4,919 research outputs found

    Sugarcane stem borers of the Colombian Cauca River Valley: current pest status, biology, and control

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    Citation: Vargas, G., Gomez, L. A., & Michaud, J. P. (2015). Sugarcane stem borers of the Colombian Cauca River Valley: current pest status, biology, and control. Florida Entomologist, 98(2), 728-735. Retrieved from ://WOS:000356451400049Sugarcane stem borers of the genus of Diatraea (Lepidoptera: Crambidae) form a species complex that causes serious economic losses to sugarcane production in the Cauca River Valley and other regions of Colombia. Two primary species, Diatraea saccharalis (F.) and D. indigenella Dyar and Heinrich, have been effectively managed for more than 4 decades through augmentative releases of the tachinid flies Lydella minense (Townsend) and Billaea claripalpis (Wulp) (Diptera: Tachinidae) and the egg parasitoid Trichogramma exiguum Pinto & Platner (Hymenoptera: Trichogrammatidae). Here we review the current pest status of Diatraea species, damage assessment protocols, management tactics, and the environmental factors and cultural practices that can affect biological control outcomes. Recent changes in the cultivars grown have the potential to increase pest populations and diminish biological control efficacy. Additionally, recent outbreaks of new Diatraea species may further increase overall pest pressure. Thus, there is a need to develop supplementary tactics for the management of these pests that will be compatible with biological control, as well as more reliable protocols for assessing host plant resistance against the increase in infestation intensity

    Functional biodiversity in the agricultural landscape: relationships between weeds and arthropod fauna

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    We reviewed studies aimed at understanding functional relationships between weeds and arthropods in agroecosystems as influenced by biodiversity at different scales, with the main goal of highlighting gaps in knowledge, research methods and approaches. We first addressed: (i) the regulation of arthropod communities by weed diversity at genetic, species and habitat levels, (ii) the regulation of weed communities by arthropods through seed predation and dispersal and (iii) belowground weed-insect interactions. We then focussed on methodologies to study weed–arthropod interactions in agricultural landscapes and discuss techniques potentially available for data analysis and the importance of joint weed–arthropod trend detection. Lastly, we discuss the implications of research findings for biodiversity conservation policies (agri-environmental schemes) and suggest some priorities for future work. Results showed that to date research has largely ignored weed–arthropod interactions in agricultural landscapes. No information is available on the role of weed genetic diversity as driver of weed–arthropod interactions, whereas studies on effects of species and habitat diversity often lack a functional perspective and ⁄ or a spatial component. Also, information on how management of the wider agricultural biotope might express positive weed– arthropod functional interactions is scarce. Another area worth being explored is the relationship between weed-leaf ⁄ root herbivores and beneficial arthropods. Tools for spatial data analysis might be useful for elucidating weed–arthropod interactions in agricultural landscapes, but some methodological aspects, e.g. the definition of the most appropriate experimental design and sampling scale ⁄ frequency, must be refined. New studies on weed–arthropod interactions should encompass an explicit spatial component; this knowledge is particularly important for improving IPM ⁄IWM systems and designing more targeted agri-environmental schemes

    The multifunctional roles of vegetated strips around and within agricultural fields : A systematic map protocol.

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    Background: Agriculture and agricultural intensification can have significant negative impacts on the environment, including nutrient and pesticide leaching, spreading of pathogens, soil erosion and reduction of ecosystem services provided by terrestrial and aquatic biodiversity. The establishment and management of vegetated strips adjacent to farmed fields (including various field margins, buffer strips and hedgerows) are key mitigation measures for these negative environmental impacts and environmental managers and other stakeholders must often make decisions about how best to design and implement vegetated strips for a variety of different outcomes. However, it may be difficult to obtain relevant, accurate and summarised information on the effects of implementation and management of vegetated strips, even though a vast body of evidence exists on multipurpose vegetated strip interventions within and around fields. To improve the situation, we describe a method for assembling a database of relevant research relating to vegetated strips undertaken in boreo-temperate farming systems (arable, pasture, horticulture, orchards and viticulture). Methods: We will search 13 bibliographic databases, 1 search engine and 37 websites for stakeholder organisations using a predefined and tested search string that focuses on a comprehensive list of vegetated strip synonyms. Non-English language searches in Danish, Finnish, German, Spanish, and Swedish will also be undertaken using a web-based search engine. We will screen search results at title, abstract and full text levels, recording the number of studies deemed non-relevant (with reasons at full text). A systematic map database that displays the meta-data (i.e. descriptive summary information about settings and methods) of relevant studies will be produced following full text assessment. The systematic map database will be displayed as a web-based geographical information system (GIS). The nature and extent of the evidence base will be discussed

    Compatibility of Intercropping with Mechanized Agriculture: Effects of Strip Intercropping of Pinto Beans and Sweet Corn on Insect Abundance in Colorado

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    The potential for management of insect pest densities by regulation of crop diversity through intercropping was examined in sweet corn and pinto beans. Insect abundance was monitored in corn and beans in alternating multiple-row patterns of 1, 2, 4, 8, and 16 rows. Insect responses to intercropping treatments were variable, with positive, negative, and neutral responses observed, depending on species of insect and crop. In some cases, insect abundance was affected by strip-intercropping widths of up to eight rows, suggesting that strip intercropping may be compatible with some types of mechanized agriculture

    Compatibility of Intercropping with Mechanized Agriculture: Effects of Strip Intercropping of Pinto Beans and Sweet Corn on Insect Abundance in Colorado

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    The potential for management of insect pest densities by regulation of crop diversity through intercropping was examined in sweet corn and pinto beans. Insect abundance was monitored in corn and beans in alternating multiple-row patterns of 1, 2, 4, 8, and 16 rows. Insect responses to intercropping treatments were variable, with positive, negative, and neutral responses observed, depending on species of insect and crop. In some cases, insect abundance was affected by strip-intercropping widths of up to eight rows, suggesting that strip intercropping may be compatible with some types of mechanized agriculture

    Expression pattern analysis of odorant-binding proteins in the pea aphid Acyrthosiphon pisum

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    Odorant-binding proteins (OBPs) are soluble proteins mediating chemoreception in insects. In previous research, we investigated the molecular mechanisms adopted by aphids to detect the alarm pheromone (E)-β-farnesene and we found that the recognition of this and structurally related molecules is mediated by OBP3 and OBP7. Here, we show the differential expression patterns of 5 selected OBPs (OBP1, OBP3, OBP6, OBP7, OBP8) obtained performing quantitative RT-PCR and immunolocalization experiments in different body parts of adults and in the 5 developmental instars, including winged and unwinged morphs, of the pea aphid Acyrthosiphon pisum. The results provide an overall picture that allows us to speculate on the relationship between the differential expression of OBPs and their putative function. The expression of OBP3, OBP6, and OBP7 in the antennal sensilla suggests a chemosensory function for these proteins, whereas the constant expression level of OBP8 in all instars could suggest a conserved role. Moreover, OBP1 and OBP3 are also expressed in nonsensory organs. A light and scanning electron microscopy study of sensilla on different body parts of aphid, in particular antennae, legs, mouthparts, and cornicles-cauda, completes this research providing a guide to facilitate the mapping of OBP expression profiles

    Influence of Weather Variables and Plant Communities on Grasshopper Density in the Southern Pampas, Argentina

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    A study was conducted to evaluate the influence of weather (precipitation and temperature) and plant communities on grasshopper density over a 14-year period (1996–2009) in Benito Juárez County, Southern Pampas, Argentina. Total density strongly varied among plant communities. Highest values were registered in 2001 and 2003 in highly disturbed pastures and in 2002 and 2009 in halophilous grasslands. Native grasslands had the lowest density values. Seasonal precipitation and temperature had no significant effect on total grasshopper density. Dichroplus elongatus (Giglio-Tos) (Orthoptera: Acridoidea), Covasacris pallidinota (Bruner), Dichroplus pratensis Bruner, Scotussa lemniscata Stål, Borellia bruneri (Rehn) and Dichroplus maculipennis (Blanchard) comprised, on average, 64% of the grasshopper assemblages during low density years and 79% during high density years. Dichroplus elongatus, S. lemniscata and C. pallidinota were the most abundant species in 2001, 2002 and 2003, while D. elongatus, B. brunneri and C. pallidinota in 2009. Dichroplus elongatus and D. pratensis, mixed feeders species, were positively affected by summer rainfall. This suggests that the increase in summer precipitation had a positive effect on the quantity and quality forage production, affecting these grasshopper populations. Scotussa lemniscata and C. pallidinota were negatively affected by winter and fall temperature, possibly affecting the embryonic development before diapause and hatching. Dichroplus elongatus and D. pratensis were associated with highly disturbed pastures, S. lemniscata with pastures and B. bruneri and D. maculipennis with halophilous grasslands. Covasacris pallidinota was closely associated with halophilous grasslands and moderately disturbed pastures. Weather conditions changed over the years, with 2001, 2002 and 2003 having excessive rainfall while 2008 and 2009 were the driest years since the study started. We suggest that although seasonal precipitation and temperature had no significant effect on total grasshopper density, these weather variables and plant communities had differential influence on the dominant grasshopper species

    Pest categorisation of Diabrotica barberi

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    The EFSA Panel on Plant Health performed a pest categorisation of Diabrotica barberi (Coleoptera: Chrysomelidae), the northern corn rootworm, for the EU. D. barberi is a univoltine species occurring in mid-western and eastern USA and Canada, where it reproduces on maize (Zea mays), the preferred larval host. A small proportion of individuals can develop to a lesser extent on spelt (Triticum spelta), rice (Oryza sativa), millet (Panicum miliaceum) and a few North American wild grasses. Eggs are laid in the soil of maize fields, where they overwinter and can enter a diapause which can extend for more than one winter. Larvae hatch in late spring and early summer. Adult emergence peaks in the summer to feed on maize tassels, silks and ear tips. Adults abandon maize fields looking for other feeding hosts and return to maize for oviposition during late summer and autumn. D. barberi is considered a key pest of maize, together with other rootworm species of the same genus. D. barberi is regulated in the EU by Directive 2000/29/EC (Annex IAI). Within this Directive, a general prohibition of soil from most third countries prevents the entry of D. barberi larvae. However, adults carried on sweetcorn or green maize are potential pathways for entry into the EU. Climatic conditions and the wide availability of maize provide conditions to support establishment in the EU. Following establishment, impact on maize yields is anticipated. Phytosanitary measures are available to inhibit entry of this pest. D. barberi satisfies the criteria, which are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest. D. barberi does not meet the criteria of occurring in the EU nor plants for planting being the principal means of spread for it to be regarded as a potential Union regulated non-quarantine pest
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