Host Range of Meloidogyne Arenaria (NEAL, 1889) Chitwood, 1949 (Nematoda: Meloidogynidae) in Spain

11 páginas, ilustraciones y tablas estadísticas.The distribution of Meloidogyne arenaria in Spain was revised and new samples collected from representative areas. Species and races of the populations were determined by morphometrics, differential host tests and SCAR-PCR. Meloidogyne arenaria was found most often in warm areas, but it can occur in Northern Spain in greenhouses. A total of 125 citations were found, corresponding to 45 different host plants, of which 41 new reports (32.8%) are from this study. The populations studied belong to race 2, which reproduces on tomato plants carrying the Mi gene, or race 3, which reproduces on both resistant pepper and tomato. The most frequent hosts were vegetables, fruit trees, tobacco, grapevine, and weeds.INIA OT- 03-006C7-4 and RTA2007-00099-C00-00; Castilla La Mancha PAI09-0010-4701, INCRECYT CICyT CTM2006-07309.Peer reviewe

Spain-Phase-out of Methyl Bromide in pepper production in Spain

En: Chapter 10. Case studies on commercial adoption of alternatives to MB. 10.2.1. Alternatives for preharvest (soil) uses. Case study 3. Spain-Phase-out of Methyl Bromide in pepper production in Spain. Report of Methyl Bromide Technical Options Committee (MBTOC). 2006 Assessment, pp. 341-344.Non-chemical alternatives to MB for soil disinfection in pepper crops have been evaluated and are being increasingly adopted in Spain. They show that integrating practices like biofumigation with fresh pepper crop residues, chicken manure and sheep manure, biosolarisation, and grafting on resistant rootstocks, can be as effective as MB for controlling plant parasitic nematodes and fungi. MB consumption in Spain has been reduced by 96% since 1997.9Peer reviewe

Exploratory analysis of the structural variability of forest soil humic acids based on multivariate processing of infrared spectral data

Semi-quantitative data of peak intensities in infrared (IR) spectra of humic acids (HAs) from semiarid soils under contrasting environmental conditions (vegetation type, geological substrate and local climate) were analysed by multivariate data treatments. Resolution-enhanced IR spectra (applying a second derivative-based subtractive operator) showed a typical lignin pattern, which was coded to obtain an index used to classify the degree of diagenetic alteration of the lignin moiety in the HA fraction. Partial least squares regression (PLS) was used in the exploratory screening for supervised data reduction previous to other multivariate data treatments as well as to identify IR peaks responsive to soil dependent variables. Regression models and multi-dimensional scaling (MDS) were applied in order to classify individual IR peaks or sets of peaks associated with the degree of diagenetic alteration of organic matter, or inform on soils' potential for carbon (C) accumulation. Soil properties co-varying with the intensities of these peaks were mainly related to soil texture and consequently to water holding capacity at different pressures. Principal component analysis (PCA) based on the IR peaks selected in the previous PLS treatments maximized differentiation in terms of the impact of environmental factors on HA characteristics (i) vegetation type (angiosperms or gymnosperms), (ii) the effect of the geological substrate (granite or limestone) on soil organic matter dynamics and (iii) soil taxonomical differences reflected by independent clusters. The successful forecasting of several factors related to soil C sequestration indicated the validity of the semi-quantitative information extracted from the IR spectra of the HAs and the potential of the multivariate data treatments used to identify biogeochemical proxies of the soil organic matter stabilization processes. © 2013 The Authors. Journal compilation © 2013 British Society of Soil Science

Assessment of the effects of environmental factors on humification processes by derivative infrared spectroscopy and discriminant analysis

The potential of infrared spectroscopy to establish differences in terms of the environmental factors on the humification processes has been assessed on Mediterranean forest soils from Central Spain developed under sclerophyllic and gymnosperm vegetation. Humic acids were isolated from 21 soil samples differing in terms of vegetation (pine, holm oak, oak), geological substrate (granite, limestone), soil type (Humic Dystrudepts, Humic Dystroxerepts, Humic Haploxerepts, Calcic Argixerolls), soil horizon (O, A1, A2), humus type (calcic mull, mesotrophic-acid mull, moder), physiographic unit (hillside, moorland, ramp), altitudinal step, epipedon (mollic or umbric) and moisture regimen (udic or xeric), which were used as environmental classification factors. Quantitative peak intensity data were obtained from the second derivative infrared spectra of the humic acids. Discriminant analysis with automatic variable backward selection was used to identify the infrared bands showing more systematic changes in their intensities depending on the above classification factors. The diagnostic infrared bands chosen were at 1720, 1260 and 1330cm-1, corresponding mainly to carboxyl and lignin-derived O-containing functional groups. The bands at 2920 and 1510cm-1, corresponding to aliphatic and aromatic structures of the carbon backbone, respectively, were not significantly responsive to the environmental variability in the studied samples. The results showed how, in the scenario under study, taking advantage of the relative intensities of specific peaks from the second derivative infrared spectra, it is possible to discriminate different soil Suborders and humus types, as well as between several physiographic and bioclimatic features. © 2010 Elsevier B.V.Peer Reviewe

Comportamiento de Meloidogyne incognita sobre tomate y pimiento resistente en Uruguay

[ES] Para evaluar la influencia del sistema de cultivo en la selección de biotipos virulentos de Meloidogyne incognita en Uruguay, se estudió la virulencia de 33 poblaciones de este nematodo procedentes de invernaderos, tanto en monocultivo como en rotación, mediante bioensayos con cultivares de tomate y pimiento resistentes a M. incognita. Se encontraron 36,4% de las poblaciones virulentas a tomate y pimiento resistentes; 33,3% virulentas a tomate resistente, pero no a pimiento; 24,2% avirulentas a tomate y pimiento resistentes y el 6,1% restante presentó virulencia sólo a pimientos portadores de genes de resistencia. Se encontró una asociación positiva entre los monocultivo de tomate o pimiento con cultivares resistentes y la presencia de virulencia en las poblaciones de M. incognita. .[EN] The virulence of 33 populations of Meloidogyne incognita collected from greenhouses under monoculture and crop rotation was studied to evaluate the influence of the cropping system on the selection of virulent biotypes in Uruguay, using bioassays including cultivars of tomato and pepper, resistant to M. incognita .Over thirty six percent of the populations were virulent on resistant tomato and pepper; 33.3% were virulent on resistant tomato, but not on pepper; 24.2% were avirulent on resistant cultivars of tomato and pepper and 6.1% were virulent only on peppers carrying resistance genes. There was a positive association between monoculture of resistant tomato or pepper and the presence of virulent populations of M. incognita.Este trabajo forma parte de los proyectos INIA OT 03-006-C7-6 y AGL2002-04040-C05-01 AGR-FOR. Ana Piedra Buena es becaria de la Agencia Española de Cooperación Internacional (AECI-MAEC).Peer reviewe