bluuebunny/crossref_metadata_2025_split huggingface dataset:
Behaviour of Phytophthora cinnamomi Zoospores on Roots of Four Avocado Cultivars
Authors: Aveling Theresa A. S. , Rijkenberg F. H. J. 
Published: May 2008

AbstractScanning electron microscopy was used to study the behaviour of Phytophthora cinnamomi zoospores on the roots of three tolerant avocado cultivars. Duke 7, G6 and Martin Grande, and a susceptible Edranol cultivar. Zoospores were attracted to the region of cell elongation and encysted on the roots of all cultivars studied. Adhesion of the zoospores appeared to be aided by root slime. Cysts usually produced one germ tube which penetrated the root directly, or formed an appressorium‐like swelling before penetration occurred. Extensive growth of germ tubes occurred where zoospores germinated some distance behind the region of elongation. Cysts germinating behind this region often formed branched germ tubes and more than one appressorium‐like swelling. There were no clear differences in the type of pre‐penetration structures, formed by zoospore cysts, on the roots of the different avocado cultivars.
Messung von Merkmalen der quantitativen Scharkaresistenz der Pflaume und Nachweis ihrer Wechselbeziehungen
Authors: Kegler H. , Kleinhempel H. , Meyer U. , Berka K. , Grüntzig Maria 
Published: May 2008

AbstractMeasurement of the characteristics of the quantitative resistance in plum to the plum pox virus and evidence for their interrelationsTwo plum clones, with different degrees of susceptibility towards the plum pox virus (PPV), were inoculated with either a weakly or strongly pathegonic strain of PPV. The symptoms which developed in the older leaves (i. e. the 3rd to 5th basal leaves) were measured by visual rating as well as with the aid of a UV‐VIS‐spectralphotometer SPECORD M 40. Additionally, the relative virus concentrations in these leaves were determined by ELISA. Significant differences were established between the infected leaves of the PPV‐sensitive and PPV‐resistant plum clones, irrespective of the method of measurement. The values recorded for the weakly and strongly pathogenic PPV strains were significantly different only with the PPV‐sensitive clone.A significant correlation was established between the visual ratings and the colormetrical values or the ELISA‐values, as well as between the individual colormetrical values a, L and b. In the system plum‐PPV, the b‐values are the most important in the evaluation of the severity of the symptoms and in the qualitative colour changes.
The Disease Cycle of Mango Malformation Induced by Fusarium moniliforme var. subglutinans and the Curative Effects of Mangiferin‐Metal Chelates
Authors: Chakrabarti D. K. , Ghosal S. 
Published: May 2008

AbstractEvidence is presented to suggest that the bunchy top, die‐back, abnormal inflorescence and blossom blight disease of Mangifera indica are interlinked and can be expressed as a disease cycle in mango malformation. The morphological and biochemical connections among these symptoms, induced by Fusarium moniliforme var. subglutinans Wollenw. and Reink., are appraised. Partial control of the mango malformation has been accomplished by spraying the diseased parts with mangiferin‐Zn2+ and mangiferin‐Cu2+ chelates. The salutory effect of niangiferin‐metal chelates is evidenced by the revival of normal balance of mangiferin and the micronutrients in the diseased parts, dechne in the fungal population and emergence of healthy shoots.
Fluorescent Pseudomonas Isolates Pathogenic on Witloof Chicory Leaves
Authors: Van Outryve M. F. , Gosselé F. , Joos H. , Swings J. 
Published: May 2008

AbstractNineteen phytopathogenic fluorescent Pseudomonas isolates were isolated from diseased witloof chicory (Cichorium intybus L. var. foliosum Hegi). They were compared with six Ps. fluorescens strains from culture collections, using SDS‐PAGE of total cell proteins. The fluorescent pseudomonads examined showed seven different fingerprint types. The major group of phytopathogenic fluorescent pseudomonas revealed a fingerprint type which was frequently found on healthy chicory roots and leaves too. Some, but not all, of the isolates from healthy plants produced typical disease symptoms upon artificial inoculation of etiolated chicory leaves. Infectivity titrations showed a reduced efficiency of the latent pathogen PGSB‐7228 to cause disease symptoms on the chicory leaves. The virulence of the latent pathogen is induced in the presence of wounded chicory tissue.
The Occurrence of Citrus Canker Disease in United Arab Emirates (U.A.E.)
Authors: El‐Goorani M. A. 
Published: May 2008

AbstractCitrus canker disease caused by Xanthomonas campestris pv, citri is reported on lime in the present study for the first time in United Arab Emirates. The disease was found only on lime in 32 orchards out of 4456 citrus orchards inspected during 1984–85. The citrus canker organism in U.A.E. has a host range similar to “A” strain.Copper hydroxide was significantly superior to all other treatments in decreasing the incidence of citrus canker disease that developed on inoculated lime seedlings. Streptocycline, Kasumin, copper oxychloride and Bordeaux mixture were not effective in reducing the incidence of the disease.
A Note on the Limitations of Identifying Soft Rot Erwinias by Temperature Tolerances and Sensitivity to Erythromycin on a Pectate Medium
Authors: Janse J. D. , Spit B. E. 
Published: May 2008

AbstractForty‐five erwinia strains from 14 different hosts have been tested lor growth on a crystal violet pectate medium with or without 70 μ/ml erythromycin at 27, 33.5 and 37°C. On the basis of positive data in the literature it was tried to identify the strains as Erwnia carotovora subsp. atroseptica, E. carotovora subsp. carotovora or E. chrysanthemi using this method.It appeared that relatively few strains reacted differentially, apparently due to strain variation (all strains were identified also by biochemical and physiological tests). The conclusion is that for a reliable identification of field isolates of soft rot crwinias other (biochemical, physiological and serological) methods have to be applied.
Induction of Resistance in Tobacco Leaves to Tobacco Mosaic Virus by Dodecylbenzenesulfonate
Authors: Hellwald K. H. , Buchenauer H. 
Published: May 2008

AbstractApplication of dodecylbenzenesulfonate (DBS) to half leaves of Nicotiana tabacum cv. Xanthi nc. before TMV inoculation resulted in a marked decrease in lesion number and size as well as in virus content of the lesions in the untreated half leaves. Systemic induction of resistance in untreated leaves of the plants was not detected.
Hyperparasitischer Angriff von Epicoccum purpurascens auf den biotrophen Kontakt‐Mykoparasiten Gonatobotrys simplex
Authors: Urbasch I. 
Published: May 2008

AbstractHyperparasitic attack of Epicoccum purpurascens on the biotrophic contact mycoparasite Gonatobotrys simplexThe in vivo‐ and in vitro‐hyperparazitation of Gonatobotrys simplex (Gs) by Epicoccum purpurascens (Ep) is presented. Ep, showing positive tropism, grows toward the host fungus Gs. After contact Ep penetrates especially the Gs‐conidia, more rarely germ tubes and the mycelium.Two types of penetration can be distinguished: 1) direct penetration and 2) penetration after previous formation of appressoria.On this attack Gs reacts with local cell wall appositions (papillae), which mostly can be pierced by the hyperparasite. At the advanced state of parasitism the host fungus finally dies.
Decay of Sclerotia of Botrytis cinerea by Trichoderma spp. at Low Temperatures
Authors: Köhl J. , Schlösser E. 
Published: May 2008

Abstract In vitro, tests were conducted at 10°C and 5°C against sclerotia of Botrytis cinerea with 58 isolates of Trichoderma spp., highly antagonistic at 24°C but differing in their cold tolerance. Some isolates macerated and colonized sclerotia even at 5 °C. With 19 isolates of Trichoderma spp. less than 10 % of the sclerotia remained viable after 42 d at 5 °C.Conidia ol some Trichoderma spp. germinated at 5 °C within a few days and reached germination rates higher than 80 %.It seems to be feasible to use selected isolates of Trichoderma spp. for biological control of sclerotia of ß. cinerea also during the colder season.
Rate of Loss of Infectivity of Maize Dwarf Mosaic Virus by Schizaphis graminum Rondani After Different Acquisition Access Periods
Authors: Berger P. H. , Harris K. F. , Toler R. W. 
Published: May 2008

AbstractThe rate of loss of infectivity for greenbugs, Schizaphis graminum Rondani, carrying maize dwarf mosaic virus (MDMV) was similar for adult apterae and alates regardless of the acquisition access period (AAP) given. The rate was rapid during the first 2 h post‐acquisition and then decreased. Weighted least squares linear regression of log % transmission were plotted against retention‐time intervals to obtain regression slopes for each of the AAP groups tested (1, 3, 17, and 30 min). There were no significant differences among the regression slopes using F‐test comparisons.In serial transmission trials, transmission frequencies among aphids allowed 1‐min or 30‐min timed acquisition probes followed by 30‐see or 1‐min timed inoculation probes were not significantly different when statistical tests that quantify categorical data were applied. This suggests little difference in the amount of virus obtained by these groups of aphids.Transmission and retention data are discussed in relation to the two principal theories of the mechanism of non‐persistent virus transmission by aphids. Transmission of MDMV by the greenbug by a two mechanism process (stylet‐borne and ingestion‐egestion) is not confirmed.
Detection of Citrus Tristeza and Greening in Pakistan Through Electron Microscopy
Authors: Grimaldi V. , Catara A. 
Published: May 2008

AbstractAn electron microscopic investigation was carried out on citrus fruits and leaves collected during a survey in Pakistan. Thread‐like particles of citrus tristeza virus (CTV) were ascertained in phloem tissues of the columclla, whereas the bacterium associated with greening was detected in sieve tubes of the columella and in leaf midribs of trees showing typical yellow vein, fruit maiformation an decline. CTV was also confirmed by ELISA tests.
Infection of Onion by the White Rot Pathogen, Sclerotium cepivorum
Authors: Stewart A. , Fullerton R. A. , Sutherland P. W. 
Published: May 2008

AbstractInfection of onion tissue by Sclerotium cepivorum occurred from germ tubes penetrating between adjacent epidermal cell walls or directly, via penetration pegs produced from slightly swollen hyphal tips or from beneath dome shaped infection cushions. After passing through the cuticle, the infection peg enlarged to form an infection hypha within the primary cell wall. Extensive degradation of the epidermal cell wall occurred, often at a distance of 2–3 cells from the advancing hyphae.As infection advanced, hyphae spread rapidly from the epidermis to the cortex growing between and within dead/dying host cells. Extensive host cell death resulted in localized collapse of the tissue around infection points. Complete colonization of the internal tissues of the root and stem base occurred within 5–7 days of inoculation.
Identification, Distribution and Vector Population Dynamics of Barley Yellow Dwarf Virus in Three Cereal‐Producing Areas of Spain
Authors: Fereres A. , Lister R. M. , Castanera P. , Foster J. E. 
Published: May 2008

AbstractELISA‐based surveys during 1985–87 in three major cereal‐growing areas of Spain confirmed the presence of barley yellow dwarf virus (BYDV). Samples of small grain cereals and grasses with and without BYDV‐like symptoms were collected in the central, southwestern, and northeastern Spain. Infections were found in all cereal species sampled and in some grasses. About 37 % of the samples collected in 1985 were infacted with isolates of the PAV serotype. Isolates of the RPV serotype were less common, and were detected only in samples from the central region at El Encin, Madrid. Only a single sample, collected from El Encin in 1987, was unequivocally diagnosed as containing an isolate of the MAV serotype.Aphid vector population dynamics was monitored during fall and winter of 1984–87 in the central region. Rhopalosiphum padi L. appeared to be the most abundant species during fall and winter months, infesting grasses and volunteer wheat. Other species present were Sitobion avenae (F.), Metopolophium dirhodum (Walker) and Rhopalosiphum maidis (Fitch). Both R. padi and S. avenae seem to be anholocyclic in the central region of Spain, and are able to remain and reproduce on wheat volunteers and grasses until the beginning of spring. S, avenae populations increase quickly on wheat volunteers in April, while populations of R. padi remain low. Therefore, spread of S. avenae‐transmitted BYDV types to neighbouring cereal fields seem more likely to occur than spread of other types. Other possible virus reservoirs, such as maize, also need investigation for a better understanding of BYDV epidemiology in the central and other cercal‐growing areas of Spain.
Assessment of Red Core Resistance of Strawberry Using Enzyme‐Linked Immunosorbent Assay (ELISA)
Authors: Mohan S. B. , Kennedy D. M. , Duncan J. M. 
Published: May 2008

AbstractThere was a strong correlation between measurements of red core disease of strawberry, assessed as percentage lengths of the adventitious roots with red steles, and ELISA values obtained from the same root systems using a polyclonal antiserum raised to Phytophthora fragariae. ELISA grouped twelve host cultivar/pathogen isolate combinations into three categories, highly resistant, partially resistant and susceptible, which agreed with disease incidence after inoculation.
Genetic Adaptation of Erysiphc graminis f. sp. Hordei to Barley with Partial Resistance
Authors: Newton A. C. 
Published: May 2008

AbstractTen Isolates of powdery mildew were tested on three spring barley cultivars known to express partial resistance and on Golden Promise. Measurements of colony lengths were made under several different environments and compared with similar data produced from several cultivars containing one of two major resistance genes. Significant isolate, cultivar and environment interactions were recorded and one isolate in particular showed adaptation to a partially resistant cultivar.Measurements of infection frequency were also made under two temperature regimes. Again significant isolate, cuitivar and temperature interactions were recorded and the same isolate showed adaptation to the same partially resistant cultivar. This indicates that adaptation to a source of partial resistance can be found amongst unselected isolates and that pleiotropically adapted genotypes may rapidly overcome such resistance in the field following its widespread deployment. Other genes for resistance were detected in the major gene cultivars, including partial resistance in the ml‐v genotypes.
Influence of Temperature, Wetness Duration, and Leaf Type on the Quantification of Monocyclic Parameters of Bean Rust
Authors: Mendes B. M. J. , Bergamin Filho A. 
Published: May 2008

AbstractMonocyclic parameters of bean rust (Uromyces phaseoli var. typical) were quantified in growth chambers, on rwo bean cultivars for three temperatures (17, 21, and 25 °C), two types of leaves (unifoliolate and trifoiiolate leaves), and nine leaf wetness periods (0, 4, 7, 10, 13, 16, 19, 22, and 25 hrs). The expression of disease was greatly influenced by past‐inoculation temperatures. The incubation and latent periods were shortest at 21 °C for both cultivars and leaf types. For both cultivars, trifoiiolate leaves were more susceptible than unifoliolate leaves. A wetness period of at least four hours was required for disease to occur. The maximum disease efficiency for both cultivars occurred with 22 hrs of leaf wetness at 17 °C. The disease efficiencies for temperatures of 17–29 °C and leaf wetness periods of 0–25 hrs were adequately described by a response‐surface model. Because of the great influence of temperature and leaf wetness on infection, bean rust is unlikely to occur at high temperatures (> 25°C) and short leaf wetness periods (< 7 hrs).
The Pathogenesis‐Related Proteins of Phsseolus Bean
Authors: RedolfiA. P. , Cantisani  , Migheli Q. 
Published: May 2008

AbstractSeven acidic low molecular weight pathogenesis‐related (PR) proteins from tobacco necrosis virus‐infected Phaseolus bean leaves were isolated, purified and partially characterized. The proteins could ba classified following the nomenclature of Antoniwet al. (1980) for tobacco PR proteins. Three groups are thus proposed, corresponding to molecular sizes of 16, 27 and 31 kD, very close to the values of three groups proposed for tobacco. Tentative correspondences between the PR proteins here described and those previously reported by other authors are also proposed.
Coat Protein‐derived Small Particles in a Tombusvirus from River Lato
Authors: Gallitelli D. , Di Franco A. , Vovals C. , Martelli G. P. 
Published: May 2008

AbstractA new tombusvirus cleariy distinguishable from other members of the group was isolated in Apulia from river Lato and therefore referred to as Lato River Tombusvirus (LRV). Purified virus preparations after storage for 5 months at 4°C in 20 mM phosphate buffer, pH 7.2, contained variable amounts of small particles (c. 17 nm in diameter) in addition to typical virus particles (c. 30 nm in diameter). LRV small particles were constituted by a single protein species with a tnol. wt of 29,000, did not contain nucleic acid and were not infective but proved to be serologically undistinguishable from ordinary virus particles. Attempts to artificially produce small particles by chemical orenzymatic treatments of full size LRV virions failed but their spontaneous production nder particularstorage conditions seems to be a remarkable feature of this virus as it does not occur with other definitive tombusviruses.
Effect of Different Strains of Soybean Mosaic Virus on Growth, Maturity, Yield, Seed Mottling and Seed Transmission in Several Soybean Cultivars
Authors: To J. C. 
Published: May 2008

AbstractEighty soybeans (Glyane max Merr) cultivars, includingx a resistant line Oxley 615 were each inoculated with seven streams of soybean mosaic virus SMV. Susceptible cultivers produced smaller plants with delaved maturity, and reduced seed yield relative to the non inoculared plants Someptible cultivars had.a higher level of morrled seeds and seat transmission ot SMV from the morrled seeds than the resistance line Oxley 615.The SMV strain cultivar interaction was significant for all traits, suggsesting that soybean cultivars should be tested against specific SMV strains to determine their response to this virus.
Characteristics of Inhibition of Suppressive Soil Created hy Monoculture with Radish in the Presence of Rhizoctonia solani
Authors: Chern L. L. , Ko W. H. 
Published: May 2008

AbstractSoils collected from five districts of Hawaii county were infested with Rhtzoctonia solani in small inoculum particles and successfully planted with radish to induce suppression, Suppressiveness was induced in some, but not all, replicates of all. soils. When fresh inoculum was added, suppressiveness was demonstrated in some, but not all, replicates of two soils, but not in the other three soils. Acidity of soil was not important in successful induction of suppression. Characteristics of induced suppression in soil from one site (S. Kohala) were further investigated.Reduction of microbial population by heat treatment of suppressive soil completely nullified its inhibitory effect. The populations of actinomycetes, fungi in general and Trichoderma spp. in suppressive and conducive soil were not significantly different. However, the population of bacteria in suppressive soil was almost four times higher than that in conducive soil. The survival time of R. solani in suppressive soil was shorter than that in conducive soil. Hyphae of R. solani also lysed faster in suppressive soil than in conducive soil. It is suggested that suppressiveness of the South Kohala soil created by monoculture is due to enhanced competitive pressure generated by an increased bacterial population, which in turn causes the rapid autolysis of R. solani hyphae.
Mode of Sour Rot Formation as Inferred from Comparative Studies with Virulent and Avirulent Strains of Geotrichum candidum
Authors: Hershenhorn J. , Bher Leah , Barash I. , Arzee Tova 
Published: May 2008

AbstractA comparative study between virulent and avinilent strains ot Geotrichum candidum was undertaken in order to identify mechanisms for virulence of this pathogen on letnons. The initial development of virulent and avirulent strains during the 48 h following inoculation, as measured by colony‐forming units, was similar. However, only virulent strains produced actively developing soft rot lesions whereas avirulent strains produced arrested dry lesions. Microscopical examination indicated that disorganization and maceration of the exocarp tissue preceded the penetration of fungal hyphae at all inoculation sites. Degradation of pectic substances progressed with maceration. Ultra.structural examination revealed cytoplasmic inclusions originated from projections of plastid membranes. Various tests for possible involvement of active defence mechanisms gave negative results. Production of endopolygalactutonase (PG) was significantly higher in virulent than in avirulent strains. When lemon fruits were treated at 80°C for 2min, active lesions were also developed by avirulent strains. The PG of the virulent strain was more effective than that of the avirulent in causing maceration of lemon albedo tissue and the heat treatment increased the rate of maceration with both enzyme preparations. It was suggested that the initial amount of PG produced in vivo and the sensitivity of the pectin in situ to this enzyme, are the main factors that govern virulence of G. candidum on citrus fruit.
Components Analysis of Race Non‐Specific Resistance to Blast Disease of Rice Caused by Pyricularia oryzae
Authors: Castano J. , MacKenzie D. R. , Nelson R. R. 
Published: May 2008

AbstractA group of 69 rice cultivars with diverse degrees of resistance to rice blast disease (at least in a qualitative sense) was chosen for a detailed study of some components of race non‐specific resistance, i.e. relative disease efficiency, latent period, and sporulation capacity. Large differences amongst cultivars were found. The overlapping of the normal curves for the qualitative reaction and the components of race non‐specific resistance point out the difficulties of rapid screening for blast resistance by simple observation in the field. One approach to overcome these difficulties could be to use component(s) analysis in the evaluation of rice germplasm to identify parents or progeny having the attributes of race non‐specific resistance.
Production of Phytotoxic Sirodesmins by Aggressive Strains of Leptosphaeria maculans Differing in Interactions with Oil Seed Rape Genotypes
Authors: Badawy H. M. A. , Hoppe H. H. 
Published: May 2008

AbstractSirodesmins were extracted from culture filtrates of 3 aggressive strains of Leptosphaeria maculans which showed different specific interactions with the oilseed rape cultivars Quinta and Jet Neuf. Up to 8 compounds were detectable showing reactions on thin layer plates which are characteristic for sirodesmins. Sirodesmin PL, sirodesmin C, deacetylsirodesmin PL and deacetyl‐sirodesmin C were identified on the basis of their UV‐spectra, by various conversion reactions and by cochromatography with known standards. Two further compounds were tentatively identified as sirodesmin B and deacetylsirodesmin B on the basis of conversion reactions only. In the cultures of all strains sirodesmin PL was the main component, followed by deacetylsirodesmin PL, sirodesmin C, and deacetylsirodesmin C. These 4 metabolities were mainly responsible for the phytotoxic activity of all culture filtrates. They were systemically transported to leaves of root treated rape seedlings. No correlation was found between the production of the 4 main sirodesmins and the differential host parasite interactions of the 3 aggressive strains of Leptosphaeria maculans.