Search results for "Urtica dioica"
showing 10 items of 15 documents
Impact of vector dispersal and host-plant fidelity on the dissemination of an emerging plant pathogen
2012
International audience; Dissemination of vector-transmitted pathogens depend on the survival and dispersal of the vector and the vector's ability to transmit the pathogen, while the host range of vector and pathogen determine the breath of transmission possibilities. In this study, we address how the interaction between dispersal and plant fidelities of a pathogen (stolbur phytoplasma tuf-a) and its vector (Hyalesthes obsoletus: Cixiidae) affect the emergence of the pathogen. Using genetic markers, we analysed the geographic origin and range expansion of both organisms in Western Europe and, specifically, whether the pathogen's dissemination in the northern range is caused by resident vecto…
Vector activity of Hyalesthes obsoletus living on nettles and transmitting a stolbur phytoplasma to grapevines: a case study
2007
International audience; We report a case study on the vector activity of a Hyalesthes obsoletus (Hemiptera: Cixiidae) population living on nettle plants (Urtica dioica) and transmitting a stolbur phytoplasma (Sp) to grapevines (Vitis vinifera). The research was conducted in a site that included a vineyard bordered with a large fallow area where nettles were the predominant plant species together with sparse old grapevines. Nettles hosted a high population of H. obsoletus. By using transparent sticky traps to sample adults, we observed that the daily flight activity of males and females to grapevines in the fallow was unimodal peaking between 15 and 21 h in the day. Adults were unable of gre…
Behavioral responses of Hyalesthes obsoletus to host-plant volatiles cues
2016
The polyphagous planthopper Hyalesthes obsoletus Signoret is considered to be the principal vector of stolbur phytoplasma, which is associated with yellow diseases of grapevine. To explore the possibility of developing novel control strategies, the behavioral responses to six synthetic mixtures and nine single compounds, previously identified from the headspace of Vitex agnus-castus L. (chaste tree) and Urtica dioica L. (nettle), were investigated in Y-tube bioassays. Choice tests revealed differences in the behavioral responses of males and females to the volatiles that they were exposed to. Males were attracted to a mixture containing (E)-β-caryophyllene, 1,8-cineole, (E,E)-α-farnesene, (…
Stinging nettle (Urtica dioica L.) as a functional food additive in egg pasta: Enrichment and bioaccessibility of Lutein and β-carotene
2018
Abstract The use of stinging nettles as an ingredient in egg pasta has been evaluated with respect to food enrichment with carotenoids. Bioaccessibility of lutein and β-carotene has been estimated by dynamic simulation of the digestion process, with particular attention to duodenum and colon stages. Higher bioaccessibility for the two carotenoids occurs between 2 and 24 h of colonic fermentation and it is around 35% for lutein and 10% for β-carotene. However, the results reveal that the food matrix has a significant role in carotenoid release during the digestion process. In general, nettle enriched pasta has a lower carotenoid bioaccessibility than dietary supplement at duodenum and after …
Data from: Effects of undergrowth removal and edge proximity on ground beetles and vascular plants in urban boreal forests
2019
Urban forests are regularly managed for human safety and aesthetic reasons, but they are crucial habitat for many species. Removals of undergrowth occur commonly in these forests, yet the ecological consequences of these operations are poorly understood. We sampled ground beetles (Coleoptera, Carabidae) and vascular plants along 20-m edge gradients in Finnish urban forests, in five stands treated 0.5−2.5 years earlier with undergrowth removal and in five untreated stands. We hypothesized that undergrowth removal and edge proximity would benefit opportunistic and open-habitat species, whereas shady-habitat species would be affected negatively. (1) Regarding carabids, diversity and evenness i…
RESISTANCE AND TOLERANCE IN A HOST PLANT–HOLOPARASITIC PLANT INTERACTION: GENETIC VARIATION AND COSTS
2002
Host organisms are believed to evolve defense mechanisms (i.e., resistance and/or tolerance) under selective pressures exerted by natural enemies. A prerequisite for the evolution of resistance and tolerance is the existence of genetic variation in these traits for natural selection to act. However, selection for resistance and/or tolerance may be constrained by negative genetic correlations with other traits that affect host fitness. We studied genetic variation in resistance and tolerance against parasitic infection and the potential fitness costs associated with these traits using a novel study system, namely the interaction between a flowering plant and a parasitic plant. In this system…
Relatedness affects competitive performance of a parasitic plant (Cuscuta europaea) in multiple infections.
2004
Theoretical models predict that parasite relatedness affects the outcome of competition between parasites, and the evolution of parasite virulence. We examined whether parasite relatedness affects competition between parasitic plants (Cuscuta europaea) that share common host plants (Urtica dioica). We infected hosts with two parasitic plants that were either half-siblings or nonrelated. Relative size asymmetry between the competing parasites was significantly higher in the nonrelated infections compared to infections with siblings. This higher asymmetry was caused by the fact that the performance of some parasite genotypes decreased and that of others increased when grown in multiple infect…
In vitro bioaccessibility, transepithelial transport and antioxidant activity of Urtica dioica L. phenolic compounds in nettle based food products
2016
Nettle (Urtica dioica L.) is a well-known plant with a wide historical background use of stems, roots and leaves. Nettle leaves are an excellent source of phenolic compounds, principally 3-caffeoylquinic acid (3-CQA), caffeoylmalic acid (CMA) and rutin. The aim of this work was to evaluate the bioaccessibility (BAC), the bioavailability (BAV) and the antioxidant activity of nettle phenolic compounds present in foods and supplements. The BAC of nettle phenolics was evaluated with an in vitro dynamic digestion of real food matrices: the type of food matrix and chemical characteristic affected the kinetics of release and solubilization, with the highest BAC after duodenal digestion. A study of…
Data from: Survival relative to new and ancestral host plants, phytoplasma infection and genetic constitution in host races of a polyphagous insect d…
2015
Dissemination of vectorborne diseases depends strongly on the vector's host range and the pathogen's reservoir range. Because vectors interact with pathogens, the direction and strength of a vector's host shift is vital for understanding epidemiology and is embedded in the framework of ecological specialization. This study investigates survival in host-race evolution of a polyphagous insect disease vector, Hyalesthes obsoletus, whether survival is related to the direction of the host shift (from field bindweed to stinging nettle), the interaction with plant-specific strains of obligate vectored pathogens/symbionts (stolbur phytoplasma), and whether survival is related to genetic differentia…
Infection of Bois-Noir tuf-type-I stolbur phytoplasma inHyalesthes obsoletus(Hemiptera: Cixiidae) larvae and influence on larval size
2009
Recent dramatic spread of the grapevine yellows disease Bois Noir (BN) in Germany is above all explained by highly increased abundances of the vector Hyalesthes obsoletus (Hemiptera: Cixiidae) associated to the plant Urtica dioica, the reservoir of the BN pathogen stolbur tuf-type-I. The vector acquires BN-phytoplasma as larvae whilst feeding on the roots of infected U. dioica. To understand the dynamics of the Urticacycle, we tested at what instar larvae become infected and whether infection affects larvae size (i.e. growth) at two sites in the Mosel Valley, Germany. Larvae were tested from infected plants and collected at instar-stages 3, 4 and 5. Larvae at stage 3 were already infected b…