bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of three techniques used to determine surfactant phytotoxicity
Authors: COUPLAND D. , ZABKIEWICZ J. A. , EDE F. J. 
Published: February 2008

SummaryThree techniques were used to measure and compare the phytotoxicities of Triton X‐45 and Agral 90 (two organic surfactants) with two organosilicone surfactants (Silwet L‐77 and L‐7607), and to compare these four non‐ionic compounds with a cationic tallow amine surfactant (Hyspray). Total ion efflux and ethylene response methods were used in vivo and in vitro, while a betacyanin efflux method was an in vitro system only. The first two methods, using intact leaves, were considered to be more closely related to normal spraying conditions than the betacyanin efflux test which used explant material. However, the use of intact leaves was thought to bias the results in favour of the leaf penetration properties of the surfactants rather than their phytotoxicities. The in vitro pigment efflux method provided a simple way of ranking the surfactants in order of their potential phytotoxicities, especially with regard to effects on membrane permeability. This ranking, in increasing order of toxicity, was: Silwet L‐7607, Silwet L‐77, Agral 90, Triton X‐45 and Hyspray.
Resistance of cereals to aphids: Interaction between hydroxamic acids and the aphid Sitobion avenae (Homoptera: Aphididae)
Authors: LESZCZYNSKI B. , DIXON A. F. G. 
Published: February 2008

SUMMARYThe hydroxamic acids in the seedlings of four varieties of winter wheat were extracted initially in boiling methanol in order to avoid enzymatic hydrolysis. The increase in numbers of aphids on these varieties of wheat were recorded. HPLC analysis of hydroxamic acids in the extracts showed the presence of DIMBOA‐glucoside, DIMBOA‐aglucone and its benzoxazolinone (MBOA). There was a highly significant negative correlation between the concentration of DIMBOA‐aglucone in the seedlings and aphid performance. However, the association between aphid performance and DIMBOA‐aglucone in the tips of the seedlings was weaker. In general aphid infestation of wheat seedlings slightly increased the concentration of all the hydroxamic acid derivatives. Moreover, aphids ingested hydroxamic acids and were able to detoxify some of the DIMBOA‐aglucone they ingested.
The effects of sowing date and choice of insecticide on cereal aphids and barley yellow dwarf virus epidemiology in northern England
Authors: McGRATH P. F. , BALE J. S. 
Published: February 2008

SUMMARYDuring the mid‐1980s, Sitobion avenae became recognised as an important vector of barley yellow dwarf virus (BYDV) in the Vale of York. A field trial at the University of Leeds Farm, North Yorkshire, was carried out during the autumn/winter of 1984‐85 to evaluate different control procedures against S. avenae‐transmitted BYDV and to investigate its epidemiology. Winter barley was sown on three dates in September, and plots were sprayed with either deltamethrin, demeton‐S‐methyl or pirimicarb on one of three dates between mid‐October and mid‐November, making a factorial design. Rhopalosiphum padi, the main vector of BYDV in southern England, were rarely found during the experiment, but the numbers of S. avenae were much higher, reaching a peak of 21% of plants infested in the unsprayed plots of the first sowing date. Single applications of each insecticide reduced populations of S. avenae to zero. Some treatments, particularly in the early sown plots and those treated with pirimicarb, however, did allow some recolonisation, and thus led to increased virus incidence and decreased yields. Sprays applied before the end of the migration of S. avenae were more efficient at controlling BYDV if the insecticide was persistent, otherwise a spray after this period, in November, was more effective.Virus incidence, although reduced by sprays, was generally low in plots sown on 18 and 27 September. In contrast, about 11% of plants were infected in unsprayed plots sown on 6 September and a small yield benefit was obtained with insecticidal treatments.Enzyme‐linked immunosorbent assay (ELISA) of plants taken from the plots indicated that MAV‐ and PAV‐like strains were present, and were most likely to have been transmitted by S. avenae.
Carabid populations in field beans and their effect on the population dynamics of Sitona lineatus (L.)
Authors: HAMON N. , BARDNER R. , ALLEN‐WILLIAMS L. , LEE J. B. 
Published: February 2008

SUMMARYThe abundance and diversity of potential carabid predators of Sitona lineatus (L.) in field beans were monitored between 1980 and 1983. The absolute abundance of the large predatory species was determined in mark‐recapture experiments and a radio‐labelling technique was used to estimate the level of predation in the field. Using previously published population data for S. lineatus, the importance of predation in the population dynamics of the weevil was estimated. The mortality of weevil larvae due to predation varied from 0.6%– 10.5% while that of adult weevils varied from 2.6%– 23.8%. It appeared that carabids played a significant role in the population dynamics of S. lineatus and, in years when abundant, could reduce the population of larvae and overwintering adults by more than 30%.
Feeding behaviour of the staphylinid beetle Tachyporus hypnorum in relation to its potential for reducing aphid numbers in wheat
Authors: DENNIS P. , WRATTEN S. D. , SOTHERTON N. W. 
Published: February 2008

SUMMARYAphid consumption by larval and adult Tachyporus hypnorum (Coleoptera: Staphylinidae) in different reproductive states was compared under laboratory conditions. Post‐overwintering (spring/summer) adults had a higher consumption rate of first/second instar Sitobion avenae (Hemiptera: Aphididae) than did overwintering adults. Choice experiments incorporating Isotoma viridis (Collembola: Isotomidae) and Sciara thomae (Diptera: Mycetophilidae) as alternative prey items showed that T. hypnorum had a strong preference for aphids at a range of prey frequencies. Numbers of aphids consumed were reduced when leaves infected with Erysiphe graminis f.sp. tritici (powdery mildew of wheat) were offered to beetles with aphids in choice experiments. Behavioural studies of adult T. hypnorum showed that foraging rates on wheat plants increased with increasing amounts of both mildew and aphids on plants. Feeding upon only the conidia of E. graminis was observed. Results are discussed in relation to previous data derived from gut dissection, to a field survey of alternative foods and to the phenology of T. hypnorum in relation to that of aphids in the wheat crop.
Genetic structure and relationships of four populations of the stalk boring moth, Eldana saccharina
Authors: BANK F. H. VAN DER , LESLIE G. W. , ALLISON J. C. S. 
Published: February 2008

SUMMARYTwenty‐seven protein coding loci were examined by means of horizontal starch gel electrophoresis in samples of larvae from four populations of the stalk borer Eldana saccharina Walker (Lepidoptera: Pyralidae) in Natal, South Africa. The populations were collected in two localities approximately 250 km apart. In each locality a sample was obtained from sugarcane and also from the locally most abundant indigenous host plant of this insect (Cyperuspapyrus L. in one locality and C. dives Delile ‐ synonomous with C. immensus CB CI. ‐ in the other).More than one allele was detected at eight of the loci in all four populations and at a further locus in three of the populations; the other 18 loci were monomorphic for the same allele in all populations. Average expected heterozygosity over the 27 loci was approximately 0.12 in all populations. Genetic distances among the populations were small, but were greater between the two populations from the indigenous hosts and the two from sugarcane than within either of these pairs of populations. Possible explanations of these results are discussed.
Effects of alien cytoplasm substitution on the response of wheat cultivars to Septoria nodorum
Authors: KEANE E. M. , JONES P. W. 
Published: February 2008

SUMMARYThe effects of alien cytoplasm substitution on the response of wheat to Septoria nodorum were studied, using alloplasmic series of two cultivars, Chris and Selkirk. In general, cytoplasmic substitution caused unidirectional effects on Septoria‐response, alloplasmic lines of both cultivars expressing lower levels of partial resistance (in leaf and head tissue) but higher levels of yield tolerance than the corresponding euplasmic line. The reduced resistance in alloplasmics was closely associated with reduced incubation periods of Septoria infection in both leaf and head tissue. Cytoplasmic substitution resulted in increased yield tolerance to Septoria‐infection in both the non‐tolerant Selkirk and the relatively tolerant Chris. Unlike their effects on partial resistance, specific cytoplasms exerted similar effects on tolerance in the two parental cultivars, several cytoplasms of the D plasmatype being particularly effective in increasing Septoria‐tolevance. The potential for the development of Septoria‐toterant cultivars by the incorporation of alien cytoplasms is discussed, in view of the observed neutral effects of D plasmatype cytoplasms on other agronomic traits.
Epidemiology of Cladosporium allii and Cladosporium allii‐cepae, leaf blotch pathogens of leek and onion.
Authors: JORDAN MARY M. , BURCHILL R. T. , MAUDE R. B. 
Published: February 2008

SUMMARYIsolates of Cladosporium allii and Cladosporium allii‐cepae grew at 20°C and 15–20°C respectively on 2.5% malt extract agar and both species tolerated a wide pH range with maximum sporulation of C. allii‐cepae between 5–8.5. C. allii did not sporulate in the light in culture and grew more rapidly in darkness. At least 8 h darkness was necessary for optimum conidiation of both fungi on lesions of leek and onion but conidiophores were produced in light and dark conditions after 2–12 h incubation at > 90% relative humidity (r.h.). Radiation of 2 W/m23 W/m2(the approximate equivalent to strong moonlight) prevented conidiation of C. allii and C. allii‐cepae respectively. Relative humidities of 95–100% increased sporulation of both fungi on leaf lesions.Laboratory and field experiments to measure the effects of temperature, light and relative humidity'on sporulation showed that maximum sporulation of both pathogens on leaf lesions occurred in the late autumn (November‐December) with a secondary peak in the early spring (March‐April). Conidia of Cladosporium allii and C. allii‐cepae were intermittently detected in the air over diseased leek and onion crops during the years 1982–1985. The simultaneous occurrence of 8 h darkness, r.h. > 95% and temperatures of 9–12°C resulted in the presence of high concentrations of conidia of C. allii in the atmosphere above leek crops in the subsequent 24 h.The pattern of spore release for both fungi was similar with maximum and minimum concentrations of conidia recorded during late‐morning early afternoon (10.00–14.00 h) and during the night respectively. There was little correlation between declining relative humidity and spore release but there was a significant correlation between concentrations of conidia trapped and increasing light intensity and to a lesser extent with temperature. Mechanical disturbance of the crops by rain, wind and human activity resulted in isolated increases in spore concentrations.
Quantitative assay of resting spores of Polymyxa graminis on barley roots
Authors: YILI RUAN , WANHE ZOU , JIANPING CHEN 
Published: February 2008

SUMMARYA procedure was developed to examine amounts of Polymyxa graminis on eleven barley cultivars from a field experiment on a site infested with barley yellow mosaic virus (BaYMV) and which differed in field response to the virus. Powder produced from dried barley roots infected with P. graminis was soaked overnight at 4°C in a solution of 1 % sodium metaphosphate and 0.25% Tween 20. This was followed by high speed homogenisation, filtering, ultrasonic treatment of the residue and differential centrifugation. A suspension of individual resting spores free from other recognisable fungi was obtained, which ranged in concentration from 0.4 to 7.3 × 107spores per g root. Repeated extraction of the residues suggested that most spores were liberated by the first cycle of treatment. The cultivar with the greatest incidence of BaYMV also had the most P. graminis; some cultivars resistant to BaYMV had less P. graminis but there was no general correlation between the incidences of virus and vector.
The impact of pests and diseases on the herbage yield of permanent grassland at eight sites in England and Wales
Authors: CLEMENTS R. O. , MURRAY P. J. , BENTLEY B. R. , LEWIS G. C. , FRENCH N. 
Published: February 2008

SUMMARYPlots at each of eight widespread permanent pasture sites below 300 m and representative of large areas of long established grassland in England and Wales, were treated with an insecticide plus molluscicide, a fungicide or nematicide treatment. Populations of various invertebrates and the occurrence of foliar fungal diseases were assessed.Leaf blotch (Drechslera) was the most common disease, but neither this nor other foliar fungal diseases were prevalent until late in the growing season. The fungicide treatment did not control diseases satisfactorily. The fungicide and nematicide treatment had little effect on total annual herbage yield. Leatherjackets, crambids, slugs and frit fly larvae were present, usually in low numbers, at most sites. The insecticide and molluscicide treatment increased yield by 11% on average across all sites and years. Losses caused by pests to UK grasslands were estimated to be over £500 million per year.
Migratory plant‐parasitic nematodes associated with cereals in Scotland
Authors: BOAG B. , BOWEN S. , SPAULL A. M. , WRIGHT G. , SMITH B. F. L. 
Published: February 2008

SUMMARYNinety‐eight soil samples were collected from cereal farms on mainland Scotland and examined for migratory plant‐parasitic and predatory nematodes. Soil analysis was also carried out on each sample. Of the 25 parasitic nematode species identified Longidorus elongatus was the most frequently found and while populations were generally low, populations great enough to cause damage were detected. Populations of other plant‐parasites were usually low. Individual species were unlikely to cause economic losses but their combined effect could possibly reduce yields. Analysis of the relationships between nematode species suggested that neither competition nor predation were important factors limiting population size. With few exceptions, none of the soil factors measured influenced the occurrence or abundance of the nematodes identified.
Breeding for increased nitrogen fixing ability among wild and cultivated species of chickpea
Authors: JAISWAL H. K. , SINGH R. K. 
Published: February 2008

SUMMARYTwo chickpea species, one wild (Cicer reticulatum JM2106) and one cultivated (C. arietinum ICC8923) were selected as the parents for this study. C. reticulatum showed high nodule number, nodule dry weight and nitrogen content/plant as compared to C. arietinum. In lines derived from the crosses H208 × (ICC8923 × JM2106) and BG274 × (ICC8923 × JM2106), increase in nodule dry weight, nitrogen content/plant, plant dry weight and grain yield was observed over the parent ICC8923. Similarly F6 lines also showed improvement in these traits over the cultivated parent. It is concluded that the increase in grain yield and dry matter is the result of improvement in nitrogen utilisation together with an increase in the available fixed nitrogen.
Thermal insulation of the winter cauliflower curd by wrapper‐leaves
Authors: TAPSELL C. R. , GROUT B. W. W. , FULLER M. P. 
Published: February 2008

SUMMARYThe role of leaves as insulation for mature curds during exposure to frost has been investigated for winter‐harvested cauliflower. The inner, wrapper‐leaves and their enclosed air spaces provided significant protection for the curd tissues in mild frost, but under more severe conditions (below – 2.5°C) were ineffective. A relationship between higher wrapper‐leaf number and increased insulation was described. The increase in insulation however, was small even with much higher wrapper‐leaf numbers. Exposure of the curd surface at maturity was found to prevent the insulating effect of wrapper‐leaves, particularly if the diameter of the exposed area was greater than 6 cm. The data also suggested a possible role for the exposed stem of the cauliflower as a site of heat loss that may adversely affect curd temperature.It is postulated that breeding for improved frost resistance by greatly increasing wrapper‐leaf number would not be effective, although any reduction in wrapper‐leaf number and the presence of tightly wrapped curds should be avoided. Furthermore, exposure of the curd surface at maturity should be kept to a minimum.
The effect of an experimental growth retardant (WL83801) on leaf growth and development in Lolium perenne L.
Authors: FOREMAN M. H. , MARSHALL C. 
Published: February 2008

SUMMARYThe experimental growth retardant WL83801, applied as a root drench, had a rapid and persistent effect in retarding the growth and development of leaves in L. perenne. Leaves of the main shoot were greatly reduced in length, were broader, and appeared faster than in control plants. The rate of extension of individual leaves was greatly reduced in retarded plants but still followed a diurnal pattern that closely corresponded with temperature. There was evidence that leaf extension was far less responsive to temperature in treated plants. At the cellular level WL83801 had no significant effect on leaf blade cell number, thus reductions in leaf length were associated with the retardation of cell elongation. Changes in leaf structure were also observed.These changes in the pattern of leaf growth and development are discussed in relation to the primary mode of action of the growth retardant in interfering with gibberellin biosynthesis.
Feeding behaviour and mortality of the slug, Deroceras reticulatum in relation to control with molluscicidal baits containing various combinations of metaldehyde with methiocarb
Authors: BOURNE N. B. , JONES G. W. , BOWEN I. D. 
Published: February 2008

SUMMARYIn terms of control of slug pests, the differing modes of action of the two molluscicides metaldehyde and methiocarb appear to provide some advantages for the former during warm, dry weather and for the latter during cool, wet weather. With a view to exploiting these different modes of action, the feeding behaviour of Deroceras reticulatum (Müller) presented with molluscicidal baits containing various combinations of metaldehyde with methiocarb was investigated. Voluntary feeding trials conducted in the laboratory with both candidate and standard treatments (containing metaldehyde or methiocarb alone) are described. By combining the two active ingredients in certain ratios the total concentration of active ingredients may be reduced without adversely affecting the efficacy of a bait formulation in terms of slug mortality.
An improved test for evaluating the pathogenicity of isolates of Fusarium solani f.sp. pisi on pea
Authors: DYER P. S. , INGRAM D. S. 
Published: February 2008

SUMMARYAn improved in vitro test is described for determining the pathogenicity of Fusarium solani f.sp. pisi isolates on pea. This technique involves the use of polypropylene fibre Milcap plugs to suspend peas in boiling tubes containing spore suspensions in 0.1% water agar. Results were available after 14 days of incubation at 25°C. Four levels of pathogenicity were detected on pea cultivars Little Marvel and Dark Skinned Perfection using a total of eight isolates and strains of F. solani f.sp. pisi.
Further investigations of the host range of the carrot fly, Psila rosae (F.)
Authors: HARDMAN J. A. , ELLIS P. R. , SAW PAMELA L. 
Published: February 2008

SummaryTechniques were developed for testing umbelliferous species against naturally‐occurring populations of carrot fly in the field. The most efficient technique involved exposure of plants to either first or second generations of the insect in the field, followed by caging of infested plots and trapping of emerged flies in water in yellow water dishes.In a series of field experiments between 1981 and 1989 inclusive, a total of 132 umbelliferous species and sub‐species were tested against carrot fly. Seventy‐eight of these proved to be new hosts, 27 were confirmed as hosts and 27 failed to support any carrot flies. Six non‐umbelliferous plant species failed to be colonised by carrot fly. Sources of variability in investigations of the host range of insects are discussed.
Alternaria alternata f.sp. cucurbitae, the cause of a new leaf spot disease of melon (Cucumis melo)
Authors: VAKALOUNAKIS D. J. 
Published: February 2008

SummaryA leaf spot disease of melon caused by Alternaria alternata f.sp. cucurbitae was recorded for the first time in Crete. Necrotic flecks surrounded by chlorotic halos developed on the cotyledons and the leaves of the middle and the upper part of the plants; the flecks enlarged and coalesced to form lesions of 2 cm or more in diameter with brown fructifications of the pathogen on their surface. Severely affected cotyledons and leaves became chlorotic and died. Of 16 species from eight botanical families that were inoculated, only those of the Cucurbitaceae were susceptible. Of four isolates of A. alternata from tomato, sunflower, pear and cucumber, only the cucumber isolate was pathogenic to melon foliage.
Selection of brown spot‐resistant rice plants from Helminthosporium oryzae toxin‐resistant calluses
Authors: VIDHYASEKARAN P. , LING D. H. , BORROMEO E. S. , ZAPATA F. J. , MEW T. W. 
Published: February 2008

Summary Helminthosporium oryzae toxin induced electrolyte leakage from rice callus tissues and caused their browning and death. A virulent isolate of the pathogen invaded and colonised callus tissues rapidly, while a less virulent and a nonpathogenic isolate colonised calluses only weakly if at all. Addition of the toxin to calluses permitted colonisation of calluses by the nonpathogenic isolate. Four toxin‐resistant calluses were selected and plants regenerated from two of these resistant calluses showed resistance to the pathogen. This resistance was heritable and stability of resistance was observed in the R1, R2 and R3 generations.