bluuebunny/crossref_metadata_2025_split huggingface dataset:
Detection of lettuce necrotic yellows virus by an enzyme‐linked immunosorbent assay in plant hosts and the insect vector
Authors: CHU P. W. G. , FRANCKI R. I. B. 
Published: February 2008

SUMMARYAn enzyme‐linked immunosorbent assay (ELISA) system for the rapid detection of the plant rhabdovirus, lettuce necrotic yellows virus (LNYV) in plant hosts and individual aphid vector is described. The method has been shown to be reliable and sensitive, and to have a number of advantages over the conventional methods of detecting LNYV in plants and insects by infectivity tests.
Observations on the population dynamics, life cycle and ecology of the plant parasitic nematode Rotylenchus robustus
Authors: BOAG B. 
Published: February 2008

SUMMARYIn a forest nursery growing Sitka spruce Rotylenchus robustus was most numerous at a soil depth of 10–19 cm, the vertical distribution being associated with that of the tree roots. Although no consistent seasonal fluctuations in nematode numbers were obvious there was a seasonal pattern in the relative frequency with which adult and larval nematodes were recovered.Experimentally, the life cycle of R. robustus was completed in 14–18 months depending upon the time of year when nematodes were added to the trees. Soil moisture content of less than 8.7% (pF 3.8) restricted the movement of 50% of the population. The overall mean basal temperature for the completion of the life cycle of R. robustus was calculated to be 6.5°C.Soil temperature was considered to be the dominant factor controlling the rate of development under field conditions in Scotland; only occasionally did soil moisture become limiting.
Production and dormancy of wild oat (Avena fatua) seed from plants grown under soil waterstress
Authors: PETERS N. C. B. 
Published: February 2008

SUMMARYIn 1974 wild oat plants grown from very dormant seed types fA, fB, fC originating from a single field, and in 1976 plants of type fB derived from another location were waterstressed from the time when the spikelets were just beginning to emerge until the seed was fully ripe. The seed production and dormancy of the seed were determined. Waterstress reduced the number of viable seeds per plant by 42% in 1974 and 49% in 1976. The number of viable seed produced on the tillers of the plants were reduced to a greater extent by waterstress than the number produced on their main stems. Some of the differences between the number of viable seeds produced by the three wild oat types were significant. In 1974, 78% of seed from stressed plants was dormant as compared with 90% of that from unstressed plants. Under a given soil moisture, the dormancy of the three types differed little, although seed dormancy was less in tiller seed than in main stem seed. In 1976 seed from stressed plants was 80% dormant, immediately after collection, whereas that from unstressed plants was totally dormant. Storage for 6 months at 25°C decreased these percentages to 17% and 90% and at 5°C to 72% and 98% respectively. Buried in soil immediately after collection, 66% of viable seed from stressed plants gave seedlings in the first autumn after burial as compared with 4% of seed from unstressed plants. Most of the seed from waterstressed plants gave rise to seedlings in the first autumn, and seed from non‐stressed plants in the second spring. The α‐amylase content was four times greater in seeds from stressed compared with non‐stressed plants.
A survey of cutworm attacks in England and Wales, and a descriptive population model for Agrotis segetum (Lepidoptera: Noctuidae)
Authors: BOWDEN J. , COCHRANE J. , EMMETT B. J. , MINALL T. E. , SHERLOCK P. L. 
Published: February 2008

SUMMARYSurveys of larval populations and numbers of reports of damage showed that from 1945 to 1978 Agrotis segetum was the commonest species of cutworm, causing most damage, to a wide range of crops, from July to October. Attacks varied in extent and severity between years, the most severe damage occurring in 1949 and in 1976.A model has been devised to estimate an index of larval survival to third instar, based on temperature‐rate of development relationships and mortality due to daily rainfall. This survival index is highly correlated with year‐to‐year changes in numbers of reported attacks by A. segetum. The model suggests that weather conditions alone were responsible for the last major cutworm outbreak in 1976.
The natural incidence of disease in the cutworm Agrotis segetum in England and Wales
Authors: SHERLOCK P. L. 
Published: February 2008

SUMMARYSoil‐dwelling noctuids, mostly cutworm larvae were collected from various arable crops, from 39 sites in England and Wales between 1975 and 1978. They were individually reared in the laboratory, usually at 20 °C; 993 (79%) pupated and 859 (68%) emerged of which 819 (95%) were Agrotis segetum. Of those that died, 60 (4·8%) were infected, from a total of 25 sites; nuclear polyhedrosis, granulosis virus and a fungus of the family Entomophthoracae, probably Entomophthora megasperma, occurred in similar proportions. Disease incidence was low probably because natural concentrations of inocula were sparse. The possibility of controlling cutworms with their pathogens is discussed.
Infection of potato stems by the gangrene pathogen, Phoma exigua var. foveata
Authors: ADAMS M. J. 
Published: February 2008

SUMMARYLimited transport of pycnidiospores of Phoma exigua var. foveata within transpiring stems was demonstrated by isolating from cut mature stems placed for 24 h in a spore suspension. Pieces of shoot dipped in spore suspension and subsequently rooted contained the pathogen which was redistributed as the plants grew but without causing symptoms until after desiccation. The fungus was only rarely detected within stems growing from rotted seed tubers suggesting that spore transport in the vascular system was relatively unimportant in these experiments.Stems were readily infected from spore suspensions applied to unwounded epidermis especially when the inoculum was held in cotton wool and secured with wax film. The progressive colonisation of growing stems was demonstrated by isolations made at different positions on the stem and at different times after inoculation. In field experiments in two years stems were inoculated with four spore concentrations on four dates from late June to late August. After desiccation the extent of pycnidial lesions was greatest from the earliest inoculation date and the largest spore concentration and these differences were reflected subsequently in the incidence of gangrene on damaged progeny tubers. Younger stems may be more susceptible and infection in early summer probably results in extensive growth within the stem before desiccation and thus in massive pycnidial production.
Control of pearl millet downy mildew caused by Sclerospora graminicola with systemic fungicides in an artificially‐contaminated plot
Authors: DANG J. K. , THAKUR D. P. , GROVER R. K. 
Published: February 2008

SUMMARYAmong four fungicides, viz. metalaxyl (two formulations), fosetyl‐Al, pro‐pamocarb and cyomaxanil tested in vitro against sporangial germination inhibition of Sclerospora graminicola, cyomaxanil was found to be most inhibitory. In an artificially contaminated plot, when used as seed treatment or foliar spray for the control of downy mildew of pearl millet, only metalaxyl was effective.Metalaxyl 25 (Ridomil) and metalaxyl 35 (Apron) seed treatments protected the pearl millet plants from downy mildew up to 30 days. As a foliar spray, metalaxyl 25 used once at 20 days or twice after 20 and 38 days of plant growth gave less disease at harvest time. Seed treatment (metalaxyl 25 or 35) followed by one metalaxyl 25 spray was found to be effective in controlling the downy mildew. These treatments improved the growth of plants and yield significantly.
Endosperm cell number in cultivars of barley differing in grain weight
Authors: COCHRANE M. P. , DUFFUS C. M. 
Published: February 2008

SUMMARYThe number of endosperm cells in caryopses 30 ‘days’ after anthesis was determined and a positive correlation was found between endosperm cell number and 1000 grain weight, and between endosperm cell number and dry grain volume in a number of cultivars of field‐grown barley. The genetic factors influencing grain weight are discussed in relation to these results and to observations made on transverse sections of immature caryopses.
Effects of deltamethrin on walking, flight and potato virus Y‐transmission by pyrethroid‐resistant Myzus persicae
Authors: RICE A. D. , GIBSON R. W. , STRIBLEY M. F. 
Published: February 2008

SUMMARYIn laboratory tests with moderately pyrethroid‐resistant (R1) Myzus persicae, more walked or flew from excised leaves pre‐treated with the pyrethroid deltamethrin, or its aqueous formulation ‘Decis’ at 10 mg a.i. litre‐1 than from untreated leaves. Neither a carbamate (pirimicarb) nor an organophosphate (demeton‐S‐methyl) induced flight. R1 alatae and apterae which had dispersed from deltamethrin‐treated leaves rarely transmitted potato virus Y (PVY); however transmission by the more pyrethroid‐resistant R2 alatae was only halved and that by R2 apterae undiminished. Treatment with deltamethrin decreased spread of PVY both in flight chamber and field experiments.
Disease spread of non‐specialised fungal pathogens from inoculated point sources in intraspecific mixed stands of cereal cultivars
Authors: JEGER M. J. , JONES D. GARETH , GRIFFITHS ELLIS 
Published: February 2008

SUMMARYSpread of Septoria nodorum from inoculated point sources was examined in pure stands and mixtures of two spring wheat cultivars Kolibri and Maris Butler. Gradients in disease were observed soon after inoculation; the presence of the more resistant cultivar (Maris Butler) in the mixtures retarded the outward spread of disease compared with the susceptible pure stand (Kolibri). Regression analysis suggested that gradients in incidence were influenced by nearness to the source whereas gradients in severity were not.Spread of disease was also examined in pure stands and mixtures for the host/pathogen combinations, winter wheat (cvs Maris Huntsman and Maris Ranger)/S. nodorum and winter barley (cvs Maris Otter and Hoppel)/Rhynchosporium secalis. In contrast to the spring wheat experiment, no gradients were observed; explanations for the uniform distribution of disease were (a) extensive spread prior to the period of assessment, (b) no physical barrier to dispersal due to the juvenile growth stage of the crop and (c) exhaustion of the point‐source.
Brown root rot of tomato, and its control, in Crete
Authors: MALATHRAKIS N. E. , KAPETANAKIS G. E. , LINARDAKIS D. C. 
Published: February 2008

SUMMARYSymptoms similar to those regarded as typical of brown root rot disease have been noticed in tomato and eggplant in Crete. Infected plants showed symptoms only during the winter. Three fungi Pyrenochaeta lycopersici, Colletotrichum coccodes and Fusarium oxysporum were consistently isolated from infected tomato roots and proved to be pathogenic to young tomato seedlings. Pycnidia of P. lycopersici were produced when small pieces of infected young tomato roots were plated out on tomato juice agar (Oxoid) and incubated at 23 °C under continuous white light. Good control of the disease was achieved when soil was fumigated with dazomet 98% (70g/m2), methyl isothiocyanate (MIC) 20%+ dichloropropane‐dichloropropene mixture (DD) 80% (‐Di‐Trapex; 50 ml/m2), methyl bromide (75 g/m2), and vapam (200 ml/m2) + ethoprophos 10% (10 g/m2) or when solarisation was applied (soil covered by 50 μm transparent polyethylene sheet) during the whole period of August and September. Dazomet (30 g/m2) or ethoprophos 10% (10 g/m2) when combined with solarisation did not improve its effectiveness. MIC 20%+ DD 80% emulsified (Di‐Trapex e.c, 50 ml/m2) was ineffective.
Pathogenic variability of downy mildew (Sclerospora graminicola) on pearl millet. I. Host cultivar reactions to infection by different pathogen isolates
Authors: BALL SARAH L. 
Published: February 2008

SUMMARYCultivars of pearl millet were challenged by isolates of downy mildew collected from various locations in West Africa and India in order to ascertain whether variability in cultivar response was genetically or environmentally determined. Results of experiments, in Polythene tunnels which imitated tropical field conditions, were confirmed by more precise experiments in an isolation plant propagator. The most important conclusion was that variation is determined by host and pathogen genotypes. West African isolates of the pathogen were generally more pathogenic than Indian isolates. However, there were also substantial differences between two isolates collected from different host cultivars at the same location in Upper Volta. Cultivar ICH105 differentiated between West African and Indian isolates. Cultivars 700516 and MBH110 also showed differential responses between isolates. In contrast two distinct types of symptom expression were recorded and found to be characteristic of cultivar genotype, independent of pathogen isolate. The possibility that both race specific and race non‐specific resistance may coexist in this little understood pathosystem is discussed and the practical implications are considered.
Resistance of Botrytis cinerea to dicarboximide fungicides in protected crops
Authors: PANAYOTAKOU M. , MALATHRAKIS N. E. 
Published: February 2008

SUMMARYDicarboximide fungicides have been used for the control of grey mould in protected crops in Crete since 1977. During the 1980 growing season a decline of their efficacy was observed. In successive surveys carried out in May 1980, February 1981 and May 1981 in 28, 10 and 13 plastic houses repectively, a considerable proportion of resistant strains was found. From each of the plastic houses sampled mostly either only resistant or only sensitive strains were isolated. In three of the plastic houses with resistant strains there was an acute disease control problem. The ED50 of 15 resistant strains studied was in the area of 3·5 μg/ml vinclozolin as compared with 0·2 μg/ml for the wild type strains. The vinclozolin‐resistant strains were also resistant to procymidone, iprodione, and dicloran. In most of the cases strains resistant to vinclozolin were also resistant to benomyl and strains sensitive to vinclozolin were also sensitive to benomyl. In the absence of fungicide, resistant strains grew more slowly on PDA than sensitive ones, but spores germinated equally well. Vinclozolin (0·75 mg a.i./ml) did not protect eggplant seedlings against resistant strains but gave satisfactory control of sensitive ones.
The occurrence of Indian peanut clump, a soil‐borne virus disease of groundnuts (Arachis hypogaea) in India*
Authors: REDDY D. V. R. , RAJESHWARI R. , IIZUKA N. , LESEMANN D. E. , NOLT B. L. , GOTO T. 
Published: February 2008

SUMMARYA disease characterised by severely stunted plants with small dark green leaves was found in groundnut (Arachis hypogaea) in sandy soils in Punjab State, India. The disease occurred in patches in the field and reappeared in the same positions in succeeding groundnut crops. Plants infected early did not produce mature pods. Seeds sown in soil collected from infected fields produced plants with typical disease symptoms. Phaseolus vulgaris cv. Local and Chenopodium quinoa were found to be good diagnostic hosts. The disease was shown to be caused by a rod‐shaped virus c. 24 nm in diameter with predominant particle lengths of c. 249 and 184 nm when stained in uranyl acetate. The virus, named Indian peanut clump virus (IPCV), resembled peanut clump virus (PCV) reported from W. Africa in symptomatology on groundnuts, particle morphology and soil‐borne nature. However, it is not serologically related to two W. African PCV isolates tested, or to tobacco rattle (PRN and CAM strains) or pea early browning virus (Dutch isolate) in microprecipitin, enzyme linked immunosorbent assay and immunosorbent electron microscopy tests.
Transmission of Spiroplasma citri by the aster leafhopper Macrosteles fascifrons (Homoptera: Cicadellidae)
Authors: O'HAYER KAREN W. , SCHULTZ GERALD A. , EASTMAN CATHERINE E. , FLETCHER JACQUELINE , GOODMAN ROBERT M. 
Published: February 2008

SUMMARYThe aster leafhopper (Macrosteles fascifrons), injected with an isolate of Spiroplasma citri obtained from brittle root‐diseased horseradish (Armoracia rusticana), transmitted the spiroplasma to horseradish and China aster (Callistephus chinensis.) After feeding on plants infected with S. citri, M. fascifrons transmitted the spiroplasma from aster to aster and horseradish, from yellow rocket (Barbarea vulgaris) to aster, and from turnip (Brassica rapa) to turnip. Symptoms in infected horseradish were chlorosis and stunting of newly formed leaves, discoloration of root phloem, and reduced plant growth typical of brittle root disease. Chlorosis, stunting, and asymmetry of young leaves occurred in affected aster and turnip. Flowers of infected aster were small and pale in colour and occasionally showed other symptoms including asymmetry, petal distortion, or light green petals. Spiroplasmas were isolated from all plants showing symptoms. Transmission rates by M. fascifrons which acquired S. citri by feeding on infected plants were very low, but injected leafhoppers transmitted more frequently. This is the first report of the transmission of S. citri from diseased to healthy plants by M. fascifrons.
A calcium‐binding sialoglycoprotein associated with an apparent eggshell membrane of Globodera rostochiensis
Authors: ATKINSON H. J. , TAYLOR JILL D. 
Published: February 2008

SUMMARYEnergy dispersive X‐ray microanalysis has been used to study the binding of two inhibitors of hatching in Globodera rostochiensis, ruthenium red and lanthanum, to a calcium binding site on the eggshell. Eggs were treated with either buffered ruthenium red or buffer only, and the levels of ruthenium and calcium that could be detected from the surface of eggshells were measured before and after repeated etching in a plasma oven. Counts for ruthenium increased during etching to a maximum after 8–12 min, just before the eggshell was eroded from the juvenile. The calcium levels on eggshells binding ruthenium red were suppressed relative to those from buffer. Similar experiments with lanthanum showed a significant increase in this inhibitor after 10 min etching and an accompanying suppression of calcium levels.The nature of the binding site was probed by measuring ruthenium red binding after pretreatment with selected enzymes. A non‐specific protease, pronase, reduced the subsequent binding of this inhibitor but the site was resistant to trypsin in the presence of calcium. Neuraminidase also had an effect suggesting that the protein is a sialoglycoprotein. Phospholipase A2 but not Phospholipase C influenced the subsequent binding of ruthenium red. Phospholipase A2 caused a loss of hatching ability and the degradation of a phospholipid from the eggshell. Ruthenium red binding was also reduced by treatment of eggshells with detergents or sonication. Apparently a calcium‐binding sialoglycoprotein forms part of the integral proteins of an eggshell membrane located on the inner surface of the eggshell.
In vitro studies on activity and survival of Hirschmanniella spp. in some chemical solutions
Authors: BABATOLA J. O. 
Published: February 2008

SUMMARYActivity and survival of three Hirschmanniella species were assessed in vitro in graded solutions of sodium chloride, urea, sucrose and artificial sea water. Both were adversely affected at high osmotic potentials. The electrolytes used in these studies appeared to impose an osmotic stress and a toxicity effect on the nematode, while in the organic compounds osmotic stress may be less important.
Differences in the tolerance of potato cultivars to potato cyst nematodes (Globodera rostochiensis and G. pallida) in field trials with and without nematicides
Authors: TRUDGILL D. L. , COTES L. M. 
Published: February 2008

SUMMARYIn field trials Cara, Brio, Maris Piper and Pentland Javelin were consistently more tolerant of damage by Globodera rostochiensis yielding more than Corsair, Pentland Dell, Maris Anchor and Maris Peer, in untreated, heavily infested soil and giving the smallest increases to nematicide treatment. No yield or growth differences were found between plants in untreated and nematicide treated plots at a nematode‐free site.The most tolerant cultivars all had a gene (H1) for resistance to G. rostochiensis derived from Solanum tuberosum ssp. andigena and in soil infested with G. pallida the tolerance of at least one resistant cultivar (Maris Piper) appeared to be lessened. However, some resistant cultivars were comparatively intolerant, even to G. rostochiensis. Early cultivars were generally less tolerant than late maturing cultivars but there were exceptions. Amongst cultivars with resistance derived from Solanum vernei the early cultivar Guardian was more tolerant than the main crop cultivar Corsair.The effect on the yield of several cultivars of a range of densities of G. rostochiensis, produced either by applying different rates of a nematicide or by cropping in the previous year, was examined at two sites. The results indicated that the slope of the regression for yield in relation to nematode density was less for tolerant than intolerant cultivars. At sites infested with G. rostochiensis Maris Piper was found to be consistently more tolerant than Pentland Crown.
A comparison of wheat bulb fly (Delia coarctata) egg numbers in ridge and furrow soil samples from potato crops
Authors: FRANKLIN M. F. , McKINLAY R. G. 
Published: February 2008

SUMMARYIn soil samples taken with a shovel from 97 potato maincrops in east Scotland during 1978 to 1981, wheat bulb fly (Delia coarctata) eggs were more numerous on ridges than in furrows. The ratio of the number of eggs on the ridge to the number of eggs in the furrow was higher in Lothian Region (3·25) than in Fife Region (1·59) but differed significantly (P < 0·05) from 1·0 in both Regions. To obtain maximum precision of the estimate of the total wheat bulb fly egg population in a potato field, more samples should be taken from the ridge than from the furrow, in approximate proportion to the egg numbers.
The infection process, sporulation and survival of Alternaria helianthi on sunflower
Authors: ALLEN S. J. , BROWN J. F. , KOCHMAN J. K. 
Published: February 2008

SUMMARYElectron microscopy was used to study the infection of sunflower leaves by Alternaria helianthi. Conidia germinated by producing one to many germ tubes which grew across the leaf surface before forming appressoria. The fungus directly penetrated its host through the cuticle and epidermis. Entry into the host through wounds and stomates was also observed. Extracellular sheaths were found to be associated with germ tubes and intercellular hyphae of A. helianthi. Conidiophores developed through collapsed stomates, from leaf veins, trichomes and also from mycelium growing across the host leaf surface. Microcylic conidia were produced directly from parent conidia under certain conditions. Studies using a volumetric spore trap showed that the airborne spore concentration followed a distinct periodicity with peaks occurring between 0900 and 1100 h each day. Laboratory studies showed that safflower, noogoora burr and bathurst burr could serve as alternative hosts for A. helianthi. The pathogen was readily isolated from sunflower crop debris from a diseased crop that had been harvested 1 yr earlier.