bluuebunny/crossref_metadata_2025_split huggingface dataset:
Observations on the epidemiology of Leptosphaeria macutans stem canker in winter oilseed rape
Authors: GLADDERS P. , MUSA T. M. 
Published: April 2007

SUMMARYThe main source of Leptosphaeria maculans (Desm.) Ces. & de Not. infection on winter oilseed rape in Cambridgeshire was stubble debris from the previous season. Heavy leaf spot infection of seedlings near unploughed oilseed rape stubble resulted in complete crop loss. The fungus actively colonised stubble debris after harvest and perithecia were formed predominantly on tissues colonised during this period. Ascospores were detected throughout the year, mainly from October to April. The degree of leaf spot infection in the autumn was correlated with stem canker infection at the end of flowering and with severe stem lesions at harvest. The incidence of leaf spot infection was greater in the spring than in the autumn, particularly during the period of extension growth and early flowering. Stem canker infections were first seen in March and continued to develop up to and after harvest.
Observations on the natural mortality of the overwintering pupa of the cabbage root fly, Delia brassicae (Wiedemann), in Ireland
Authors: RYAN J. , RYAN M. F. 
Published: April 2007

SUMMARYThe mean winter loss of pupae in four cabbage root fly populations in two peatland sites in Ireland in 1971/72, 1974/75 and 1975/76 was 58 · 4 per cent. Predation by carabids may have been involved as pupal loss was associated, in three winters, with the abundance of either Nebria brevicollis (F.) adults or carabid larvae. The parasites Trybliographa rapae (Westw.) (Hymenoptera: Cynipidae) and Aleochara bilineata Gyll. (Coleoptera: Staphylinidae) were recorded at average rates of 10·4 and 3·9 per cent respectively.
Colorado beetles reported in England, Wales and Scotland, 1979
Authors: BARTLETT P. W. 
Published: April 2007

SUMMARYIn 1979, 29 adults and one larva of the Colorado beetle, Leptinotarsa decemlineata (Say), were found associated with imports in England; 19 of these specimens were alive. This is the lowest annual total for seven years. Details of these finds are presented. None was found in Wales. One dead beetle was found in Scotland. No breeding colony of Colorado beetle was found. Live female beetles kept in the laboratory after capture laid an average of 524 eggs each (range 0–644) and the average percentage hatch was 24 (range 0–42).
Control of lettuce big‐vein disease by soil sterilisation
Authors: WHITE J. G. 
Published: April 2007

SUMMARYLettuce plants grown in the glasshouse in big‐vein‐contaminated soil previously treated with methyl bromide at 125–2000 kg/ha (x 0.125– 2.0 the dose used in the field) did not develop big‐vein symptoms, although at dosages up to 500 kg/ha their roots were infected by Olpidium brassicae(Wor.) Dang., the vector of the disease. Soil treatment with dazomet, chloropicrin, 1, 3‐dichloropropene or metham sodium gave symptom‐free plants at doses corresponding to those normally applied in the field. When applied to contaminated field plots, methyl bromide at 750 or 1000 kg/ha controlled the disease, but 10 per cent of plants showed big‐vein symptoms in plots treated at 500 kg/ha. All methyl bromide treatments significantly increased lettuce head weight compared with the untreated controls, and resulted in bromide residues in the plants of 2300–5300 ng/g of dry tissue compared with 30 μg/g in plants from untreated plots. Plants were harvested 12 weeks after completion of methyl bromide application, by which time there was evidence of leaching of bromide from the upper 10 cm of soil.
Observations on the termination of diapause in eggs of the wheat bnlb fly (Delia coarctata (Fall.)) and soil temperature
Authors: McKINLAY R. G. 
Published: April 2007

SUMMARYThe temperature of the soil 15 cm deep was recorded before, during and after hatching of wheat bulb fly eggs at several sites in eastern Scotland during 1976 and 1978–80 inclusive. Eggs were extracted from soil cores and examined microscopically to monitor the progress of hatching. In 1976, 1978 and 1979, the difference between the minimum and maximum soil temperatures was small just before the start of hatching and large at or immediately afterwards. The termination of diapause and initiation of hatching of wheat bulb fly eggs in Scotland appeared to be associated with diurnal fluctuations of more than 5°C between the minimum and maximum soil temperatures.
The spread of arabis mosaic virus through non‐cultivated vegetation
Authors: McNAMARA D. G. 
Published: April 2007

SUMMARYSoil sampling for Xiphinema diversicaudatum (Micol.) Thorne over several years suggested that arabis mosaic virus was spreading through an elm woodland into an adjoining pasture. The rate of spread was estimated to be 11 m/year. Nematode movement was not believed to be entirely responsible for such a relatively high rate; other contributory factors were thought to be systemic movement of virus within root systems and the dissemination of virus‐infected seed.
The toxicity of diflubenzuron to honey bee (Apis mellifera L.) colonies in apple orchards
Authors: EMMETT B. J. , ARCHER B. M. 
Published: April 2007

SUMMARYThe effect of diflubenzuron on honey bees in apple orchards in southeastern England was studied in 1976. In two experiments apple trees cv. Cox's Orange Pippin, in full flower and with honey bees foraging on the blossom, were sprayed with diflubenzuron at 0.11, 0.20 or 0.40 kg a.i.†/ha, HCH at 0.25 kg a.i./ha or malathion at 2.52 kg a.i./ha. Diflubenzuron did not reduce the numbers of adult or larval bees, whereas HCH or malathion killed many adult bees. In a third experiment in 1978 in eastern England diflubenzuron at 0.22 kg a.i./ha was sprayed on to bees returning to their hive. Neither adult nor larval bees were killed by this treatment. Small quantities (0.11 and 0.30 μg/g) of diflubenzuron were found in samples of honey from hives sited in plots treated with this insecticide.
Colorado beetles reported in England, Wales and Scotland, 1980
Authors: BARTLETT P. W. 
Published: April 2007

SUMMARYIn 1980, 110 adults of the Colorado beetle, Leptinotarsa decemlineata (Say), were found associated with imports in England and Wales; 89 of these specimens were alive. This is the highest annual total for three years and the highest annual total of live beetles for 28 years. Details of these finds are presented. The outstanding features were the large numbers associated with imports of Italian spinach (55) and Portuguese timber (25). Fourteen beetles were found in Scotland of which one was alive and 13 were dead preserved specimens reported as a hoax. No breeding colony of Colorado, beetle was found. Live female beetles kept in the laboratory after capture laid an average of 871 eggs each (range 165–2462) and the average percentage hatch was 46 (range 0–73). Observations on egg laying by beetles found during the past six years showed that 34 per cent of females were capable of laying fertile eggs when they arrived in the United Kingdom.
Interaction between barley yellow dwarf virus and powdery mildew in four barley genotypes
Authors: POTTER L. R. , JONES I. T. 
Published: April 2007

SUMMARYThe effect of infection by barley yellow dwarf virus (BYDV) on host reaction to powdery mildew (Erysiphe graminis DC. f. sp. hordei Marchal) in four barley genotypes with different types of resistance to barley mildew isolate AB3, was studied in pot‐grown plants at 7,12 and 26 days after mildew inoculation. Cv. Engledow India (hypersensitive resistance) showed necrotic spotting only at the third scoring date, but the area showing symptoms was significantly less in BYDV‐infected than in control plants. On Vada (intermediately resistant), the reaction type value (a measure of host/pathogen compatibility), the percentage leaf area covered with mildew and the coefficient of infection (C.I., a mathematical combination of the other two characters mentioned) were initially less and subsequently greater on BYDV‐infected than on virus‐free plants. However, the initial trend was significant only for reaction type and C. I., and the subsequent trend only for percentage mildew cover and C.I. Reaction type values, percentage mildew cover and C.l. on cv. Emir (susceptible with some degree of adult plant resistance) and cv. Golden Promise (very susceptible) were also initially significantly less on BYDV‐infected plants, but subsequently all three characters increased to amounts not significantly different from those on virus‐free plants.
Some hosts of a Meloidogyne ardenensis population found in Scotland
Authors: THOMAS P. R. , BROWN D. J. F. 
Published: April 2007

SUMMARYForty‐one candidate host plant species were grown in pots of soil infested with Meloidogyne ardenensis Santos. Females and eggs were found on 11 of them: Cucumis sativus L., Daucus carota L., Fragaria x ananassa Duchesne, Fraxinus excelsior L., Hordeum vulgare L., Lolium multiflorum Lam., Lycopersicon esculentum Mill., Pinnus spinosa L., Rosa canina L., Sambucus nigra L. and Triticum aestivum L. Saccate larvae only were found on seven plant species, namely Allium cepa L., Anemone coronaria. L., Beta vulgaris L., Chenopodium album L., Poa annua L., Rubus idaeus L. and Stellaria media (L.) Vili., while females only were found on Acer pseudoplatanus L., Avena sativa L. and Chenopodium quinoa Willd. No stage of Meloidogyne ardenensis was found on any of the remaining 20 plant species. A morphometric study of specimens from this population confirmed the identify of the nema‐ tode.
Field tests with acaricides for the control of Tetranychus urticae Koch on strawherries
Authors: GOULD H. J. , JESSOP N. 
Published: April 2007

SUMMARYTwenty‐three pesticides were evaluated in 18 trials in 1974–79 for the control of red spider mite (Tetranychus urticae) on strawberries in areas in England where strains of mites resistant to the organophosphorus pesticides and dicofol were known to occur.The organophosphorus pesticides chlorpyrifos and triazophos continued to give good control at most of the sites. Demeton‐S‐methyl, dioxathion and omethoate used at only two of the sites significantly reduced the number of mites. Pirimiphos‐methyl, dimethoate and quinalphos used at only a few sites did not give a significant control. The carbamates aldicarb, thiofanox, formetanate and methiocarb usually gave significant control.Of all the pesticides tested, cyhexatin consistently gave the best control The specific acaricides amitraz, dienochlor, dinobuton, fenbu‐ tatin oxide, propargite and quinomethionate were usually effective. Dicofol gave much more variable results than in earlier trials, probably because of resistance.
The persistence of Botrytis allii in field soil
Authors: MAUDE R. B. , BAMBRIDGE JUDITH M. , PRESLY A. H. 
Published: April 2007

Neck rot (Botrytis allii) affected bulbs of onions for 2 successive years when these were grown either in the field in soil from which an infected crop had been cleared 6 months previously or when infected debris was incorporated into field soil 6 months before the first crop was sown. These sources did not continue to cause infection of onion crops grown on the contaminated areas in the four succeeding years.The white storage tissue of onion bulbs (healthy or infected) persisted for less than 6 months in unsterile field soil contained in pots while sclerotia present in similar soil varied in their rate of decay but lost their capacity to produce conidiophores of B. allii after 6 months. In one sample, sclerotia were not recovered after 5 months; Gliocladium roseum, a mycoparasite, was present in this sample and may have affected survival.
Field assessment of resistance to powdery mildew in mature wheat plants
Authors: BENNETT FIONA G. A. , WESTCOTT B. 
Published: April 2007

Rankit transformation of mildew scores was used in regression analyses to compare the times and methods of scoring resistance. This showed that time and method of assessment significantly altered the relative rank positions of different cultivars. Examination of 10 cultivars in detail showed that changes in rank were associated with differences in organ resistance.Whole plot assessments based on a 0–9 scale provided a rapid and reliable means of ranking cultivars. Where possible, and particularly for breeders, at least two assessments are recommended, the first at or soon after flowering to estimate foliar infection, and the second 2 or 3 weeks later to estimate ear infection. For general comparisons of cultivars, sufficient information may be acquired from a single assessment when all plant organs are present and when the disease has had time to become well established.
The annual leatheijacket survey in Northern Ireland, 1965–82, and some factors affecting populations
Authors: BLACKSHAW R. P. 
Published: April 2007

An annual leatherjacket survey was made each winter in Northern Ireland from 1965 to 1982. Over this period the mean population was 520,130/ha and showed less annual variation than in some parts of Britain. This appears to be due to the regulation of populations by rainfall in July, August and November rather than in September and October as has been shown elsewhere.It is concluded that in Northern Ireland 18,096 ha of grassland would benefit from an insecticide treatment each year. Grassland with leatheijacket populations of 1 × 106/ha or more may suffer damage and up to 100,000 ha are at risk each year. Leatherjackets are therefore considered to be serious pests of grassland in Northern Ireland.
Comparison of laboratory methods for assessing numbers of apple rust mite (Aculus schlechtendali) overwintering on apple
Authors: LOW L. R. WARD , JACKSON A. W. 
Published: April 2007

During the winter of 1980/81 apple shoots from the preceding season's growth were collected from 19 orchards in Kent and East Sussex. Five buds from each of 10 shoots per orchard were dissected under a stereoscopic microscope at × 30 magnification and apple rust mites (Aculus rchlechtendali) were counted. These dissected buds were then used to test a more rapid method of extraction and counting. The buds were added to methanol and mixed with a vibrating machine, mites were then collected in sieves and counted. Counts of mites by this method were similar to those of the first method when there were fewer than 100 mites on 50 buds, but there was greater variation when mites were more numerous.An even more rapid method using five other buds from the same 10 shoots was also tested; the buds were bisected, then vibrated in methanol, and the mites were collected in sieves and counted. Results were comparable with those obtained by the dissection/methanol method and can be used with similar confidence in advisory work on apple rust mite.
Barley net blotch: influence of straw disposal and cultivation methods on inoculum potential, and on incidence and severity of autumn disease
Authors: JORDAN V. W. L , ALLEN ELIZABETH C. 
Published: April 2007

Effects of ploughing or direct drilling with three methods of straw disposal on amounts of inoculum of Pyrenophora teres, and on frequency of infection and severity of net blotch in the autumn, were studied in winter barley. Prior to ploughing, many conidia of P. teres were caught above areas where infected straw from a previous crop of winter barley had been bated and removed leaving culm bases, or where barley straw had been chopped and left in situ, but relatively few were caught above areas where straw had been burnt. Thereafter, where ploughing had buried surface residues, irrespective of the method of straw disposal, conidia were not caught for at least 3 weeks, and subsequently were substantially fewer than in direct‐drilled areas where many spores were caught. Production of conidia (measured as numbers per unit length of straw) was greatest on chopped straw, less on culm bases and least on burnt straw residues. Sporulation on volunteer barley plants was much reduced by application of paraquat + diquat, but some still occurred on visually‘dead’volunteer barley.All direct‐drilled barley plants were diseased within 27 days of sowing, whereas 42 days elapsed before all plants sown in ploughed areas were diseased. Disease on individual plants was also more severe in direct‐drilled areas: 20% of the area of the first leaf to emerge was diseased 19 days after crop emergence in direct‐drilled plots, whereas less than 9% was diseased in ploughed areas 50 days after emergence.There was an additive effect of straw disposal methods and direct‐drilling on disease, which in turn affected plant vigour. The adverse effect of direct‐drilling on the incidence and severity of net blotch appeared to be far greater than that of the straw disposal methods.
Variation for isozymes and double‐stranded RNA among isolates of Puccinia striiformis and two other cereal rusts
Authors: NEWTON A. C. , CATEN C. E. , JOHNSON R. 
Published: April 2007

Gel electrophoresis was used to examine the variation in isozymes and dsRNA within and between the rust species Puccinia striiformis, P. recondita and P. hordei. No differences in isozyme phenotype were found among 29 diverse isolates of the wheat‐attacking form of P. striiformis (WYR). Smaller numbers of isolates of the barley‐attacking form (BYR) of P. recondita and of P. hordei showed similar intra‐group uniformity. There were major differences in isozyme phenotypes between the three species, while WYR and BYR differed for two of 12 enzymes. Double‐stranded RNA was detected in each species and in all 26 isolates examined. For WYR and BYR, all isolates within each group had the same or a similar phenotype. In contrast, each isolate of P. recondita and P. hordei had a unique phenotype. There were differences in dsRNA phenotypes both between the three species and between WYR and BYR.The uniformity of these rust populations and species for isozyme phenotype is contrasted with their variability in pathogenicity and with the variability in isozymes encountered in higher organisms. Uniformity may result from a feature of the biology of the rust species and populations examined, or from the relative homogeneity of the environment of biotrophic pathogens. Consistent differences in isozyme and dsRNA phenotype between the WYR and BYR isolates of P. striiformis indicate that these are two discrete populations, supporting the view that they should be recognized as f.sp. tritici and f.sp. hordei, respectively.
Interaction of red raspberry cultivars with isolates of Phragmidium rubi‐idaei
Authors: ANTHONY VIVIENNE M. , SHATTOCK R. C. , WILLIAMSON B. 
Published: April 2007

Seven cultivars of red raspberry (Rubus idaeus) showed different susceptibility to infection by yellow rust (Phragmidium rubi‐idaei) at two commercial plantations in Scotland and North Wales, The cultivars Latham, Chief and Boyne were completely resistant. Mailing Delight and Glen Clova supported more telial more than Mailing Jewel. In contrast the last named was the most susceptible cultivar at the aecial stage in Scotland but developed similar numbers of aecia to Glen Clova and Mailing Delight in Wales.Meeker had an extended latent period, fewer and smaller pustules and a very small yield of urediniospores compared to the other susceptible cultivars, thus showing the characteristics of slow‐rusting genotypes. At the Scottish site in 1982, where rust was less than in Wales, Meeker and Mailing Jewel performed differently to the other cultivars at the telial stage. Inoculation studies under controlled environmental conditions with urediniospores from each site revealed an interaction between cultivars and isolates suggesting that variation in pathogenicity is present in populations of P. rubi‐idaei in the UK.
Integrated control ofRhizoctonia solaniby methyl bromide andTrichoderma harzianum
Authors: STRASHNOW Y. , ELAD Y. , SIVAN A. , CHET I. 
Published: April 2007

Under laboratory conditions, isolate TH–203 ofTrichoderma harzianumwas found to be tolerant of up to 20 000 ppm methyl bromide (MB) (v/v), whereas the plant pathogenRhizoctonia solaniwas susceptible to a dose of less than 9000 ppm (v/v). Exposure to sub–lethal concentrations of MB had no effect on thein vitroantagonistic ability ofT. harzianum. Soil fumigation with MB at the equivalent of a commercial dose of 500 kg/ha did not reduce the population ofTrichodermain soil and allowed rapid colonization ofTrichodermato develop in the soil.Under greenhouse conditions a combination ofT. harzianumand a reduced dose of MB (equivalent to 200 kg/ha) completely controlled disease incidence ofR. solaniin bean seedlings compared with controls in untreated soils. Similar disease control was achieved with the recommended dose of MB. Under field conditions, the combination of 200 kg/ha MB andT. harzianumgave a significant synergistic effect on damping–off of carrot seedlings caused byR. solani, and had a similar effect on growth, yield and disease control to that of the recommended dose.T. harzianumwas also able to prevent reinfestation byR. solaniin fumigated soils.
The relative resistance of wheat, rye and triticale to take‐all caused by Gaeumannomyces graminis
Authors: HOLLINS T. W. , SCOTT P. R. , GREGORY R. S. 
Published: April 2007

In seven field experiments conducted over 6 years with a wide range of disease severities, triticale was intermediate in resistance to Gaeumannomyces graminis between wheat (susceptible) and rye (resistant). Use of triticale is suggested as an immediately available means of introducing take‐all resistance into cereal cultivation.Octoploid triticale was slightly more susceptible than hexaploid triticale. There was little evidence of consistent variation in resistance among wheat or rye cultivars but a few hexaploid triticale cultivars varied in resistance. The resistance of triticale was not reliably expressed in the glasshouse tests used, so selection for resistance to take‐all in a breeding programme would need to be conducted in the field. Individual pairs of rye chromosomes added to wheat did not significantly reduce its susceptibility. The feasibility of transferring the resistance of rye to wheat is considered.
Assessment of resistance to Plasmodiophora brassicae in swedes
Authors: WILLIAMSON CYNTHIA J. 
Published: April 2007

A method is described in which swede seedlings inoculated with standardized concentrations of resting spores of specific populations of Plasmodiophora brassicae can be evaluated for resistance in different environments. Similar ranking for resistance of four swede cultivars inoculated with one pathogen population was obtained from seedling tests in a glasshouse, from young plants in a polythene tunnel, and from mature plants in field trials. Differential resistance of the four cultivars to two pathogen populations evident in glasshouse seedling tests was more clearly demonstrated in the field where there was a highly significant cuitivar × pathogen population interaction (p<0 001) for both root fresh weight and mean disease category.The inclusion of uninoculated control plants in field trials enabled a direct comparison of yield with that from inoculated plants. Cultivars were defined as resistant in terms of yield if they did not suffer any crop loss in comparison with uninoculated plants, even though some plants showed restricted gall development. The distribution of fresh weight to galls, roots and shoots could be used to characterize the relative resistance of cultivars; in the most susceptible cultivars there was rapid gall development but little increase in root or shoot fresh weight between 6 and 12 weeks after inoculation. Differential response was determined during the 6 weeks following inoculation; the implications of this observation are discussed in relation to growth stage and rate of development of host and pathogen.