Integrated Management of Fusarium Wilt Diseases

The integrated management concept is one of the fundamental paradigms that have emerged in crop protection in the last 50 yrs and yet a matter for legislation as exemplified by the European Union that recently has establishes the integrated management as the fundamental procedure for the management of crop diseases, pests and weeds. However, the integrated management is not a panacea for the control of plant diseases. It is an ecology-based approach aiming minimizing damage caused by diseases through ‘the combined use of all available disease control measures, either simultaneously or in a sequence, through actions taken prior and after establishing the crop’. In this chapter, we propose and develop a strategy for the integrated management for Fusarium wilts, one of the most devastating and challenging type of diseases impairing agricultural production worldwide,, based on the: (i) use of pathogen-free planting material; (ii) site selection to avoid planting into high risk soils; (iii) reduction or elimination of F. oxysporum inoculum in soil; (iv) use of biocontrol agents for protection of healthy planting material from infection by resident or incoming inoculum subsequent to planting; (v) use of resistant cultivars regardless the level of resistance; and (vi) choice of cropping practices to avoid conditions favouring infection of the plant. The integrated management of Fusarium wilt diseases is difficult because complexities of target pathosystems are overlaid on the inherent complexities of the management strategy itself. Much research is still needed on population biology and genetic diversity in Fusarium wilt pathogens, disease risk prediction, disease-incidence-yield losses relationships, biological control, biotechnological breeding for disease resistance. On top of difficulties pointed out above, the practice of integrated management requires involvement of well-trained professional plant pathologists able to implement the tenets of the concept at the local level, as well as to incorporate into decision-making framework new knowledge and technologies that may be developed from scientific research. As the demand has increased for knowledgeable practitioners capable of integrating multifaceted controls in rigorous IDM programs, institutional support has declined through declining or even vanishing University education in Plant Pathology and the loss of extension-related activities in commercial agriculture. Erosion at the top of the trickle-down structure responsible for knowledge transfer to the field is one of the most serious threats to IDM

Etiología, importancia y distribución de la seca del garbanzo en el valle del Guadalquivir

La «Seca» o «Fusariosis» del garbanzo (Cicer arietinum, L.)> fue señalada por algunos autores como la enfermedad más importante del cultivo en Andalucía, atribuyéndole importantes pérdidas de cosecha. Sin embargo, el conocimiento en nuestro país sobre su etiología, epidemiología y lucha era prácticamente inexistente, salvo por investigaciones preliminares que indicaron la posibilidad de que la «Fusariosis» incluyera un complejo de enfermedades, que denominamos Marchitez y Podredumbre de Raíz (MPR). Los objetivos generales de las investigaciones incluidas en este trabajo fueron determinar la importancia y distribución de la MPR en el valle del Guadalquivir y su naturaleza etiológica y sintomatológica. Durante 1979 a 1981, se realizaron prospecciones sistemáticas en 108 campos de garbanzo en la Campiña de Córdoba y Sevilla, con un total de más de 1.300 ha., en las que se efectuaron observaciones sobre la sintomatología, incidencia y severidad de los ataques de la MPR. Plantas afectadas con los síntomas característicos se muestrearon para completar las descripciones sintomatológicas de campo y aislar en cultivo puro e identificar los posibles agentes asociados. La patogenicidad de los organismos consistentemente aislados se investigó en inoculaciones con suelo infestado artificialmente, o por inmersión de raices o cultivo de plantas, en una suspensión de inoculo. En suelo infestado con aislamiento patogénicos de Fusarium oxysporum y F. solani, se investigó lá susceptibilidad a ellos de once especies de leguminosas cultivadas, así como las diferencias en patogenicidad para varios cultivos de garbanzo. Cinco complejos sintomatología», amarilleamiento, marchitez, podredumbre seca de raíz, enanismo amarillento y clorosis, se identificaron asociados con la MPR del garbanzo. Todos ellos estuvieron uniformemente distribuidos en la campiña de Córdoba y Sevilla, siendo amarilleamiento y marchitez los más importantes. Tres especies fúngicas, F. oxysporum, F. solani y Macrophomina phaseolina, se aislaron consistentemente de plantas afectadas de los diferentes complejos sintomatológicos y resultaron patogénicos sobre garbanzo en inoculaciones artificiales. Los aislamientos de F. oxysporum fueron clasificados en tres grupos por características morfofisiológicas y patogénicas, caracterizándose, principalmente, por el tipo de síntoma que causaron: marchitez vascular, amarilleamiento vascular y amarilleamiento no vascular con lesiones necróticas corticales en el cuello y raíz. Los dos primeros grupos mostraron especificidad patogénica para garbanzo, por lo que pueden ser considerados como F. oxysporum f. sp. ciceri. La patogenicidad diferencial de ambos grupos sobre cultivares de garbanzo indica que petenecen a diferentes razas fisiológicas. F. solani causó amarilleamiento y podredumbre negra de cuello y raíz, existiendo diferencias morfofisiológicas y de patogenicidad entre aislamientos. Uno de los más virulentos fue identificado como F. eumartii. Los aislamientos de F. solani y F. eumartii resultaron patogénicos sobre garbanzo, haba (Vicia faba L.), guisante (Pisum sativum L.), lenteja (Lens escuelenta Moench.), Lupinus albus, L. angustifolius, L. luteus y L. mutabilis, por lo que rigurosamente no pueden ser caracterizados como alguna de las formas especializadas conocidas, aunque por la reacción observada parecen mejor adaptados a garbanzo, haba y guisante que a las restantes especies. M. phaseolina causó amarilleamiento y podredumbre seca de cuello y raíz. Las infecciones en inoculaciones artificiales fueron mas severas a altas temperaturas y bajo contenido de agua en el suelo, confirmando asi las observaciones de campo. Nuestros resultados señalan a F. oxysporum como agente de la marchitez y del amarilleamiento vasculares, a F. solani como agente del amarilleamiento no vascular asociado con podredumbre negra de cuello y raíz y a M. phaseolina como agente de la podredumbre seca de raíz; si bien, en el complejo amarilleamiento estuvieron implicadas las tres especies fúngicas, así como factores abióticos. Nuestras observaciones indican, asimismo, que el enanismo amarillento puede ser causado por el virus del enrollado de las hojas del guisante (PLRV), aunque otros virus pueden estar implicados, y que la clorosis resulta de una deficiencia férricaSeveral authors have considered the «Seca or fusariosis» disease as the most important disease that causes severe losses of seed yield of chickpea (Cicer arietinum L.) in Andalucía. Nevertheless, there is little knowledge of the etiology, epidemiology and control of that disease, except for some preliminary research which indicated that «Seca» might include a disease complex hereafter named Will and Root Rot (WRR). The objetives of the present study were to determine the etiology, symptomatology, importance and distribution of WRR of chickpeas in the Guadalquivir Valley (Southern Spain). Systematic disease surveys were carried out in the Cordoba and Sevilla provinces of Andalucía, including 108 chickpea fields and 1.300 ha. Observations were made on symptomatology, incidence and severity of WRR attacks. Samples of affected plants were used for further observations and isolations. Pathogenicity of the fungi which were isolated was investigated in artificially infested soil or by dipping the roots or growing plants in a inoculum suspension. Differential pathogenicity to chickpea cultivars and pathogenicity to eleven legume species were investigated in soil artificially infested with isolates of Fusarium oxysporum and F. solani. Five symptom complexes were found associated with WRR attacks: Will, Yellowing, Dry Root Rot, Yellow Stunt and Chlorosis. All symptom complexes were widely and uniformly distributed in Cordoba and Sevilla provinces, but Will and Yellowing cxcurred with higher prevalence, incidence and severity. F. oxysporum, F. solani and Macrophomina phaseolina, were consistently isolated from plants affected by the various symptom complexes. Isolates of those fungi were found to be pathogenic to chickpea in artificial inoculation experiments. Three groups of F. oxysporum isolates were distinguished according to morphological and pathogenic characteristics. Isolates of the different groups caused either vascular will, vascular yellowing, or nonvascular yellowing along with cortical necrotic lesions of collar and root. Isolates inducing vascular wilt or yellowing showed pathogenic specialization to chickpea and may be consideres as F. oxysporum f. sp. ciceri. Those isolates also showed differential pathogenicity to chickpea cultivars, indicating that they belong to different pathogenic races. Isolates of F. solani induced foliar yellowing and black collar and root rot, but differed in morpho-physiological characteristics and virulence. One of the most virulent isolates of F. solani induced foliar yellowing and black collar and root rot, but differed in morpho-physiological characteristics and virulence. One of the most virulent isolates of F. solani was further identified as F. eumartii. Isolates of F. solani and F. eumartii were pathogenic to chickpea, faba bean (Vicia faba L.). pea (Pisum sativum L.), lentil (Lens esculenta Moench), Lupinus albus L., L. angustifolius L., L. luteus L. and L. mutabilis Sweet., and therefore cannot be considered as belonging to any of the known formae speciales of F. solani. Nevertheless, as indicated by the severity of disease reactions observed, those isolates seem to be more adapted to chickpea, faba bean and pea than to any of the other species. M. phaseolina induced yellowing and dry collar and root rot. Infections by this pathogen in artificial inoculations were most severe at high temperatures and low soil water content, thus confirming field observations on incidence and severity of the disease. Our results indicate that F. oxysporum, F. solani and M. phaseolina are, respectively, the agents of Vascular Will and Yellowing, Non-Vascular Yellowing and Black Collar and Root Rot, and Dry Root Rot, However, those three species as well as abiotic factors were involved in the etiology of the Yellowing symptom complex in the field. Also, our observations in the field indicate that the Chlorosis complex is due to an iron deficiency, and that the Yellow Stunt symptom complex might be induced by pea leaf roll virus, although other plants viruses could be involved as well

The Fusarium oxysporum f. sp. ciceris/Cicer arietinum pathosystem: a case study of the evolution of plantpathogenic fungi into races and pathotypes

The use of resistant cultivars is one of the most practical and costefficient strategies for managing plant diseases. However, the efficiency of resistant cultivars in disease management is limited by pathogenic variability in pathogen populations. Knowledge of the evolutionary history and potential of the pathogen population may help to optimize the management of disease-resistance genes, irrespective of the breeding strategy used for their development. In this review, we examine the diversity in virulence phenotypes of Fusarium oxysporum f. sp. ciceris, the causal agent of Fusarium wilt of chickpeas, analyze the genetic variability existing within and among those phenotypes, and infer a phylogenetic relationship among the eight known pathogenic races of this fungus. The inferred intraspecific phylogeny shows that each of those races forms a monophyletic lineage. Moreover, virulence of races to resistant chickpea cultivars has been acquired in a simple stepwise pattern, with few parallel gains or losses. Although chickpea cultivars resistant to Fusarium wilt are available, they have not yet been extensively deployed, so that the stepwise acquisition of virulence is still clearly evident. [Int Microbiol 2004; 7(2):95–104

Las enfermedades de las plantas: impactos, amenazas y control

Las enfermedades reducen significativamente la cosecha agrícola alcanzable y los productos cosechados pueden ser vehículo de micoto-xinas y patógenos humanos. En España, 30 enfermedades afectan gra-vemente a cultivos estratégicos y durante los últimos 25 años se han introducido al menos 49 nuevos patógenos que inciden gravemente sobre aquéllos. La introducción de patógenos exóticos, la homogeneidad gené-tica de los cultivos y la intensificación en el manejo de éstos propician la emergencia y re-emergencia de enfermedades que constituyen nuevas amenazas para la sanidad vegetal. Afrontar estas amenazas requiere mejoras en la investigación científica y translacional, promover la forma-ción universitaria especializada, y una profesión en la Medicina de los Vegetales que sirva a la producción agrícola como la profesión Veterina-ria sirve a la sanidad animalPlant diseases significantly reduce attainable crop yields and harvest products can be contaminated with mycotoxins and human pathogens. In Spain, 30 diseases severely affect strategic crops and at least 49 new pathogens have been introduced during the last 25 years that are addi-tional threats for those crops. Exotic pathogens, crop genetic homogeneity and intensive crop management promote the emergence and reemergence of plant diseases that are new threats for crops health and yield. In order to counteract these new threats, there is a need of improv-ing the scientific and translational research, foster education in Plant Pathology and establishing Plant Medicine profession that serves agricul-ture as Veterinary Science serves animal healt

Host-parasite relationships in root-knot disease of white mulberry

Severe infections of white mulberry feeder roots and heavy soil infestations by Meloidogyne arenaria race 2 were found in southern Spain. This is the first record of M. arenaria on white mulberry in Europe. Morphometric observations, analysis of the esterase electrophoretic pattern, and artificial inoculations of race differentials were used to characterize nematodes. Nematode-induced mature galls were spherical and usually contained one or more females, males, and egg masses with eggs. Feeding sites were characterized by the development of giant cells that contained granular cytoplasm and many hypertrophied nuclei. Giant cell cytoplasm was aggregated along a thickened cell wall. Vascular tissues within galls appeared disorganized. The relationship between the initial nematode population density (Pi) in a series from 0 to 1,024 eggs and juveniles/cm3 soil and growth of white mulberry seedlings was tested in the greenhouse. A Seinhorst model was fitted to plant height and top fresh weight. Tolerance limits of white mulberry to M. arenaria race 2 for plant height and top fresh weight were, respectively, 1.1 and 1.38 eggs and juveniles/cm3 soil. The minimum relative values for plant height and top fresh weight were 0 at Pi > 64 and Pi > 128 eggs and juveniles/cm3 soil, respectively. Maximum nematode reproduction rate was 435-fold at the lowest Pi. Additional keywords: histopathology, Morus alba, pathogenicity, threshold limitPeer reviewe

Los diccionarios ante el argot «gay» en España (1970-1984)

Dubet François. François de Singly , Le soi, le couple et la famille, Essais et recherches, 1996. In: Sociologie du travail, 39ᵉ année n°1, Janvier-mars 1997. pp. 123-125

El argot sexual en la narrativa erótica española de los 80

III Congreso Internacional de Literatura y Cultura Españolas Contemporáneas. Diálogos transatlánticos: puntos de encuentro. La Plata 8, 9 y 10 de octubre de 2014