262 research outputs found

    Screening of organically based fungicides for apple scab (Venturia inaequalis) control and a histopathological study of the mode of action of a resistance inducer.

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    A range of possible substitutes for copper-based fungicides for control of apple scab (Venturia inaequalis) in organic growing were tested in laboratory and growth chamber experiments in the Danish project StopScab (2002-2004). Eighteen crude plant extracts, 19 commercial plant-based products and 6 miscellaneous compounds were tested for their ability to reduce scab symptoms on apple seedlings. Most of the compounds were also tested for their effect on conidium germination on glass slides. Fourteen of the crude plant extracts, 13 of the commercial plant products and 5 of the miscellaneous compounds showed promising control efficacies when used either preventively or curatively in the plant assay. A histopathological study was carried out on the mode of action of the resistance inducer, acibenzolar-S-methyl (ASM), which reduced scab severity and sporulation on apple seedlings in several plant assays when applied as preventive treatment. The effect of the inducer on key pre- and post-penetration events of V. inaequalis was studied and compared to these events in water-treated control leaves. The histopathological study showed that the inducer had its strongest effect on post-penetration events indicated by delayed infection and reduced stroma development. In addition, a small but significant inhibition of conidial germination and a stimulation of germ tube length were observed. This investigation provides new histopathological evidence for the mode of action of ASM against V. inaequalis and serves as a model for evaluation of the mechanisms by which the organically based fungicides reduce infection of V. inaequalis

    New fungicides for apple scab control in organic growing

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    In the future control of apple scab in organic apple growing could be based on the use of natural fungicides like plant extracts and oils. Current projects are testing this idea

    Field efficacy of new compounds to replace copper for scab control in organic apple production

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    Efficacy of compounds was investigated in field experiments in Denmark and the Netherlands according to EPPO guidelines. Some Yucca extracts and potassium bicarbonate had an efficacy similar to sulphur on leaves. Addition of sulphur to Yucca 1 and to potassium bicarbonate increased the level of efficacy to that of copper. This confirms results from earlier years. Although a dose increase resulted in better efficacy, this was more prominent for Yucca1 than for potassium bicarbonate

    Preliminary Behavioural Observations of Horseback Safaris:Initial Insights into the Welfare Implications for Horses and Herbivorous Plains Game Species

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    SIMPLE SUMMARY: Horseback safari rides, where tourists are led by experienced guides on horseback to find and observe wildlife, are a popular activity in Africa. However, close encounters between horses and wildlife on safari rides may be stressful for both types of animals. In this study we looked at the behaviour of horses and wildlife during close encounters on horseback safari rides, focusing on their behaviour at the start and end of each encounter, and the most extreme behaviour seen. Encounters with seven wildlife species were observed, all large herbivores. The seven species differed in their behaviour towards the horses. The horses also differed in their behaviour towards the different wildlife species, being more wary of giraffe. Horses generally approached the wildlife species at walk and few flight behaviours were observed. Further studies, including those incorporating physiological measures of stress, are recommended. ABSTRACT: In Africa, wildlife-watching experiences create substantial revenue from tourists that can finance wildlife conservation. Horseback safaris, where an experienced guide takes guests through the bush on horseback to observe plains game species, are a popular activity. Close encounters between ridden horses and game species are unnatural and potentially stressful situations, and horseback safaris may have adverse impacts on both the horses and the wildlife they have come to observe. This study aims to provide a preliminary insight into the behavioural responses of horses and herbivorous plains game species, including giraffe, zebra and impala, as a proxy measure of the potential welfare implications of horseback safaris. Seventeen group safari rides were observed encompassing 72 encounters with plains game species. Game species differed in their response to encounters with the horseback safari ride. Equine response behaviour appeared to be influenced by the species of game encountered. Horses seemed more wary of giraffe than other species, with a higher percentage of horses showing stationary and retreat behaviour at the start of giraffe encounters. They were also most likely to shy at giraffe. The behavioural responses suggest that game encounters can elicit a stress response in both animal groups, although it is not usually extreme, potentially indicating that some degree of habituation has occurred. Balancing the welfare of both the horses and the plains game species along with tourist preferences may be challenging in this context

    Some microstructural features of fatigue in an aluminium alloy

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    The microstructures produced by the heat treatment of a commercial age hardening At-4.4 Cu alloy have been examined by thin foil electron microscopy. Whilst there is similarity of the microstructures in the commercial alloy to those which have been reported for simple binary At-Cu alloys, there is a strong association of dislocation structures and incoherent precipitates with undissolved Mn bearing intermetallic particles. Fatigue tests made on the alloy at both 50 Hz and 20 kHz have shown that there are changes in microstructure during fatigue; more markedly at 20 kHz in which tests the heating effect has some importance. There is some evidence of both accelerated ageing and also the by-passing or resolution of coherent phases during fatigue, particular at 20 kHz

    Bekæmpelse af æbleskurv ved brug af plantens egne forsvarsmekanismer

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    En oplagt mulighed for at bekæmpe æbleskurv, forårsaget af Venturia inaequalis, er at udnytte plantens egne evner til at forsvare sig gennem induceret resistens. Indledende forsøg med induceret resistens mod æbleskurv er sat i gang i projektet StopScab, som er et samarbejde mellem KVl og DJF. I artiklen beskrives kort hvad induceret resistens er, og hvad det kan anvendes til

    Prevention and control of apple scab

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    Improved prevention and control of apple scab caused by Venturia inaequalis is aimed at without the use of copper containing products in the Repco-project. Substantial progress is made in selection of potential products against summer epidemics. A patent application is made for E73. New effective biocontrol agents are selected to reduce inoculum during winter. The product potassium bicarbonate has shown good efficacy and Repco contributes to the registration of this product in Europe. Earthworms tended to be stimulated to consume apple leaves treated with amino acids or beetpulp, especially when applied fresh under controlled environmental condi-tons

    Understanding the Attitudes of Communities to the Social, Economic, and Cultural Importance of Working Donkeys in Rural, Peri-urban, and Urban Areas of Ethiopia

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    This is the final version. Available on open access from Frontiers media via the DOI in this recordData Availability Statement: The datasets generated for this study will not be made publicly available as the study participants did not explicitly give their consent for the full interview transcripts to be made publicly available.Working donkeys (Equus africanus asinus) are vital to the development and support of people's livelihoods in rural, peri-urban, and urban areas of Ethiopia. However, despite their critical role in providing transport, food security, and income generation to some of the poorest and most marginalized households, donkey contributions to human livelihoods have been largely unexplored. Donkey users, veterinary surgeons, business owners, and civil servants were interviewed to investigate the role humans play in shaping donkey lives while furthering our understanding of the social and economic impacts of working donkeys to human lives. Findings are discussed through seven guiding themes; donkeys as generators of income, the relationship between donkeys and social status, donkeys and affect, empowerment through donkeys, the role of donkeys in reducing vulnerability and encouraging resilience, donkey husbandry, and gender dynamics all of which gave a broader and richer insight into the value of donkeys. Donkeys are an important support in rural, peri-urban, and urban settings through the creation of economic security, independence, and participation in local saving schemes. In addition, donkeys provide social status, empowerment to marginalized groups such as women and the very poor and provide a sense of companionship. Whether the interviewee was a donkey user or a key informant appeared to influence their views on donkeys and their welfare, as did their location. The variations in views and practices between urban and rural settings suggests that assessing the socioeconomic value of donkeys in different locations within the same area or country is critical, rather than assuming that similar views are held between compatriots. Despite their centrality to many people's lives in Ethiopia, working donkeys often hold lowly status, are misunderstood, and given little husbandry and healthcare.The Donkey Sanctuary

    Come to Daddy? Claiming Chris Cunningham for British Art Cinema

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    Twenty years after he came to prominence via a series of provocative, ground-breaking music videos, Chris Cunningham remains a troubling, elusive figure within British visual culture. His output – which includes short films, advertisements, art gallery commissions, installations, music production and a touring multi-screen live performance – is relatively slim, and his seemingly slow work rate (and tendency to leave projects uncompleted or unreleased) has been a frustration for fans and commentators, particularly those who hoped he would channel his interests and talents into a full-length ‘feature’ film project. There has been a diverse critical response to his musical sensitivity, his associations with UK electronica culture – and the Warp label in particular – his working relationship with Aphex Twin, his importance within the history of the pop video and his deployment of transgressive, suggestive imagery involving mutated, traumatised or robotic bodies. However, this article makes a claim for placing Cunningham within discourses of British art cinema. It proposes that the many contradictions that define and animate Cunningham's work – narrative versus abstraction, political engagement versus surrealism, sincerity versus provocation, commerce versus experimentation, art versus craft, a ‘British’ sensibility versus a transnational one – are also those that typify a particular terrain of British film culture that falls awkwardly between populism and experimentalism
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