bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wissadula Proliferation in Jamaica II. Psyllid transmission and antibiotic therapy
Authors: Dabek A. J. 
Published: May 2008

AbstractField symptoms of Wissadula proliferation (WP) in Jamaica were reproduced on W. periplocifolia (L.) C. Presl. ex Thwaites test plants, using field‐collected or laboratory reared and infected Paracarsidara concolor Crawford. This psyllid naturally is associated with W. periplocifolia in the field. Diseased plants contained phloem‐restricted prokaryotes, most of which resembled the phloem‐restricted rickettsialike organisms (RLO) known to be associated with a small group of plant diseases. They were bound by a “cell wall” composed of a double unit membrane separated by an electron‐lucent layer. A small proportion of the prokaryotes, which were bound by only one recognizable unit membrane and were ill‐defined at the periphery, were difficult to distinguish from mycoplasmalike organisms (MLO). Penicillin, applied as a soil drench of 200—400 %mUg/ml caused remission of symptoms of the psyllid‐infected test plants 6—17 days after first effective application, with the concomitant disappearance of all of the structures in the resulting new growth. Since MLO are not known to be penicillin‐sensitive, it is proposed that the “MLO” were in fact, poorly preserved RLO and it is suggested that RLO may be the aetiological agent of WP. Achromycin also caused symptom remission in WP at a soil drench of 100—400 %mUg/ml, but was generally slightly slower‐acting than penicillin, eliciting a response in 12—23 days. Both antibiotics could produce lengthy remissions; neither seemed curative since two penicillin‐ and two achromycin‐treated plants redeveloped symptoms after cessation of treatment. WP was not transmitted by two cicadellids, Protalebra maculata Baker and Scaphytopius fuliginosus Osborn. P. concolor did not transmit disease to test plants of Abutilon hulseanum (Torr. & A. Gray) Torr, ex. Chapm. which was affected by a proliferation disease (Abutilon proliferation), symptomatologically similar to, and which occurred in the same locations, as WP. WP and AP thus may be aetiologically distinct. The putative RLO aetiology of WP provides evidence against Wissadula being an alternate host of the MLO‐associated coconut lethal yellowing (CLY) disease in Jamaica, a fact reinforced by negative psyllid transmission tests to CLY‐susceptible palms. The results for WP are discussed in relation to other diseases possibly caused by phloem‐restricted RLO.
The Association of Brome Mosaic Virus and Wheat Rusts.
Authors: Erasmus D. S. , Rybicki E. P. , Von Wechmar M. B. 
Published: May 2008

AbstractEvidence is presented in support of transmission of brome mosaic virus by uredospores of wheat stem rust (Puccinia graminis f. sp. tritici). The presence of BMV associated with uredospores is shown by the use of sensitive serological assays such as, fluorescent antibody binding studies, enzyme‐linked immunosorbent assay and immunosorbent electron microscopy. The virus is shown to be carried externally on the uredospores. The nature of the association of the virus with uredospores and its relation to the mode of carriage and transmission of the virus by the uredospores, as well as the importance of this association in the epidemiology of the virus is discussed.
Detection of Potato Viruses Y and A in Tubers by Enzyme‐Linked Immunosorbent Assay after Natural and Artificial Break of Dormancy
Authors: Vetten H. J. , Ehlers U. , Paul H. L. 
Published: May 2008

AbstractThe effects of natural and artificial break of dormancy on the detection of potato viruses Y (PVY) and A (PVA) in tubers of field‐grown potato cultivars with primary and secondary infections were studied by enzyme‐linked immunosorbent assay (ELISA). Both viruses were at low concentration and unevenly distributed in dormant ‐tubers. Four to six weeks after treatment with Rindite, maximum concentrations of PVY and PVA were detected at both tuber ends with generally higher values at the rose end than at the heel end. Slower and smaller virus increase and a retarded and/or limited virus translocation were observed in treated tubers of resistant cultivars. Consequently, detectability of PVY and PVA was higher in tubers of susceptible cultivars than in those of the resistant ones. Detection of both viruses was very difficult and unreliable in tubers after natural break of dormancy. The very low concentration of PVY and PVA in dormant tubers and their drastic multiplication in Rindite‐ treated tubers appear to be characteristic of potyviruses and are unique among the major potato viruses.
Über Entstehung und Keimung der Chlamydosporen von Botrytis cinerea Pers.
Authors: Urbasch I. 
Published: May 2008

AbstractOn the genesis and germination of the chlamydospores of Botrytis cinerea Pers.The chlamydospores of Botrytis cinerea are hyaline single cells of extremely variable form and size. They are formed under conditions unfavourable for growth as terminal or intercalary cells by transformation of vegetative mycelium parts and are liberated by hyphal disintegration.The chlamydospore genesis in vitro in aging malt agar cultures began about after one month. But the chlamydospore formation could also be initiated earlier by different conditions of culture.The chlamydospores germinated either with hypha or by microconidia — a herewith first described mode of germination. Intermediates of these both modes of chlamydospore germination could be regulated very differentiatedly by transferring the chlamydospores into malt solution (2%)and/or destilled water and by changing the duration of stay in the individual media. Under adverse external conditions no germination occurred.The three Botrytis cinerea‐isolates did not show any differences in habitus, genesis and germination of their chlamydospores.Also in vivo on outdoor‐ and greenhouse‐tomatoplants the occurrence of chlamydospores was no rarity. Since the chlamydospores are produced under very different adverse conditions of growth but cannot survive a period of drought lasting longer than three months without damage, they do not represent long‐termed resistant perennating structures, but temporary stages of the fungus for intervening periods.
A Test System for the Quantitative Assessment of Resistance to Mildew in Rye (Secale cereale L.)
Authors: Llnd V. 
Published: May 2008

AbstractA test system is presented allowing the quantitative measurement of two resistance components, number of mildew infections per cm2 and spore production. The infection frequency is obtained from segments of the first leaf. The spore production is determined spectrophotometrically using suspensions from the infected second leaf of the same plant.The assessment of resistance can be extended to later growth stages of the genotypes, thus providing information about the dynamics of mildew development and the existence of adult plant resistance. Multiple measurements of resistance (two components, several growth stages) increase the reliability of single plant evaluation and enhance the response to selection. This point is especially important in population breeding of rye.
Development of Cronartium flaccidum (Alb. et Schw.) Wint. on Vincetoxicum officinale Moench in Connection with some Environmental Factors
Authors: Ragazzi A. 
Published: May 2008

AbstractExperiments on the development of Cronartium flaccidum on Vincetoxicum officinale in connection with environmental factors (temperature, moisture, brightness) in the years 1975, 1976, and 1977 are reported.Uredia appeared from the 7th to the 13th day after inoculation and terminated from the 14th to the 18th day. Urediospores appeared from the 9th to the 18th day and ended from the 18th to the 25th day.High temperatures advanced the beginning of the disease's development, but interfered with subsequent development.Telial columns formed from the 18th to the 22nd day after inoculation. They were particularly influenced by precipitation, but high temperatures had a negative effect on their formation.Telial columns ripened 2–3 days after their formation. Light affected the appearance of uredia and telial columns: many more uredia and telial columns were formed at 4000/5000 lux than at 5000/6000 and 8000/9000 lux.The first occurrence of the symptoms was on the young leaves. Leaves of V. officinale, inoculated with dried aeciospores, did not show any infection.
Seasonal Changes in the Chloroplast Ultrastructure in Abutilon Mosaic Virus (AbMV) infected Abutilon spec. (Malvaceae)
Authors: Schuchalter‐Eicke Gabriela , Jeske Holger 
Published: May 2008

AbstractVarious kinds of pathological effects of the Abutilon Mosaic Virus (AbMV) in seasonal dependency have been observed on the macroscopic as well as on the microscopic level. The annual rhythmic fluctuation of light caused by the varying length and intensity of light incidence is directly correlated with the realization of symptoms, leading to an intensification of the leaf mosaic and to an increase in the light leaf areas during the summer. These macroscopic observations are correlated with an annual change in the plastid fine structure in the mesophyll of the lightest areas of the leaf. The grana‐stroma‐organization of the plastids is completely eliminated through a reduction and disorganization in the thylakoid system during the spring and summer, restored in the autumn, and preserved over the winter. This change in the plastid fine structure is limited to the leaf mesophyll. The plastids of the leaf stem, like the plastids of non‐infected plants, do not display any change in their fine structure.
Effects of Plant Nutrition on Susceptibility of Potato Leaves to Phytophthora infestans
Authors: Carnegie S. F. , Colhoun J. 
Published: May 2008

AbstractA complete NPK fertilizer applied at planting, but not at later times, influenced the resistance of potato leaves to infection by Phytophthora infestans and the subsequent growth of lesions. Lesion size (7 days after inoculation) and lesion growth rate (between 7 and 9 days after inoculation) increased linearly with increasing fertilizer rates. Increasing rates of phosphate or potash, applied separately, did not significantly affect the development of blight lesions but a linear increase in lesion size was associated with increasing application rates of nitrogen.
Activation of Teliospore Germination in Uromyces appendiculatus var. appendiculatus1)
Authors: Gold R. E. , Mendgen K. 
Published: May 2008

AbstractThe effects of aging and temperature on teliospore germination in Uromyces appendiculatus var. appendiculatus were studied.1. Indoor storage was good at ∼ 4 °C in the dark. Under these conditions spores remained dormant for ∼ 9 mo, but thereafter germination gradually increased to a maximum (∼ 63 %) after 36 mo. Spores stored outdoors showed a marked increase in germination after ∼ 4 mo and reached maximum (∼ 73 %) at 7–8 mo.2. The optimum temperature for germination was at 18°C. While freezing (–18°C) and thawing (20 °C) had no beneficial effect on spore germination, heat treatments from 30–32 °C for 3–4d proved effective in activating teliospore germination. Heat treatments caused an increase in spore mortality. Basidiospore release from heat‐treated teliospores was markedly reduced compared to control spores.3. In all experiments the emergence of metabasidia was preceded by an obligatory 3–5 d lag period regardless of the treatment given, the age or level of germinability of treated and control spores.
Effect of Aliette on AMV Infection of Bean Leaves and on the Resultant Alterations in the Patterns of Proteins and Peroxidases
Authors: Abu‐Jawdah Y. , Kummert J. 
Published: May 2008

AbstractIncreased peroxidase activity as well as changes in the patterns of soluble proteins, and peroxidases were observed following infection of bean leaves with AMV.Foliar sprays with Aliette® (phosethyl Al) at 2000 ppm a. i. delayed the appearance of necrotic local lesions and reduced their final number on primary bean leaves following inoculation with alfalfa mosaic virus (AMV).The delay in the appearance of symptoms observed on Aliette‐treated inoculated leaves was correlative with a delay in all the above cited alterations, while reduction of final symptoms was correlative with a decrease of these alterations.
Radiation Effects on Cellular Metabolism and Disease Resistance of Jute
Authors: Purkayastha R. P. , Ray Chandi 
Published: May 2008

AbstractAir dried seeds of seven jute (Corchorus capsularis L.) cultivars were irradiated with different doses of X‐rays. JRC 1108 and JRC 412 were most and least sensitive to X‐rays, respectively. JRC 412 was susceptible to Colletotrichum corchorum both before and after X‐irradiation while JRC1108 became more resistant after treatment. Leaf diffusates but not leaf exudates of both non‐irradiated and X‐irradiated (40,000 r) cvs. exhibited antifungal activity which was more pronounced in case of irradiated JRC 1108. JRC 412 contained greater amounts of amino acids than JRC 1108 both before and after X‐irradiation. Signifinon‐irradiated, infected ones. The physiological implications of the results are discussed in relation to greater resistance of X‐irradiated JRC 1108.
Lutte Contre le Chancre à Didymella lycopersici de la Tomate par Chauffage Solaire (Solarisation) des Tuteurs
Authors: Besri M. 
Published: May 2008

AbstractSolar heating (solarization) of tomato supports for control of Didymella lycopersici stem canker Previous studies have shown that Didymella lycopersici survives mainly in reed canes (Arundo donax) and Eucalyptus stakes used to support tomatoes. The solarization of the supports during the hot months of the year (May‐August), by an old transparent plastic film (180μ) which was used for two years as a cover to a plastic tunnel, reduced considerably, and without any cost, the incidence of the disease. In the plots trellised with solarized and unsolarized supports, the percentage of plants with Didymella cankers at the last month of tomato crop was respectively 1.9 and 20.7%. The maximum temperatures recorded in the atmosphere, from May to September vary from 26 oC to 34 oC. The maximum temperatures recorded during the same period under plastic were always higher than 50 oC. U.S.
Common Leafspot of Alfalfa: Ascospore Discharge and Plant Infection in the Field
Authors: Semeniuk G. 
Published: May 2008

AbstractPeak daily discharge of Pseudopeziza medicaginis ascospores in the field occurred after sunrise with attendant rises in temperature, wind, speed, and. dissipation of moisture. Protracted discharge over many days rose with initial development of robust, uncrowded apothecia and fell as these became spent and were joined by less productive, small, crowded ones. In the laboratory, detached field‐infected leaves discharged ascospores at 5°C to 32.5°C and at relative humidities as low as 90% when fresh, and at 94% or higher when wilted or dried. Pathogen‐free alfalfa plants placed overnight in a diseased affalfa plot were inoculated but uninfeeted more frequently in July than they were inoculated and infected. Artificially‐inoculated plants placed at the same time in a nearby sugar beet plot became infected every overnight. From early September through early October artificially inoculated plants placed in a plot of sugar beets or a plot of nearly disease‐free alfalfa for 24 h periods, became infected in 18 and 19 of 29 such periods. Light rain, fog and dew were frequent during these periods and early morning temperatures fell between ‐ 3 °C and 5 °C‐ in one‐half of the overnights. Dormant ascospores on foliage remained fully infective in the greenhouse for at least 10 days.
Isolation and Identification of Pythiaceous Fungi from Irrigation Water and their Pathogenicity to Antirrhinum, Tomato and Chamaecyparis lawsoniana
Authors: Pittis J. E. , Colhoun J. 
Published: May 2008

AbstractPythiaceous fungi were isolated from irrigation water using a variety of natural and artificial baits. Isolates were also obtained by plating water samples directly on the surface of selective agar media. The selective medium of Ocana and Tsaq (1966) PlOVP, was modified by substituting rifampicin and ampicillin (10 and 500 μg cm−3 respectively) for vancomycin to suppress bacterial growth from water samples.The pythiaceous fungi were identified as Pythiitm dissotocitm, P. middletonii, P. mamillatum, P. rostratum, Pythium“group 1”, “group 2” and “group 3” and Phytophtbom gona‐podyides. All isolates of P. gonapodyides were the A1 strain and produced oospores when paired with an A2 isolate of P. drechsleri.Isolates were tested for their pathogenicity to Antirrhinum, tomato and Chatmaecyparis lawsoniana cv. Ellwoodii. Pythium middletonii and Pythium“group 1” caused severe pre‐emergence damping‐off of Antirrhinum seedlings, P. mamillatuni, P. rostratum and Pythium“group 3” were less pathogenic to the same host while P. dissotocum, Pythium“group 2” and Phytophthora gonapodyides were non‐pathogenic. Only isolates of Pythium“group 1” were pathogenic to tomato seedlings. None of the fungi was pathogenic to rooted cuttings of Chamaecyparis lawsoniana cv. Ellwoodii.
The Use of a Simple Electron Microscope Serology Procedure to Observe Relationships of Seven Potyviruses
Authors: Walkey D. G. A. , Webb M. J. W. 
Published: May 2008

AbstractThe relationships between bean yellow mosaic (BYMV), bean common mosaic (BCMV), clover yellow vein (CYVV), lettuce mosaic (LMV), potato virus Y (PVY), turnip mosaic (TuMV) and celery mosaic (CeMV) viruses were studied in homologous and heterologous reactions, using simple and relatively rapid electron microscope serology decoration tests. The degree of relationship between these viruses was assessed by the intensity of antibody coating when the viruses were decorated by heterologous antibodies. A close relationship was observed between BYMV and CYVV, and between BYMV and LMV but not between CYVV and LMV. CeMV was quite closely related to BYMV and CYVV.Antibodies to BCMV and BYMV intensely decorated different strains of their own virus, but decoration was negligible in cross reactions.
Dieback of Passion Fruit in Surinam
Authors: Power R. H. , Verhoeff K. 
Published: May 2008

AbstractIn Surinam, the commercial cultivation of the yellow passion fruit (Passiflora edulis f. flavicarpa) is difficult due to the occurrence of dieback. Symptoms referred to as dieback include a decrease in elongation of the shoot end internodes after a period of normal growth leading to wilting and death of the shoots. Fruits from plants showing dieback symptoms are much smaller than those from healthy plants. From shoots with dieback symptoms, three fungi were isolated including Colletotrichum gloeosporioides. However, inoculation experiments with these fungi on shoots of vigorously growing plants were negative, even after wound inoculation.It appeared that plants with dieback symptoms had a poorly developed root system, From these roots Fusarium solani was isolated, which appeared to be highly pathogenic to roots of the yellow passion fruit. After inoculation of the roots of 3‐month‐old plants, roots became infected and the aerial plant parts showed typical dieback symptoms.Plants with their root system reduced either by inoculating with F. solani or by clipping, and subsequently inoculated with C. gloeosporioides on the aerial parts 2 weeks later, showed dieback symptoms and infection by C. gloeosporioides in shoots with these symptoms. Thus, a badly functioning root system, for example caused by infection of F. solani leads to dieback and predisposes plants to infection by C. gloeosporioides. The latter fungus itself is not a primary pathogen of shoots of the yellow passion fruit in Surinam.
Antiphytovirale Verbindungen mit nichtzyklischer Azin Struktur
Authors: Schuster G. , Heinisch L , Schulze W. , Ulbright H. , Willitzer H 
Published: May 2008

Abstract Antiphytoviral compounds with noncyclic azine structutre The antiphytoviral activities of variously substituted compounds with noncylic azine structures have been studied f a total of 90 tested compunds 42 had the effect of more or less strong inhibiting the concentration of potato virus X (PVX) in inoculated and / or secondarily infected leaves of Nicotiana tabacum L. cv Samsun (Table.1) An effect on the virion of PVX in vitro couldn't be observed (Table.2) Thus the substances may interact with the virus replication. Some of them also reduced the number of local lesions caused by tabacco mosaic virus on leaves of Nicotiana glutinosa L. (Table‐3) Several Compounds proved exellent synergists of 2,4‐ dioxohexahydro‐ 1,3,5‐ triazine (DHT = 5 azadihydrouracil; Table 4) Pyridine‐ 3‐ aldehyde S ethyl isothiosemicarbazone and the Cu complex of 1‐ ethyl‐isatine S‐ ethyl isothisosemicarbazone when used in combination with 2,4 dioxohexahydro‐ 1,3,5, triazine, greatly increased the mass of potato tubers produced from plantlets grown up from patato eye cutting as compared with the indentical control Simultaneously the mentioned substances reduced the number of symptom bearing eye cutting plants Quinoline 2‐ aldehyde‐ N‐ oxide S‐ allyl‐isothiosemicarbazone had the effect of very greatly reducing the number of symptom‐bearing plants without substantially influencing the mass of tubers (Table 5). Thus some compounds with noncyclic azine structure especially when used in combinitation with DHT, may be of high interest for practical application Comparing the structures of compounds with noncyclic azine structure active against plant or human viruses it should be noted that antiphytoviral compounds active in these two different virus host systems often are closely related structurally.
Purification and Characterization of a Jordanian Isolate of Watermelon Mosaic Virus
Authors: Karam N. , Al‐Musa A. 
Published: May 2008

AbstractThe Jordanian isolate of watermelon mosaic virus‐2 (WMV‐2Jo) was purified from infected Cucurbita pepo cv. Top Capi by extraction in 0.05 M sodium citrate buffer containing 0.01 M sodium diethyl dithiocarbamate and 0.01 M cysteine hydrochloride (0.01 M D + C), clarification with chloroform and n‐butanol, sedimentation by ultracentrifugation, and rate‐zonal centrifugation in 10–40% sucrose gradient. The purified virus had an ultraviolet absorption spectrum typical of a nucleoprotein with a low nucleic acid content. Homologous antiserum had a titre of 1: 256, as determined by the ring interface test. Electron microscopy of negatively stained purified virus revealed flexuous particles with a normal length of 750 nm. Cytoplasmic spindle‐shaped inclusions were readily detectable in infected epidermal cells under the light microscope. Thin sections of infected tissue revealed the presence of laminated aggregates, pinwheel and scroll inclusions. The virus reacted with antisera prepared to the Florida strain of WMV‐2 and zucchini yellow mosaic virus in a sodium dodecyl sulfate (SDS) agar gel diffusion test. Using the Derrick‐decoration combined technique of immune electron microscopy, the virus reacted strongly with the homologous antiserum and zucchini yellow mosaic virus antiserum, but less with antiserum prepared to the Florida strain of WMV‐2.
Detection of Seed‐Borne Inoculum of Peronosclerospora sorghi in Sorghum
Authors: Prabhu M. S. C. , Safeeulla K. M. , Venkatasubbaiah P. , Shetty H. S. 
Published: May 2008

AbstractAn alkali maceration technique has been developed to detect internally seed‐borne inoculum of Peronosclerospora sorghi in sorghum seeds. Optimum period for maceration was found to be 36 h. Oospores in the glumes and mycelia in the pericarp and endosperm were clearly demonstrated. Mycelium was found in the pericarp of 40 % of the seeds tested and in the endosperm of 5 % of seeds. The possibility of using this technique to detect seed‐borne downy mildew infection has been emphasized.