scholarly journals Hospedeiros alternativos de Xanthomonas campestris pv. viticola

2007 ◽  
Vol 32 (2) ◽  
pp. 161-164 ◽  
Author(s):  
Ana Rosa Peixoto ◽  
Rosa L.R. Mariano ◽  
José Osmã T. Moreira ◽  
Ivanise O. Viana

Xanthomonas campestris pv. viticola (Xcv), que causa o cancro bacteriano da videira, sobrevive em plantas infectadas, epifiticamente em órgãos da parte aérea e pode ser veiculada em mudas e/ou bacelos infectados. O trabalho teve como objetivo investigar possíveis hospedeiros alternativos do patógeno, visando fornecer subsídios para o manejo da doença. A partir das plantas invasoras Alternanthera tenella, Amaranthus sp., Glycine sp. e Senna obtusifolia com sintomas similares aos do cancro bacteriano da videira, coletadas em parreirais de Juazeiro e Petrolina, no Submédio São Francisco, foram isoladas bactérias semelhantes a Xcv. No entanto, nenhuma bactéria foi isolada de plantas de Commelina benghalensis e Azadirachta indica com sintomas semelhantes. A patogenicidade dos isolados bacterianos obtidos foi confirmada em plantas de A. tenella, Amaranthus sp., Glycine sp., S. obtusifolia e em mudas de videira cv. Red Globe, em condições de casa de vegetação. As plantas invasoras Chamaesyce hirta, Dactyloctenium aegyptium, Eragrostis pilosa e Pilea sp., inoculadas artificialmente com os isolados Xcv1 e UnB1216, também desenvolveram sintomas típicos do cancro bacteriano.

2014 ◽  
Vol 44 (4) ◽  
pp. 595-598
Author(s):  
Morgana Mateus Santos ◽  
Ana Rosa Peixoto ◽  
Esmailly de Sousa Pessoa ◽  
Marco Aurélio Gama ◽  
Rosa de Lima Ramos Mariano ◽  
...  

Este estudo teve como objetivo identificar possíveis hospedeiras alternativas de Xanthomonas campestris pv. viticola (Xcv), visando a fornecer subsídios para o manejo do cancro bacteriano da videira. Vinte e seis espécies vegetais foram inoculadas artificialmente com o isolado Xcv3 e mantidas em condições de casa de vegetação, sendo avaliada a evolução sintomatológica da doença, como manchas necróticas angulares e lesões nas nervuras. O Xcv3 foi reisolado a partir de cada hospedeiro alternativo com sintomas, sendo identificado por PCR (Polymerase Chain Reaction), com iniciadores específicos. As espécies inoculadas que apresentaram os sintomas típicos da doença foram Glycine sp., Senna obtusifolia, Desmodium discolor, Amaranthus deflexus, Azadirachta indica, Solanum lycopersicum e Vigna unguiculata. As espécies da família Poaceae, Bidens pilosa, Emilia fosbergii, Praxelis pauciflora, Macroptilium lathyroides e Portulaca oleracea não apresentaram sintomas durante o período da avaliação.


HortScience ◽  
2002 ◽  
Vol 37 (6) ◽  
pp. 969-972 ◽  
Author(s):  
Harold A.A. Gibbs

Xanthomonas campestris pv. vesicatoria (Xcv) recovered from Commelina benghalensis L., caused bacterial spot disease in cultivars of pepper and tomato susceptible to the pathogen. This is the first reported case of a dicot-infecting Xc pathovar infecting a monocot plant, represented here by a member of the Family Commelinaceae. Laboratory strains of the pathogen that included 81-23, 81-23M13, 82:4, 2595, and P6AD4, known to be pathogenic to pepper and tomato, promoted bacterial spot symptoms on leaves of C. benghalensis L. Of the 63 field isolates recovered from infected C. benghalensis L., 30 gave biochemical and physiological reactions consistent with Xcv pathogens, whereas 10 of the latter promoted bacterial spot disease in the test cultivars resulting in the identification of seven pathogenic races, including P2, P5, P6, P5T1, P5T2, P6T2, and P6T3. Bacterial spot disease symptoms developed on stems only when C. benghalensis L. was spray-inoculated with strains 81-23, 81-23M13, and P6AD4. Bacterial concentration increased in planta by as much as 103 per lesion of the leaf, whereas growth of the same strains was restricted in the stem of this weed. Growth of these three strains was, however, significantly (P ≤ 0.05) lower on NYGA amended with C. benghalensis L. stem extract than on NYGA amended with leaf extract. The ability of the bacterial spot pathogen to infect the stem of C. benghalensis L. has serious implications for management of bacterial spot disease in fields populated with this weed since stems of this plant infected with the pathogen continue to grow vegetatively and disperse throughout all fields in which it is found.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Karim Ouédraogo ◽  
Alhassane Zaré ◽  
Gabin Korbéogo ◽  
Oumarou Ouédraogo ◽  
Anja Linstädter

AbstractFinding sufficient natural fodder resources to feed livestock has become a challenge for herders in the Sahel zone of Burkina Faso. Despite the existence of pastoral reserves, the issue of fodder shortage remains unsolved. This article highlights the changes in behaviour and the evolution of pastoral practices caused by the scarcity of forage resources. These changes are defined and classified as resilience strategies. Thus, this paper aims to analyse these strategies using new semantics that calls for other forms of perceptions or approach to the questions of pastoralists’ resilience strategies. Interviews (semi-structured and casual conversations), ethnographic observations and ethnobotanical surveys were used to collect data. In rangelands, such high value fodder species as Andropogon gayanus, Pennisetum pedicellatum and Dactyloctenium aegyptium that were abundant herbaceous plants during the last decades are disappearing. Concomitantly, species with lower forage value, such as Senna obtusifolia, which are more resilient to ecological disturbance factors, are colonizing rangelands. Faced with these ecological changes, pastoralists are trying to redefine and reconfigure their practices, and this implies a redefinition of their identity. They use resilience strategies such as mowing grasses, building up fodder bundles, conserving crop residues, exploiting Senna obtusifolia (a previously neglected species), using woody fodder and adapting the type of livestock and the size of the herds to the ability of pastoralists to feed them. Strategies that are older than these are the integration of agriculture with livestock and decollectivized transhumance. It is these resilience strategies that this article exposes and analyses as defence mechanisms of Sahelian pastoralists in the face of the depletion of forage resources in their environments.


2017 ◽  
Vol 3 (4) ◽  
pp. 383-391
Author(s):  
Mohd Asif Khan ◽  
Shashi Bhooshan Tiwari ◽  
Himanshu Gupta ◽  
Huma Noor

Since ancient time, herbal drugs were highly used in the prevention and cure of various human illnesses. In India, Azadirachta indica being commonly known as Neem or Margosa is one of the multi-functional trees; belonging to Meliaceae family. In 1992, the US National Academy of Sciences was published a report entitled ‘Neem- a tree for solving global problems’. It is still considered as ‘village dispensary’ throughout the India. There are two species of Azadirachta which have been investigated; Azadirachta indica that is found in the Indian subcontinent and Azadirachta excelsa Kack that is homegrown to Indonesia and Philippines. A large number of pharmacologically active substances have been identified and isolated from the different parts of neem including azadirachtin, meliacin, gedunin, salanin, nimbin, valassin and various other components which are derived from these main compounds. Many different studies have been evaluated and authenticated for its various traditional and pharmacological activities like itching, leprosy, wound healing, spermicidal, anti-inflammatory, insecticidal, antidiabetic and analgesic etc. In the beginning of 1979, patenting on neem was started by CSIR to separate the active compounds from neem oil. Its great implantation fights with soil erosion, global warming, deforestations and desertification world-wide. In 2002, World Neem Conference raised the neem tree as an industrial or commercial plant. This review is going to explore comprehensively; traditional, pharmacological potential along with patenting, environmental & industrial significant of various parts of neem tree with safety concerns.


2020 ◽  
Vol 4 (2) ◽  
pp. 41-45
Author(s):  
Sadam Sulaiman Indabo ◽  
Rufai Zakari

Dermestes maculatus is a major pest of stored fish in Nigeria, fish is preserved with highly persistent synthetic chemicals. There have been an increasing effort at developing plant-based toxicants that are environmentally friendly. Therefore, this study was conducted to screen the leaf extract of Azadirachta indica for phytochemical constituents. The efficacy of the methanolic leaf extract of the plant against D. maculatus was also evaluated. The leaves of A. indica were obtained, processed and taken to laboratory for methanolic extraction. Phytochemical screening was carried out to identify saponins, flavonoids, alkaloids, tannins, steroids, cardiac glycosides, glycosides, triterpenes and carbohydrates using standard procedure.  Both clean and infested samples of smoke-dried Clarias gariepinus were purchased from Sabon Gari Market, Zaria. The infested samples were used as initial source of D. maculatus larvae. Range finding test was carried out prior to the bioassay. During the bioassay, clean un-infested fish samples were weighed and introduced into kilner jars and respective dosages of 0.2g, 0.4g, 0.6g and 0.8g of extract were added. Another set of fish samples without the extract were maintained as control. The experiment was arranged in Completely Randomized Design with three replicates. Fifteen larvae of D. maculatus were introduced into both treated and control containers and covered. Mortality was recorded after 24, 48, 72 and 96 hours. Data obtained revealed an increase in mortality with increasing dose and time. Mortality ranged from 1.67 to 11.00. Therefore, leaf extract of A. indica should be incorporated in the development of larvicide against D. maculatus.   


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