bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spore Dispersal and Plant Disease Gradients; a Comparison between two Empirical Models
Authors: Fitt B. D. L. , Gregory† P. H. , Todd A. D. , McCartney H. A. , Macdonald O. C. 
Published: May 2008

AbstractPower law and exponential models were fitted to 325 sets of observations which described decreases with distance in deposition of air‐borne or splash‐borne spores, or pollen, or in amounts of plant disease caused by fungi, bacteria or viruses. There, was generally little difference between the models in the goodness of fit to these data, although deposition gradients for spores borne in splash droplets were fitted better by exponential models and gradients for fungi with air‐borne spores less than 10 μm in diameter were fitted better by power law models. The exponential model has the property that the observed variable decreases by half as the distance from the source increases by a constant increment (the half‐distance); this provides a measureof the gradient that is more easy to visualize than the exponent in power law model. The half‐distances of gradients for air‐borne pathogens were greater than those for splash‐borne or soil‐borne pathogens. The exponential model is easier to incorporate into models of disease development than the power law model because the boundary condition at the source (the estimated number of spores or amount of disease at the source) is finite rather than infinite. However, both these empirical models have limitations and should not be extrapolated to distances outside the observed range.
Deposition of Erysiphe graminis Conidia on a Barley Crop II. Consequences for Spore Dispersal
Authors: McCartney H. A. 
Published: May 2008

AbstractMeasured deposition rates of Erysiphe graminis conidia are often greater than those calculated from spore fall speed, vs, and mean wind speed. The predictions of two gradient transfer models of spore dispersal in crops, in which sedimentation and inertial impaction were calculated from vs and local wind speed or estimated from measured values (McCartney and Bainbridge 1987), were compared. Comparisons of the models suggest that deposition rates close to the source may be underestimated by a factor of two and deposition half distances may be doubled when deposition is calculated conventionally. The results illustrate the importance of accurately describing deposition processes when constructing spore dispersal models.
Susceptibility of Rubus Species and Cultivars to Blackberry Leaf Rust (Phragmidium violaceum) and its Control by Fungicides
Authors: Washington W. S. 
Published: May 2008

Abstract Rubus cultivars were compared with R. procerus for their susceptibility to Phragmidium violaceum, a pathogen first recorded in Victoria in February 1984, by inoculation of detached leaflets in the laboratory. The cultivar ‘Thornless Evergreen’ was highly susceptible. Cultivars ‘Thornfree’, ‘Dirksen Thornless’ and ‘Smoothstem’ were moderately susceptible whilst cvs ‘Silvan’ and ‘Lawtonberry’ were resistant. Cultivars ‘Cherokee’, ‘Cheyenne’, ‘Comanche’, ‘Marionberry’, ‘Boysenberry’, ‘Youngberry’, and ‘Olallie’ were highly resistant. ‘Loganberry’ and the raspberry cv. ‘Malling Landmark’ were immune.Seven fungicides were evaluated for their effect on P. violaceum. Mancozeb and triforine were the most effective against spore germination in vitro. RH 3866, triforine, propiconazole and mancozeb were the most effective in protective tests on detached leaflets of R. procerus, while RH 3866, propiconazole and flutriafol were the most effective in similar, curative tests. Phytotoxicity on detached leaflets was severe at high concentrations of triadimefon and propiconazole, and moderate to slight at similar concentrations of RH 3866 and copper hydroxide.
Der Haustorienkomplex von Erysiphe betae (Vanha) Weltzien
Authors: Hamacher J. 
Published: May 2008

Abstract The haustorial complex of Erysiphe betae (Vanha) Weltzien The haustorial complex of Erysiphe betae resembles the type of haustorium of other powdery mildew species on dicotyledonous plants. A collar of polysaccharide material with an invaginated electrondense channel surrounds the septed infection peg. The nearly elliptic haustorial body with appendices at both poles is surrounded by the plasmalemma, which had been transferred to the extrahaustorial membrane. Dictyosomes and endoplasmatic reticulum are presumably be involved in this process. Haustorial body and appendices contain many mitochondria, and with progressing senescence, the number of vacuoles with partly membrane‐like inclusions increases.
Activation of Glycosidases as a Consequence of Infection Stress in Fusarium Wilt of Tomato
Authors: Ferraris L. , Gentile I. Abbattista , Matta A. 
Published: May 2008

AbstractChanges of β‐1,3‐glucanase, chitinase, β‐1,4‐glucosidase and N‐acetylglucosaminidase activity have been investigated in relation to the development of symptoms and colonization by the pathogen in roots, stems and leaves of susceptible (‘Improved, Pearson’) and resistant (‘Improved Pearson VF11’) tomato plants infected by Fusarium oxysporum f. sp. lycopersici.Glycosidase activities increased after inoculation to different extents depending on the plant part and cultivar. Increases were always higher in susceptible than in resistant plants. Changes in the β‐1,3‐glucanase activity after inoculation were particularly large in stems of infected plants. In contrast, chitinase activity increased more in roots than in stems.The β‐1,3‐glucosidase and chitinase activity decreased slightly from the basal to the apical third of stems.The trend of changes of the glycosidase activity generally were well related with the severity of disease symptoms and the fungal colonization of basal stem segments.There was no evidence that the increase of glycosidase activity after the infection was directly related with the resistance to Fusarium wilt in tomato.
The Influence of Glycoalkaloids and Impact Damage on Resistance to Fusarium solani var. coeruleum and Phoma exigua var. foveata in Potato Tubers
Authors: Olsson Kerstin 
Published: May 2008

AbstractPotato glycoalkaloids were determined in tubers of a wide range of genotypes in order to study their influence on resistance to storage rots caused by Fusarium solani var. coeruleum and Phoma exigua var. foveata. No relationships were found. This indicates that breeders selection for low glycoalkaloid potato clones is not in conflict with the demands for high levels of resistance to these pathogens. It was also observed that genotypes susceptible to skin‐breaking types of, damage were more easily infected than genotypes susceptible to other types of damage.
Evaluation of Rice Cultivars under Greenhouse Conditions for Adult‐Plant Resistance to Pyricularia oryzae
Authors: Kim K. D. , Hwang B. K. , Koh Y. J. 
Published: May 2008

AbstractSix rice cultivars showing various types of resistance or susceptibility to Pyricularia oryzae in the field were compared under controlled environmental conditions. The resistance of the cultivars with adult‐plant resistance was race‐specificat early growth stage. On all cultivars tested, blast infection became increasingly reduced on either leaves of adult plants or older leaves, as observed in rice plants of different leaf stages infected with different individual races. Their increase inhost resistance was marked by an apparent transition in infection type and reduced blast severity depending on leaf age and developmental stage of plants. The ranking of disease severity of the adult‐plantresistant cultivars to different races was constant during plant development, whereas that of the susceptible cultivars was differential. It is suggested that different degrees of resistance in rice cultivars may exist in seedlings and be consistently maintained during plant development, probably becoming more distinct as rice plants mature.
Influence of Nitrogen Fertilizers on Growth, Spore Production and Germination, and Biocontrol Potential of Trichoderma and Gliocladium
Authors: Watanabe Naomichi , Lewis Jack A. , Papavizas George C. 
Published: May 2008

AbstractThe mycelial weight of eight out of nine isolates of Trichoderma spp. and Gliocladium virens increased in media supplemented with 2000 mg/l of nitrogen (N) from the fertilizers NH4Cl, NaNO3, and a commercial 20–20–20. In general, the greatest increase in growth (up to 311 %) occurred with 20–20–20. The extent of growth was similar with either NH4Cl or NaNO3, but was less than that with 20–20–20. Measured by radial development on agar surfacesgrowth of isolates was either not affected or was constricted by supplemental fertilizers. Production of conidia by six out of eight isolates was stimulated by 20–20–20 but not by NH4Cl or NaNO3. Germination of conidia of all isolates, generally was high (> 85 %) on amended and nonamended agar. Chlamydospore formation by three Trichoderma isolates in liquid media was not affected by fertilizers. Antagonism or overgrowth of the pathogen Rhizoctonia solani by Trichoderma isolates in culture was reduced appreciably by NaNO3, but was not affected by NH4Cl or 20–20–20. Addition of 20–20–20 to natural soil did not reduce further the survival of R. solani caused by germling preparations of six out of seven Trichoderma isolates. However, reduction in survival of the pathogen caused by a T. hamatum isolate was stimulated further (45 %) by the fertilizer.
Detection of the Grapevine Fanleaf Viruses Away from the Period of Vegetation
Authors: Walter B. , Etienne L. 
Published: May 2008

AbstractBest conditions for the detection of AMV (Arabis Mosaic Virus) and GFV (Grapevine Fanleaf Virus) in grapevine tissues at different seasons in the year have been determined.Leaves, rootlets and wood shavings are good virus sources for ELISA. The commonly used nicotine solution can be replaced by a PBS‐ or Tris‐HCl buffer, as extraction medium, provided its molarity is high and it contains polyvinylpyrrolidone.In our conditions, detection of AMV and GFV was possible in leaves from May to October, There was no clear‐cut advantage in using extracts prepared either from leaves obtained from the top, middle or bottom parts of a plant.Away from the period of vegetation, the use of wood shavings allowed virus detection, even when cuttings were harvested a few months ago and kept at 6°C.
Remarks on the Biological Activity of Aspergillomarasmine A Fe3+ Chelate and Other Iron Transporting Phytotoxins with Reference to their Role in the Photodegradation of Aromatic Amino‐Acids in Infected Plant Leaves
Authors: Barbier M. 
Published: May 2008

AbstractAspergillomarasmine A Fe3+ chelate catalyzes the photodecomposition of a phenylalanine containing peptide and of L‐phenylalaline itself to benzaldehydein vitro.This reaction can be repeated with FeCl3so that the phytotoxin appearsto be essentially an iron carrier from the microorganisms to the leaf surface where occur the leaf destructions.
A Screening Method for Detecting Resistance Against Cassava Bacterial Blight Disease
Authors: Pacumbaba R. P. 
Published: May 2008

AbstractInoculation of the cassava bacterial blight (CBB) pathogen by using a modified pair of tongs on cassava shoots (1‐month‐old) in the glasshouse and in the field resulted in symptoms within 24‐48 h on susceptible cassava lines ‘02864’ and ‘M'pelolongi’. Gum exudates on inoculated young stems and die‐back appeared 7‐12 and 20‐25 days later, respectively. No symptoms of CBB were observed on cv. ‘Kadanga Malombe’. Symptom development and CBB ratings on 3‐month‐old cassava shoots in the glasshouse and inthe field were not consistent. Inoculation of CBB pathogen on 521 cassava shoots (1‐month‐old) using the tongs method gave 81 and 82 resistant and moderately resistant plants to CBB, respectively. The tongs method is an excellent field‐screening technique for detecting resistance to CBB on 1‐month‐old cassava shoots.
Inhibition of Plant Viruses by Human Gamma Interferon
Authors: Vicente M. , De Fazio G. , Menezes M. E. , Golgher R. R. 
Published: May 2008

AbstractIn order to evaluate the inhibitory effect induced by gamma interferon (Hu g IFN) on plant viruses, pre‐inoculation treatments (brushing the leaves) were carried out in two different plant‐virus systems: D. stramonium* TMV and G. globosa* PVX. Results showed that Hu g IFN induced a higher inhibitory effect (IP = 90%) in D. stramonium* TMV system (Table 1). Comparing the antiviral effect of the three IFNs: gamma, alpha and beta‐like interferons, it was verified that Hu g IFN was more effective than the other two (Table 2).Hu g IFN was also used for post‐inoculation treatments (incubation of tobacco leaf‐discs) and using different dilutions a dose response curve could be obtained (Fig. 1). Hu g IFN inhibitory effect was confirmed by the neutralization of its inhibitory effect using monoclonal antibody (Table 3).Results suggest that although the three IFNs differ in their composition, they present similarities in their biological activities probably triggering an antiviral state in plants.
Eggplant Mottled Dwarf Virus Associated with Vein Yellowing of Honeysuckle
Authors: Martelli G. P. , Cherif C. 
Published: May 2008

AbstractA rhabdovirus isolated in Tunisia by mechanical inoculation from honeysuckle (Lonicera sp.) plants with vein yellowing, was compared with a Tunisian isolate of eggplant mottled dwarf virus (EMDV). The two viruses had similar host ranges and caused the same symptoms in artificially infected hosts. The honeysuckle virus induced in eggplant a syndrome indistinguishable from that typical of EMDV. The two viruses could not be differentiated serologically, had particles of the same size and elicited identical cytopathological alterations in naturally and artificially infected hosts. Honeysuckle is the first host, besides eggplant, found to be naturally infected with EMDV.
Effect of Light on Uredospore Germination and Germ Tube Growth of Soybean Rust (Phakopsora pachyrhizi Syd.)
Authors: Koch E. , Hoppe H. H. 
Published: May 2008

AbstractThe effect of light on uredospore germination and germ tube growth of Phakopsora pachyrhizi was studied. Frequency of uredospore germination was only partially reduced by high light intensity (> 1,9 * 104 mW * m−2). In uredospores unilaterally irradiated with polychromatic light germ tubes always emerged from the shadowed side. Already developed germ tubes showed a negative phototropic response. Both effects were inducible by low light intensities. Negative phototropism of germ tubes was a blue light effect. Light of 441 nm was more effective than that of 422 nm or 372 nm. Red light (> 600 nm) was ineffective, green light (513 nm) induced medium responses. In half‐side illumination studies longitudinal halves of germ tube tips and spores were irradiated under a microscope. The tips of the germ tubes bent into the illuminating beam. In half‐side illumination studies germ tubes always emerged from the illuminated spore halves. Under unilateral illumination liquid paraffin reversed this light “polarization” of spores and the negative phototropism of germ tubes. These results suggest that during unilateral illumination spores and germ tube tips act as a lens focussing the light on the wall farthest away from the light source., There, in uredospores emergence of germ tubes is stimulated and in germ tubes growth is inhibited. As a consequence, under unilateral illumination germ tubes emerge at the shadowed side of the spores and grow away from the light.
Systemic Induction of Resistance in Potato Plants Against Phytophthora infestans by Local Treatment with Hyphal Wall Components of the Fungus
Authors: Doke N. , Ramirez Adan Vite , Tomiyama K. 
Published: May 2008

AbstractPotato plants (cv.‘Irish Cobbler’ with no major resistance genes to Phytophthora infestans), the lower or upper leaves of which were previously treated with hyphal wall components (HWC) of the fungus by rubbing with carborundum, acquired an induced resistance in other untreated leaves against cultivar‐pathogenic races of P. infestans when challenged by spraying with a zoospore suspension. Such induced resistance was significantly shown to exist from at least 1 to 20 days after induction treatment with HWC. Thus, the treated plants were protected from severe late blight disease while non‐induced control plants finally died of the disease. The induced resistance was due to a reduction of the number of successfully germinating zoospores, and subsequent penetration and then occurrence of hypersensitive‐like cell response to the penetrating organisms.These results suggested that local leaf tissues of potato plants reacting to HWC may provide some systemic information that activates or enhances some resistance to P. infestans.
Antiphytovirale Wirkungen von 1,5‐Diacetyl‐2,4‐dioxohexahydro‐1,3,5‐triazin (DA‐DHT)*
Authors: Schuster G. 
Published: May 2008

Abstract Antiphytoviral activities of 1,5‐diacetyl‐2,4‐dioxohexahydro‐1,3,5‐triazine Substitution of 2,4‐dioxohexahydro‐1,3,5‐triazine (DHT) by two acetyl groups resulted in an antiphytoviral compound, 1,5‐diacetyl‐2,4‐dioxohexahydro‐1,3,5‐triazine (DA‐DHT), which inhibits PVX, PVY, ToMV, TMV and TRV better than DHT, but only after, application at relatively high concentrations (10−2 mol/1). The antiphytoviral activity of DA‐DHT is enhanced by combined treatments with DHT as well as with cyanoguanidine, sodiumalkanemonosulfonate and 2‐anilino‐5‐adamantyl‐1,3,4‐thiadiazole., DA‐DHT reduced the number of symptoms of PLRV bearing potato eye cutting plants to a higher percentage than DHT. But the highest reduction was brought about by combined treatments with DA‐DHT, cyanoguanidine, sodiumalkanemonosulfonate and 2‐anilino‐5‐adamantyl‐1,3,5‐thiadiazole. Moreover, treatments with DA‐DHT increased more than treatments with DHT the mass of potato tubers produced by potato eye cutting plants. Combined treatments with DA‐DHT and the above mentioned substances reduced the natural infection with PLRV of a completely healthy potato stock for about 70 % and that of PVY for about 40 %. Thus, the DA‐DHT containing preparations may be capable of keeping potatoes in a good state of health even in regions with a high infection pressure.
Frequencies of Virulence and Fungicide Resistance in the European Barley Mildew Population in 1985*
Authors: Limpert E. 
Published: May 2008

AbstractRepresentative random samples of spores of Erysiphe graminis f. sp. hordei, causing powdery mildew of barley, were taken from the atmosphere by means of a Schwarzbach jet spore sampler over important barley growing areas in Europe and tested in the laboratory for their virulence on host plants with resistance Ml 41/145, Mlg, Mla6, Mla12, Mla7+Mlk, MlLa, Mla1, Mla9, Mla3, Mla13+Ml (Ru3) and mlo. Virulence frequencies mostly showed regional differentiation and efficiency of, the resistance factors generally increased in the order given. Frequency and level of resistance against triadimenol also showed significant regional differences. Against fenpropimorph similar levels of sensitivity were observed in different parts ofEurope, close to that of standard‐isolates, which had a mean position. The results are discussed with respect to current and previous conditions of cultivation, to the spread of the pathogen by wind and towards strategies for more effective use of hostresistance and of fungicides.
Assimilatverteilung in Sommergerstensorten mit unterschiedlicher Resistenz gegenüber dem Echten Mehltau (Erysiphe graminisf. sp.hordei)
Authors: Kern M. , Ibenthal W.‐D. , Heitefuss R. 
Published: May 2008

AbstractDistribution of assimilates in cultivars of spring barley with different resistance against powdery mildew (Erysiphe graminisf. sp.hordei)Transport and distribution of radioactive labelled assimilates in spring barley cultivars with different degrees of resistance to powdery mildew were studied after14CO2‐treatment of single leaves. Plants of the cultivars ‘Amsel’ (susceptible), ‘Asse’ (adult plant resistant), and ‘Rupee’ (resistant) were analyzed at the vegetative growth stage (5. leaf unfolded) and the generative growth stage (anthesis). At the vegetative growth stage the assimilate export from the mildew inoculated 5. leaf of ‘Amsel’ and ‘Rupee’ is decreased; in ‘Asse’, there is no considerable change of assimilate distribution due to infection. At the generative growth stage the assimilate export from the infected flag leaf of ‘Amsel’ is reduced when the fungus, is sporulating. In the cultivar ‘Asse’ the assimilates are bound at the infection site until the seventh day after inoculation, then the transport of assimilates to the ear is increased. In ‘Rupee’ mildew inoculation causes an enhanced assimilate transport to the ear. The changes in assimilate distribution due to mildew inoculation are discussed with respect to the different types of host‐parasite‐interactions and the source‐sink‐activities in the different cultivars.
Cucumber Mosaic Virus on Banana in Crete
Authors: Avgelis A. 
Published: May 2008

AbstractA virus was isolated from banana plants grown in plastic houses and showing chlorotic striping on leaves and stunting. On the basis of host range symptomatology, aphid transmission and serological tests, it was identified as a strain of cucumber mosaic virus. Infected propagating material was more responsible for the outbreak of the disease than aphids.
Comparison of Three Plant Rhabdovirus Isolates by Two Different Serological Techniques
Authors: Adam G. , Chagas C. M. , Lesemann D.‐E. 
Published: May 2008

AbstractThree different rhabdovirus isolates, eggplant mottled dwarf virus (EMDV), tomato veinyellowing virus (TVYV) and a hitherto undefined isolate from tomato in Portugal (Tom‐P) were compared by two different serological techniques, immunosorbent electron microscopy (ISEM) and electro‐blot‐immunoassay (EBIA). Antisera were prepared either against purified virus or against partially purified virus preparations extracted by a one‐step procedure. Even the partially purified virus preparations yielded antisera that allowed unequivocal identification of two of the five structural virus proteins, G and N, in EBIA and were suitable for specific trapping of complete virus particles on electron microscope grids.With both serological techniques identical results were obtained indicating a close serological relationship between the three isolates tested. Cross‐reactions between the G proteins could be deduced from heterologous trapping of complete virus particles in ISEM. The cross‐reactions for the G proteins were substantiated by the EBIA‐results which indicated in addition cross‐reactions between the remaining three major structural virus proteins, N, M1, and M2, but also revealed significant differences in the molecular weights of the G and M1 proteins between TVYV and the other two isolates. The results obtained indicate that Tom‐P is serologically closely related and in respect of protein molecular weights identical to EMDV, and that TVYV is not a separate virus but rather a strain of EMDV.
Involvement of Volatile Substances in Systemic Resistance of Barley Against Erysiphe graminis f. sp. hordei Induced by Pruning of Leaves
Authors: Fujiwara M. , Oku H. , Shiraishi T. 
Published: May 2008

AbstractIncubation of barley seedlings in a container with seedlings of which primary leaves were pruned induced in the intact seedlings a systemic resistance to the infection by Erysiphe graminis f. sp. hordei. The induced resistance was moreprominent in the primary leaf than in the secondary leaf. Hence, some volative substances released after pruning of barley leaves seem to be responsible for the induced resistance against the powdery mildew fungus.