bluuebunny/crossref_metadata_2025_split huggingface dataset:
Narcissus late season yellows potyvirus: symptoms, properties and serological detection
Authors: MOWAT W. P. , DUNCAN G. H. , DAWSON SHEILA 
Published: February 2008

SUMMARYNarcissus late season yellows virus (NLSYV) was obtained, apparently unmixed with other viruses, in selected naturally infected narcissus plants. The virus was not transmitted by manual inoculation to any of the 12 herbaceous species tested but was transmitted by Myzus persicae to virus‐tested narcissus plants, which then developed symptoms characteristic of late season yellows. Typically, symptoms develop late in the growing season but their expression is unreliable. NLSYV particles, which measured c. 750 ± 12 nm, were purified from fresh leaf extracts of narcissus in 0·3 m sodium citrate containing 10 mm sodium EDTA and 10 mm sodium DIECA by differential centrifugation followed by clarification with diethyl ether, gel filtration and isopycnic banding in caesium sulphate. Using antibodies from antisera prepared to virus particles, NLSYV was detected by ELISA in 14 of the 18 cultivars examined and nine seemed totally infected. Detection of the virus by immunosorbent electron microscopy was as sensitive as by ELISA but neither test detected all infections. The virus was detected by ELISA only in samples collected after flowering and capsid antigen concentration was greatest in the distal region of leaves. The reliability of detection depended on the cultivar. Immuno‐electron microscopy tests confirmed the occurrence of a distinct potyvirus, presumably narcissus degeneration, in narcissus cv. Grand Soleil d'Or, failed to detect any virus other than NLSYV in narcissus plants affected by white streak disease, and showed that NLSYV is related to three of five other potyviruses tested.
The effect of partially resistant potato clones and aldicarb on the multiplication of the potato cyst nematode Globodera pallida in field trials
Authors: PHILLIPS M. S. , DALE M. F. B. , GREEN D. I. , HANCOCK M. , HOLLIDAY M. , LACEY C. N. D. , TONES S. J. 
Published: February 2008

SUMMARYPotato cultivars with different degrees of resistance to Globodera pallida (PCN) were trialled at three infested sites in 1983, 1984 and 1985. These trials were primarily intended to assess the effects of PCN damage on the yield of tubers and consequently the sites chosen had high initial population densities of G. pallida. The population density of G. pallida was determined from samples taken both pre‐planting and post‐harvest and results showed that there were significant differences between the clones in the nematode multiplication rates. Although actual rates of multiplication varied between sites the relative differences between clones were maintained across sites. Under the susceptible control cultivars the populations generally increased even in the presence of nematicide. The partially resistant clones gave best control, as measured by nematode multiplication, at the sites with the highest initial population densities but gave good control at all sites when treated with nematicide irrespective of initial population density. The role of partial resistance in integrated control systems and the effectiveness of nematicides against G. pallida is discussed.
A survey of insect parasitic nematodes in Northern Ireland
Authors: BLACKSHAW R. P. 
Published: February 2008

SUMMARYA survey of insect parasitic nematodes was carried out in Northern Ireland between November 1986 and June 1987. A total of 1093 soils were examined using Galleria mellonella larvae as bait. Nematodes were recovered from 41 of these soils. The rate of recovery declined from February onwards and possible reasons for this are discussed. Clay and clay loam types accounted for 56·1% of the survey samples but only 9·8% of the recovered nematode populations. Loams comprised 39·6% of samples and 85·4% of nematodes, indicating a greater likelihood of recovering insect parasitic nematodes from lighter soils. The nematodes were also recovered from peat soils (4·3% of samples and 4·9% of nematodes). All the recovered isolates were Neoaplectana bibionis.
A photographic technique for investigating the splashing of water drops on leaves
Authors: MACDONALD O. C. , McCARTNEY H. A. 
Published: February 2008

SUMMARYThe formation of splash from water drops falling onto bean leaves was investigated by multiple exposure flash photography. A relatively simple technique was developed which recorded up to four images at 2 ms intervals, of a splash on one photograph. The images were recorded on colour reversal film, and the flash sequence was colour coded to aid the interpretion of the superimposed images. Analysis of the photographs allowed measurement of the initial speed and angle of ejection of different sized splash droplets. Droplets were ejected at speeds of up to about 10 m s‐1although most speeds were less than about 3 m s‐1, and small droplets tended to travel faster than large ones. Droplets were ejected at all angles but the majority were ejected almost horizontally; there was little correlation between droplet size and angle of ejection. Deposition patterns estimated from calculated droplet trajectories compared well with measured ones.
Systemic infection of black currant flowers by Botrytis cinerea and its possible involvement in premature abscission of fruits
Authors: McNICOL R. J. , WILLIAMSON B. 
Published: February 2008

SummaryEmasculated flowers of several black currant cultivars were pollinated and then inoculated with dry conidia of Botrytis cinerea in the field and glasshouse. The infection of pistils was examined by U.V. fluorescence microscopy and the incidence of premature flower abscission recorded. Conidia germinated in the stigmatic fluid in all cultivars and hyphae spread symptomlessly throughout the style to infect the pericarp and ovules.Of six cultivars inoculated in the field, cv. Ojebyn was the most, and cv. Ben More the least resistant to flower shedding. Natural infection of stigmas by B. cinerea was common in the field and a high proportion of apparently healthy non‐inoculated flowers which abscissed were found to contain infected ovules. Fewer flowers abscissed if inoculations were made 6 days after pollination. Symptomless or latent infection of black currant flowers by B. cinerea may be a contributory cause of premature abscission of developing fruits, or ‘running‐off’, recorded in these experiments.
Stem canker (Rhizoctonia solani) on five early and seven maincrop potato cultivars. II Effects on growth and yield
Authors: HIDE G. A. , READ P. J. , FIRMAGER JANET P. , HALL SHARON M. 
Published: February 2008

SummaryIn 1983 and 1984, potato seed tubers of five early and seven maincrop cultivars were inoculated with cultures of Rhizoctonia solani during planting in field experiments to simulate severe seed infection. The size of foliage was assessed during June‐August and tuber yields recorded during growth and at harvest in October.Stem canker delayed shoot emergence, decreased the number and length of stems and caused increased variation in stem length; these effects were greatest with Maris Peer and Arran Comet (early cultivars) and King Edward and Pentland Squire (maincrop cultivars). Total weight of foliage was decreased, especially with earlies, dry matter of stems increased and the proportion of foliage on lateral stems increased.With the early cultivars, tuber yield from sprouted Maris Peer seed 11 wk after planting in 1983 was decreased by 24%, and 13 wk after planting in 1984 yields were decreased by 42% (Maris Peer), 40% (Ulster Sceptre), 34% (Estima), 30% (Arran Comet) and 17% (Ulster Prince) with sprouted seed and by 20, 29, 53, 39 and 28% respectively with non‐sprouted seed. Decrease in total yield at harvest in October averaged 13% with sprouted seed and 10% with non‐sprouted seed. In all cultivars the weight of small tubers was decreased and with Estima the weight of large tubers was increased.Tuber bulking was also delayed with all maincrop cultivars and at harvest yields from sprouted King Edward seed were decreased by 13% in 1983 and by 16% (sprouted seed) and 23% (non‐sprouted seed) in 1984; yields of Pentland Squire were decreased by 5, 16 and 21% respectively. Yield losses with other cultivars ranged from 5–13% with sprouted seed and 0–16% with non‐sprouted seed. The yields of small tubers were decreased with all cultivars and yields of large tubers were increased with Pentland Squire, Pentland Crown and Cara.
Inheritance of adult plant resistance to powdery mildew in swedes
Authors: BRADSHAW J. E. , GEMMELL DOROTHY J. , WILLIAMSON CYNTHIA J. 
Published: February 2008

SummaryA complete diallel set of crosses, including selfs, was produced from 11 inbred lines of swedes and assessed for adult plant resistance to powdery mildew in a replicated field trial. The plants were inoculated with powdery mildew spores on 23 July 1987. Traces of mildew were visible on 3 August. By 14 September the most susceptible inbred line had 95% of its leaf area infected, whereas the three most resistant lines derived from cvs Bangholm Dima (two lines) and Bangholm Magres (one line) had only 5%. Resistance was controlled by partially recessive genes. There was no evidence of maternal effects. The implications for breeding inbred and F1 hybrid swede cultivars are discussed.
Distribution of 14CO2 during ontogeny of chickpea (Cicer arietinum) grown at two moisture levels
Authors: HOODA R.S. , SHEORAN I. S. , SINGH RANDHIR 
Published: February 2008

SummaryThe distribution of assimilates of 14CO2 in ethanol soluble and insoluble fractions was measured at 20‐day intervals from 45–135 days after sowing (DAS) in chickpea (Cicer arietinum) grown at two moisture levels. The contribution of pre‐flowering assimilates to pods, although very low, was higher under the stress conditions. At the time of harvest, the recovery of 14C in pods was 0.4 and 0.9% of the total 14C fed 45 DAS in soluble and 2.5 and 5.1% in insoluble fractions in control and stressed plants, respectively. The %14C received by nodules continuously decreased with increasing age of plants. Stressed plants diverted more 14C to nodules, compared to control, during vegetative and flowering stages. During active seed filling, stressed plants diverted more 14C to reproductive parts and less to nodules, compared to control. Significant amounts of 14C were retgined by the stem and leaves during the seed‐filling period and it appears that there is scope for the remobilisation of pre‐flowering, as well as post‐flowering assimilates for seed‐filling of chickpea.
Quality losses in wheat caused by the orange wheat blossom midge Sitodiplosis mosellana
Authors: HELENIUS J. , KURPPA S. 
Published: February 2008

SummaryIn three sets of data pooled over spring wheat varieties and lines a number of grain quality measurements were related to the levels of infestation by Sitodiplosis mosellana larvae. The Hagberg falling number value was negatively correlated with the proportion of damaged grains. The 1000‐grain weight, protein content and gluten content were not affected. Differences between cultivars in infestation and damage level were found to depend on the development phenology (timing of ear emergence) and on the percentage of damaged grains remaining in the yield after harvest. The falling number values were reduced most when the attainable values remained low in cultivars prone to sprouting damage, and in seasons with unfavourable weather conditions for quality maintenance.The proportion of damaged grains in relation to the number of larvae was well described by a logit‐transformed regression. Sampling for infestation level and preventive measures against quality loss are discussed.
Forecasting the incidence of virus yellows in sugar beet in England
Authors: HARRINGTON RICHARD , DEWAR ALAN M. , GEORGE BRIAN 
Published: February 2008

SummaryA new forecasting system for virus yellows incidence in sugar beet in the UK has been devised using multiple regression analyses. The forecast equations include data on (1) the previous year's virus incidence, (2) temperature in January and February and (3) the timing of the spring migration of Mytus persicae. Forecasts using the first two of these variables account for 63% of the variance in virus incidence in the main beet growing area of Eastern England and give growers information in time to decide on whether to apply aphicidal granules at drilling to control the vectors of the disease. Forecasts using all three variables account for 87% of the variance in virus incidence and can forewarn growers and the sugar industry of the likelihood of an epidemic. Forecasts for the northern and western regions of the beet growing area are derived from the forecast for the eastern region.
Biological characteristics of grass geminiviruses from eastern Australia
Authors: GREBER R. S. 
Published: February 2008

SummaryTwo serotypes of chloris striate mosaic virus (CSMV), paspalum striate mosaic virus (PSMV) and geminiviruses infecting Bromus catharticus and Digitaria didactyla were investigated. Their field occurrence and experimental hosts are listed. Serial transmission data for CSMV by single Nesoclutha pallida show a minimum latent period of 12–14 h, and regular transmission with occasional breaks for up to 50 days. Cicadulina bimaculata did not transmit any isolates after plant feeding acquisition, but transmitted CSMV inefficiently after insect injection. The vector of PSMV was found to be a specific biotype of N. pallida which bred only on Paspalum spp. The rate of transmission of CSMV with the Chloris biotype of N. pallida and of PSMV with the Paspalum biotype reached c. 50% with single insects, but only when freshly‐infected source plants were used. Geminate particles were found in thin sections of leaf tissue infected with all four viruses, and partially purified preparations were made of three of these. In gel diffusion tests, the virus from Microlaena stipoides produced a spur reaction with CSMV, when reacted with CSMV antiserum. The B. catharticus and D. didactyla isolates failed to react serologically with CSMV, maize streak or Vanuatu digitaria streak viruses.
Host range, purification and some properties of a new ilarvirus from Humulus japonicus
Authors: ADAMS A. N. , CLARK M. F. , BARBARA D. J. 
Published: February 2008

SummaryIn 1986, during routine quarantine testing, an apparently undescribed virus was isolated from two of 21 plants of Humulus japonicus grown from seed imported into the UK from Beijing, Peoples Republic of China. The virus, for which we propose the name humulus japonicus virus (HJV), was transmitted mechanically to a wide range of herbaceous plants. No symptoms were seen in virus‐infected H. japonicus plants. HJV infected, but did not become systemic, in the cultivated hop (Humulus lupulus) under our conditions although it has been detected serologically in both species of Humulus growing near Beijing. The virus was transmitted through seed of Chenopodium quinoa and was also associated externally with pollen of that species, but no pollen‐transmission tests were conducted. HJV was easily purified. Virus particles comprised a single polypeptide (mol. wt c. 26 350) and four RNA molecules (mol. wts 1.31, 1.05, 0.75 and 0.39×106). The three larger mol. wt RNAs were not infective in the absence of the smallest RNA. The particles were quasi‐isometric and variable in size. Purified preparations of particles formed four bands in sucrose density gradients but (after fixing with formaldehyde) only a single band (with a density of 1.364 g/ml) in caesium chloride isopycnic gradients.These properties are similar to those of ilarviruses, and HJV was very distantly related serologically to prunus necrotic ringspot ilarvirus. We suggest, therefore, that HJV be regarded as a new member of the ilarvirus group.All known infected plants of H. japonicus at the site of introduction have been destroyed and the virus has probably been eliminated from there. Testing is continuing to confirm this.
Effects of increasing weed‐beet density on sugar‐beet yield and quality
Authors: LONGDEN P. C. 
Published: February 2008

SummaryWeed beets are an increasing problem in many sugar‐beet crops in many countries. At present about one sugar‐beet field in four in England is infested with weed‐beet seed. Control in other crops can be achieved using selective herbicides but in sugar beet the weed beets, many of which are of annual habit, are not easily controlled and often compete with the crop. Experiments were done to quantify the yield loss caused by weed beet in sugar‐beet crops. Transects were laid out across three fields in 1985 and 1986 and plots located thereon to include the range of weed‐beet densities found in the field. Weed beet did not affect the concentration of sugar (sucrose), potassium, sodium, α amino nitrogen or invert sugar in the crop beets. Root and sugar yields were progressively reduced by increasing densities of weed beet. A rectangular hyperbola described the data slightly better than an asymptotic model. There was no indication of a threshold density of weed beet below which there was no yield loss, which averaged 11.7% for each weed beet plant/m2. This corresponds to an average 0.6% sugar yield loss for each 1% of bolted weed beet in the root crop up to 100%, which is similar to the reported losses resulting from bolters in the root crop.
Viability of rape (Brassica napus L.) seeds following selection on the basis of newly‐emerged radicles then subsequent drying and storage
Authors: FINCH‐SAVAGE W. E. , McKEE J. M. T. 
Published: February 2008

SummaryGerminating rape seeds selected on the basis of newly‐emerged radicles (1 ± 0.5 mm) were dried to an equilibrium moisture content (c. 11%) in air at 20°C and 80% relative humidity without loss of viability. Storage life of these low‐moisture‐content germinating (LMCG) seeds at 15°C was limited to 7 days before viability was significantly reduced. However, viability of LMCG seeds was maintained for 84 days in storage at ‐20°C. Longer periods in store reduced viability, but 96% of seeds still remained viable after 336 days at ‐ 20°C. Increasing periods of storage at ‐20°C reduced the subsequent seed longevity at 15°C, indicating a reduction in vigour during storage. Storage under reduced pressure or in a nitrogen atmosphere had little significant effect on seed longevity. Reduction of moisture content below 11% using vacuum drying at a range of temperatures reduced seed vigour.
An analysis of rain‐mediated dispersal of Drechslera teres conidia in field plots of spring barley
Authors: DEADMAN M. L. , COOKE B. M. 
Published: February 2008

SummaryIn two separate trials rain‐mediated dispersal of Drechslera teres conidia was observed in field plots of cv. Beatrice spring barley. Within the crop spore number was greater towards the base reflecting both the downward movement of conidia and the greater availability of spores on older leaves. From the edge of the crop half as many conidia were trapped at 100 cm as at 25 cm. In both trials the cumulative spore catch total lagged behind the increase in net blotch infection levels on the top two leaves. The number of spores sampled appeared closely related to rainfall intensity.
Use of three screening techniques for the evaluation of fungicides to control rhizoctonia root rot of wheat
Authors: COTTERILL P. J. , BALLINGER D. J. , KOLLMORGEN J. F. 
Published: February 2008

SummaryTwenty fungicides were screened for their abilities to reduce the saprophytic growth of Rhizoctonia solani on agar and in soil, and to control root rot of wheat (Triticum aestivum) in pots of soil. Thirteen showed some activity against the in vitro growth of R. solani, the most promising being Sandoz 619F and flutolanil, although none of these reduced saprophytic growth of the fungus in soil. Only benomyl and thiabendazole, which were ineffective on agar and against disease in pots, reduced saprophytic growth in soil. None of the fungicides reduced the number of plants infected in the pot experiments and only six (flutriafol, diniconazole, Schering 539865, propiconazole, Bayer HWG1608 and flutolanil) of the thirteen active on agar (+ triadimefon which was not) reduced root rot severity. The results of this study indicate the differing reactions towards R. solani of chemicals in the three screening tests and confirm the potential for chemical control of rhizoctonia root rot of wheat.
The effects of fungicide‐coated seeds on the establishment of VA mycorrhizal infection
Authors: SPOKES J. R. , HAYMAN D. S. , KANDASAMY D. 
Published: February 2008

SummaryCommercial fungicide‐coated seed of five plant species was tested to determine whether the fungicides used affected seedling infection by VA mycorrhizal fungi. All the plants became mycorrhizal, with no differences between those emerging from fungicide‐coated or non‐fungicide‐coated seed. However, when the same fungicides were applied as soil drenches, mycorrhizal infection was greatly inhibited, and in some instances was absent throughout the duration of the experiment.
Seed‐borne alfalfa mosaic virus infecting annual medics (Medicago spp.) in Western Australia
Authors: JONES R. A. C. , PATHIPANAWAT W. 
Published: February 2008

SummaryInfection with alfalfa mosaic virus (AMV) was widespread in introduction, evaluation and seed increase plots of cultivars and numbered selections of annual medics (Medicago spp.) in Western Australia; the virus was detected in plots of seven species. When seed stocks from the West Australian annual medic collection harvested in 1984–1986 were sown and seedlings tested, seed‐borne AMV was found in all 12 cultivars and in 44/50 numbered selections, belonging to 10 species. Seed transmission rates to seedlings ranged from 0.3–74% and exceeded 5% in 33 seed lots. By contrast, when seedlings of four species grown from seed harvested in 1971–1978 were tested, no AMV was detected; the oldest infected seed stock found was from 1980. In commercial seed stocks of two cultivars released in 1987, the levels of seedling infection with AMV found were 0–0.2% for M. polymorpha cv. Santiago and 526% for M. murex cv. Zodiac. In commercial 1986 seed of M. polymorpha cvs Serena and Circle Valley, AMV was detected in 3/13 and 6/9 stocks respectively; transmission rates to seedlings in infected stocks were 0.1–0.7%. In a survey of 47 annual medic pastures in medium and low rainfall zones of the Western Australian wheat belt in 1987, the virus was detected in leaf samples from only three sites.When inoculated mechanically, AMV systemically infected 11 cultivars and 12 selections belonging to 13 species, but did not infect one selection each of M. aculeata and M. orbicularis. Infected plants in ten species developed only faint mosaics or were symptomlessly infected, but M. littoralis, M. polymorpha and M. tornata developed distinct mottling, reduction in leaf size and, in some instances, leaf deformation and dwarfing. In pot tests, AMV infection decreased herbage and root production (dry wts) of M. polymorpha cvs Serena and Circle Valley by about 30% and 50–60% respectively, but did not decrease herbage production in M. murexcv. Zodiac. In spaced plants growing outside, AMV decreased herbage, root (dry wts) and seed production of M. polymorpha cvs Circle Valley and Santiago by about 60%.