bluuebunny/crossref_metadata_2025_split huggingface dataset:
Susceptibility of apples to infection by Gloeosporium album
Authors: EDNEY K. L. , TAN A. M. , BURCHILL R. T. 
Published: February 2008

SUMMARYA rain simulator was used to show that the susceptibility of apples to infection by conidia of Gloeosporium album was markedly influenced by the amount of water falling on the fruit prior to inoculation. The rate of infection by G. perennans was also increased by this treatment.
Neck rot (Botrytis allii) of bulb onions
Authors: MAUDE R. B. , PRESLY A. H. 
Published: February 2008

SUMMARYExperiments on neck rot of onions, caused byBotrytis alliishowed that, although the disease only became evident in store, a major source of the pathogen was samples of infected seeds. In 1972 and 1973, 39·5 and 71·4% respectively of commercial onion seed samples tested at Wellesbourne were infected. The pathogen was internal in seed and persisted for 3 ½ yr in infected seeds kept in a seed store at 10°C and 50% r.h.Seedlings raised from diseased seeds became infected by mycelial invasion of the cotyledon leaf tips from seed‐coats many of which remained attached to the cotyledons when seedlings emerged from the soil. The fungus attacked the living tissues of these leaves symptomlessly, producing conidiophores only after the leaf tissue senesced and became necrotic. Because the fungus was symptomless, the rate of spread of the pathogen in onion crops was assessed by incubating successive samples of plants from the field in humid conditions when infected tissues developed conidiophores of the fungus. This method showed that the disease was progressive in onion crops spreading more rapidly in wet humid conditions (e.g. 1972) than in dry ones (e.g. 1973). The principal means of spread were probably fungal spores; conidiophores bearing spores being produced abundantly on plants in the field under high humidity. The fungus invaded the leaves of plants successively, first infecting each leaf at the tip and then growing downwards in the tissues and eventually invading the neck of the onion bulb via the leaves which emerged directly from the top of the neck. By harvest, the fungus was situated deep within the neck tissues of infected maturing onion bulbs.
Neck rot (Botrytis allii) of bulb onions
Authors: MAUDE R. B. , PRESLY A. H. 
Published: February 2008

SUMMARYThe percentage of bulbs with neck rot in store was determined by the number of onion plants with Botrytis allii infected neck tissues in the field. Since infected plants were obtained mainly by sowing infected seeds, it was established that the seeds were main source of neck rot in stored bulbs.The disease failed to spread from infected bulbs to healthy bulbs in store but affected bulbs became progressively more rotten during storage.In 1972, dusting seeds with 1 g benomyl/kg reduced neck rot in the stored bulbs from 50 to 8%. However, there was some cross infection from the control plots to the plots raised from benomyl dusted seeds 1·5 m distant. In 1973 and 1974, all plots were placed 165 m or more from one another to reduce spread of the disease. Benomyl applied to seed samples containing 1, 10 and 20% infection reduced the average neck rot percentage in stored bulbs from 10·1 to 0·4% in 1973 and from 26·2 to 3·8 % in 1974. The amount of neck rot in store was directly related to the percentage infection of the onion seeds. However, the number of infected bulbs in store was proportionally greater in 1974 when weather conditions were more conducive to spread of the disease in the field.
A method for comparing pesticide usage patterns between farmers
Authors: TAIT E. J. 
Published: February 2008

SUMMARYA method is described for standardizing data from surveys of insecticide and fungicide usage, to enable comparisons to be made between farmers. Pesticide usage by the fruit and vegetable farmers surveyed was initially coded in units, and then standardized by taking each farmer's deviation from a regional average for the crop, expressed as standard measure. The vegetable farmers studied were less variable in their usage of pesticides for the control of aphid, caterpillar and blight on crops harvested late in the season rather than early (cabbage, lettuce, potatoes and sprouts). There was evidence that farmers did not heed the Beaumont period warnings issued by the Agricultural Development and Advisory Service (ADAS) for blight attack on potatoes. Also on potato crops, insecticide use against aphids was influenced by the level of fungicide usage for blight control. Standardized insecticide and fungicide usage values for individual farmers were very uniform. A two‐way analysis of variance showed that most of the variation in the model was accounted for by variation between farmers rather than by variation between crops on the same farm. By expressing pesticide usage data in this standardized form, one can measure the element in pesticide usage which is not related to pest incidence. This can then be used to study the influence of other factors on pesticide usage.
Evaluation and use of a screening method to aid selection of cocoa (Theobroma cacao) with field resistance to cocoa swollen‐shoot virus in Ghana
Authors: LEGG J. T. , LOCKWOOD G. 
Published: February 2008

SUMMARYSeeds of cocoa progenies were inoculated with cocoa swollen‐shoot virus manually or by vector transfer techniques to assess the relative resistance of the progenies to infection. Assessment of progeny included in both inoculation tests and in field trials were positively correlated, indicating that the inoculation technique is suitable for the selection of progenies for testing in the field.Pure Upper Amazon progenies were more resistant than selfed Amelonado, with hybrids between Amelonado and Upper Amazons usually intermediate. Among the main Upper Amazon populations, Iquitos and Nanay clones were better sources of resistance than Parinari and Scavina clones. A survey of these populations indicated that, within populations, resistance levels do not vary greatly.A range of progenies based on the Upper Amazon female parents in existing seed gardens was screened for resistance and some were consistently more resistant than the equivalent Amazon x Amelonado hybrid now being distributed to farmers.
An interpretation of the frequencies of host specific phenotypes of Phytophthora infestans in North Wales
Authors: SHATTOCK R. C. , JANSSEN B. D. , WHITBREAD R. , SHAW D. S. 
Published: February 2008

SUMMARYRace surveys of Phytophthora infestans over 4 years in North Wales have shown that races unselected by host resistance are frequent. In most cases frequencies of complex races are those expected from the frequencies of simple race characters if these assort at random. These results suggest that recombination between races may be unrestricted. The significance of unexpected deviations from the predicted frequencies are discussed.
Effects of seed deterioration and seed‐bed environment on emergence and yield of spring‐sown barley
Authors: PERRY D. A. , HARRISON J. G. 
Published: February 2008

SUMMARYSeedling emergence from barley seeds, deteriorated by storage at supra‐optimal moisture contents and temperatures, was adversely affected by sowing early in spring when soil temperatures were low, and by sowing into wet seed beds. There were significant interactions between seed lots of varying levels of deterioration and seed bed condition, because the more severely deteriorated lots emerged proportionately less well than the control, non‐deteriorated lots.The yield results also showed significant interactions between seed lots and seed‐bed condition because plants from deteriorated seeds in low populations resulting from partial emergence failure were unable to compensate and produce plot yields similar to those of higher populations.
Studies on an overwintering population of the mushroom phorid Megaselia halterata (Diptera: Phoridae) parasitized by Howardula husseyi (Nematoda: Allantonematidae)
Authors: RICHARDSON P. N. , HESLING J. J. 
Published: February 2008

SUMMARYAn overwintering population of the mushroom phorid fly Megaselia halterata parasitized by Howardula husseyi was studied in an attempt to explain the winter decline in incidence of parasitism that has been observed in flies from mushroom farms. Fly larvae from eggs hatching in November developed into pupae in December and flies emerged in May. No selective mortality of parasitized specimens of larvae, pupae, or flies was observed. Dead parasites were found in only 10% of parasitized flies. The incidence of parasitism in the emerging flies (50%) was five times that of their parental generation and although parasitism significantly delayed fly emergence the delay was only 2–3 days. There was no evidence of winter decline in parasitism; instead there was strong evidence that parasitism enhanced phorid survival through the winter.
The activity and distribution of wheat bulb fly (Delia coarctata) (Diptera:Anthomyiidae) in cereal crops and over fallow land
Authors: BARDNER R. , FLETCHER K. E. , JONES MARGARET G. 
Published: February 2008

SUMMARYThe flight activity and local distribution of adult D. coarctata were studied on Rothamsted Farm during 1970‐5 using several trapping methods. Changes in the activity and distribution of the flies were followed as the population aged, and in females these changes were associated with maturation of their eggs. Most females appeared to stay at their emergence sites in winter wheat until egg‐laying started about 1 month later. They then dispersed and both sexes were found in previously uninfested cereals and grass as well as on fallow land where the eggs are laid. Flight occurred chiefly in the late afternoon and evening. The concentration of flies at their emergence sites for several weeks before egg laying could facilitate chemical control, provided the practical difficulties of application can be overcome.
Predisposition of Aster to Phialophora wilt
Authors: BURGE M. N. , ISAAC I. 
Published: February 2008

SUMMARYThe susceptibility of Aster novi‐belgii to infection by the vascular wilt pathogen Phialophora asteris varied according to the growing conditions to which the host was subjected before inoculation. Relatively low air temperature, high soil moisture, and soil nutrients rich in potassium or phosphorus were pre‐inoculation conditions in which Aster became relatively susceptible. Increased resistance was favoured by growing plants at relatively high air temperatures, low soil moisture, and soil nutrients rich in nitrogen or calcium but low in potassium or phosphorus prior to inoculation.
Effect of thermal shock treatments on symptom expression in test plants inoculated with potato aucuba mosaic virus
Authors: HENDERSON HELEN M. , COOPER J. I. 
Published: February 2008

SUMMARYPotato aucuba mosaic virus (PAMV) has few reliable local lesion assay hosts. However, lesions formed when PAMV‐inoculated leaves were exposed to thermal shock (dipping for 40 s in water at 50 or 2 °C). Leaves of Nicotiana tabacum (cv. Xanthi‐nc, Samsun or Samsun NN), Hyoscyamus niger and Datura metel consistently developed necrotic lesions, leaves of Chenopodium amaranticolor developed whitish rings, and leaves of N. glutinosa developed diffuse cream‐coloured rings and spots. In PAMV‐inoculated leaves of Xanthi‐nc tobacco, C. amaranticolor and D. metel, lesions formed only in areas exposed to light. Thermal shocks applied to systemically infected leaves of Xanthi‐nc tobacco induced necrotic vein banding patterns.In inoculated Xanthi‐nc tobacco leaves, PAMV seemed confined to local lesions. The rate of lesion enlargement was therefore a measure of rate of virus spread. Lesion size increased as the interval between inoculation and shock treatment increased. The mean rates of increase in lesion radius were 17 and 27 Cμm/h at 15 and 25°C respectively. ‘Target’ lesions, composed of concentric necrotic rings, formed when inoculated Xanthi‐nc tobacco leaves were given two or more 50°C shocks. The first of two 50°C treatments decreased subsequent rates of lesion enlargement.
Growth and yield of high‐density cauliflower crops treated with pesticides to control weeds and cabbage root fly (Delia brassicae)
Authors: THOMPSON A. R. , PRICE JEAN L. , ROBERTS H. A. 
Published: February 2008

SUMMARYEffects of combinations of insecticides and herbicides on the growth and yield of cauliflower plants (cvs No. 110, Garant and Strong) were determined in two field experiments with seed drilled to give a stand of c. 300000 plants/ha. Granular formulations of chlorfenvinphos or fonofos were applied by the bow‐wave method at 2 kg a.i./ha to control cabbage root fly (Delia brassicae). Weeds were successfully controlled with combinations of trifluralin, incorporated into the soil at 0·6 or 1·2 kg a.i./ha before drilling, and propachlor, applied pre‐emergence at 2·2 or 4·4 kg a.i./ha. Fonofos, with and without herbicides, significantly lessened (P < 0·01) numbers of seedlings that would survive to harvest. Herbicides and chlorfenvinphos generally did not significantly affect the emergence of healthy seedlings of any cultivar. Combinations of herbicides and chlorfenvinphos were compatible for control of target species. Chlorfenvinphos reduced root damage by at least 50% but did not significantly increase (P > 0·05) the total or marketable weight of curds. Numbers of curds were not usually affected and consistent effects of treatments on maturation periods of the three cultivars were not detected.
Matching inbred lines of Brussels sprouts for flowering characteristics, as an aid to improving F1 hybrid seed production
Authors: FAULKNER G. J. , SMITH B. M. , DRAYCOTT A. 
Published: February 2008

SUMMARYPrevious work at the National Vegetable Research Station indicated that cross‐pollination of Brussels sprouts by honeybees could be improved when parent lines with similar flowering characteristics were used. During 1973‐5 inbred lines were tested at three sites for matching ability based on flowering times, plant height and flower colour. One pair of inbreds satisfied all criteria at all sites, and a further twelve gave satisfactory results.Two pairs visually matched in 1973 were grown in larger plots in 1973‐4 to assess the effect of matching on honeybee behaviour. Results showed that matching improved cross‐pollination by honeybees between the parent lines.
Effects of temperature and inoculum concentration on infection of narcissus bulbs by Fusarium oxysporum f.sp. narcissi
Authors: PRICE D. 
Published: February 2008

SUMMARYChlamydospores of Fusarium oxysporum germinated, and mycelium grew on agar, at 10 but not 8°C. Numbers of chlamydospores needed to initiate disease suggest that the principal sources of infection are within the stock of bulbs and not the soil.
Microplot studies with Xiphinema diversicaudatum under annual and perennial cropping regimes
Authors: Cotten J. 
Published: February 2008

ABSTRACTAnnual and perennial crops were grown in monoculture over three‐ or four‐year experiments. Strawberry, raspberry and ryegrass maintained high population densities of Xiphinema diversicaudatum. Hop maintained relatively low population densities as did all annual crops tested, including winter wheat, winter beans, spring barley, potatoes, sugar beet and cabbage. Differences in nematode population density were not due to differences in soil porosity.
Distribution of damson‐hop aphid (Phorodon humuli) migrants on hops in relation to hop variety and wind shelter
Authors: CAMPBELL C. A. M. 
Published: February 2008

SUMMARYThe distribution of migrant Phorodon humuli was studied in two hopgardens during June 1972. Migrants accumulating upon the young tissues near the bines' apices were counted. Plant size affected distribution, 100 % more migrants were found on 2‐bine than on single bine strings and there was a positive linear relation between bine height and log10 aphid numbers. Plants surrounding wire‐trellis support poles were more heavily infested than plants not at poles, and migrants were more abundant on leeward orientated than windward strings. It is argued that the distribution of alatae reflected local patterns of wind shelter. Differences between plants declined in successive weeks.The influence of hop variety on migrant settling was studied in one of the hop‐gardens. Fewer migrants settled on the variety Tolhurst than on Northern Brewer, and Fuggle was intermediate. Part, but not all, of the difference between varieties was explained by the larger average size of Northern Brewer plants.The observed aphid deposition rates in the two hop gardens were compared with hypothetical deposition rates calculated from numbers of P. humuli caught in a nearby 12‐2 m Rothamsted Insect Survey suction‐trap, and used to estimate flight durations. The estimates indicated that most infestation probably resulted from aphids within 1 h flying time of their primary host source.
Ethirimol‐sensitivity in populations of Erysiphe graminis from plots of spring barley
Authors: SMITH JANET E. , PAYNE R. W. , BAINBRIDGE A. 
Published: February 2008

SUMMARYBarley plots, cv. Proctor were sown with either ethirimol‐treated or untreated seed. At seedling emergence, plots were inoculated with isolates of Erysiphe graminis either sensitive or insensitive to ethirimol, or left uninoculated.Mildew samples taken from the coleoptile leaves of seedlings, and later from leaf 6 (next but one to the flag leaf) were compared for ethirimol sensitivity using probit analysis. Probit lines were derived using ‘Wadley's analysis’. This analysis uses the number of survivors to estimate the total number of individuals originally present. In the test for ethirimol sensitivity a count of colonies on inoculated test leaves was taken to represent survivors. Microscopic counting of the original inoculum was thus avoided.The analyses snowed that the initial leaf inoculation treatments established mildew populations in the plots, which differed considerably in ethirimol sensitivity. Some 6 wk after inoculation the levels of sensitivity in these populations remained unchanged even though inoculum coming into the experiment from external sources was often much more insensitive than the mildew in some plots.Probit lines of response to ethirimol had shallow slopes, showing that large variability exists in the pathogen for this character.
Further studies on seed transmission of broad bean stain virus and Echtes Ackerbohnenmosaik ‐Virus in field beans (Vicia faba)
Authors: VORRA‐URAI S. , COCKBAIN A. J. 
Published: February 2008

SUMMARYBroad bean stain virus (BBSV) and Echtes Ackerbohnenmosaik‐Virus (EAMV) were detected in the seed coat and embryo sac fluid of immature seeds from infected field beans (Viciafaba minor) by inoculation to Phaseolus vulgaris; BBSV was also detected in immature embryos. The proportion of seeds infected with either virus decreased during maturation. The viruses were transmitted to seedlings as often through fully ripened seeds from which the seed coats had been removed as through intact seeds. Both viruses were detected in pollen from infected plants, but in glasshouse tests only BBSV was transmitted through pollen to seeds. Delaying fertilization in plants infected with BBSV or EAMV seemed not to affect seed transmission of either virus.In glasshouse tests BBSV was transmitted more often through seeds from plants that were inoculated before flowering than during flowering, and was not transmitted through seeds from plants inoculated after flowering; EAMV was transmitted only through seeds from plants inoculated before flowering. In tests on seed from naturally infected plants BBSV was transmitted more often through seeds from plants that developed symptoms before flowering than during flowering. Both viruses were seed‐borne in all cultivars tested and there was no marked difference in the frequency of transmission of either virus among the spring‐sown cultivars most common in Britain. Both viruses persisted in seed for more than 4 yr.
The adenosine triphosphate content of cysts of Globodera pallida and G. rostochiensis as a possible quantitative estimate of field populations
Authors: ATKINSON H. J. , BALLANTYNE A. J. 
Published: February 2008

SUMMARYA rapid method is described for estimating the number of juveniles of Globodera pallida and G. rostochiensis in cysts collected from field soils. The technique uses a photometer to measure the adenosine triphosphate (ATP) content of the cysts by bioluminescence. Results for ten to twelve soil samples of 100 g taken from each of four fields showed that the number of juveniles that emerged when the samples were placed in potato root diffusate was significantly related to ATP content of a second series of cyst samples from these fields. Cysts from one field gave a higher ATP content per hatched juvenile than was recorded for the remaining three fields. There are several, untested, explanations of this discrepancy, but some evidence suggests that the hatching test and not the ATP method may have given an unreliable estimate of the viable egg content of cysts from this field. Further work may result in an enhanced precision and increased rapidity in estimating field populations of cyst nematodes by this technique.
The effect of seed deterioration on the growth of barley
Authors: HARRISON J. G. 
Published: February 2008

SUMMARYDeterioration of barley seeds, caused by storing them at high moisture contents, was associated with slower germination and seedling emergence, reduced root and shoot growth and a smaller first true leaf compared with non‐deteriorated controls. Growth differences were related to meristematic activity. Plants from deteriorated seeds started to tiller later than controls, but tillering rates were similar. In the field in 1974 more tillers died after ear appearance on plants from deteriorated seeds than those on controls, but the following year similar numbers died. Grain yields from plants from deteriorated and control seeds were similar in both seasons. These results are discussed in relation to season and soil conditions.
Reproductive strategy of winged and wingless morphs of the aphids Sitobion avenae and Metopolophium dirhodum
Authors: WRATTEN S. D. 
Published: February 2008

SUMMARYThe reproduction of apterous and alate morphs of the aphidsSitobion avenaeandMetopolophium dirhodumis compared on the basis of fecundity in 5‐ and 10‐day periods of adult life. Apterae of both species are consistently more fecund than alatae of comparable weight, producing about three more nymphs on average in any 5‐day period. The reproductive differences are related to the number and quality of embryos at eclosion and to ovulation rates, both of which in turn appear to be linked to wing‐muscle maintenance. These relationships between weight, embryos and reproduction may be used to predict a newly moulted adult aphid's fecundity, a method which may facilitate the assessment of resistance to aphids in new cereal varieties, by obviating lengthy recording of reproduction. The strategies by which alatae of these and other aphid species minimize the difference between their fecundity and that of apterae are discussed.