bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on the biology of Botrytis species on overwintered salad onions
Authors: MAUDE R. B. , PRESLY A. H. 
Published: February 2008

SUMMARYIn the years 1973/4–1974/5, Botrytis cinerea was responsible for losses of 26% and 37% respectively in overwintered salad (green) onion crops grown at Wellesbourne. The fungus invaded the tips of cotyledonary and young true leaves and then grew downwards and inwards through the leaf axils to colonise the internal tissues and produce a collar rot which caused plants to collapse and die. More direct infection of the junction between an older and younger leaf produced a similar effect. Symptoms were rarely noticeable (except occasionally in the later stages of the disease) and affected plants disappeared unobtrusively. The incidence of collar rot increased as the rate of leaf production fell with the drop in temperatures in winter months but decreased as leaf growth resumed with increases in temperature in the spring. The fungus grew and sporulated well at low temperatures (5°C) and more inoculated seedlings developed collar rot when maintained at simulated winter temperatures (7°C) than when kept at simulated spring temperatures (15°C). B. squamosa occurred spasmodically producing white leaf lesions but caused no loss of plants. B. allii although present at a low incidence did not increase in the crops but in common with B. cinerea caused some damage to the bases of plants at harvest.
The effect of seed, furrow and stem base spray treatment with iprodione on white rot disease (Sclerotium cepivorum) in spring‐sown salad onions
Authors: ENTWISTLE A. R. , MUNASINGHE H. L. 
Published: February 2008

SUMMARYSeed treatment with iprodione at 125 and 150 g a.i./kg was superior to calomel seed treatment at 500 g a.i./kg in reducing disease losses and increasing yields in field experiments with salad onions infected with white rot; iprodione at 50, 62·5 and 100 g a.i./kg and thiophanate‐methyl at 150 g a.i./kg were as effective as calomel.Furrow treatment with iprodione or thiophanate‐methyl at 0·05 and 0·15 g a.i./m row or calomel at 0·5 g a.i./m row gave similar control as equivalent rates of seed treatment. Neither seed nor furrow treatments gave adequate control with prolonged exposure of the crop to the disease.A single stem base spray of iprodione at 0·0625 g a.i./m row applied 5 wk after drilling, reduced losses from 46% with a standard calomel seed treatment to 20%; increasing the stem base spray concentration to 0·25 g a.i./m row did not improve the control but resulted in a doubling of yields. The most effective control was obtained with iprodione applied as a seed treatment at 62·5 g a.i./kg combined with a single stem base spray at 0·0625 g a.i./m row 5 wk after drilling and this reduced losses to 6% compared with losses of 46% with calomel treated seed and 88% with untreated seed; increasing the stem base spray concentration did not improve control but resulted in higher yields.
The relationship between glycoalkaloids and resistance to the white potato cyst nematode, Globodera pallida in potato clones derived from Solanum vernei
Authors: FORREST J. M. S. , COXON D. T. 
Published: February 2008

SUMMARYNo relationship was found between the degree of resistance to Globodera pallida and total glycoalkaloid content of the roots or tubers of a number of potato clones derived from Solanum vernei × S. tuberosum. Nematode infestation of the roots did not lead to increases in the glycoalkaloid content of susceptible or resistant potatoes.
Cabbage stem weevil (Ceutorhynchus quadridens) on spring oilseed rape in Southern England and its control
Authors: GRAHAM C. W. , GOULD And H. J. 
Published: February 2008

SUMMARYSurveys in 1974–75 in which 20 plants were examined in each of 105 fields showed that cabbage stem weevil was widespread on spring oilseed rape in the south of England, the larvae sometimes infesting a large percentage of plants and reducing vigour and yield. In replicated field trials during 1974–77, infestations were reduced by seed treatments of gamma‐HCH or sprays of gamma‐HCH, azinphos‐methyl, azinphos‐methyl + demeton‐S‐methyl sulphone, chlorpyrifos or triazophos. In some experiments treatments significantly improved plant growth or yield, or both. Granules of carbofuran or phorate also reduced larval infestations and damage, but both thiofanox granules and dimethoate sprays were ineffective. Sprays of gamma‐HCH or azinphos‐methyl + demeton‐S‐methyl sulphone which were effective against stem weevil could also in some years give improved control of blossom beetles (Meligethes spp.)
Epidemiology of eyespot (Pseudocercosporella herpotrichoides) on winter wheat, with particular reference to the period of infection
Authors: HOLLINS T. W. , SCOTT P. R. 
Published: February 2008

SUMMARYThe period of infection by Pseudocercosporella herpotrichoides was investigated by transplanting winter wheat from uninfested to infested sites at Cambridge. Maximum infection was found on plants moved between November and March; most conidia were trapped during winter but infection was not closely related to the numbers of conidia. Plants exposed at intervals on infested land and incubated in a standard environment became infected throughout the period from October to July; infection was not closely related to the numbers of conidia trapped or plant age, but was positively correlated with the number of wet days/wk. Thus, while enough P. herpotrichoides conidia were dispersed throughout the life of winter wheat crops to cause substantial infection, environmental factors limited the development of new infections from April onwards. Practical implications of these results for the choice of sowing date, the development of resistant varieties, and fungicide use, are discussed.
Predisposition to Septoria nodorum as a result of take‐all (Gaeumannomyces graminis) infection of wheat
Authors: JENKINS P. D. , JONES D. GARETH 
Published: February 2008

SUMMARYIn a series of experiments excised leaves from take‐all infected wheat plants and from control plants were inoculated with Septoria nodorum. Larger lesions, more lesions/leaf and more pycnidia/unit area of lesion were produced from take‐all plants. Significant effects of predisposition were demonstrated when only 3% of the area of the total root system was infected by take‐all.Microscopical investigations revealed that germ‐tubes of S. nodorum grew more rapidly on leaves from take‐all plants, but the time of penetration was not affected. It is proposed that the observed effects of predisposition arose because more germ‐tubes produced successful infections and host tissue was more rapidly colonised.The importance of these results for the epidemiology of glume blotch is discussed.
Vector relationships and other characteristics of barley yellow striate mosaic virus (BYSMV)
Authors: CONTI MAURIZIO 
Published: February 2008

SUMMARYBarley yellow striate mosaic virus (BYSMV) was inoculated by its planthopper vector Laodelphax striatellus (Homoptera, Delphacidae) to 44 species of Gramineae, 26 of which in eight tribes were infected. The virus was not transmitted through wheat seed nor did it infect five dicotyledonous hosts of other rhabdoviruses. The most susceptible species were in the tribes Festuceae and Hordeae. Barley, Bromus spp., oats, Phalaris canariensis, Setaria italica, Sorghum spp., and sweet corn cv. Golden were diagnostic hosts. Electron microscopy of crude sap was also a sensitive diagnostic method. Properties of BYSMV were determined by injecting L. striatellus with crude sap from infected barley. Sap was infectious after 10 min at 50–55 °C but not after 10 min at 60 °C, when diluted with buffer to 10‐‐2 but not to 10‐‐3, when stored for 2 but not 4 days at 5 °C or when kept for 1 but not 2 days at 22 °C.The planthopper Javesella pellucida was an experimental vector of BYSMV but the virus was not transmitted by the leafhoppers Macrosteles sexnotatus or Psammotettix striatus (Homoptera, Cicadellidae). The latent period of BYSMV in L. striatellus was most commonly 15 or 16 days (minimum, 9 days; maximum, 29 days). The minimum acquisition access period for transmission was between 1 h and 5 h, and the minimum inoculation feeding time was 15 min. After 24 h and 8 day acquisition feeds, 30.4% and 42.8% respectively of L. striatellus transmitted BYSMV. When transferred daily, infective hoppers transmitted virus intermittently. The maximum retention of infectivity by L. striatellus was 36 days.Two of five infective females transmitted BYSMV transovarially. Larvae became infective in the second wk after hatching and transmitted for up to 3 wk.
Properties of a resistance‐breaking strain of potato virus X
Authors: MOREIRA A. , JONES R. A. C. , FRIBOURG C. E. 
Published: February 2008

SUMMARYDuring indexing of a potato germplasm collection from Bolivia, a strain of potato virus X (PVX), XHB, which failed to cause local lesions in inoculated leaves of Gomphrena globosa was found in 7% of the clones. XHB was transmitted by inoculation of sap to 56 species from 11 families out of 64 species from 12 families tested. It was best propagated in Nicotiana glutinosa or N. debneyi; Montia perfolia and Petunia hybrida were useful as local lesion hosts. Inoculated leaves of G. globosa plants kept at 10°, 14°, 18°, 22°, or 26 °C after inoculation were always infected symptomlessly. XHB caused a mild mosaic, systemic chlorotic blotching or symptomless infection in 16 wild potato species and eight Andean potato cultivars, systemic necrotic symptoms in clone A6 and cultivar Mi Peru, and bright yellow leaf markings in cultivar Renacimiento. It caused necrotic local lesions in inoculated leaves of British potato cultivars with the PVX hypersensitivity gene Nb but then invaded the plants systemically without causing further necrosis; with gene Nx systemic invasion occurred but no necrotic symptoms developed. These reactions resemble those of PVX strain group four. XHB differed from other known strains of PVX in readily infecting PVX‐immune clones 44/1016/10, G. 4298.69 and USDA 41956, cultivars Saphir and Saco, and Solanum acaule PI 230554.XHB had slightly flexuous filamentous particles with a normal length of 516 nm. It was transmitted readily by plant contact and it partially protected G. globosa leaves from infection with XCP, a group two strain of PVX. Sap from infected N. glutinosa was infective after dilution to 10‐‐6 but not 10‐‐7 after 10 min at 75° but not 80 °C and after 1 yr at 20 °C. XHB was readily purified from infected N. debneyi leaves by precipitation with polyethylene glycol followed by differential centrifugation. Microprecipitin tests showed that XHB and XCP are closely related serologically.
The effects of nematode resistant and susceptible spring oat cultivars and aldicarb on the cereal cyst nematode Heterodera avenae and yields in contrasting soil types
Authors: WILLIAMS T. D. , BEANE J. 
Published: February 2008

SUMMARYThe effects of the cereal cyst‐nematode, Heterodera auenae Woll. on resistant and susceptible oat cultivars, with and without aldicarb treatment, were compared on a clay‐with‐flints soil at Rothamsted and a loamy sand at Woburn. At both sites, when H. auenae was extremely scarce, yields were not further enhanced by aldicarb. At Rothamsted aldicarb increased yields by 48–72% when H. auenae averaged 10 eggs/g soil. At Woburn, aldicarb increased yields of both susceptible and resistant varieties by 80–90% with 20 eggs/g. The resistant varieties conferred yield benefits in the following oat crop equal to the residual effects of aldicarb applied before the previous crop, demonstrating that H. auenae was wholly responsible for the yield losses. Nematode resistant oats suffered as much or more damage from root invasion by H. auenae juveniles as the susceptible varieties but the resulting decrease in nematode numbers led to considerable yield improvements in the following year. At Woburn in 1977, when formalin was an added treatment, fewer females were infected by parasitic fungi and post‐crop egg numbers were greater.
Nematodes associated with peas and beans in Scotland
Authors: BOAG B. 
Published: February 2008

SUMMARYSix hundred and sixty‐four soil samples from farms growing peas and beans in eastern Scotland were examined for plant parasitic and predatory nematodes. Neither pea cyst‐nematode, Heterodera goettingiana nor pea early‐browning virus disease were found. Stem nematode, Ditylenchus dipsaci was recorded in broad beans once. The most frequently occurring plant parasitic nematodes were Tylenchorhynchus dubius, Longidorus elongatus, Rotylenchus goodeyi and Helicotylenchus vulgaris but numbers were generally too small to cause damage. It is concluded that although potentially damaging plant parasitic nematodes occur in Scotland, nematode‐related diseases occur infrequently and are of little significance to the crop.
Insect feeding on different sorghum cultivars in relation to cyanide and phenolic acid content
Authors: WOODHEAD S. , PADGHAM D. E. , BERNAYS E. A. 
Published: February 2008

SUMMARYInsect feeding on sorghum was studied in the field and in the laboratory. Quantitative differences in cyanogenesis and phenolic acid content were also measured on the same or simillar plants. High concentrations of cyanide were correlated with a reduction in feeding by grasshoppers and by first‐instar larvae of Chilo partellus; high concentrations of phenolic acids were correlated with reduced feeding by various grasshoppers and by the planthopper Peregrinus maidis. Mythimna separata larvae, and adults and nymphs of Rhopalosiphum maidis, were apparently unaffected by these chemicals. Some sorghum cvs which were relatively unpalatable to grasshoppers and to P. maidis had low levels of the test chemicals, so that here some other factor or factors must be involved.
An evaluation of the sampling variation when estimating the population of Verticillium dahliae in field soil
Authors: EVANS G. , GLEESON A. C. 
Published: February 2008

SUMMARYThis paper describes a study designed to find a reliable sampling procedure for estimating the population of Verticillium duhliue in field plots that would not be too demanding in terms of the time required to assay soil samples. In the soil under study, the amount of time needed to obtain reliable estimates of the inoculum density was reduced by taking the larger plot sizes in the range considered, generally taking more plots with fewer samples per plot, and mixing the samples within a plot before redividing for assaying.
Tolerance trials with young cocoa trees infected with cocoa swollen‐shoot virus
Authors: LEGG J. T. , KENTEN R. H. , LOCKWOOD G. 
Published: February 2008

SUMMARYIn three short‐term field trials, 24 cocoa progenies were assessed for sensitivity to infection with a severe Ghanaian strain of cocoa swollen‐shoot virus. Some of the progenies were derived from tolerant parents, others had themselves shown mild symptoms as young seedlings. Stem diameters, diameter increments, canopy scores and latent periods (time between inoculation and expression of symptoms) of plants infected when 12 to 22 months old were compared with similar measurements of healthy plants.During the period between 6 and 18 months after inoculation, infection reduced the stem diameter increment of the least sensitive progeny in each trial by 52, 25 and 7%, the last value increasing to 38% during the period between 24 and 30 months after inoculation. Within trials, the effects of virus infection on stem diameter increments and canopy scores were well correlated but latent periods were not significantly correlated with any other variate.In one trial, pod yield was more closely related to canopy condition at the time of cropping than to stem diameter increment 2 yr earlier. Weak correlations between pre‐ and post‐bearing increases in diameters in these trials indicated that tolerance was not directly related to vigour. None of the progenies is considered suitable for direct use as tolerant varieties in Ghana.
Factors affecting the detection of potato leafroll virus in potato foliage by enzyme‐linked immunosorbent assay
Authors: TAMADA T. , HARRISON B. D. 
Published: February 2008

SUMMARYUsing antiserum globulins that reacted only weakly with plant materials, potato leafroll virus (PLRV) at 10 ng/ml was detected consistently by enzyme‐linked immunosorbent assay (ELISA). The reaction with PLRV particles was slightly impaired in potato leaf extracts that were diluted less than 10‐1 but not at greater dilutions. Antiserum globulins that reacted more strongly with plant materials could be used satisfactorily for coating microtitre plates but were unsuitable for conjugating with enzyme.The detection end‐point of PLRV, in leaf sap of potato cv. Cara plants grown from infected tubers in the glasshouse, was about 10‐2 and the virus was reliably detected in extracts of composite samples of one infected and 15 virus‐free leaves. PLRV concentration was much less in extracts of roots or stolons than in leaf extracts. The virus was detected in infected leaves of all 27 cultivars tested.PLRV was readily detectable 2 wk before symptoms of secondary infection developed in field‐grown plants of cv. Cara and Maris Piper and remained so for at least 5 wk. Its concentration was slightly greater in old than in young leaves and was similar to that in glasshouse‐grown plants. In field‐grown plants of cv. Maris Piper with primary infection, PLRV was detected in tip leaves 21–42 days after lower leaves were inoculated by aphids; in some shoots it later reached a concentration, in tip leaves, similar to that in leaves with secondary infection. Symptoms of primary infection developed in the young leaves of some infected shoots but were inconspicuous and were not observed until at least a week after PLRV was detected by ELISA.
The effect of different periods of dehydrationhehydration upon the ability of second stage larvae of Anguina tritici to survive desiccation at 0% relative humidity
Authors: WOMERSLEY CHRISTOPHER 
Published: February 2008

SUMMARYThe effect of various desiccation regimes on the ability of second stage larvae of Anguina tritici (Steinbuch, 1799) to survive drying at 0% relative humidity has been studied. It was found that both repeated dehydrationhehydration cycles and the length of the desiccation period itself decreased viability of the larvae. The results are discussed in relation to the mechanisms which may facilitate anhydrobiosis.
A method of measuring differences between bean varieties in tolerance to sub‐optimal temperatures
Authors: HARDWICK R. C. , ‘ANDREWS D. J. 
Published: February 2008

SUMMARYBean (Phaseolus vulgaris and P. coccineus) plants were grown in controlled environments at (day/night) temperatures of either 25°/20 °C or 20°/15 °C. The lower temperatures tended to reduce the weight of stem relative to the weight of leaf. An interpolation procedure was devised for estimating the magnitude of this effect, which varied between cultivars. It is suggested that the interpolation parameter can be used as an indication of varietal cold tolerance. Thus estimated values of the parameter (h), normalised so that 1 unit = 1 S.E.D, were large and positive in a cv. Seafarer previously characterised as cold intolerant (h = 4–19), large and negative in the relatively cold tolerant P. coccineus cv. Hammond's Dwarf Scarlet (h = ‐3.03), and near to zero (h = 1–11) in the standard commercial variety of P. vulgaris cv. Prelude.The experiment with cvs Seafarer and Prelude was repeated three times and similar values of h were obtained on each occasion. There was only a small variation of h with harvest date; over a period in which plant weight increased at least 3.5 and up to 9 times. In the third experiment a modification of the harvesting procedure was adopted so that plants could be tested for cold tolerance and then grown on for seed production. This semi‐destructive test was applied to, and the results are reported for, nine cultivars which are of interest as potential dry‐bean cultivars for the United Kingdom.
Fireblight in Kent, England in relation to weather (1955–1976)
Authors: BILLING EVE 
Published: February 2008

SUMMARYA system for the assessment of potential for fireblight Erwinia amylovora activity (PFA), based on standard temperature and rainfall records, has previously been outlined. Here some recent modifications are described and the system is discussed more fully and tested for its ability to explain outbreaks of fireblight in different hosts in Kent, south‐east England for the years 1955–76.In most cases, there was a satisfactory match between PFA patterns and recorded field outbreaks and incidents and it is concluded that warnings based on the system could have lessened risk of disease in some hosts in past years. In the short term (depending on the accuracy of weather forecasts) the system can be used predictively. Its use in this way is discussed together with underlying principles of some of the criteria used and possible ways in which the precision of the system might be improved.
Fireblight Erwinia amylovora and weather: a comparison of warning systems
Authors: BILLING EVE 
Published: February 2008

SUMMARYWarning systems for fireblight Erwinia amylovora developed in New York, Illinois and California, USA, and in south‐east England are compared. General principles which might be applicable in the different climates were sought. The consequences of applying threshold temperature values chosen for one area in a different climatic area were examined using Sacramento, California; Rochester, New York; Vlissingen, The Netherlands; Kent, England as examples. A graded system for assessing fireblight risks, derived from all the systems, is suggested. It takes into account both risks of infection and risks of high insect activity and it is best used in conjunction with Billing's incubation period assessment system.
The resistance of the perennial ryegrass cultivar Endura to ryegrass mosaic virus
Authors: GIBSON R. W. , WOODS R. D. , PICKERING S. PETA 
Published: February 2008

SUMMARYThe perennial ryegrass cv. Endura is particularly resistant to infection with two ryegrass mosaic virus isolates, RMV‐Roth and RMV‐Sax. A few plants appeared immune to RMV‐Roth but were infected by RMV‐Sax. Two plants that developed only mild symptoms after infection with RMV‐Roth contained few virus particles, but passage through these resistant plants caused no detectable change in the virulence of RMV‐Roth towards S 22 Italian ryegrass. In offsets derived from one of these resistant plants, RMV‐Sax caused severe symptoms and attained a high virus concentration but it was unable to infect if the plant was already infected with RMV‐Roth.
Hibiscus latent ringspot virus, a newly recognised virus from Hibiscus rosa‐sinensis (Malvaceae) in western Nigeria
Authors: BRUNT A. A. , BARTON R. J. , PHILLIPS SUE , LANA A. O. 
Published: February 2008

SUMMARYHibiscus latent ringspot virus (HLRV) was prevalent in Hibiscus rosa‐sinensis in Ibadan, Nigeria. It was readily transmitted mechanically to 22 of 73 species from seven of 20 families, but was best propagated in Nicotiana clevelandii or Hibiscus cannabinus and assayed in Chenopodium murale. HLRV was readily purified from systemically infected hosts by differential centrifugation of leaf extracts clarified with 8.0% n‐butanol, followed by molecular permeation chromatography on controlled‐pore glass beads (700 Å, 120–200 mesh). The virus has isometric particles c. 28 nm in diameter which sedimented as three components (T, M and B), with sedimentation coefficients (s°20, w) of 51; 114 and 132 S and buoyant densities in caesium chloride of 1.32, 1.49 and 1.52 g/cm3, respectively. All three components contained a single polypeptide of rnol. wt 53.6 × 103. T component particles contained only protein but M and B components also contained single‐stranded RNA of rnol. wt 2.2 × 106 and 2.5 × 106, respectively. The properties of HLRV suggest affinities with nepoviruses but no serological relationship was detected between HLRV and 15 recognised or possible members of the nepovirus group.