bluuebunny/crossref_metadata_2025_split huggingface dataset:
Viruses detected in Ullucus tuberosus (Basellaceae) from Peru and Bolivia
Authors: BRUNT A. A. , PHILLIPS SUE , JONES R. A. C. , KENTEN R. H. 
Published: February 2008

SUMMARY Ullucus tuberosus (Basellaceae) plants from 12 locations in the Andean highlands of Peru and Bolivia contained complexes of either three or four viruses. Specimens from six sites in Peru contained a potexvirus, a tobamovirus, a potyvirus and a comovirus, but those from another location lacked the potexvirus. All samples from five sites in Bolivia lacked the tobamovirus.The potexvirus (PMV/U) is a strain of papaya mosaic virus differing slightly from the type strain (PMV/T) in inducing milder symptoms in some common hosts and failing to infect a few other species. It symptomlessly infected U. tuberosus, and infected 15 of 29 species from seven of nine other families. PMV/U showed a close serological relationship to PMV/T and to boussingaultia mosaic virus and a distant relationship to commelina virus X, but it is apparently unrelated to any of ten other potexviruses.The tobamovirus (TMV/U) induced symptomless or inconspicuous infection in U. tuberosus, and infected 21 of 30 species from six of eight other families. It showed a very distant serological relationship to some strains of ribgrass mosaic, tobacco mosaic and tomato mosaic viruses, but failed to react with antisera to cucumber green mottle mosaic, frangipani mosaic, odontoglossum ringspot and sunn‐hemp mosaic viruses.The potyvirus, tentatively designated ullucus mosaic virus (UMV), alone in U. tuberosus induced leaf symptoms indistinguishable from the chlorotic mottling and distortion found in naturally infected plants. UMV infected 12 of 20 species from four other families, and was transmitted in the non‐persistent manner by Myzus persicae. It showed a distant serological relationship to only two (bidens mottle and alstroemeria mosaic) of 25 members or possible members of the potyvirus group tested.Some hosts and properties of the comovirus are described in an accompanying paper.None of the four viruses infected potato (Solanum tuberosum) and, with the possible exception of UMV, they differed from viruses reported previously to infect three other vegetatively propagated Andean crops (Oxalis tuberosa, Arracacia xanthorrhiza and Tropaeolum tuberosum).
The influence of berries infected with Botrytis cinerea on the enzymic breakdown of sulphited strawberries
Authors: HARRIS JANE E. , DENNIS COLIN 
Published: February 2008

SUMMARYEndo‐polygalacturonase produced by Botrytis cinerea is rapidly inactivated in infected strawberry tissue both by the naturally occurring fruit phenolics and also by those oxidised compounds formed as a result of polyphenol oxidase activity in the infected tissue. In contrast, the endo‐polygalacturonases of Mucor piriformis, Rhizopus sexualis and R. stolonifer are more resistant to inactivation by the fruit phenolics and no polyphenol oxidase was detected in tissue infected by these fungi. The presence of Botrytis‐infected berries in sulphited fruit containing tissue infected with Mucor or Rhizopus resulted in more rapid inactivation of the endopolygalacturonases from the latter fungi, and hence reduced the amount of softening and breakdown of the fruit. This inactivation is considered to be due largely to the oxidised phenolics present in Botrytis‐infected tissue.
The effect of host quality and crowding on the settling and take‐off of cereal aphids
Authors: WALTERS K. F. A. , DIXON A. F. G. 
Published: February 2008

SUMMARYSettling and take‐off behaviour of Sitobion avenae was studied in the laboratory using infested and uninfested wheat at a range of developmental stages.Of the later developmental stages of wheat alate S. avenae preferred to settle on and gave birth to relatively more offspring on flowering and watery‐ripe plants.The time to take‐off of alatae which matured on wheat was influenced by both the developmental stage of their host plant and the degree of crowding they experienced. All alatae flew but those isolated on flowering plants stayed longer than those crowded or isolated on any of the other developmental stages tested. Similarly the number of offspring produced before take‐off was inversely related to the degree of crowding and positively to the time spent on a plant before take‐off.
The protection of carrots against carrot fly (Psila rosae) with granular and emulsifiable concentrate formulations of chlorfenvinphos incorporated in gels used for drilling pre germinated seed in a sandy loam
Authors: THOMPSON A. R. , SUETT D. L. , PERCIVALL A. L. 
Published: February 2008

SUMMARYField experiments were done in a sandy loam in 1979 and 1980 to investigate the performance against carrot fly on carrots of e. c. and granular formulations of chlorfenvinphos incorporated in gels used for drilling pre‐germinated seed.With 9·4–66·7 mg a. i./m row, the two formulations performed similarly in a natural hydrocolloid and a mineral colloid gel. Thus the emergence of carrot seedlings 6–7 wk after drilling was similar on plots with untreated gel and those with insecticide‐treated gel and, about 6 months after drilling when > 90% of carrots grown without insecticide were damaged by carrot fly larvae, an approximately six‐fold increase in dose of both formulations increased the estimated larval mortality from about 70 to 95%. Mean concentrations of residues of total (Z + E) isomers of chlorfenvinphos in harvested carrots treated with 9·4–56·5 mg a. i./m row were<the proposed FAO/WHO tolerance for chlorfenvinphos (0·4 mg/kg). The initial rates of release of available chlorfenvinphos from a granular formulation immersed in the two types of gel differed markedly but, after 48‐h immersion, >50% of the insecticide had been released into both gels.
Fungicidal control of Rhizoctonia solani in soil amended with organic manures
Authors: BANDYOPADHYAY R. , YADAV J. P. S. , KATARIA H. R. , GROVER R. K. 
Published: February 2008

SUMMARYAmendments of nutrient‐deficient soil with three organic manures and one non‐edible oil‐cake reduced the disease controlling potential of methoxyethyl mercury chloride (MEMC), quintozene and carbendazim used as seed treatments on cowpea and cotton against seedling rot caused by Rhizoctonia solani.Biogas sludge (BGS) and farm yard manure (FYM) nullified the activity of MEMC and quintozene and reduced markedly the efficacy of carbendazim. Humic acid extracted from BGS inactivated MEMC and carbendazim but had little effect on quintozene. Green manure (Sesbania aculeata) slightly reduced the efficacy of MEMC only. Soil amendment with mahua (Madhuca indica) cake and soil drench with its aqueous extract greatly reduced the efficacy of the three fungicides.
Identification of Rhizobium strains on antibiotic concentration gradients
Authors: BROMFIELD E. S. P. , STEIN MICHÈLE , WHITE R. P. 
Published: February 2008

SUMMARYAntibiotic concentration gradients were used to characterise several cultures of R. phaseoli and Rhizobium spp. (isolated from Cicer arietinum) by differences in intrinsic antibiotic resistance (IAR). Differentiation between cultures was facilitated by use of cluster analyses. The method permitted 15/16 cultures of R. phaseoli to be distinguished on 14 antibiotics. Two cultures which exhibited similar IAR patterns were shown to be the same strain obtained from different collections. The validity of the technique for strain identification was demonstrated by fluorescent antibody tests which gave corresponding identity for 50 nodule isolates from plants inoculated with a mixture of three strains of R. phaseoli. The method was less suitable for characterising cultures of the slow‐growing Rhizobium spp. because several antibiotics produced growth lacking a clearly defined boundary between resistance and susceptibility. Although 15/16 cultures of Rhizobium spp. could be differentiated, several isolates were distinguishable only by a difference on a single antibiotic. Similarity between stock cultures and derivative nodule isolates indicated that IAR on gradient plates was a stable property unaffected by plant passage.
Artichoke latent virus: characterisation, ultrastructure and geographical distribution
Authors: RANA G. L. , RUSSO M. , GALLITELLI D. , MARTELLI G. P. 
Published: February 2008

SUMMARYAn isolate of artichoke latent virus (ALV‐I) obtained from a symptomless artichoke plant in Southern Italy was characterised and compared with ALV isolates from other countries. ALV occurs in California and throughout the western part of the Mediterranean basin but of Mediterranean countries east of Italy, it was found only in Israel and Turkey.ALV‐I was readily transmissible by inoculation of sap to a moderate range of hosts, was transmitted in a non‐persistent manner by Aphis fabae, Brachicaudus cardui and Myzus persicae, but was not seed transmitted. The virus has flexuous rod‐shaped particles measuring c. 12 nm × 746 nm with a sedimentation coefficient of 145 S and a buoyant density of 1·31 g/cm3. The particles contain single stranded RNA with a mol. wt of 3 × 106 and protein composed of a single polypeptide species with a mol. wt of 33 000. Cylindrical cytoplasmic inclusions consisting of pinwheels and laminated aggregates were present in cells of naturally and artificially infected plants. ALV isolates from different geographical origin were indistinguishable from ALV‐I biologically, morphologically, serologically and ultrastructurally. These properties place ALV in the Potyvirus group, but it was serologically unrelated to 12 other potyviruses 10 of which occur commonly in Italy.
Investigations into the movement of glyphosate from treated to adjacent untreated plants
Authors: COUPLAND D. , LUTMAN P. J. W. 
Published: February 2008

SUMMARYTransfer of glyphosate from treated to adjacent untreated plants was investigated under glasshouse conditions using wheat and Agropyron repens. When glyphosate was used at concentrations characteristic of conventional field application rates, and where shoot contact was prevented, no symptoms were observed on untreated plants. When there was shoot contact, and when glyphosate was used at 2 kg a. i./ha (10 g a. i./litre), phytotoxic effects were observed on untreated plants. At higher concentrations of glyphosate (90 or 180 g a. i./litre), typical of selective applications with ropewick or roller applicators, evidence of root transfer of herbicide was found. In pot experiments these phytotoxic effects were variable, due, perhaps, to variable amounts of root contact. Confining the roots, by growing the plants in tubes, increased the level of phytotoxicity.
Photosynthesis, respiration and evaporation of a field‐grown potato crop
Authors: LEACH J. E. , PARKINSON K. J. , WOODHEAD T. 
Published: February 2008

SUMMARYMeasurements are reported of the effects of irradiance, air temperature and water stress on the photosynthesis, respiration and transpiration of a field‐grown potato crop. The measurements, relating to one season (1974) only, were made using a field enclosure system on plots of irrigated (I) and non‐irrigated (NI) potatoes.In the moist summer of 1974, soil moisture deficits differed little between I and NI plots, and water stress had no significant effect on the NI plants. Results show that maximum rates of net CO2 uptake (whole plants) were about 6 g h‐1 m‐2 ground area, and rates of respiration, for above‐ground and for below‐ground plant parts, were essentially constant, at about 0·3 g h‐1 m‐2 ground area, throughout the 3 months of measurement. The dependence on irradiance of the whole plants gross photosynthesis was for each measurement day adequately represented by a rectangular hyperbola relation. The season's accumulations of dry matter as calculated from these hyperbolae and from the season's measured irradiance agreed well with values derived from plant weighings.
Comparative effects of acetylene and ethylene gas on initiation of banana ripening
Authors: THOMPSON A. K. , SEYMOUR G. B. 
Published: February 2008

SUMMARYBananas were exposed to acetylene or ethylene at 0·01, 0·1 and 1 ml/litre, under high humidity, for 24 h at 18 °C. They were then transferred to an atmosphere of air alone for a further 4 days and during this period the respiration rate of three fruit from each treatment was measured. Ripeness was then assessed by colour score and soluble solids content.All levels of ethylene initiated ripening. Treatment with ethylene induced a climacteric rise in respiration, an increase in the soluble solids content of the pulp and degreening of the peel. All levels of acetylene, except 0·01 ml/litre, induced a climacteric rise in respiration. Fruit treated with acetylene at 1 ml/litre had a similar colour score and soluble solids content to those ripened by exposure to ethylene. Fruits treated with acetylene at 0·1 ml/litre had a lower soluble solids content and their peel remained green. Treatment with acetylene at 0·01 ml/litre failed to initiate ripening. Sensory evaluation of fruit ripened by acetylene at 1 ml/litre indicated that the acetylene treated fruit ripened slightly more slowly. When compared at the same stage of ripeness fruits from the two treatments were equally palatable.
Pheromone‐trap catch in relation to the phenology of codling moth (Cydia pomonella)
Authors: GLEN D. M. , BRAIN PHILIP 
Published: February 2008

SUMMARYRelationships between a pheromone‐trap catch, adult emergence and penetration of fruit by first‐instar larvae of Cydia pomonella were investigated from 1975 to 1977 in an orchard in South West England. For the first generation the times of moth emergence and catch in the pheromone trap were not significantly different; nor were male and female emergence times. The catch of moths of the first generation in the pheromone trap anticipated the appearance of their larvae in the fruit by 140–169 day‐degrees > 10 °C. Eggs hatched after 94 day‐degrees in the laboratory but in the orchard, wind and sunshine modified the microclimate so that the number of day‐degrees required for egg development, as measured by standard meteorological instruments, was affected by wind and sunshine but development lasted on average about 90 day‐degrees. This indicated a lag of 50–80 day‐degrees between the curves for trap catch and oviposition: the pre‐oviposition period in the orchard was shorter than expected from laboratory studies. In 1975 and 1976, some larvae developed to produce a second generation of moths which gave rise to a second generation of eggs and larvae, after an interval of 161 day‐degrees in 1975, but only 41 day‐degrees in 1976, indicating that in 1976 some eggs were laid before moths of the second generation were trapped. These results indicate that the first insecticidal spray against first‐generation larvae should be applied about 140 day‐degrees after the start of the reference week in which five moths of the spring brood are caught per trap. A second spray, if required to maintain insecticidal cover, should be applied about 100 day‐degrees later. A spray should be applied against second‐generation larvae immediately after the reference week for second‐generation moths.
Asymptotes of diseases caused by non‐specialised fungal pathogens in intraspecific mixed stands of cereal cultivars
Authors: JEGER M. J. , GRIFFITHS ELLIS , JONES D. GARETH 
Published: February 2008

SUMMARYA model describing disease progress of non‐specialised fungal pathogens in intraspecific mixed stands of cereal cultivars (Jeger, Griffiths & Jones, 1981b) has been extended beyond the logarithmic phase of disease development. The extended. logistic model indicates that whatever the outcome in the early stages (disease less than or more than the mean of disease in the pure stands), disease will eventually level off at a value equal to the mean of disease asymptotes in the pure stands. The time scale involved in such levelling‐off, however, means that substantial benefit may still be expected from deployment of such mixtures.Analytical solutions for the model are obtained for the special case where the ratio of disease asymptote to initial disease is the same for each pure stand.
The use of F(ab‘)2‐based ELISA to detect serological relationships among carlaviruses
Authors: ADAMS A. N. , BARBARA D. J. 
Published: February 2008

SUMMARYAn indirect, F(ab)2‐based ELISA was used to assess the reactions of seven carlaviruses with antisera to 16 viruses within the group and with antisera to seven other filamentous viruses. There were no specific reactions with antisera to non‐carlaviruses and serological relationships between the seven carlaviruses were generally consistent with results reported by other workers using different methods. Thus, hop latent, hop mosaic, carnation latent, potato virus S and lily symptomless viruses seem antigenically similar while American hop latent and poplar mosaic viruses are distinct from these viruses and from each other. The F(ab)2‐based method is simple and rapid and it is particularly useful for probing relationships when only small quantities of antisera are available.
Increased sensitivity of detection of plant viruses obtained by using a fluorogenic substrate in enzyme‐linked immunosorbent assay
Authors: TORRANCE L. , JONES R. A. C. 
Published: February 2008

SUMMARYThe fluorogenic substrate 4‐methylumbelliferyl phosphate (MUP) of alkaline phosphatase was compared with the chromogenic substrate p‐nitrophenyl phosphate (NPP) in tests for plant viruses by enzyme‐linked immunosorbent assay (ELISA). In tests on leaf extracts of squash infected with prune dwarf virus, Chenopodium quinoa and apple infected with apple mosaic virus (ApMV), and potato infected with potato leafroll virus (PLRV), MUP increased sensitivity 2–16 times, the smallest and greatest increases being obtained with ApMV (in apple) and PLRV respectively. In similar tests on 21 dormant PLRV‐infected potato tubers, sensitivity was increased 2–4 times with 13 tubers, but the two substrates gave the same detection end‐points with eight tubers. When individual seeds of potato plants infected with the Andean potato calico strain of tobacco ringspot virus were tested, the virus was detected in virtually all seeds by MUP‐ELISA, but detection by NPP‐ELISA was inefficient unless absorbance values were measured after overnight incubation at 4 °C, instead of after 2 h at room temperature.In tests on Myzus persicae carrying PLRV and Sitobion avenae carrying barley yellow dwarf virus (BYDV), both viruses were consistently detected in a greater proportion of individual aphids by MUP‐ELISA than NPP‐ELISA irrespective of whether incubation was for 2 h at room temperature or overnight at 4 °C. The effeciency of detection of virus in single viruliferous aphids by MUP‐ELISA was not decreased by grouping with one or four non‐viruliferous aphids but was decreased (PLRV) or greatly decreased (BYDV) by grouping with nine. MUP‐ELISA and transmission tests to Physalis floridana seedlings (2–3 day inoculation access periods) both detected PLRV in most individual M. persicae, but the results obtained with the two methods did not correlate completely. In similar tests for BYDV in individual S. avenae, virtually all aphids transmitted BYDV to oat seedlings during a 3‐day inoculation access period but it was subsequently detected by MUP‐ELISA in less than half of them. By contrast, MUP‐ELISA detected PLRV in most viruliferous M. persicae even after they had fed for 3 days on Chinese cabbage, a non‐host for this virus.
Detection of potato virus Y in the aphid Myzus persicae by enzyme‐linked immunosorbent assay (ELISA)
Authors: CARLEBACH RACHEL , RACCAH B. , LOEBENSTEIN G. 
Published: February 2008

SUMMARYPotato virus Y was detected by enzyme linked immunosorbent assay (ELISA) in at least 50% of groups of five Myzus persicae. The mean A405 value for groups of viruliferous aphids was 2–3 times greater than that for virus‐free ones. PVY was not detected in Aphis craccivora, A. citricola or A. gossypii, three other species which transmitted the virus to peppers, and it was detected in only a small proportion of groups of Acyrthosiphon pisum. In a series of trials, success in detection of PVY by ELISA was not correlated with the ability of other aphids from the same source plant to transmit the virus to test plants. The limitation of ELISA for quantitative assay of PVY in aphids and for epidemiological work is discussed.
The influence of form of deposit on the phytotoxicity of difenzoquat applied as individual drops to Avena fatua
Authors: MERRITT C. R. 
Published: February 2008

SUMMARYDifenzoquat was applied as individual drops (200–400 μm diameter) to Avena fatua, using concentrations in the range 25–200 g/litre, this being appropriate to very low volume, controlled drop application. Increases in the concentration of difenzoquat within this range, or the use of larger drops, reduced the inhibition of growth of A. fatua. Increasing or decreasing the surfactant concentration from that recommended for field use also decreased performance of difenzoquat. The herbicide was more active when applied to the base of leaves and to younger leaves than to leaf tips and older leaves. In most cases reduced activity of difenzoquat was related to increased localised scorch and reduced movement of 14C‐labelled herbicide from the treated region.
Pre‐harvest retting of flax: a light microscope study of the effects of glyphosate treatment on the maturation of stem tissues
Authors: FRASER T. W. , COURTNEY A. D. , HARVEY B. M. R. 
Published: February 2008

SUMMARYA range of glyphosate treatments was applied to flax at three stages of flowering. Spraying at a rate equivalent to 1.4 kg a. e./ha at the start of flowering gave satisfactorily uniform premature desiccation and was selected for investigation of the effects of the herbicide on stem tissues, using light microscopy.During normal maturation, increase in fibre cell wall thickness, lignification of the fibres and differentiation of the secondary xylem continued for 3–5 wk after the beginning of flowering. This differentiation was halted by the application of glyphosate. Three wk after treatment various types of tissue damage were observed. In some sections epidermal and cortical cells showed the most damage, this being consistent with herbicide uptake at the stem surface. In other sections phloem and associated parenchyma cells showed the most damage. Disintegration of phloem and cortical cells occurred in some treated stem segments and caused separation of the fibre bundles from their surrounding tissues. This resembled the release of fibre bundles which results from conventional post‐harvest retting. The potential of glyphosate application to flax as a pre‐harvest retting technique is discussed.
Phenetic similarity among Dioscorea cayenensis cultivars as estimated by cluster analysis and minimum spanning tree
Authors: AKORODA M. O. 
Published: February 2008

SUMMARYTwo numerical taxonomic methods, cluster analysis and minimum spanning tree, were applied to classify 20 Nigerian cultivars of yellow yam (Dioscorea cayenensis). Cultivars were grown for 3 yr and 49 plant characters observed. The results were summarised as a dendrogram and an undirected minimum spanning tree. The classifications from both methods were complementary and facilitated a better understanding of the phenetic similarity between cultivars. Four main clusters were revealed with different intra‐cluster variation. The clustering pattern was not remarkably affected by the two classificatory methods employed.