Search results for "Weed"
showing 10 items of 321 documents
Interleukin 12 enhances deficient HCV-antigen-induced Th1-type immune response of peripheral blood mononuclear cells
1998
The aim of this study was to examine the possible immunomodulating effects of rhIL-12 on the immune response induced by different hepatitis C virus (HCV) antigens. Freshly isolated peripheral blood mononuclear cells (PBMC) of 33 patients with chronic HCV infection were stimulated with optimal concentrations of antigens from the NS3, NS4, NS5, and core region of HCV in the absence or presence of interleukin12 (IL-12). Stimulation by α-CD3 + α-CD28, lipopolysaccharide (LPS), and pokeweed mitogen (PWM) were used as controls. Proliferation and cytokine production were determined by 3H-thymidine uptake and enzyme-linked immunosorbent assay (ELISA) after 72 hr. After stimulation with antigen or a…
Bioenergy willow: protection from the negative impact of biological factors
2017
W rozdziale przedstawiono wyniki badań patologii bakteryjnych oraz grzybicowych wierzby, oraz szkodników i chwastów, które prowadzą do zaginięcia roślin lub znacznego spadku plonu biomasy plantacji energetycznych. Wyświetlono metody ochrony i zapobiegania.
Modelling the effects of cropping systems on weed dynamics: the trade-off between process analysis and decision support
2022
Models are essential to synthesize knowledge on weeds and to design integrated weed-management strategies. These models must rank cropping systems as a function of weed infestation, and account for variability in effects to estimate probabilities of success or failure. Three case studies are presented: (1) an empirical static single-equation model that directly relates weed biomass to crop management, with few inputs and parameters, (2) a matrix-based multiannual model predicting a few key weed stages annually, from weed control options and a few parameters, (3) a mechanistic process-based multiannual model predicting detailed soil, crop and weed state variables daily, with an individual-ba…
Identification et caractérisation de candidats d’origine naturelle à action herbicide pour contrôler les adventices
2016
EASPEIPMGESTADAGROSUPINRA; The use of herbicides to control weeds is very common. However, some herbicides are both environmentally detrimental and human unhealthy. The use of microorganisms acting as natural herbicide could be an alternative control method. Symptomatic weeds will be collected in field. Microorganisms will be isolated from symptomatic weeds, purified, identified and inoculated on weeds to confirm Koch’s postulates. The identified pathogenic microorganisms will be tested against a selection of weeds and crops to characterize the host range and the specificity of these microorganisms. In parallel, the diversity of endophytic microorganisms of symptomatic weeds will be charact…
Prévenir et réduire les risques de sélection de résistances : de la théorie à la pratique, des pistes pour améliorer la durabilité des PPP
2015
SPEPôle GEAPSICT2communication orale invitée, résumé; La résistance est le résultat inéluctable de la sélection exercée par les PPP sur les populations de bio-agresseurs. On ne peut pas empêcher une résistance d’évoluer, mais on peut retarder substantiellement son évolution en mettant en place des stratégies appropriées avant (prévention) et après (gestion) la détection des premiers individus résistants. Le point-clef à retenir pour cela est que plus le contrôle d’un bio-agresseur est basé sur une chimie peu diversifiée, plus le risque de sélectionner rapidement une résistance est élevé. Un exemple type de ce qu’il ne faut pas faire est de contrôler un bio-agresseur présent sur de grandes s…
Modélisation des effets des systèmes de culture sur la dynamique de la plante parasite orobanche rameuse en interaction avec les adventices
2019
Reducing pesticide use is a major challenge in agriculture and involves developing more sustainable methods that rely on non-chemical cropping techniques and biological regulations according to agroecological principles. Branched broomrape (Phelipanche ramosa (L.) Pomel) is a root parasitic plant which infects crops and causes dramatic yield losses worldwide. Managing broomrape is complex because it requires combining several cropping techniques whithin a global weed management strategy because broomrape is also able to infect non-parasitic weeds. The aim of this thesis was to stynthetize knowledge on branched broomrape dynamics in agroecosystems and to aggregate it within a mechanistic mod…
Diversifying crop rotations with temporary grasslands: potentials for weed management and farmland biodiversity
2010
Fruchtfolgen können dazu dienen, die kontinuierliche Selektion von Unkrautarten zu verhindern, die an eine bestimmte Kultur angepasst sind. Dies könnte dem Unkrautmanagement, der Einsparung von Herbiziden, und der Biodiversität dienen. Heutige, sehr einfache Furchtfolgen könnten durch mehrjährige Futterkulturen diversifiziert werden. Die Einflüsse solcher mehrjähriger Kulturen auf Unkräuter wurden in vier Ansätzen untersucht : 1) Vegetationsaufnahmen auf 632 Feldern in Westfrankreich zeigten, dass die Unkrautzusammensetzung zwischen mehrjährigen Futterkulturen und einjährigen Kulturen stark variiert. Der Vergleich von Feldern vor, während und nach mehrjährigen Futterkulturen legte nahe, das…
Use of Biostimulants for Organic Apple Production: Effects on Tree Growth, Yield, and Fruit Quality at Harvest and During Storage
2018
The experiment was conducted during two consecutive seasons (years 2016 and 2017) in an organic apple orchard of the cultivar Jonathan. Several biostimulants were tested (10 in total), including humic acids, macro and micro seaweed extracts, alfalfa protein hydrolysate, amino acids alone or in combination with zinc, B-group vitamins, chitosan and a commercial product containing silicon. Treatments were performed at weekly intervals, starting from the end of May until mid-August. The macroseaweed extract was effective in stimulate tree growth potential in both years, as shown by a significantly larger leaf area (+20% as compared to control) and by an higher chlorophyll content and leaf photo…
Estimation of the pollen and seed production of common ragweed in Europe
2007
International audience; Common ragweed (Ambrosia artemisiifolia L.) is an invasive weed of fieldcrops and human-disturbed habitats in Europe. As well as in its natural range (NorthAmerica), common ragweed is a threat to human health due to its abundant allergenicpollen release. Most studies have been focused on airborne pollen monitoring, but todate, no data have been available on precise individual plant pollen and seed productionrelated to plant traits growing in natural environment and on their corresponding sourceof variation. The aim of this study was to evaluate pollen and seed production of commonragweed plants in several populations in France. Seasonal pollen production per plantran…
Spontaneous urban weeds: a resource against environmental pollution
2022
Quality of the environment and social well-being, both at a collective and individual level, are closely interrelated issues. It is, in fact, a relationship that invests values of primary importance, such as those relating to human health and safety, heritage and resources to be passed on to future generations. Plant growth and survival can be challenged by harsh urban conditions. Many studies show the persistence of endemic species in built-up areas and document the ecosystem services provided. With this research we wanted to investigate the bioaccumulation of heavy metals such as cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), molibden (Mo), cadmium (Cd), lead (Pb) and mer…