 10.1590/S1516-05722010000300017
Abstract: spider mites are important pests to several crops worldwide. during prospecting in erytrina velutina specimens from s?o cristov?o district, sergipe state, brazil, their occurrence was observed in 15% seedlings, which were taken to the laboratory for description of damages. the seedlings presented leaf blade reduction and crumpling symptoms. one hundred mites were collected from these seedlings and mounted on microscope slides for taxonomic identification. the identified mites belonged to the species tetranychus neocaledonicus (acari: tetranychidae). this is the first report of e. velutina as host for t. neocaledonicus in brazil.
Rela??o entre zingibereno, tricomas foliares e repelência de tomateiros a Tetranychus evansi
Gon?alves, Luciano Donizete;Maluf, Wilson Roberto;Cardoso, Maria das Gra?as;Resende, Juliano Tadeu Vilela de;Castro, Evaristo Mauro de;Santos, Nicolau Macedo;Nascimento, Ildon Rodrigues do;Faria, Marcos Ventura;
Pesquisa Agropecuária Brasileira , 2006, DOI: 10.1590/S0100-204X2006000200011
Abstract: the objective of this work was to quantify zingiberene contents in a segregating population (f2) of the second backcross generation to lycopersicon esculentum after the initial cross with the wild species l. hirsutum var. hirsutum, and to analyse the relationship between zingiberene and both glandular trichome density on tomato leaves and levels of repellence to spider mites tetranychus evansi. a spectrophotometric assay was used to quantify zingiberene in leaf disks. trichome counting was made in paradermic preparations of leaf and mite repellence was accessed by a quick thumbtack assay. indirect selection for high zingiberene contents increased both glandular trichome density and the level of mite repellence. zingiberene in glandular trichomes therefore mediates mite repellence in the tomato population. glandular trichome densities, especially that of type vi trichomes, were highly and positively correlated with zingiberene contents. high zingiberene levels and their relationship with both glandular trichome densities and resistance (repellence) to spider mites remained significant after two backcross generations, indicating an indirect selection for high zingiberene as an effective way of selecting mite resistant tomato genotypes.
Rediscovery of Tetranychus abacae Baker & Pritchard, additional description and notes on South American spider mites (Acari, Prostigmata, Tetranychidae)
Flechtmann, Carlos H.W;
Revista Brasileira de Zoologia , 1996, DOI: 10.1590/S0101-81751996000300005
Abstract: the rediscovery of tetranychus abacae baker & pritchard, 1962 is reported and additional description and drawings presented. new host and distribution records for 19 species of spider mites (tctranychidae) in south america are given.
Evaluation of cucumber (Cucumis sativus L.) accessions (cultivars and lines) against the two-spotted spider mite (Tetranychus urticae Koch.) and kanzawa spider mite (T. kanzawai Kishida, Acari: Tetranychidae)
Farman Ullah,Joon-Ho Lee,Farhatullh
Songklanakarin Journal of Science and Technology , 2006,
Abstract: Forty three cucumber (Cucumis sativus L.) accessions (cultivars and lines) were tested against the two-spotted spider mite (Tetranychus urticae Koch) and kanzawa spider mite (Tetranychus kanzawai Kishida). The highest number of T. urticae and T. kanzawai eggs /female/ day (5.98, and 6.23 respectively) was recorded on the cucumber genotype Blackish Green while the lowest eggs/female/day (2.95 and 3.31) was recorded on Winter Long Green (WLG) for T. urticae and T. kanzawai respectively. On a scale of 1 to 5, the highest visual damage rating was recorded on Blackish Green (4.75 for T. urticae and 4.78 for T. kanzawai) and the lowest damages rating of 1.50 and 1.70 were recorded on WLG for T. urticae and T. kanzawai respectively. Instead of distinct categories of resistance and/or susceptibility, an array of responses (number of eggs laid/female/ day and damage rating) was recorded on the tested cucumber accessions, suggesting two or more genes with additive effects. Based on our findings, Blackish Green was foud to be a susceptible cultivar and Winter Long Green proved to be a resistant one. These two cultivars could be used as a differential host in further studies. Among the Korean cucumber lines, K-4, K-6, and K-20 where found susceptible while K-1, K-2, K-13, and K-15 exhibited some type of resistance to the two mite species.
Greenhouse and Field Evaluation of Two Biopesticides Against Tetranychus urticae and Panonychus ulmi (Acari: Tetranychidae)
Dejan Mar?i?,Mirjana Prijovi?,Tanja Drobnjakovi?,Irena Me?o
Pesticidi i Fitomedicina , 2012,
Abstract: The mycopesticide Naturalis (based on Beauveria bassiana strain ATCC 74040) andbotanical pesticide Kingbo (based on oxymatrine, an alkaloid from Sophora flavescens, a traditionalChinese herb) were tested against the two-spotted spider mite (Tetranychus urticae)on greenhouse vegetables and the European red mite (Panonychus ulmi) on apples. Thesebiopesticide products were applied twice at 5-day interval and concentrations of 0.1% and0.2%, and their effectiveness was compared to abamectin-based products and the syntheticacaricides acrinathrin and spirodiclofen, applied once at their recommended rates.The mycopesticide Naturalis, applied at 0.1% concentration against T. urticae on cucumber,reduced mite population density by 85-86%, achieving 91-93% efficacy. In a trial on tomato,efficacy reached some 96%, while population density was reduced by 93%. In a field trialon apple, Naturalis demonstrated an increasing and long-lasting effectiveness against thesummer population of P. ulmi of nearly 100%, and population reduction was achieved inassessments 30 days after the first treatment. Naturalis applied at a double rate achieved asomewhat better effect but only in the first trial. The botanical pesticide Kingbo, applied at0.1% concentration, demonstrated very high control efficacy (≥98%) and population densityreduction (≥96%) of T. urticae in both trials. A high and long-lasting effectiveness of thisbioacaricide was also achieved in a trial on P. ulmi. Its concentration of 0.2% achieved similareffect. The results in these trials indicate that applications of the mycopesticide Naturalisand the botanical pesticide Kingbo can provide effective control of T. urticae on cucumberand tomato grown in greenhouses, as well as P. ulmi on apple.
Tetranychus bastosi Tuttle, Baker & Sales (Prostigmata: Tetranychidae) mites on Jatropha curcas (Linaeus) in Sergipe State, Brazil
Heloisa Oliveira dos Santos,Renata Silva-Mann,Alessandra de Jesus Boari
Comunicata Scientiae , 2010,
Abstract: Tetranychid mites represent important pests that attack different agricultural crops worldwide. In anevaluation of germplasm of physic nut, Jatropha curcas L. in the state of Sergipe, Brazil, the miteswere observed on less vigorous plants with symptoms such as leaf blade reduction and curling.One hundred mites were collected from those plants and observed on microscope for taxonomicidentification. The mites were assigned to the species Tetranychus bastosi (Acari: Tetranychidae).This is the first report of physic nut, J. curcas as host plant of T. bastosi in Brazil.
Use of Variogram Parameters in Analysis of Hyperspectral Imaging Data Acquired from Dual-Stressed Crop Leaves
Christian Nansen
Remote Sensing , 2012, DOI: 10.3390/rs4010180
Abstract: A detailed introduction to variogram analysis of reflectance data is provided, and variogram parameters (nugget, sill, and range values) were examined as possible indicators of abiotic (irrigation regime) and biotic (spider mite infestation) stressors. Reflectance data was acquired from 2 maize hybrids (Zea mays L.) at multiple time points in 2 data sets (229 hyperspectral images), and data from 160 individual spectral bands in the spectrum from 405 to 907 nm were analyzed. Based on 480 analyses of variance (160 spectral bands × 3 variogram parameters), it was seen that most of the combinations of spectral bands and variogram parameters were unsuitable as stress indicators mainly because of significant difference between the 2 data sets. However, several combinations of spectral bands and variogram parameters (especially nugget values) could be considered unique indicators of either abiotic or biotic stress. Furthermore, nugget values at 683 and 775 nm responded significantly to abiotic stress, and nugget values at 731 nm and range values at 715 nm responded significantly to biotic stress. Based on qualitative characterization of actual hyperspectral images, it was seen that even subtle changes in spatial patterns of reflectance values can elicit several-fold changes in variogram parameters despite non-significant changes in average and median reflectance values and in width of 95% confidence limits. Such scattered stress expression is in accordance with documented within-leaf variation in both mineral content and chlorophyll concentration and therefore supports the need for reflectance-based stress detection at a high spatial resolution (many hyperspectral reflectance profiles acquired from a single leaf) and may be used to explain or characterize within-leaf foraging patterns of herbivorous arthropods.
Two new spider mites (Acari, Prostigmata, Tetranychidae) from South America
Flechtmann, Carlos H.W.;
Revista Brasileira de Zoologia , 1993, DOI: 10.1590/S0101-81751993000400017
Abstract: oligonychus viranoplos, sp.n. from a bamboo (poaceae) from piracicaba, s?o paulo, brasil and eotetranychus vinealis, sp.n. from vitis vinifera l. (vitaceae) from cerrito, valle, colombia, are described.
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