bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison and characterization of maize stripe and maize line viruses
Authors: KULKARNI H. Y. 
Published: February 2008

SUMMARYTwo morphologically similar viruses isolated from maize in East Africa induced two distinct symptom types in maize. One, designated maize stripe virus (MSV), showed broad yellow stripes or a yellowing of the entire leaf, acute bending of the shoot apex and severe stunting. The second, maize line virus (MLV), induced continuous, narrow yellow lines along the leaf veins and did not cause apical bending or stunting. MSV and MLV were both transmitted by Peregrinus maidis (Delphacidae), but not by Cicadulina mbila (Jassidae) or by sap inoculation.Both viruses were purified by extracting systemically infected leaves in 0–5 M sodium citrate buffer and clarifying with 7 ml n‐butanol/100 ml extract, followed by differential, and finally sucrose density gradient, centrifugation.Partially purified preparations of both viruses contained isometric viruslike particles of two sizes: MSV particles were 35 and 40 nm in diameter with sedimentation coefficients (so2o, w) I09 anI0o respectively; MLV particles were 28 and 34 nm in diameter. Antisera prepared against MSV and MLV had dilution end points of 1/128 and 1/64 respectively in agar‐gel diffusion tests.In tests with low‐titre antisera, MSV did not react with MLV antiserum and MLV did not react with MSV antisreum; in the presence of antiserum containing antibodies to both MSV and MLV, the two viruses formed precipitin bands which crossed in the pattern of non‐identity. Maize streak virus and maize mottle virus showed no serological relationship with MSV or MLV.On the basis of particle size and serology MSV and MLV are shown to be two distinct and possibly unrelated viruses.MSV and MLV apparently are dissimilar from any characterized viruses of the Gramineae.
Control of potato cyst‐nematode, Heterodera rostochiensis, in sandy, peaty and silt loam soils by dazomet and Telone applied in different ways
Authors: WHITEHEAD A. G. , TITE D. J. , FRASER JANET E. , FRENCH EILEEN M. 
Published: February 2008

SUMMARYDazomet applied in the ridges in autumn or in spring, before potatoes were planted in them, controlled potato cyst‐nematode (Heterodera rostochiensis), British pathotype A, better in sandy loam and peaty loam than Telone (1,3‐dichloropropene mixture). In sandy loam dazomet controlled potato cyst‐nematode as well when applied in spring as when applied in autumn and as well when the soil was ridged after treatment as when it was not. Telone was as effective when applied to ridges in autumn as when applied to ridges in spring. In peaty loam potato cyst‐nematodes were least abundant after a crop of Maris Piper potatoes. The yields of King Edward potatoes were greatly increased and nematode multiplication was greatly reduced by dazomet incorporated in the ridges in autumn. Two equal doses of dazomet, one incorporated in the topsoil before, the other after ploughing, controlled potato cyst‐nematode as well and increased the yield of King Edward potatoes more than an equivalent amount of dazomet applied after ploughing. Dazomet applied to silt loam soil in two dressings, one before, the other after, ploughing, controlled potato cyst‐nematode better than an equal amount applied as a single dressing after ploughing. The nematode was controlled best by two large dressings of dazomet or by a combined treatment of dazomet and Telone.
Changes in growth regulator content of radish seedlings, Raphanus sativus, infested with the aphid Myzus persicae
Authors: HUSSAIN A. , FORREST J. M. S. , DIXON A. F. G. 
Published: February 2008

SUMMARYFollowing 10 days of infestation by the aphid Myzus persicae there was an increase in the amount of growth inhibiting substances and a decrease in cytokinins, gibberellins and auxins in infested as compared with similar uninfested radish seedlings. Even after previously infested seedlings have been freed of aphids for 10 days, differences in the hormone balance remained. The possible relationships between the changes in hormonal balance and the effect of the aphid infestation on growth, translocation and wilting are discussed.
Laboratory and field investigations with organophosphorus resistant Tetranychus urticae on strawberries
Authors: GOULD H. J. 
Published: February 2008

SUMMARYLaboratory tests using a slide dip technique confirmed that strains of Tetranychus urticae resistant to demeton‐S‐methyl and dimethoate had developed on strawberries in south Hampshire. These pesticides had been used very successfully for many years for the combined control of aphids and red spider mite.In small plot screening trials dicofol, phenisobromolate, chloropropylate, quinomethionate and dinobuton gave consistently good results. Binapacryl was very effective but caused damage to the plants. A number of other acaricides including formetanate and methiocarb were shown to be worth further investigation.Tetradifon, also used for some years on strawberries, gave variable results.
Potato blight control in east and south‐east Scotland 1959–68
Authors: BOYD A. E. W. 
Published: February 2008

SUMMARYRoutine protective spray application to commercial Majestic potato crops on two farms in south‐east Scotland for 9 and 10 years respectively gave highly significant average increases in total yield of 1.2 and 2.1 tons per acre (3.0 and 5.3 tonnes per ha) respectively in rows not affected by tractor wheels. In 6 and 7 years respectively the increases were more than 1 ton per acre. These increases were composed almost entirely of ware tubers. There was no average difference in yield whether the first spray application was made when the haulm closed in the rows or after the first general forecast based on the Beaumont period was announced.The average total yield reduction in the four rows affected by tractor wheels tended to offset the benefit given by spray application, and, where an eight‐row spray boom was employed, halved the potential overall yield increase. Reduction was again confined to the ware fraction.Similar experiments with cv. King Edward over a shorter period in eastern Scotland generally showed little consistent effect on yield, possibly partly because of the late appearance of blight in some of these crops.Considerable yield gains were obtained in Majestic crops even when the disease first appeared in mid‐August in some seasons which could not be classified as ‘blight years’. Over the 10 years of the investigation, there were 5 blight years as defined by Large (1959) compared with the 1 in 10 which Large mentioned for the north of England.Spread of blight from local sources, such as discard heaps outside the crop and before the occurrence of the field epidemic phase, was found to interfere with adequate timing of spray applications and with the effectiveness of the general forecast based on the Beaumont period.Infection of Majestic tubers was generally low but at one Majestic site and in the King Edward series the overall average tuber infection was significantly decreased by spraying. Tuber blight was shown to vary inversely with the size of tubers of Majestic as well as of King Edward.
Glasshouse evaluation of some systemic fungicides for control of clubroot of brassicae
Authors: BUCZACKI S. T. 
Published: February 2008

SUMMARYOf nine systemic fungicides screened as soil mixes against clubroot, only the precursors of methyl benzimidazol‐2‐ylcarbamate (MBC) or ethyl benzimidazol‐2‐ylcarbamate (EBC) gave promising results. Benomyl was the most effective, usually giving control at 250 mg/kg dry soil. Most fungicides were less effective against an isolate of Plasmodiophora brassicae from Brussels sprouts than against one from rape. Disease control was slightly better on cabbage than on a highly susceptible rape variety.
Effects of soil fumigation on the growth of apple and cherry rootstocks on land previously cropped with apples
Authors: JACKSON J. E. 
Published: February 2008

SUMMARYApple and cherry rootstocks were planted into land on which apple trees had previously been grown and which pot tests had shown to be subject to apple replant disease. Prior to planting the land was either left unfumigated or zones of progressively increasing area (0.052 m2, 0.839 m3, 3.356 m2) centred on the proposed planting holes were fumigated with chloropicrin. Fumigation greatly increased the growth of the apple rootstocks but not of the cherry rootstocks. In the first year after planting the effects of the two larger fumigated areas were identical but in later years apple rootstock growth was directly related to the size of the fumigated area. This indicated that the replant disease does not simply affect tree establishment as was previously thought to be the case. The implications of this are discussed.
Effects of D‐D, Telone or dazomet applied to potato ridges in spring on potato cyst‐nematode, Heterodera rostochiensis, in sandy loam and silt loam soils
Authors: WHITEHEAD A. G. , TITE D. J. , FRASER JANET E. , FRENCH EILEEN M. 
Published: February 2008

SUMMARYLarge amounts of dazomet (329, 439 kg/ha) applied to potato ridge soil in spring, before potatoes were planted, controlled potato cyst‐nematode (Heterodera rostochiensis) in sandy loam and silt loam more effectively than large amounts of D‐D (359, 448 kg/ha). In heavily infested sandy loam, 329 kg dazomet/ha or 857 kg methyl bromide/ha applied in spring 1969 or 439 kg dazomet/ha applied in autumn 1968, greatly decreased the number of larvae able to invade potato roots, so Majestic potatoes grew and yielded well without increasing the number of nematodes left in the soil after harvest. Large amounts of D‐D or Telone applied to the topsoil in autumn or to the ridges in spring were less effective in controlling potato cyst‐nematode or increasing potato yields. Applied in spring 1969 to silt loam ridges, 439 kg dazomet/ha had more effect than 448 kg D‐D/ha on potato cyst‐nematode and on the increase in yield of Majestic potato. The yield of Maris Piper potatoes (resistant to H. rostochiensis pathotype A) in infested silt loam was increased greatly by D‐D, as much by 112 as by 224 or 448 kg/ha.
Phytophthora collar rot of apple: seasonal effects on infection and disease development
Authors: SEWELL G. W. F. , WILSON J. F. 
Published: February 2008

SUMMARYOne‐to three‐year‐old trees of the apple variety Cox's Orange Pippin were highly resistant to infection by Phytophthora cactorum except during the spring from March to May. A rapid increase in resistance occurred after this time from the commencement of shoot growth. The period of susceptibility to infection by P. syringae was from October to December, when trees were dormant. Inoculations with either fungus during the respective susceptible periods caused rapidly extending lesions which girdled and killed the trees; established lesions continued to enlarge in months when trees were resistant to infection.Similar seasonal fluctuations in resistance to infection by P. cactorum also occurred in mature (35‐year‐old) Cox trees but the susceptible period was longer. Lesions resulting from inoculations at the optimum time (the ‘mouseear’ to ‘pink‐bud’ stages of development) extended at similar rates in both young and old trees.The infrequent incidence of collar rot in young trees is probably related to factors other than inherent resistance. In resistance and pathogenicity studies young trees gave reliable and consistent results, provided that inoculations were correctly timed in relation to bud development.
Phytophthora collar rot of apple: influence of the rootstock on scion variety resistance
Authors: SEWELL G. W. F. , WILSON J. F. 
Published: February 2008

SUMMARYIn field experiments with young trees great differences were found in the resistance to Phytophthora cactorum of Cox's Orange Pippin apple scions grafted on different clonal rootstocks. The rootstock effect on scion resistance was inversely related to the effect on tree vigour: the rootstocks inducing high resistance were dwarfing (M. 9) or semi‐dwarfing (M. 7, M. 26, MM. 106), and those inducing low resistance were vigorous or very vigorous (M. 25, MM. 104, MM. 109). Mean lesion lengths in Cox on MM. 104 were five to eight times greater than those in Cox on M. 9. The rootstock influence on scion resistance was associated primarily with effects on the rate of lesion extension: during the early stages only of host colonization there appeared to be threshold extension rates below which host resistance factors effectively suppressed a large proportion of infections. The influence of the root‐stock on scion resistance was apparently unrelated to inherent rootstock resistance.On all rootstocks Cox showed diminished resistance to infection during the period from the swelling of buds to the early stages of shoot growth. Although most susceptible during the ‘mouse‐ear’ and ‘pink bud’ stages of development, suscpetibility was not associated with flowering per se.Rootstock type did not affect the resistance of Cox scions to P. syringae, for which the period of susceptibility to infection occurred in the dormant season.
Peanut mottle virus in East Africa
Authors: BOCK K. R. 
Published: February 2008

SUMMARYA very common and widespread virus pathogen of groundnut and soybean in East Africa was identified as peanut mottle virus (PnMV)* on the basis of particle morphology, serology, host range and reaction, transmission and physical properties.Virus concentration adequate for serological tests was obtained from cowpea (Vigna unguiculata) cultured at 27 °C but not at 23 °C. Purified preparations from this source gave a single, specific light‐scattering zone in sucrose density gradients.PnMV was purified using 0.5 M sodium citrate buffer containing 1% mercapto‐ethanol; an antiserum made against such preparations had a homologous titre of 1/8192.Groundnut and soya isolates from N., N.E., N.W. and S. districts of Uganda, N.W. Tanzania, and W. and E. (coastal) districts of Kenya were serologically similar and varied, within narrow limits, in symptoms induced in certain groundnut and soya varieties. A serologically related but distinct virus was isolated from Voandzeia subterranea.PnMV was not related serologically to any of ten viruses of the PVY group.Glasshouse experiments simulating groundkeeper conditions in the field indicated 20% seed transmission in groundnut; PnMV was transmitted by Aphis craccivora in the non‐persistent manner.All twenty‐one varieties and breeding lines of soybean tested were highly susceptible.The prevalence of PnMV in East Africa and the reduction in yield caused in groundnut indicates the virus to be economically important, and groundnut and soybean improvement programmes should include routine PnMV susceptibility tests.
Purification and serology of the W strain of cucumber mosaic virus
Authors: TOMLINSON J. A. , ELIZABETH ANNE L. CARTER , FAITHFULL M. , WEBB M. J. W. 
Published: February 2008

SUMMARYDuring studies on the purification of cucumber mosaic virus (strain W) it was found that preparations were most infective and stable when made from tobacco leaves (10–12 days after inoculation) homogenized in phosphate buffer containing EDTA and thioglycollic acid and clarified with diethyl ether.The preparations were further purified by centrifugation in sucrose density gradients containing EDTA at pH 9.0 and were then stable at 2 °C for > 100 days. When mounted in neutralized ammonium molybdate they were shown to consist of predominantly intact particles.In tube and ring precipitin tests and in agar gel‐diffusion tests, specific precipitation with homologous antiserum occurred only in media containing alkaline adjusted solutions (ammonium molybdate and dipotassium hydrogen phosphate).
Effect of additives and storage conditions on antibody titres of tobacco mosaic and southern bean mosaic virus antisera
Authors: WATERWORTH H. E. , LAWSON R. H. , BLIZZARD J. W. 
Published: February 2008

SUMMARYThe effect on serological activity of methods of storing antisera to southern bean mosaic virus and tobacco mosaic virus was tested. Aliquots (0.5 ml) were (1) stored at —70, —20, +4, +26 or +37 °C, (2) repeatedly frozen and thawed, (3) stored in 5% peptone, 0.02% sodium azide or 50% glycerol, (4) diluted before storage, or (5) freeze‐dried. All samples were titrated against purified virus after 1, 6 and 12 months. Most of the treatments had little effect on the precipitin titres of the antisera, but the titres were decreased by storage at 37 °C.Mention of specific equipment, trade products or commercial companies does not constitute their endorsement by the U.S. Department of Agriculture over similar products or companies not mentioned.
Virus‐like particles in the take‐all fungus, Gaeumannomyces graminis
Authors: RAWLINSON C. J. , HORNBY D. , PEARSON V. , CARPENTER J. M. 
Published: February 2008

SUMMARYIsometric virus‐like particles (VLP) measuring 35 nm and 27 nm occurred in cultured mycelium of Gaeumannomyces graminis var. tritici and G. graminis var. avenae. These VLP had, respectively, sedimentation coefficients (s°20, W) 148S and 110S and ultraviolet absorption (maximum 260 nm, minimum 240 nm) typical of nucleoprotein (A260:280 = 1.6, A260:240 = 1.2). Preparations of the 35 nm particles had two major and one minor component in caesium chloride, and 27 nm particles had two components (buoyant densities 1.37, 1.36, 1.30, 1.35, and 1.29 g/cm3 respectively). Preparations of the 35 nm particles or 35 nm plus 27 nm particles had one major protein species with estimated molecular weight 70000 daltons.The 35 nm VLP were absent from 11 isolates of G. graminis var. tritici from first cereal crops after fallow or non‐susceptible break crops; two of these contained the 27 nm particles. More than half of 145 isolates, from cereals after 2–12 consecutive susceptible crops, contained either 35 nm or 27 nm VLP. VLP were not confined to G. graminis isolates from soils exhibiting ‘take‐all decline’ nor consistently associated with weak pathogenicity or with isolates of unusual growth, morphology, pigmentation, lysis or readiness to form perithecia. Isolates with one kind of particle were mostly more pathogenic and those with both kinds less pathogenic than isolates without VLP. The proportion of isolates with 27 nm and 35 nm particles increased progressively in samples from different consecutive crops during the first 9 years of cropping, then decreased.Isolates did not gain or lose VLP during infection and re‐isolation from wheat seedlings grown in sand.Four ‘infected’ isolates were freed from VLP either by culturing ascospores or by growing hyphal tips excised from colonies kept near their thermal death point. Both VLP appeared in cultures which had undergone anastomosis with infected isolates.
Chemical control of the frog‐eye disease (Cercospora nicotianae) of tobacco (Nicotiana tabacum) in Nigeria
Authors: FAJOLA A. O. , ALASOADURA S. O. 
Published: February 2008

SUMMARYSix fungicides‐Bordeaux mixture, Verdasan, Tillex, Coprantol, Karathane and Dithane M 45‐were evaluated for the control of the spore germination of Cercospora nicotianae, causing the frog‐eye disease of tobacco. Four of these were also tried against artificial infection in the greenhouse and two against natural infection in the field during three growing seasons of the crop in Southern Nigeria.The results of the laboratory evaluations were in general agreement with those obtained from the greenhouse and field trials. It was found that Dithane M 45 had a higher fungicidal value and tenacity than the other fungicides tested, and gave the best control of the disease. A marked luxuriant growth induced by Dithane M 45 on treated plants is reported and discussed.
A method for assessing the efficacy of seed disinfectants for the control of seed‐borne Septoria nodorum on wheat
Authors: HOLMES S. J. I. , COLHOUN J. 
Published: February 2008

SUMMARYThe most rigorous tests of the effectiveness of seed disinfectants for the control of Septoria nodorum on wheat can be made by growing seedlings from treated seeds in the glasshouse at an air temperature of 12 °C and a soil moisture content of 30% of the maximum water holding capacity. In carrying out such tests assessments were made of the percentage of diseased seedlings and of the disease index. Based on the results obtained a schedule of testing is recommended.
The use of canonical analysis for selection within a population of spring barley
Authors: RIGGS T. J. 
Published: February 2008

SUMMARYA selection method is described involving the application of canonical analysis to data for a number of measured traits in a composite population of spring barley grown in two seasons.Lines were selected which fell within the Euclidean space defined by the range, for a number of standard cultivars, on each significant canonical variate. Alternatively, limits were fixed for an acceptable range for each trait and transformed to canonical variates. Lines were selected which fell nearest to the centroid of this acceptable space.The method might be used as an alternative to the selection index method where difficulty is often encountered in assigning appropriate economic weightings to the traits measured.
The effect of plant spacing on the number of aphids trapped over cocksfoot and kale crops
Authors: A'BROOK JOHN 
Published: February 2008

SUMMARYThe response to plant spacing by flying and landing aphids has been studied using cylindrical and horizontal sticky traps over cocksfoot and kale crops. Some aphid species showed a significant response to spacing, being caught more frequently over wide‐than close‐spaced crops; the regressions of catches over widely‐spaced on those over close‐spaced plants suggested that most of the species caught followed this trend irrespective of the host plant. The landing response to spacing on horizontal traps at 0.3 m was normally greater than that on cylindrical traps at 1 m. At 1 m, some species (e.g. Aphis fabae gp.) gave a different response to spacing in the two crops, whilst others (e.g. Rhopalosiphum oxyacanthaé) responded similarly to both crop spacings. In contrast to previous results with other aphid species and spaced groundnuts, the landing response of Rhopalosiphum spp. was elicited both when there was a cover crop (clover) between widely‐spaced drills of cocksfoot and by widely‐spaced cocksfoot alone. It is suggested that one stimulus eliciting the landing response with widely‐spaced plants is the electromagnetic emission from bare earth between the plants. Aphid landing behaviour was influenced by the spacing of both cocksfoot and kale plants.
Growth of crop roots in relation to soil moisture extraction
Authors: DURRANT M. J. , LOVE B. J. G. , MESSEM A. B. , DRAYCOTT A. P. 
Published: February 2008

SUMMARYGrowth of the roots of sugar beet, potato and barley in the field was observed through glass panels and related to changes in soil moisture measured by a neutron probe during 1969–71. The depth of observed root growth was generally related to, but 10–15 cm deeper than, the maximum depth of soil‐moisture extraction. On average of three years, sugar beet, potato and barley used water from the top 23, 33 and 45 cm soil respectively by the beginning of June, and from the top 70, 68 and > 100 cm soil by the end of June. Maximum soil drying in each horizon gave an in situ measure of available water capacity, and showed that sugar beet and barley eventually extracted similar amounts of water from each horizon, but potatoes extracted less, especially from below 60 cm. Between 30 and 100 cm deep, the in situ available water capacity (per 10 cm soil) progressively decreased from 16 to 10, 15 to 5 and 16 to 8 mm under sugar beet, potato and barley respectively. The calculated soil‐moisture deficit (potential evapotranspiration minus rainfall) and measured soil moisture deficit were not related early in the growing period before the crops established much leaf cover.