bluuebunny/crossref_metadata_2025_split huggingface dataset:
An investigation of difenacoum resistance in Norway rat populations in Hampshire
Authors: GREAVES J. H. , SHEPHERD D. S. , GILL J. E. 
Published: February 2008

SUMMARYObservations are presented to show that resistance to difenacoum, a rodenticide commonly used for the control of warfarin‐resistant rodents, is widespread in populations of the Norway rat, Rattus norvegicus, in an area centred in north‐east Hampshire. Of 202 rats trapped on 42 farms in this district and tested in the laboratory, 85% were resistant to warfarin and 14% were resistant to difenacoum. Only rats that were resistant to warfarin showed difenacoum resistance, indicating it to be a form of cross resistance. The difenacoum‐resistant rats survived a dose of difenacoum that was lethal to more than 99% of susceptibles, but succumbed when this dose was increased fivefold. The results of four treatments carried out with difenacoum on farms illustrate that this level of resistance seriously reduces the effectiveness of difenacoum as a rodenticide in the field.
The effect of fungicides on field populations of Aphis fabae and on the infection of the aphids by Entomophthoraceae
Authors: WILDING N. 
Published: February 2008

SUMMARYNumbers of Aphis fabae on spring‐sown field beans were little affected by weekly applications of the systemic fungicides benomyl or tridemorph or the non‐systemic captafol, manocozeb or maneb. Benomyl diminished the mortality of aphids caused by Erynia neoaphidis but not that caused by other species of entomophthoraceous fungi. The other fungicides failed to affect consistently the proportion of aphids infected by any fungus.
Effects of adding calcium and sodium salts to field soils on the incidence of clubroot
Authors: FLETCHER J. T. , HIMS M. J. , ARCHER F. C. , BROWN A. 
Published: February 2008

SUMMARYThe effect on clubroot of the addition to a mineral soil of calcium carbonate, calcium sulphate and sodium carbonate was studied in two field experiments during a 3‐yr period. Applications of calcium carbonate (ground limestone) at 10 or 20 t/ha increased the soil pH from 6×7 to 7×9; sodium carbonate at 7×5 t/ha to pH 8×3 and calcium sulphate (gypsum) at 20 t/ha caused a slight depression in pH to 6×6. 98% of cabbage plants showed clubroot symptoms in the untreated plots after 3 yr and the percentages were 0×7, 1×6 and 66×6 for the calcium carbonate, sodium carbonate and calcium sulphate treatments respectively. Yields were significantly increased by all three materials. There were no significant differences in disease incidence or in yield when calcium carbonate was used at 10 or 20 t/ha either applied as a single application or as two half‐rate applications. Soil from the calcium carbonate treated plots was used in a greenhouse experiment where the addition of inoculum of Plasmodiophora brassicae resulted in a large increase in clubroot incidence. There was no evidence that a biological suppressor was present in the high pH, low disease incidence soils.
Progress of infection by Erysiphe graminis on fungicide‐treated and untreated barley
Authors: LAWS F. A. , WALMSLEY‐WOODWARD DIANNE J. , WHITTINGTON W. J. 
Published: February 2008

SUMMARYTridemorph‐treated and untreated barley plants wre grown either in separate growth rooms or together. They were inoculated either with a sensitive or a tolerant isolate, and the progress of mildew was recorded. Comparisons were made between the rates of progress of sensitive and tolerant isolates on separated and unseparated fungicide treatments. Results suggested that interactions took place between pathogen populations on adjacent treated and untreated plants.Barley cv. Golden Promise was sown in plots made up of two adjacent fungicide treatments. Triadimefon, triforine, tridemorph and ethirimol were paired with each other and with untreated crops in all combinations. The progress of mildew on each plot was recorded, and differences were found between similar fungicide treatments from different plot pairs. The likelihood of interactions between mildew populations exposed in the field to different fungicide treatments is discussed.
The effect of three herbicides on the number of spores of Rhynchosporium secalis on barley stubble and volunteer plants
Authors: STEDMAN O. J. 
Published: February 2008

SUMMARYSingle sprays of paraquat, glyphosate or dinoseb‐in‐oil, were applied to barley stubble or volunteer plants and their effects on the number of spores of Rhynchosporium secalis were studied weekly. Spore concentrations were measured by washing samples of stubble or volunteer plants and counting spores using a haemocytometer.The number of spores recovered from stubbles was relatively small; both paraquat and glyphosate caused some reductions but the results were not consistent. Treatment with paraquat generally caused a transitory increase on volunteer plants; this effect was not found after glyphosate. Both herbicides caused persisting reductions from 4 wk after treatment. Volunteer plants treated with dinoseb‐in‐oil had fewer spores for 6 wk after treatment, but the plants were not killed and when new growth became infected, spore production recovered to equal that on untreated plants.The fungicide captafol caused some reductions in spore number on stubble but results were not consistent, applied after paraquat it had no effect. It was generally ineffective when applied to volunteer plants; applied after paraquat it tended to increase spore number, but the differences were seldom significant.Spores washed from volunteer plants treated with paraquat or glyphosate were inoculated to pot‐grown barley seedlings; neither herbicide had any effect on spore viability. Viable spores were recovered in February from stubble or volunteer plants treated the previous autumn with paraquat or glyphosate respectively.
Effects of fungicide timing on control of Rhynchosporium secalis in barley plants
Authors: JORDAN V. W. L. , TARR HILARY S. , MILES D. M. 
Published: February 2008

SUMMARYSprays of captafol, carbendazim, carbendazim + tridemorph + maneb, diclobutrazol, triadimefon or triadimefon + carbendazim all completely protected barley plants in a glasshouse against R. secalis for at least 30 days. However, their effectiveness in preventing disease development when applied after inoculation differed: triadimefon, traidimefon + carbendazim, or diclobutrazol were the most effective, completely preventing symptom development when applied up to 5 days after inoculation to plants grown above 16 °C, and up to 8 days below 8 °C. All the fungicides decreased the number of viable conidia produced by leaf blotch lesions, and when applied to infected plants at G. S. 30, greatly decreased the upward spread of the disease under simulated rain conditions; the most effective fungicides in these respects were triadimefon and triadimefon + carbendazim.The above fungicides and fungicide mixtures, together with the recently introduced materials fenpropimorph and propiconazole were applied to diseased winter barley crops in winter or in spring. All treatments decreased leaf blotch development and increased yields. In most cases, a winter application was more effective than spring applications, particularly if applied in mid‐November. The most effective fungicides were triadimefon and propiconazole. The field trials data fitted well with the predictions of performance indicated by the glasshouse investigations.
Cowpea mottle virus: field resistance and seed transmission in virus‐tolerant cowpea*
Authors: ALLEN D. J. , THOTTAPPILLY G. , ROSSEL H. W. 
Published: February 2008

SUMMARYCultivars of cowpea (Vigna unguiculata) possessing tolerance to infection by cowpea mottle virus (CMeV) under screenhouse conditions exhibited both tolerance and resistance to infection by beetle vectors under field conditions. Resistance to infection was exemplified by delayed and reduced incidence of infection resulting from natural infection pressure, and appeared to be unrelated to vector feeding preference. This suggests that certain cowpea cultivars such as TVu 3901 possess more than one component of resistance (sensu Russell, 1978) to CMeV.Despite some correspondence between results from artificial (mechanical) and natural (vector) inoculation, we suggest that field evaluation is often an important adjunct to greenhouse screening for virus disease resistance since resistance mechanisms operative under field conditions may be overlooked in artificial screening programmes.In the susceptible cultivar TVu 612, when artificially inoculated, CMeV is transmissible through cowpea seed up to 0.4%. In only one instance was CMeV seed transmitted from natural infection. We suggest that apparent inefficiency in seed transmission may in part account for the restricted ecological and geographical distribution of CMeV.
Resistance to Botrytis cinerea in canes of Rubus idaeus and some related species
Authors: JENNINGS D. L. , WILLIAMSON B. 
Published: February 2008

SUMMARYMycelial inoculation of canes with Botrytis cinerea proved a useful method for assessing Rubus material for resistance. When canes were inoculated in summer resistant genotypes developed relatively small lesions which produced few small sclerotia in the following spring. The size of lesions in autumn generally provided the best discrimination between genotypes. Very strong resistance was found in several species, of which Rubus pileatus and R. occidentalis are the most useful for breeding; hybrids of raspberry with these species or with R. crataegifolius also had strong resistance. The resistance shown by a derivative of red raspberry cv. Chief was less strong, as was the resistance conferred by gene H, which determines cane pubescence.
Short and long term effects of simulated bullfinch damage on the cropping of Conference pear trees
Authors: SUMMERS D. D. B. 
Published: February 2008

SUMMARYTrials in which Conference pear trees were disbudded by hand to simulate bullfinch damage were carried out over 5 years to ascertain the short and long term effects on yield. The first crop following damage was depressed in proportion to the severity of bud loss; the second crop following damage was enhanced in proportion to bud loss but cumulative yields for the 2 years were still depressed, though not significantly so.Trees that were damaged annually for 5 years had yields depressed in every year, but crop loss was not consistently related to damage level after the first year. Trees that were damaged in alternate years had significantly depressed yields in the first year only. No difference could be detected between the yields of trees subjected to simulated bullfinch damage (clustered disbudding) and those of trees which had been evenly disbudded.
Resistance to organophosphates, and the genetic background, in fruit tree red spider mite, Panonychus ulmi, from English apple orchards
Authors: CRANHAM J. E. 
Published: February 2008

SUMMARYAssays on adult females and eggs of Panonychus ulmi, on leaf discs of Myrobalan plum, were used to characterise and establish homogenous organophosphateresistant (OR) and susceptible strains. Reciprocal crosses of these strains, and assays on adult mites and eggs of the parent, F1 and F2 generations confirmed that resistance was controlled by a single major gene, the expression of which was dominant in the response to parathion, and incompletely dominant to vamidothion, dimethoate and demeton‐S‐methyl. Reproductive incompatibility, between strains, as in Tetranychus urticae, was not found.Bioassays on larvae hatched from winter eggs, collected from several orchards in Kent, Essex and Somerset, were used to evaluate the spectrum of cross‐resistance to a range of 20 organophosphates (OPs). Together with assays on adult females, these tests showed 10‐ to 100‐fold resistance to most of the OPs used for several years including those noted above, but less than 10‐fold to azinphos compounds and to several recently‐introduced OPs, e. g. dialifos, triazophos, dioxathion. The resistance spectrum in strain OR and five field strains was similar, but some had higher levels to parathion and demeton‐S‐methyl, and others to dioxathion after 3–4 years' exposure. Resistance levels to individual OPs may be enhanced by specific selection. Strains resistant to OPs showed only 2‐ to 5‐fold resistance to two carbamates, and were fully susceptible to dicofol.
Epidemiology of ergot disease (Claviceps purpurea) in open‐flowering male‐sterile cereals
Authors: WOOD G. , COLEY‐SMITH J. R. 
Published: February 2008

SUMMARYErgot sclerotia collected from one source germinated over a period of about 6 wk, but those from many sources, over a period of about 5 months. The duration of ascospore discharge followed a similar pattern.Individual ovaries of male‐sterile barley remained susceptible to infection for about 3 wk. After infection, 7 to 10 days elapsed before honeydew production started and this secondary source of inoculum (conidia) continued to be produced for about 2 wk in individual ovaries before ergot sclerotia started to develop.A field trial demonstrated that the duration of ovary susceptibility is lengthened in practice because of unevenness in flowering and the production of successive flushes of tillers. The potential for increase of the disease from a small primary focus of infection was large with the majority of the infections occurring in the back‐ or late‐tillers.
Chemical techniques for control of stem canker and black scurf (Rhizctonia solani) disease of potatoes
Authors: HIDE G. A. , CAYLEY G. R. 
Published: February 2008

SUMMARYThiabendazole, iprodione and benodanil were tested for control of stem canker and black scurf disease of potatoes using seed tubers with or without black scurf planted in soil infested or not with Rhizoctonia solani. Dormant seed tubers were treated with fungicide dusts, dips or sprays and before planting dusts were applied to soil or to sprouts on seed tubers.Plants grown from seed tubers with black scurf had more stem canker, stolon infection and Thanatephorus cucumeris and progeny tubers had more black scurf than from seed without black scurf. Infesting soil with R. solani increased black scurf but not stem canker or stolon infection.Fungicide treatment of seed tubers controlled all phases of the disease and sprout and soil treatments also had significant effects. Numbers of tubers in July were usually increased by treatment although by harvest many small tubers (>3 cm) had been resorbed. Fungicide treatment substantially increased yield only when shoot tips were pruned by R. solani.Regression analyses showed that stolon pruning, Thanatephorus and black scurf were significantly related to stem canker, and numbers of tubers in July but not in September were inversely related to stolon pruning.The significance of sources of inoculum and the effects of controlling disease on tuber production are discussed in relation to methods of fungicide use.
Association of raspberry bushy dwarf virus with raspberry yellows disease; reaction of Rubus species and cultivars, and the inheritance of resistance.
Authors: Jones A. T. , Murant A. F. , Jennings D. L. , Wood G. A. 
Published: February 2008

SUMMARYThe agent of raspberry yellows disease is transmitted by grafting but not by aphids and is resistant to thermotherapy. Further studies showed that it is transmitted by inoculation of sap through seed; it is probably transmitted to plants by pollination. Raspberry bushy dwarf virus (RBDV) shares all these attributes and is known to infect all yellows‐sensitive raspberry cultivars except Puyallup and Sumner; however, neither of these cultivars has been tested by graft inoculation with RBDV. RBDV commonly infects plants symptomiessly, even those of yellows‐sensitive cultivars, but it induced yellows when inoculated either manually to Norfolk Giant raspberry or by grafting to a yellows‐sensitive raspberry selection. The evidence suggests that RBDV is the causal agent of yellows disease but that symptom expression is greatiy dependent on genetic and environmental factors. Many red raspberry cultivars are resistant, probably immune, to the type culture of RBDV and this character was shown to be conferred by a single dominant gene designated Bu.
Effects of aerial pollutants on the growth and yield of spring barley
Authors: BUCKENHAM A. H. , PARRYy M. A. J. , WHITTINGHAM C. P. 
Published: February 2008

SUMMARYOpen‐topped chambers were used to determine the effect of field concentrations of aerial pollutants on the growth and yield of spring barley. Experiments were conducted in the Marston Valley, Bedfordshire, where sulphur dioxide and fluoride are the major pollutants. The charcoal filtered chambers enabled pollutant concentrations to be reduced by 60–70%. Cleaning the air increased straw and grain yields. The filtration was non‐selective and did not identify the injurious agent. The chambers were found to accelerate the crop's development by 7–8 days and reduce yield by suppressing tillering.
Determination of firmness of field‐grown tomatoes during storage in controlled atmosphere or ripened at different temperatures
Authors: THOMAS T. H. , DREW R. L. K. , GOODENOUGH P. W. 
Published: February 2008

SUMMARYDurometer readings indicated that although differences in firmness of maturegreen fruits were small, there were large varietal differences in red‐ripe fruit after preor post‐storage ripening treatment at different temperatures. Such differences were positively related to the performance of the different cultivars in controlled atmosphere storage. Thus the durometer provides a simple means of assessing the firmness of ripe tomato fruits and hence of predicting the long‐term storage potential of different cultivars.
The life‐history of the leaf‐curling plum aphid Brachycaudus helichrysi in Northern Ireland and its ability to transmit potato virus YC(AB)
Authors: BELL A. C. 
Published: February 2008

SUMMARYThe life‐history of leaf‐curling plum aphid, Brachycaudus helichrysi was studied in Northern Ireland from 1977–1980. It was shown that the life cycle differed in several respects from those of geographically distinct populations, reported by other authors, especially with regard to the timing of egg hatch. Body length and antennal segment measurements of the adult stages on Prunus spinosa and Trifolium pratense correlated well with published dimensions for the species.Virological studies showed B. helichrysi to be capable of transmitting potato virus YC(AB) with a vector efficiency of 34%. This value is higher than previous estimates and enhances the significance of the species as a virus vector in potato crops early in the growing season.
Influence of temperature and duration of leaf wetness on infection of Acyrthosiphon kondoi with Erynia neoaphidis
Authors: MILNER R. J. , BOURNE JENNY 
Published: February 2008

SUMMARYBioassays were carried out to examine the influence of temperature and duration of leaf wetness on the infectivity of an isolate of Erynia neoaphidis for its aphid host Acyrthosiphon kondoi. Preliminary experiments demonstrated that primary spores produced in vitro were as infectious as those formed in vivo. No consistent effect of temperature on infectivity of primary spores could be detected. The time taken to kill an aphid increased as temperature decreased, from 3–5 days at 20 °C to 12–15 days at 8 °C, suggesting a threshold for disease development of 4 °C. Increasing duration of the period of leaf wetness up to 24 h after inoculation increased the final level of infection. At 20 °C, a minimum moisture period of 3 h was required for infection with maximum infection occurring after about 7 h. These times increased slightly at 15 °C but extending to 7 and 16 h respectively at 10 °C. The epizootiological implications of these results are discussed with reference to previously published data on in vivo production of primary spores of E. neoaphidis.
The effects of barley yellow dwarf virus, aphids and honeydew on Cladosporium infection of winter wheat and barley
Authors: AJAYI OLUPOMI , DEWAR ALAN M. 
Published: February 2008

SUMMARYPrior infection of both wheat and barley plants by BYDV predisposed their ears to infection by Cladosporium spp. and Verticillium spp. Aphids and honeydew increased the incidence of Cladosporium on wheat ears but not on barley. This difference between crops was attributed to the larger number ot aphids on the wheat. In the glasshouse, aphids and honeydew, but not honeydew alone, increased Cladosporium populations.
Effects of delaying fungicide treatment on the incidence of gangrene in stored potato tubers
Authors: HIDE G. A. , CAYLEY G. R. 
Published: February 2008

SUMMARYPotato titbers infested with Phoma exigua var. foveata were uniformly wounded and sprayed or dipped in fungicide suspensions either immediately or after periods of up to 21 days' storage at 5, 10, 15 or 20 °C. Tubers were then stored at 5 °C and gangrene assessed after 12 wk.Incidence of gangrene on untreated tubers was progressively decreased by increasing the length of storage at 15 or 20° (curing) but was not affected by 3 days' storage at any temperature. Fungicide treatment immediately after wounding gave best control of the disease; treatment after 3 days' delay was less effective and after 14 or 21 days was usually ineffective. Gangrene was decreased by fungicides more on tubers stored for 3 or 7 days at 5 °C than at higher temperatures.Control of gangrene by curing or fungicides diminished when the amount of inoculum on tubers was increased. Increasing the amount of fungicide applied improved control and fungicides were more effective in decreasing gangrene on cut and crush wounds than on cut wounds. At the arbitrary concentrations used in these experiments imazalil gave better disease control than thiabendazole, prochloraz, carbendazim plus quinolin 8‐ol or triadimefon.
Chenopodium necrosis: a distinctive strain of tobacco necrosis virus isolated from river water
Authors: TOMLINSON J. A. , FAITHFULL ELIZABETH M. , WEBB M. J. W. , FRASER R. S. S. , SEELEY N. D. 
Published: February 2008

SUMMARYA distinctive strain of tobacco necrosis virus (TNV) of unknown source was repeatedly isolated from water of the River Avon (Warwickshire) and two of its tributaries (R. Swift and R. Alne) using a technique developed for the concentration and isolation of water‐borne bacteriophages. The same strain was isolated from the rivers Cam and Thames and from Lake Esthwaite (Cumbria) together with tomato bushy stunt virus.The TNV strain, designated Chenopodium necrosis (TNV‐CN) was mechanically transmissible to C. amaranticolor and C. quinoa in both of which it caused local lesions and systemic infection. TNV‐CN caused no infection when inoculated to tobacco (Nicotiana tabacum cv. White Burley) plants.The virus was not adsorbed to soil, could be isolated from leachate of soil in which systemically infected C. quinoa were grown and C. quinoa plants became infected when grown in soil watered with suspensions of the virus.The virus was not transmitted by Myzus persicae but was vectored by the zoospores of a lettuce isolate of Olpidium brassicae.TNV‐CN was infective after 10 min at 85 °C., 3 wk at 20 °C and when diluted to 10‐8 but not 10‐9. Purified virus preparations contained c. 26 nm isometric virus particles.TNV‐CN contained single‐stranded RNA (mol. wt 1·5 × 106) and one protein (mol. wt c. 26·4 × 103) which co‐electrophoresed in polyacrylamide gels with the protein of the D strain of TNV (TNV‐D). Analytical centrifugation of TNV‐CN indicated a single component virus with the same sedimentation coefficient (s20, w= 115S) and buoyant density (1·385) in a CsCl gradient as those of TNV‐D. TNV‐CN and TNV‐D were indistinguishable serologically.