737 resultados para Spittlebug infestation
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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A cigarrinha-das-raízes Mahanarva fimbriolata (Stål) (Hemiptera: Cercopidae) tornou-se uma praga importante da cultura da cana-de-açúcar na região centro-sul do Brasil. Estratégias de controle têm sido desenvolvidas, mas os danos promovidos por essa praga e sua interação com a cana-de-açúcar ainda são pouco caracterizados. em altos níveis de infestação da praga, os sintomas nas plantas são muito semelhantes à restrição hídrica severa. Este trabalho foi conduzido com o objetivo de determinar se o estresse promovido pela infestação de ninfas de cigarrinha-das-raízes resulta em acúmulo de prolina livre, além de comparar dois genótipos de cana-de-açúcar quanto à tolerância ao déficit hídrico. Dois experimentos foram conduzidos em delineamento inteiramente casualizado, em esquema fatorial 2 x 2 x 4 com duas cultivares (SP80-1816 e RB72454), dois níveis de estresse (controle e dez ninfas por planta ou 50% de restrição hídrica) e quatro épocas. O déficit hídrico promovido por M. fimbriolata não resultou em acúmulo de prolina, ilustrando a existência de mecanismos distintos para a percepção do estresse hídrico promovido pela praga e pela variação no potencial osmótico nas células das raízes. A cultivar RB72454 acumula maiores teores de prolina livre, e o acúmulo de massa seca e o crescimento dos colmos são menos afetados nessa cultivar sob restrição hídrica. Os teores de solutos compatíveis provavelmente não podem ser utilizados para quantificar o estresse promovido por M. fimbriolata em cana-de-açúcar. A cultivar RB72454 é mais tolerante ao déficit hídrico do que a cultivar SP80-1816.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The Mt Garnet Landcare Group commissioned a survey of landholders within the Upper Herbert and Upper Burdekin River Catchments to assess the density of native woodlands and to gauge the extent of exotic weed infestation. Twenty-four of 49 landholders responded, representing an area of nearly 500 000 ha or 47% of the total area. Dense native woodland covers 24% (>117 000 ha) of the area surveyed, while a further 30% (140 000 ha) supports moderately dense stands. The dense stands are largely confined to the highly fertile alluvial soils (26% dense woodland) and the lower fertility sandy-surfaced soils (33% or >96 000 ha). Moderate and dense infestations of exotic weeds, principally Lantana camara, occur on 54% (20 000 ha) of alluvial soils and on 13% of sandy-surfaced soils (39 000 ha), where praxelis (Praxelis clematidia) is the major weed. Basaltic soils have low levels of both dense woodland and exotic weed infestation. Some implications of the results are discussed.
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Tick resistant cattle could provide a potentially sustainable and environmentally sound method of controlling cattle ticks. Advances in genomics and the availability of the bovine genome sequence open up opportunities to identify useful and selectable genes controlling cattle tick resistance. Using quantitative real-time PCR and the Affymetrix bovine array platform, differences in gene expression of skin biopsies from tick resistant Bos indicus (Brahman) and tick susceptible Bos taurus (Holstein-Friesian) cattle following tick challenge were examined. We identified 138 significant differentially-expressed genes, including several immunological/host defence genes, extracellular matrix proteins, and transcription factors as well as genes involved in lipid metabolism. Three key pathways, represented by genes differentially expressed in resistant Brahmans, were identified; the development of the cell-mediated immune response, structural integrity of the dermis and intracellular Ca 2+ levels. Ca2+, which is implicated in host responses to microbial stimuli, may be required for the enhancement or fine-tuning of transcriptional activation of Ca2+- dependant host defence signalling pathways. Animal Genomics for Animal Health International Symposium, Paris, October 2007: (Proceedings)
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It is widely acknowledged that changes in intracellular calcium ion (Ca2+) concentration provide dynamic signals that control a plethora of cellular processes, including triggering and mediating host defence mechanisms. In this study, quantitative real-time PCR was used to analyse gene expression of 14 Ca2+ signalling proteins in skin obtained from high tick-resistant (HR) and low tick-resistant (LR) cattle following artificial challenge with cattle tick (Rhipicephalus (Boophilus) microplus). Up-regulation of numerous genes was observed in both HR and LR skin following tick challenge, however substantially higher transcription activation was found in HR tissue. The elevated expression in HR skin of specific Ca2+ signalling genes such as AHNAK, CASQ, IL2, NFAT2CIP and PLCG1 may be related to host resistance. Our data suggest that Ca2+ and its associated proteins might play an important role in host response to ticks and that further investigation is warranted.
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The cattle tick, Rhipicephalus (Boophilus) microplus, and the diseases it transmits pose a persistent threat to tropical beef production. Genetic selection of host resistance has become the method of choice for non-chemical control of cattle tick. Previous studies have suggested that larval stages are most susceptible to host resistance mechanisms. To gain insights into the molecular basis of host resistance that occurs during R. microplus attachment, we assessed the abundance of proteins (by isobaric tag for relative and absolute quantitation (iTRAQ) and Western blot analyses) and mRNAs (by quantitative reverse transcription PCR (qRT-PCR)) in skin adjacent to tick bite sites from high tick-resistant (HR) and low tick-resistant (LR) Belmont Red cattle following challenge with cattle tick. We showed substantially higher expression of the basal epidermal keratins KRT5 and KRT14, the lipid processing protein, lipocalin 9 (LCN9), the epidermal barrier catalysing enzyme transglutaminase 1 (TGM1), and the transcriptional regulator B lymphocyte-induced maturation protein 1 (Blimp1) in HR skin. Our data reveals the essential role of the epidermal permeability barrier in conferring greater resistance of cattle to tick infestation, and suggest that the physical structure of the epidermal layers of the skin may represent the first line of defence against ectoparasite invasion. Crown Copyright. © Australian Society for Parasitology Inc.
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A simulation model that combines biological, search and economic components is applied to the eradication of a Miconia calvescens infestation at El Arish in tropical Queensland, Australia. Information on the year M. calvescens was introduced to the site, the number of plants controlled and the timing of control, is used to show that currently there could be M. calvescens plants remaining undetected at the site, including some mature plants. Modelling results indicate that the eradication programme has had a significant impact on the population of M. calvescens, as shown by simulated results for uncontrolled and controlled populations. The model was also used to investigate the effect of changing search effort on the cost of and time to eradication. Control costs were found to be negligible over all levels of search effort tested. Importantly, results suggest eradication may be achieved within several decades, if resources are increased slightly from their current levels and if there is a long-term commitment to funding the eradication programme.
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Ants are the dominant soil faunal group in many if not most terrestrial ecosystems, and play a key role in soil structure and function. This study documents the impacts of invasion by the exotic cat’s claw creeper vine, Macfadyena unguis-cati (L.) Gentry (Bignoniaceae) on surface-situated (epigaeic) and subterranean (hypogaeic) ant communities in subtropical SE Queensland Australia where it is a major environmental weed of riparian areas, rainforest communities and remnant natural vegetation, smothering standing vegetation and causing canopy collapse. Soil ants were sampled in infested and uninfested areas at eight sites spanning both riparian and non-riparian habitats in subtropical SE Queensland. Patterns of ant species composition and functional grouping in response to patch invasion status, landscape type and habitat stratum were investigated using ANOVA and non-metric multidimensional scaling ordination. The epigaeic and subterranean strata supported markedly different ant assemblages, and ant communities also differed between riparian and non-riparian habitats. However, M. unguis-cati invasion had a surprisingly limited impact. There was a tendency for ant abundance and species richness to be lower in infested patches, and overall species composition was different between infested and uninfested patches, but these differences were relatively small, and did not occur consistently across sites. There were changes in functional group composition that conformed to known functional group responses to environmental change, but these were similarly limited and inconsistent across sites. Our study has shown that ant communities are surprisingly resilient to invasion by M. unguis-cati, and serves as a warning against making assumptions about invasion impacts based on visual appearances.
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Describes: the Queensland Building Act, how termites infest buildings, prevention, being aware of the risks, regular inspections, precaution, eliminate conditions that favour infestation, termite resistant timbers, physical barriers, chemical barriers, integrated management for prevention and treatment, treating active infestation by professionals.
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Background: The most common treatments for scabies in human and veterinary settings are topical 5% permethrin or systemic treatment with ivermectin. However, these treatments have very little activity against arthropod eggs, and therefore repeated treatment is frequently required. In-vitro, biochemical and molecular studies have demonstrated that human mites are becoming increasingly resistant to both acaricides. To identify alternate acaricides, we undertook a pilot study of the in vivo activity of the benzoylphenyl urea inhibitor of chitin synthesis, fluazuron, in pigs with sarcoptic mange. Findings: Pigs (n = 5) were infested with S. scabei var suis, and randomised to treatment at the start of peak infestation with fluazuron at a dose of 10 mg/kg/day per os for 7 days (n = 3) or no treatment (n = 2). Clinical scores, skin scrapings for mite counts and blood sampling for pharmacokinetic analysis were undertaken. Fluazuron was well absorbed in treated pigs with measureable blood levels up to 4 weeks post treatment. No adverse effects were observed. Modest acaricidal activity of the compound was observed, with a reduction in severity of skin lesions in treated pigs, as well as a reduction in number of scabies mite's early life stages. Conclusions: The moderate efficacy of fluazuron against scabies mites indicates a lead to the development of alternate treatments for scabies, such as combination therapies that maybe applicable for human use in the future.