bluuebunny/crossref_metadata_2025_split huggingface dataset:
The influence of powdery mildew (Erysiphe graminis) infection on the development of four spring wheats
Authors: LUPTON F. G. H. , SUTHERLAND JENNIFER 
Published: February 2008

SUMMARYInfection with Erysiphe graminis reduced the weight of the roots and aerial parts of four wheat cultivars of contrasting susceptibility at the three‐leaf stage. It had little effect on the more resistant varieties at the five‐leaf and flag‐leaf stages. When 14C was supplied to the youngest fully expanded leaves at successive stages of growth, the proportion recovered from the roots, and that translocated to other tillers when present, was reduced, especially in the more susceptible cultivars.
Sites of contamination and numbers of Erwinia carotovora present in stored seed potato stocks in Scotland
Authors: PÉROMBELON M. C. M. 
Published: February 2008

SUMMARYForty‐eight bulk and crate stored commercial seed potato stocks from the east of Scotland were examined for contamination by Erwinia carotovora in 1967 and 1968. Both E. carotovora var. carotovora and E. carotovora var. atroseptica were present, the latter, the blackleg pathogen, being detected four times more frequently. Most contamination was located on the tuber surface and in the lenticels; it was rare in the vascular ring and the organism was never detected in the cortex. The level of contamination of lenticels was only slightly affected after winter storage, which, however, substantially reduced surface contamination. More than 103 cells were detected on the surface of tubers in over half the stocks and in half the stocks each lenticel sampled contained more than 102 bacteria.
Control of potato cyst‐nematode, Heterodera rostochiensis, in three soils by small amounts of aldicarb, Du Pont 1410 or Nemacur applied to the soil at planting time
Authors: WHITEHEAD A. G. , TITE D. J. , FRASER JANET E. , FRENCH EILEEN M. 
Published: February 2008

SUMMARYAldicarb or Du Pont 1410 (S‐methyl 1‐(dimethylcarbamoyl)‐N‐[(methylcarbamoyl) oxy] thioformimidate) at 2.6–11.2 kg a.i./ha applied to the soil at planting time controlled potato cyst‐nematode, Heterodera rostochiensis, in sandy loam, peaty loam and silt loam and greatly increased tuber yields of susceptible potatoes. Nemacur (O‐ethyl‐O‐(3‐methyl‐4‐methylthiophenyl) isopropylamido‐phosphate) controlled potato cyst‐nematode in sandy loam at 2.9–10.3 kg a.i./ha and in silt loam at 11.2 kg a.i./ha but did not control the nematode well in peaty loam even at 22.4 kg a.i./ha. In peaty loam aldicarb and Nemacur were more effectively incorporated by rotavation than by a modified power harrow.
Growth regulatory effect of three benzimidazole fungicides on the germination of celery (Apium graveolens) seeds
Authors: THOMAS T. H. 
Published: February 2008

SUMMARYSeeds of four celery cultivars did not germinate when incubated in buffered solutions in the dark at 22 °C. This high‐temperature‐induced dormancy was broken with either of the systemic fungicides benomyl or BAS 3460 F (mainly methyl‐2‐benzimidazole carbamate) when used in combination with a mixture of the gibberellins A4 and A7 (GA4/7). The fungicide thiabendazole was ineffective in these tests.
Observations on different methods of aphid trapping
Authors: A'BROOK JOHN 
Published: February 2008

SUMMARYCylindrical and horizontal sticky traps painted in a range of spectral colours were used to determine the flight and landing behaviour of aphids. Data are also presented on aphid catches in suction traps at two heights and in light traps. Apart from colour sensitivity (yellow versus white) there was apparently a separate response to colour which in some species varied with season. Within yellow‐sensitive species there was also a differential response to colour. With the experimental methods used, it was not possible to define mathematically the active and passive landing components on cylindrical traps. Though the active landing component was large it varied between aphid species. Most species caught on horizontal traps at ground level had been flying above 1 m. In some species the response of males to colour and their landing behaviour differed from that of viviparae and oviparae.Four years data from suction traps suggest that aphid species can be divided into three categories on the basis of the height at which they normally fly. One group, mostly tree‐feeders, always show the greatest density at a high level (12.2 m) throughout the season. The second group always have the highest density at a low level (1 m) whilst a third group of species change at a specific date each autumn from a maximum density at 1–12.2 m. Attraction to light (moth trap) appeared to be linked with the grouping of species by height of flight. The interpretation of catch data is discussed in the light of these observations.
The field behaviour of seed‐borne Ascochyta fabae and disease control in field beans
Authors: HEWETT P. D. 
Published: February 2008

SUMMARYIn field sowings at Cambridge 2–15% of field bean seeds carrying Ascochyta fabae produced seedlings with leaf lesions. The fungus spread for distances up to 10 m in an average season and usually infected the new crop of seed. The amount of such infection arising from a single lot varied widely when samples were grown at different centres, presumably because of differences in local weather conditions.Seed lots with approximately 1% infected seeds seem suitable for ware crop production but little or no A. fabae can be tolerated in seed intended for multiplication. Infection in British‐grown commercial seed has been greatly reduced by the selection of clean seed. Health standards adopted in the Field Bean Seed Scheme may have eliminated A. fabae from one cultivar.
The biology of Puccinia chondrillina a potential biological control agent of skeleton weed
Authors: HASAN S. , WAPSHERE A. J. 
Published: February 2008

SUMMARYDuring investigations on the parasites of Chondrillajuncea in the Mediterranean region, the rust, Puccinia chondrillina, was found to be one of the most damaging. This macrocyclic and autoecious rust which is specific to the genus Chondrilla, remains active throughout the year and attacks all stages and all parts of the plant. In the Mediterranean region the rust appears to multiply solely by the uredo‐stages and the teleutospores produced at the end of the summer have no obvious role in the life‐cycle of the fungus. The uredospores germinated at temperatures of 0–36 °C and were used for inoculation of Chondrilla seedlings in the greenhouse.The rust occurs from the cold continental climates of southern Siberia to the hot, Mediterranean ones of Portugal and North Africa. In many situations the rust has been found to play an important role in the reduction of C. juncea populations. Young seedlings were highly susceptible to attack and were often destroyed. Older rusted plants gave many fewer viable seeds than healthy plants and were also often unable to produce new rosettes from their roots.
Some properties of chrysanthemum stunt, a virus with the characteristics of an uncoated ribonucleic acid
Authors: HOLLINGS M. , STONE OLWEN M. 
Published: February 2008

SUMMARYGrafting to virus‐free Mistletoe chrysanthemums was the most reliable method of detecting the chrysanthemum stunt agent, but specific light and temperature conditions were required for the diagnostic ‘measles’ symptoms to develop. Although stunt agent was highly infectious, leaf‐rubbing inoculations with chrysanthemum sap gave erratic results. Colorimetric and electrophoretic tests were unreliable for indexing chrysanthemums.Stunt agent infected eight of twenty‐nine species in the family Compositae, but none of 116 species in forty‐seven other families. Stunt spread rapidly by foliage contact and by handling plants, but dipping the hands in 2% trisodium orthophosphate when handling plants increased the amount of spread. Stunt agent was not transmitted by four species of aphids, the glasshouse redspider mite, dodder (Cuscuta campestris) or through chrysanthemum seed.Stunt agent withstood 10 min at c. 98 °C and dilution to 10‐4, was not pelleted by ultracentrifugation, and was inactivated by RNase in weak, but not strong, buffer, suggestive of an uncoated RNA ‘viroid’. Partially purified preparations were made by homogenizing frozen chrysanthemum leaves in 0.5 m phosphate buffer with antioxidant at c. 2 °C, and clarification by n‐but‐anol and chloroform, followed by centrifugation. Highly infective RNA was precipitated from the supernant fluid by 2.5 vol. cold ethanol, and resuspended in a small volume of buffer.The u.v. absorption spectra of infective preparations and the u.v. absorbance profiles of density‐gradients, were very similar to those of preparations from healthy chrysanthemum. Infective partially purified preparations of stunt agent withstood exposure to 2% formaldehyde or tri‐sodium orthophosphate, u.v. irradiation, and sonication. Stunt preparations contained no virus particles recognizable by electron microscopy, gave no distinct peak on analytical ultracentrifugation, and did not consistently contain any specific antigen. Although similar to the ‘viroids’ potato spindle tuber and citrus exocortis, stunt agent did not infect Citrus limon, Gynura aurantiaca or tomato.
Identification, purification and some properties of a mosaic virus of okra (Hibiscus esculentus)
Authors: GIVORD L. , HIRTH L. 
Published: February 2008

SUMMARYIn the Ivory Coast, an apparently undescribed virus was isolated from okra (Hibiscus esculentus) in which it caused mosaic and leaf vein banding. The virus was sap transmissible to a wide range of plants and had a thermal inactivation point of 80 °C. It was named okra mosaic virus (OMV). A purification procedure was developed. Electron microscopy and analytical and density gradient centrifugation showed that OMV was an isometric virus accompanied by empty shells (top component). Serological tests showed OMV to be a member of the tymovirus group.
Effect of sowing date on incidence of Sudanese broad bean mosaic virus in, and yield of, Viciafaba
Authors: SALIH H. S. ABU , ISHAG H. M. , SIDDIG S. A. 
Published: February 2008

SUMMARYDelaying the sowing of irrigated field beans in the Sudan after October greatly lowered the yield of seed, and increased both infestation by aphids and the incidence of Sudanese broad bean mosaic virus (SBBMV). Yield per plant was positively correlated with number of pods, but negatively with percentage infection with SBBMV. In greenhouse conditions, SBBMV was readily acquired from diseased plants and inoculated to healthy plants in 5 min feeding periods by both Aphis craccivora and Acyrthosiphon sesbaniae.
The influence of seedling age and development on the infection of lettuce by Bremia lactucae
Authors: DICKINSON C. H. , CRUTE I. R. 
Published: February 2008

SUMMARYLaboratory methods are described for the culture and observation of Bremia lactucae on lettuce.Mycelial growth of the fungus within the cotyledons of the cultivar Cheshunt Early Giant progressed to a minimum density at which sporulation occurred, and then continued to a maximum density coinciding with peak sporulation. The timing and intensity of sporulation was influenced by the concentration of the inoculum. Seedlings often became systemically infected and this, together with intensity of sporulation, was a good indicator of fungal growth and hence host susceptibility.The severity of disease development on four susceptible lettuce cultivars (Cheshunt Early Giant, Paris White, Trocadero Improved and Crackling Ice) decreased with age and development of the seedlings at inoculation. The reasons for this are discussed.
Moulding of sugar‐cane bagasse and its prevention
Authors: LACEY J. 
Published: February 2008

SUMMARYWhen fresh sugar‐cane bagasse containing about 50% water and 3% sugar was baled and stacked, it quickly heated to over 50°C and remained hotter than 40°C for 50 days. The residual sucrose was utilized by microbial growth and the content of fungal, bacterial and actinomycete spores increased to more than 108/g dry wt. The spores in heated bagasse were mostly of thermophilic actinomycetes and fungi, and included two actinomycetes implicated in bagassosis. Thermoactinomycetes sacchari occurred in 40% of samples examined, some of which yielded up to 5 × 106 colonies/g, while T. vulgaris occurred in 80% of samples, but these rarely yielded more than 105 colonies/g. Other organisms were cellulolytic and caused fibre deterioration. Heating and moulding could be much decreased either by drying to about 25% water content, which halved the spore content after storage, mostly at the expense of the actinomycetes, or by adding 2% by weight of propionic acid, which decreased the spore content to 4 × 106 spores/g or less even after 18 months' storage. Sometimes adding only 0·6% of propionic acid or 2% of propionic acid applied as a 50% aqueous solution had a similar effect. Treatment with propionic acid thus decreased the deterioration of bagasse, permitted its storage between harvests and prevented the hazard of bagassosis to workers.
The effect of nematicides, applied to the seed rows in spring, on growth and yield of sugar beet in Docking‐disorder‐affected fields
Authors: COOKE D. A. , DUNNING R. A. , WINDER G. H. 
Published: February 2008

SUMMARYBoth Trichodorus spp. and Longidorus spp. damage roots of sugar‐beet seedlings in sandy soil, causing Docking disorder. Trials in infested fields between 1969 and 1972 tested the effects of fumigation along the rows with different amounts of D‐D or Telone applied either two weeks before sowing or immediately before sowing, application of the systemic nematicide aldicarb (Temik) in the furrow with the seed during sowing, and top‐dressing with nitrogen. Seedling establishment was often decreased by fumigation immediately before sowing, especially when followed by excessive rainfall, but only rarely by earlier fumigation or by aldicarb; differences in numbers of roots harvested were smaller because hand‐singling removed excess seedlings. There was usually little difference between the yield increases given by the most effective treatments, which were aldicarb at 1·12 kg active ingredient/ha and 2·2–6·6 ml D‐D or Telone/m of row at either time of application. Nitrogen top‐dressing never affected sugar yield significantly. Longidorus spp. and Trichodorus spp. were both controlled well in the fumigated row but much less well at 13 cm, and not at all at 25 cm from the row (i.e. mid‐way between two treated rows).
Insect vectors of cowpea mosaic virus in Nigeria
Authors: WHITNEY W. K. , GILMER R. M. 
Published: February 2008

SUMMARYA yellow strain of cowpea mosaic virus (CPMV) was transmitted in cowpea by two thrips, Sericothrips occipitalis and Taeniothrips sjostedti; two chrysomelid beetles, Ootheca mutabilis and Paraluperodes quaternus; a curculionid beetle, Nematocerus acerbus; and two acridid grasshoppers, Catantops spissus spissus and Zonocerus variegatus. Summarizing trials with single insects, the efficiency of transmission of CPMV averaged 18—21% for N. acerbus and the two grasshoppers, 55% for P. quaternus, and 71% for O. mutabilis. Twenty‐two and 40% of the plants exposed to large populations of S. occipitalis and T. sjostedti, respectively, were infected. In three trials with an aphid, Aphis craccivora, 4 of 49 plants were infected with CPMV, but these infections were considered spurious because no infections occurred in any of 63 plants exposed to this insect in four other trials. A coreid bug, Riptortus dentipes, did not transmit CPMV. Mosaic symptoms in infected plants appeared 5—39 days after they were exposed to vectors. Infective virus was recovered from fresh faecal pellets of each grasshopper vector.
Taxonomic patterns in the host ranges of viruses among grasses, and suggestions on generic sampling for host‐range studies
Authors: WATSON L. , GIBBS A. J. 
Published: February 2008

SUMMARYAnalyses of published host‐range data for certain viruses reveal correlations with taxonomic groupings of grasses. Barley yellow dwarf virus (BYDV), cocksfoot mottle and phleum mottle viruses are found to have infected greater proportions of the festucoid grasses than of the non‐festucoids to which they were inoculated. By contrast, all strains of sugarcane mosaic virus (SCMV) and of the closely related maize dwarf mosaic virus (MDMV) infected more non‐festucoids than festucoids. In addition, infected plants from grass groups containing higher concentrations of genera susceptible to BYDV, SCMV and MDMV usually show clear symptoms, whereas infected plants from less susceptible groups are frequently symptomless. Some viruses, such as barley stripe mosaic, brome mosaic, cocksfoot streak and ryegrass mosaic, show no apparent preferences for particular grass groups.Samples of grasses employed in host‐range studies are usually strongly biased towards festucoids. It is suggested that viruses ought to be adequately tested against genera from all the major groups, and a classified list of grass genera suitable for host‐range studies is provided.
Properties and isolates of barley yellow dwarf virus
Authors: Plumb R. T. 
Published: February 2008

SUMMARYBarley yellow dwarf virus is persistently transmitted by a number of aphid species of which three, Rhopalosiphum padi, Sitobion avenae and Metopolophium dirhodum, are common in most years. Other aphids may be locally important. Isolates of the virus differ in their virulence and geographical distribution and are not transmitted equally well by all aphid vectors. Isolates with similar properties are grouped into strains according to their transmission by vectors and their severity. Changes in strain and aphid occurrence from year to year alter the incidence of virus and its effect on yield. These changes emphasize the need for detailed knowledge of cereal aphid biology and epidemiology of BYDV before effective control can be used.
Effects of gangrene (Phoma exigua) on potatoes
Authors: GRIFFITH R. L. , HIDE G. A. , HIRST J. M. , STEDMAN O. J. 
Published: February 2008

SUMMARYSeed tubers of the varieties King Edward, Majestic and Pentland Crown selected as ‘clean’ (lesion‐free), moderately, or severely affected by gangrene lesions were planted in field experiments. Infection delayed plant emergence, increased the number of stems/plant, sometimes caused gaps in crops and was associated with increased blackleg. On average severely affected seed yielded 20% less than ‘clean’ seed. Seed infection also increased the proportion of tubers in smaller size grades so that crops from severely infected King Edward seed averaged 1·4 ton/acre (3·5 t/ha) less small ware and 2·5 ton/acre (6·3 t/ha) less large ware than ‘clean’ seed. With Majestic, small ware was increased (0·7 ton/acre (1·8 t/ha)) and large ware decreased (4·4 ton/acre(11·0 t/ha)); Pentland Crown was similarly affected (small ware increased 0·8 ton/acre (2·0 t/ha); large ware decreased 3·9 ton/acre (9·8 t/ha)). In eight of twelve experiments unselected diseased stocks yielded significantly less than ‘clean’ tubers.Other experiments compared seed stocks with different proportions of gangrene‐infected seed tubers. Yields decreased as the proportion of diseased seed tubers increased, but differences were significant only when more than 60% were affected. Surprisingly, yields from ‘clean’ tubers also decreased as the proportion of diseased tubers increased in the stocks from which they were selected.Gangrene on progeny tubers after storage was not always related to the amount of gangrene visible on the seed. It was increased by riddling or wounding and decreased by dipping tubers in organo‐mercury fungicide before or soon after wounding.
A rapid method for measuring production of yellow rust spores on single seedlings to assess differential interactions of wheat cultivars with Puccinia striiformis
Authors: JOHNSON R. , BOWYER D. E. 
Published: February 2008

SUMMARYUredospore production of Puccinia striiformis in single wheat seedlings was assessed by weighing spores on an electrical microbalance, by counting on a haemocytometer or by measuring turbidity of spore suspensions with a spectrophotometer and compared with production from groups of seedlings determined by weighing spores on an analytical balance. The data were used to assess differential interaction of wheat cultivars Hybrid 46 and Joss Cambier with two isolates of race 104 E137 of P. striiformis and cvs Maris Templar and Joss Cambier with two isolates of race 41 E136. A significant differential interaction was shown in both experiments by each method but most rapidly and with the minimum of materials by the single‐plant microbalance technique. Measurements of spore production demonstrated differences between isolates within races more clearly than the conventional visual assessment of yellow rust symptoms.
Intra‐racial variation in Phytophthora infestans and adaptation to field resistance for potato blight
Authors: CATEN C. E. 
Published: February 2008

SUMMARYStrains of Phytophthora infestans of the same race (P4) isolated from a range of R0 potato varieties differed markedly in their rate of growth on agar but differences in growth rate were not related to variety of origin. Two isolates from each of the varieties Duke of York, Majestic and Arran Consul were grown for six successive subcultures on tubers of these three varieties. The six isolates differed in aggressiveness as shown by their growth on individual varieties. There was a marked difference in growth rate between alternate subcultures which is attributed to the use of too long an incubation period. Analysis of the data for subcultures 1, 3 and 5 revealed a significant interaction between isolates and varieties which reflected the enhanced growth of five of the isolates on the variety from which they had been obtained. Serial subculture on potato tubers of the same variety had no general or specific effect on the aggressiveness of the isolates. It is concluded that strains of P. infestans of the same race may be differentially adapted to the variety on which they are growing in the field. Differential interactions between pathogen biotypes and non‐immune hosts are considered to be widespread in host‐pathogen systems.
Association of different kinds of bacilliform particle with vein chlorosis and mosaic diseases of raspberry (Rubus idaeus)
Authors: JONES A. T. , ROBERTS I. M. , MURANT A. F. 
Published: February 2008

SUMMARYThin sections of diseased raspberry (Rubus idaeus) were examined by electron microscopy. Plants of the cv. Baumforth's B and of an aphid (Amphorophora rubi)‐resistant breeding selection (6820/54), both infected with raspberry vein chlorosis virus (RVCV) but not with other detectable viruses, contained large bacilliform particles c. 430 × 65 nm. Particles occurred in the cytoplasm and perinuclear space of a small proportion of xylem parenchyma cells. They had an inner core c. 25–30 nm in diameter with cross‐banding of periodicity 4·5 nm, and were bounded by an outer membrane. They are probably the particles of RVCV.Plants of cv. Mailing Jewel and of a selection (M14) both showing symptoms of raspberry mosaic (veinbanding) disease contained smaller bacilliform particles c. 125 × 30 nm, which occurred singly or in clusters in the cytoplasm of a small proportion of vascular parenchyma cells. It is not known which, if any, of the viruses associated with raspberry mosaic are represented by the particles.