198,946 research outputs found

    Biological control of Trialeurodes vaporariorum by Encarsia formosa on tomato in unheated greenhouses in the high altitude tropics

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    Biological control of Trialeurodes vaporariorum (Westwood) by Encarsia formosa Gahan was tested during three consecutive production cycles (16-28 weeks) on a beef tomato (Solanum lycopersicum L.) crop in a glasshouse and a plastic greenhouse on the Bogota Plateau in Colombia. During the course of this study over the period 1997-1999, the mean temperature was around 16 °C in the plastic greenhouse and around 17 °C in the glasshouse. E. formosa was introduced at a rate of 3 adults per m2 per week in the 1997 production cycle, and at a rate of 3 and 5 pupae per m2 per week in 1998 and 1999, respectively. In 1997, the adult whitefly population increased exponentially to a peak of 76 adults per plant in the plastic greenhouse, while the whitefly population in the glasshouse reached a peak of only 12 adults per plant. The percentage parasitism fluctuated between 42 and 82% in the glasshouse and between 28 and 47% in the plastic greenhouse. In 1998, the T. vaporariorum population could not be brought under control in both greenhouses and reached a peak of 80 and 53 T. vaporariorum adults per plant in the plastic greenhouse and the glasshouse, respectively. Parasitism fluctuated between 55 and 97% in the glasshouse and between 32 and 84% in the plastic greenhouse. In 1999, biological control was successful in both greenhouses. Most of the time, populations of T. vaporariorum were lower than 1.2 adults per plant and parasitism by E. formosa was 80% or higher. We suggest that the higher temperature is the main reason for better parasitism in the glasshouse when compared to the plastic greenhouse. The successful results of 1999 show that biological control is possible under the short day and low temperature conditions of greenhouses situated in the high altitude tropics such as the Bogota Plateau. Recommendations are given for the application of E. formosa based on the results of these experiments

    Defining Hierarchical Decision Trees for Encarsia Formosa Strategies from Greenhouse Tomato Consultants' Perspectives

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    Market pressure is forcing New Zealand greenhouse tomato growers to shift from conventional to more environmentally-friendly pest control methods such as IPM (Integrated Pest Management). Growers can access IPM manuals, but these tend to provide generalized advice, which they find difficult to apply to their own situations. Alternatively, growers can use consultants to tailor IPM strategies to their own situations. One method of providing growers with better advice is to capture the knowledge of "expert" consultants and translate this into a form that can be used by growers. To this end, two consultants with expertise in IPM strategy were studied and their knowledge documented. This paper focuses on the strategies the expert consultants used to tailor Encarsia formosa, a natural enemy of greenhouse whitefly, to individual greenhouse's specific needs. Both consultants used an IPM template and seven to eight decision criteria to tailor their advice to individual grower's situations. These decisions were represented as hierarchical decision trees. One consultant started with low Encarsia rates for a short time before increasing them while the other consultant started with high Encarsia rates for a longer period before decreasing them later. Growers' risk perceptions and acceptance of the consultants' pest threshold levels influenced the success of the IPM strategy.decision trees, consultants, Encarsia, greenhouse tomato, Farm Management,

    European Union policy on older adult learning : a critical commentary

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    This critical commentary discusses the strengths and lacunae in the European Union’s policy on older adult learning. Late-life learning is deemed as a productive investment on the basis that it not only engenders positive returns of economic growth but also improves the quality of life and social development of older persons. This article argues that although European Union policy on lifelong learning does hold some promise toward more optimum levels of physical, psychological, and social well-being in later life, it remains characterized by a range of limitations ranging from mindless activism, to economic bias, to ageism.peer-reviewe

    Renewing Universities of the Third Age : challenges and visions for the future

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    The University of the Third Age [UTA] has developed into a global success story. Whether holding a ‘top-down’ administrative arrangement or embodying a culture of self-help, there can be no doubt as to the triumph of UTAs in meeting the educational, social, and psychological needs of older persons. However, on the basis of fieldwork conducted at the UTA in Malta a cautionary note must be warranted. UTAs may also function as yet another example of glorified occupational therapy that is both conservative and oppressive. At the same time, UTA models seem to be running the risk of becoming obsolete as societies embark on a ‘late-modern’ model of the life course in which the sequential division between learning, work and retirement is becoming increasingly blurred. This article calls for the UTA movement to go through a cultural revolution to remain relevant to contemporary ageing lifestyles. Six key directions are forwarded: embracing a trans formational rationale, ensuring that access overcomes class, gender and ethnic biases, guaranteeing that teaching and learning strategies are skilfully suited to older persons, making greater use of eLearning techniques, extending its activities to frail and physically dependent older people especially those in residential/nursing homes, and organising activities that promote intergenerational learning.peer-reviewe

    The variation and taxonomy of Cicindela formosa Say (Coleoptera: Cicindelidae)

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    Vita.The variation of Cicindela Formosa Say was studied using various morphometric methods. The adults and third instar larvae were examined by principal components analyses and by clustering techniques using unweighted pair-group method using arithmetric means of product moment correlation coefficients and taxonomic distance. Color characters of the adults were studied using graphic means. Certain selected characters of the adults were examined graphically using the plotting programs TRIANG, CONREC, and SRFACE. Keys to adults and third instar larvae were provided. Synonymy, descriptions and distributions for each recognized subspecies were presented. Of five previously described subspecies (C. f. Formosa Say, C. f. generosa Dejean, C. f. Manitoba Leng, C. f. pigmentosignata W. Horn and C. f. gibsoni Brown) C. f. Manitoba was synonymized under C. f. generosa. Two previously undescribed subspecies, C. f. Mescalero and C. f. yampa, were described. Conclusions were drawn as to the evolution of the subspecies of C. Formosa, and possible rates of evolution for certain subspecies were suggested

    Chacodelphys formosa

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    Chacodelphys formosa (Shamel, 1930) TYPE MATERIAL AND TYPE LOCALITY: USNM 236330, the holotype by original designation, consists of the skin and skull of a young adult male collected at Estancia Linda Vista (25.22° S, 59.78° W; ca. 100 m) on the Riacho Pilagá, Formosa province, Argentina. SYNONYMS: muscula Shamel, 1930 (preoccupied). DISTRIBUTION: All known specimens of Chacodelphys formosa are from Chacoan landscapes in northern Argentina (Chaco, Formosa, and Misiones; Teta et al., 2006; Teta and Pardiñas, 2007) REMARKS: Chacodelphys formosa is currently known from just a handful of specimens, most of which were recovered from owl vomitus.Published as part of Voss, Robert S., 2022, An Annotated Checklist Of Recent Opossums (Mammalia: Didelphidae), pp. 1-77 in Bulletin of the American Museum of Natural History 2022 (455) on page 41, DOI: 10.1206/0003-0090.455.1.1, http://zenodo.org/record/716137

    Critical educational gerontology : a third statement of first principles

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    This article elaborates upon the initial statement of first principles for critical educational gerontology [CEG] established by Glendenning and Battersby some two decades ago, whilst taking stock of the body of critique levelled at such principles by the humanist strand in older adult learning. Keeping in mind the gritty realities which embed older persons in structured positions of social inequality on one hand, and the difficulty of subjects to work towards the transformation of such realities in individualist and self-directed ways, this article voices support for CEG. Acknowledging a need to renew CEG in line with contemporary socio-cultural realities, it is argued that the weakness of CEG lies in its current, rather than its potential, usage. Hence, the way forward does not lie in ditching the critical epistemological framework for late-life education, but to renew CEG in a way that rediscovers its liberatory spark in an excessively globalised and individualised world. It forwards four key proposals with respect to such a goal: a transformative rationale that challenges the cultural hegemony of neo-liberalism, the centrality of directive educators, embedding geragogy in a critical epistemology, and a praxeological engagement with historically accumulated concepts and practices.peer-reviewe

    Territorialising Colonial Environments: A Comparison of Colonial Sciences on Land Demarcation in Japanese Taiwan and British Malaya

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    The thesis seeks to establish how far, and in what ways, colonial science articulates a distinctive mode of environmental conceptions and governance. It concerns the entanglement between the government, science, and knowledge. To examine how these combinations may vary it compares how land demarcation progressed in two different imperial territories: Japanese Taiwan (Formosa) and British Malaya. The discussion is based on this pair of case studies of environmental territorialisation, driven by imperial forces, whose legacy is still apparent today. The abrupt nineteenth-century colonial intrusion into these two sparsely populated areas, though occurring in different ways and scales, evoked a similarly dramatic landscape change from the centuries-old indigenous practice of subsistence activities. There are both similarities and considerable divergences referring to land classification in these two dependencies. In both cases most of the land was delineated as state-controlled forest reserve, which not only enhanced the revenue of government but also supplied the required timber or fuel resources. Another space delimited was aboriginal reservation that sustained the native subsistence or usufructory rights at least in part. By examining the genealogy and material discursive practices of territorialisation as they interacted with local environments and peoples the thesis offers a comparative account of the logics of different empires and the construction of territorial administration. It examines the political ecology of how colonial nature was produced as a resource, with the commodification of forest areas. It unpacks the two cases by studying the role of colonial science, especially cartographic practices, in demarcating and defining territories and peoples. It contrasts the state run surveys in Colonised Formosa with the networks of knowledge production in British Malaya

    Bougainvillea formosa (Cultivated)

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    Bougainvillea formosa, plant/flower. Family Nyctaginaceae, Subclass Caryophyllidae. Origin: Cultivated
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