bluuebunny/crossref_metadata_2025_split huggingface dataset:
The influence of pre‐floral growth and development on the pathway of floral development, dry matter distribution and seed yield in oilseed rape (Brassica napus L.)
Authors: TOMMEY ANDREW M. , EVANS ERIC J. 
Published: February 2008

SummaryPatterns of floral development, dry matter distribution and seed yield were examined in winter oilseed rape plants subjected to different pre‐floral growth environments. The duration of pre‐floral growth and plant size at flower initiation, measured in terms of total mainstem leaf number, were manipulated by varying the temperature between seedling emergence and flower initiation.Exposure of seedlings to low temperatures from cotyledon expansion onwards markedly reduced the duration of pre‐floral growth and the number of leaves on the mainstem. The subsequent development pattern of plants was largely dependent on the date of flower initiation and therefore vernalisation requirement. Indeed, the period of growth from flower initiation to maturity, considered on the basis of thermal time, was directly related to the duration of pre‐floral growth and mainstem leaf number. The thermal durations of the bud development phase and flowering period in plants exposed to different pre‐floral cold treatments but with a common date of flower initiation were similarly linked to these two parameters.Plants exposed to prolonged periods of low temperature treatment from cotyledon expansion onwards initiated fewer mainstem leaves during a relatively short pre‐floral growth phase and their yield potential was limited by a reduction in branch and flower numbers. Plants maintained at higher temperatures produced more mainstem leaves during an extended period of pre‐floral growth and supported a greater number of branches and flowers. However, this additional yield potential was not realised due to a reduction in seed numbers and mean seed weight. It appeared that seed yield of these plants was limited by increased competition between an excessive number of lower branches and flowers, a problem apparently created by excessive pre‐floral growth. Minimal competition for available assimilates between the limited number of branches of plants with a shorter pre‐floral growth phase and fewer mainstem leaves, resulted in lower levels of pod abortion, greater seed production and ultimately increased seed yields.
Host‐specificity of Uromyces heliotropii, a fungal agent for the biological control of common heliotrope (Heliotropium europaeum) in Australia
Authors: HASAN S. , DELFOSSE E. S. , ARACIL E. , LEWIS R. C. 
Published: February 2008

SummaryCommon heliotrope, Heliotropium europaeum (Boraginaceae), a summer annual, is a serious weed of pastures in Australia causing poisoning in sheep and other grazing animals. The weed is native to Mediterranean and Middle Eastern regions of Eurasia where it is attacked by several arthropods and pathogens including the rust fungus Uromyces heliotropii. The host‐specificity of a virulent and effective strain of the rust from Turkey has been tested by inoculating 96 plants of importance to the Australasian region using both microscopic and macroscopic observations of the reaction of host and non‐host plants. The test plants included several members of the Boraginaceae and related families as well as species of Heliotropium native to Australia. The infection was mostly limited to European species of Heliotropium. U. heliotropii was thus found to represent a safe introduction and has recently been introduced to Australia for the biological control of common heliotrope.
A large improved rotary trap for sampling aerial invertebrates
Authors: TOPPING C. J. , SUNDERLAND K. D. , BEWSEY J. 
Published: February 2008

SummaryA large rotary trap designed to measure aerial spider density is described. A comparison of the rotary trap catch and a suction trap catch of spiders and other invertebrate groups showed that the rotary trap was operating at a greater efficiency for most groups. For spiders and non‐staphylinid beetles the two traps caught equal numbers. There were no differences in the species composition of spiders between the rotary and suction trap catch.
A technique for assessing damage to roots of white clover caused by root feeding insects
Authors: MURRAY P. J. , CLEMENTS R. O. 
Published: February 2008

SummaryA nutrient, slant‐board technique was developed in order to estimate the losses to roots of white clover (Trifolium repens L.), caused by the feeding of the larvae of Sitona weevils. In this preliminary experiment losses of up to 50% of root length were found. This simple technique was straightforward to use and has the potential for applications in a large range of root‐pest/feeding studies.
Effects of temperature, feeding position and crop growth stage on the population dynamics of the rose grain aphid, Metopolophium dirhodum (Hemiptera: Aphididae)
Authors: ZHOU X. , CARTER N. 
Published: February 2008

SummaryThe population dynamics of Metopolophium dirhodum were studied on winter wheat seedlings at constant (10°C, 15°C, 20°C, 25°C and 30°C) and fluctuating (12(night)‐22(day)°C) temperatures, and during booting to early inflorescence, and anthesis to early milky ripe stage, at 19°C. The pre‐reproductive development time was decreased by increasing the temperature from 10°C to 25°C. It was significantly shorter when the aphids were feeding during booting to early inflorescence than during anthesis to early milky ripe stage but was similar when the aphids were feeding on the flag, second or third leaves. The total number of nymphs produced/apterous adult was not significantly affected by temperature from 10°C to 25°C but adult reproductive lifespan was reduced by increasing temperature from 10°C and 12–22°C to 15°C, 20°C and 25°C. The daily intrinsic rate of increase changed from 0.11 to 0.25, and the cohort generation time decreased from 31 to 12 days, with increase of temperature from 10°C to 25°C. Reproductive rate was similar when the aphids were feeding on the flag, second or third leaves during booting to early inflorescence at 19°C. The reproductive rate was higher when the aphids fed from mid‐inflorescence to mid‐milky ripe stage than from mid‐milky to early ripe stage. These results were compared with those from other studies. Predictions from a simulation model using development and reproductive rates from this study and literature were compared and the former rates resulted in a more accurate prediction of field observations in 1979, an outbreak year.
Seasonal changes in primary and secondary inoculum during epidemics of leaf blotch (Rhynchosporium secalis) on winter barley
Authors: DAVIS HELENA , FITT B. D. L. 
Published: February 2008

SummarySeasonal changes in numbers of conidia of Rhynchosporium secalis on debris from previous barley crops infected with leaf blotch (primary inoculum) were monitored in 1985–86 and 1986–87. In 1986–87, changes in numbers of conidia on leaves of plants in the new winter barley crop (secondary inoculum) were also recorded. The greatest increases in production of primary inoculum were in early spring after rain, when temperatures were increasing after periods of sub‐zero temperatures when there was little conidial production. Subsequently, more conidia were recovered from this debris after cycles of drying and rewetting than when it remained wet. After January 1987, amounts of secondary inoculum produced on the crop were much greater than amounts of primary inoculum on debris. Most spores were produced on the basal leaves and more spores were present on the September‐sown than on the November‐sown crop. Thus, while primary inoculum was a source of disease when plants were emerging, secondary inoculum on basal leaves was the main source of disease at stem extension, especially on early‐sown crops.
Improvements in the detection of pea seed‐borne mosaic virus by ELISA
Authors: DING X. S. , COCKBAIN A. J. , GOVIER D. A. 
Published: February 2008

SummaryThe detection by ELISA of pea seed‐borne mosaic virus (PSbMV) in pea leaves and seeds was improved by the addition of cellulase or Triton X‐100 to the extraction fluid, probably because the additives aided the release of virus particles from host materials. With leaf extracts the additives were most effective at 0.1%. In initial tests cellulase was used with macerozyme, but the latter enzyme was then shown to decrease the effectiveness of cellulase. Triton X‐100 was as effective as cellulase and the absorbance values obtained in ELISA of infected leaf extracts, diluted to 1/10 in extraction fluid containing the additive, were about six times greater than those of infected extracts diluted in normal extraction fluid. Five named isolates of PSbMV, in addition to the homologous isolate, were readily detected in infected leaves extracted in fluid containing Triton X‐100.In tests on seeds and seedlings of seven infected seed lots of pea cv. Waverex, using Triton X‐100 in the extraction fluid, PSbMV was detected in five times as many seeds as seedlings, probably mainly because in many infected seeds the virus was in the testa and not in the embryo. About 9% of infected seedlings were without recognisable symptoms 4 wk after emergence.
A study of the mode of transmission of maize streak virus by Cicadulina mbila using an enzyme‐linked immunosorbent assay
Authors: REYNAUD B. , PETERSCHMITT M. 
Published: February 2008

SummaryTwo batches of Cicadulina mbila were given two distinct acquisition access periods (AAP) (3 h and 50 h) on maize plants infected with maize streak virus (MSV). Infectivity assays on susceptible maize were carried out 1, 3, 10, 17, 26 and 35 days after the AAP. Transmission efficiency was significantly higher for C. mbila subjected to the 50‐h AAP. At the same time as the infectivity assays, the amount of MSV in each leafhopper was determined by an indirect double antibody sandwich (IDAS) ELISA. There were more ELISA‐positive insects after the 50‐h AAP than after the 3‐h AAP. In the group given a 3‐h AAP, only 7% of the insects tested between day 1 and 35 were found to be positive by ELISA. In contrast, after the 50‐h AAP, the majority of C. mbila were positive, yet a decrease in ELISA‐positive insects was noticed from day 17 onwards. Using a calibration curve obtained with purified virus, as little as 0.15 ng of MSV per insect could be measured by the IDAS‐ELISA. A mean value of 0.36 ng of MSV per C. mbila was found 3 days after the 50–h acquisition, whereas 14 days later there was only 0.20 ng of virus per insect. For comparison, when leafhoppers were kept on infected maize, they displayed substantial accumulation of MSV up to an average of 3.83 ng of MSV per insect after 35 days of continuous acquisition. The amount of virus per insect detected in females was usually greater than the amount detected in males. Our results suggest that MSV does not multiply in C. mbila and contribute to the understanding of the persistence of transmission efficiency in the absence of virus multiplication.
Cloned DNA probes for detection of grapevine Flavescence dorée mycoplasma‐like organism (MLO)
Authors: DAIRE X. , BOUDON‐PADIEU E. , BERVILLE A. , SCHNEIDER B. , CAUDWELL A. 
Published: February 2008

SummaryFlavescence dorée (FD), a yellows disease of grapevine is caused by a non cultivable mycoplasma‐like organism (MLO) transmitted in vineyards by the leafhopper vector Scaphoideus titanus. In the laboratory, FD is transmitted from broadbean to broadbean by the leafhopper Euscelidius variegatus. Total DNA from FD‐diseased broadbean was centrifuged in a bisbenzimide‐CsCl density gradient. Low density DNA was collected from the gradient, digested with HindIII, ligated into plasmid pUC18 and cloned in Escherichia coli. Trans‐formants were differentially screened by colony hybridisation with 32P‐iabelled healthy and FD‐infected leafhopper DNA as probes. The selected clones were shown to carry inserts which all hybridised with FD‐diseased host DNA and not with DNA from healthy host. These 32P‐labelled inserts, used as probes in dot blot hybridisation, enabled detection of FD‐MLO in field‐collected samples of grapevine. However, because of the low MLO titre in this plant, an MLO enrichment procedure using tissue from main leaf veins was necessary to ensure efficient DNA extraction.
Broad bean wrinkly seed caused by artichoke yellow ringspot nepovirus
Authors: AVGELIS A. D. , KATIS N. , GRAMMATIKAKI G. 
Published: February 2008

SummaryArtichoke yellow ringspot nepovirus (AYRV) was isolated from stunted broad bean plants in Crete showing leaf mottling and deformation and wrinkling of seed testas. AYRV identification was based on host range, behaviour during purification, electron microscopy and serology.AYRV‐broad bean isolate was seed‐transmitted in broad bean, and embryo infection appeared to be a prerequisite for virus transmission to seedlings. Transmission through pollen was not detected in broad bean plants, although pollen grains were externally contaminated by the virus. Ovule infection occurred in a high proportion of seed and was independent of pollination.
Monoclonal antibodies to beet soil‐borne virus
Authors: BARBAROSSA L. , VETTEN H. J. , KAUFMANN A. , LESEMANN D.‐E. , KOENIG R. 
Published: February 2008

SummaryFour monoclonal antibodies (MCA) were obtained to the ‘Ahlum’ serotype of beet soil‐borne virus (BSBV). On ELISA plates which had been precoated with polyclonal antibodies (PCA) all four MCA detected this serotype with a higher sensitivity than alkaline phosphatase‐labelled PCA. Three of the MCA were specific for the ‘Ahlum’ serotype, but a fourth one also detected the distantly related ‘Wierthe’ serotype. Cross‐reactions with wheat soil‐borne or oat golden stripe furoviruses were not observed. One of the MCA reacted with an epitope which is exposed along the entire length of the BSBV particles, whereas two others were specific for epitopes which are exposed on one particle extremity only. Although these latter two epitopes occur apparently on the same extremity of the particles, they seem to be different, because one is found only on the particles of the ‘Ahlum’ serotype, whereas the other one is present also on the particles of the ‘Wierthe’ serotype. The fourth MCA is specific for a cryptotope which is not exposed on the intact virus particles, but presumably on some degradation product or precursor of the viral coat protein present in crude sap preparations. All four epitopes are SDS‐labile; they are not detected on denatured viral coat protein on Western blots.
Influence of nematicide, resistant and susceptible potato cultivars and bare fallow on the population dynamics of Globodera rostochiensis Woll. Rol under field conditions in Spain
Authors: SALAZAR A. , RITTER E. 
Published: February 2008

SummaryThe susceptible potato cultivar Désirée and the resistant cv. Diamant were cultivated on untreated and nematicide‐treated plots on two fields in northern Spain infested with Globodera rostochiensis Rol. Initial and final infestations of cysts and viable eggs were assessed. Multiplication rates differentiated more accurately the effects of the different treatments than final number of cysts and eggs, due to the elimination of some of the errors associated with variability of the initial infestation. Many new cysts were observed on all plots where susceptible potatoes had been grown, whether they had been treated with nematicide or not, although significantly fewer cysts were actually found on the nematicide‐treated plots. With the resistant cultivar no significant effects of the nematicide were detected even though there was a noticeable reduction of viable cyst contents over and above the effect of the resistant cultivar.
Control of potato cyst nematode (Globodera pallida) by host plant resistance and nematicide
Authors: GURR G. M. 
Published: February 2008

SummarySeven trials conducted over four years on sites naturally infested with the white potato cyst nematode established that potato clones bred for resistance to Globodera pallida allowed significantly less nematode multiplication than conventional cultivars under field conditions. Nematode multiplication was inversely related to initial infestation level. The nematicide, aldicarb, significantly reduced nematode multiplication. However, nematode multiplication on nematicide treated susceptible cultivars was greater than on untreated partially resistant clones, indicating that resistance may offer more effective control of G. pallida than chemical treatment. Integration of host plant resistance and nematicide treatment is discussed.
Apple replant disease: the assessment and results of seedling bio‐assays of growth responses to soil fumigation with chloropicrin
Authors: SEWELL G. W. F. , ROBERTS A. L. , ELSEY R. F. 
Published: February 2008

SummaryThe effects of chloropicrin fumigation of field soils before replanting apple are frequently predicted from bio‐assays using pot‐grown apple seedlings. The results of 506 such bio‐assays carried out during 12 years are discussed with reference to modifications which were made to the test method. The interpretation of the most recent and valid bio‐assay results is considered in relation to the different purposes for which such tests may be conducted.When all test soils were amended with phosphorus (to compensate for the eradication of vesicular‐arbuscular mycorrhizal fungi by fumigation) the proportion of old orchard soils yielding economically significant growth responses increased from 39% to 68%. When, additionally, plant growth was assessed by shoot fresh weight (rather than shoot length) the proportion further increased to 82%.The traditional method of expressing growth responses to soil sterilisation, as proportionate growth increases, was found to be subject to skewing effects of non‐biological fertility factors; this feature was avoided when results were given as actual growth increases. The latter value therefore is considered preferable when assessing the relative disease status of soils for etiological purposes (as opposed to predicting the cost‐benefits of field soil treatment).The data indicated that disease severity was on average diminished in the most acidic soils (pH 4.8–6.1), but did not support the generalisation that disease severity increases progressively with soil pH.
Comparative epitope profiles of the particle proteins of whitefly‐transmitted geminiviruses from nine crop legumes in India
Authors: SWANSON M. M. , VARMA A. , MUNIYAPPA V. , HARRISON B. D. 
Published: February 2008

SummaryGeminiviruses associated with yellow or golden mosaic diseases of legume crops in two regions of India were compared by testing their reactivity with 27 monoclonal antibodies (MAbs) prepared to the particles of African cassava mosaic (ACMV) or Indian cassava mosaic (ICMV) viruses. The viruses fell into two main groups. Group 1 comprised isolates of dolichos yellow mosaic virus; these reacted with three or four ACMV MAbs and four ICMV MAbs. Group 2 comprised isolates of horsegram yellow mosaic virus, together with isolates from blackgram, cowpea, French bean, pigeonpea, soybean, Indigofera hirsuta and probably also isolates from mungbean. These reacted with three or four ACMV MAbs but with few or no ICMV MAbs. Isolates within each group differed slightly in epitope profile, depending on the source species (Group 2) or geographical origin (Groups 1 and 2). Isolates from lima bean resembled those in Group 2 but had some antigenic differences, and their status is uncertain. The poor detectability of geminivirus isolates in mungbean may reflect a low virus concentration in this species.
The restricted distribution of potato leafroll luteovirus antigen in potato plants with transgenic resistance resembles that in clones with one type of host genemediated resistance
Authors: DERRICK PETER M. , BARKER HUGH 
Published: February 2008

SummaryThe distribution of virus‐infected cells was examined, by fluorescence microscopy, within plants of a range of potato clones infected with potato leafroll luteovirus (PLRV). This range included nine PLRV‐resistant clones, of which four were transgenic lines carrying the PLRV coat protein gene and five were conventionally bred. Plants of these clones were resistant to PLRV multiplication and accumulated less virus antigen in leaf tissue than did susceptible clones. Indirect fluorescent antibody staining of thin sections from carbodiimide‐fixed petiole tissue revealed that in plants of PLRV‐susceptible clones, virus‐infected cells were abundant within both external (abaxial) and internal (adaxial) phloem bundles. In plants of the PLRV‐resistant conventionally bred clones and in resistant transgenic lines of cv. Pentland Squire, virus‐infected cells were much fewer in number and largely restricted to internal phloem bundles. In resistant transgenic lines of cv. Désirée, this restricted distribution of PLRV antigen was only detected in petioles of young leaves. The results suggest that the transgenic and a host‐mediated type of resistance that restricts virtis multiplication have underlying similarities.
Emergence of juvenile potato cyst‐nematodes Globodera rostochiensis and G. pallida and the control of G. pallida
Authors: WHITEHEAD A. G. 
Published: February 2008

SummarySpeed of emergence of juveniles from cysts in potato root diffusate (PRD) in vitro differed between Globodera rostochiensis and G. pallida and between populations within each species. Early emergence in vitro was slower in most populations of G. pallida than in most populations of G. rostochiensis. Fewer G. rostochiensis juveniles emerged from 4 or 6 month old than from 4 yr old cysts.More G. rostochiensis emerged in solutions of sodium metavanadate at concentrations of 10‐2 and 10‐3 M than in PRD and as many G. pallida emerged in the same solutions as in PRD. In plots of bare fallowed sandy loam, emergence of G. pallida was stimulated by 10‐‐3 M sodium metavanadate. The emergence of two populations of C. pallida in PRD was stimulated by the addition of benomyl at 0.1 ppm (3.4 × 10‐‐7 m). In microplots, cv. Cara potatoes grown for 8 wk decreased four populations of G. pallida by up to 93%. During a 4 wk period in PRD, more than 20 juveniles per gravid female emerged from five of 25 populations of G. pallida. In root observation boxes in which cv. Désirée was grown, oxamyl applied to the top 15 cm of a peaty loam soil greatly increased G. pallida in soil 1545 cm deep. In another peaty loam, but not in a sandy loam, the same treatment appeared to increase the nematode in soil 15–30 cm deep. Oxamyl incorporated in the uninfested top 15 cm of all three soils largely prevented nematode increase from juveniles migrating upwards from untreated heavily infested soil 15–30 cm deep.These experiments suggest that inadequate control of G. pallida increase on susceptible potatoes by an oximecarbamate nematicide of short persistence, such as oxamyl, is primarily due to the slow rate of juvenile emergence in most populations of G. pallida, with a second generation and the upward migration of juveniles from deeper untreated soil later in the growing season as potential contributory factors.