bluuebunny/crossref_metadata_2025_split huggingface dataset:
Population studies on pea cyst‐nematode Heterodera goettingiana Liebs.
Authors: JONES F. G. W. , MEATON V. H. , PARROTT D. M. , SHEPHERD A. M. , KING J. M. 
Published: February 2008

SUMMARYChanges in populations of Heterodera goettingiana Liebs. were studied in microplots containing three kinds of soil. Starting with an artificially uniform population, varieties of pea which matured quickly induced smaller numbers of cysts and eggs than later‐maturing varieties although there was ample time for completion of the life cycle on the former. Field bean was comparable with the late‐, and broad bean with the early‐maturing pea varieties.When one variety of pea was grown on all plots of a group, yield decreased in proportion to the density of the population before planting. The relationship between yield and initial population over a narrow population range was expressed equally well by the simple equations Y=a+bx or Y=a+blogx, where Y= yield, x= the number of eggs, a= the Y intercept and b the regression coefficient. For plots with a wide range of initial populations (4–359 eggs/g. soil), neither equation was adequate and the relationship was best fitted by a sigmoid curve.In two sets of plots, the influence of two population levels, nitrogen versus no nitrogen, and light versus heavy soil, was tested. Soils and populations affected yield significantly; nitrogen was ineffective on light soil but increased yield on the heavy soil. Only soil type affected the final population, that in the heavy soil which gave the greater yield being twice as large.When peas were grown, the final population rose to a ceiling level independent of the initial population size. In the plots with widest initial population range, the ceiling level was determined by the number of females (new cysts) formed. Their number was almost constant over the whole initial population range and they produced on average 129 eggs/cyst which was the maximum theoretically possible rate of increase under the conditions of the experiment. At small initial egg densities (4 eggs/g.) about 50% of the eggs became female and at great densities (359 eggs/g.) only 1% or less.Final populations in the microplots bore no relationship to yield of peas. It is suggested that the size and form of the central part of the root system determines how many females the roots can support and that root size is one of the factors that determines ceiling levels.Nematicides used to decrease numbers of cyst‐nematode eggs or larvae in soil tend to remove only those surplus to the carrying capacity of root systems. Nematicides or enemies able to kill established females before they produce eggs would control reproduction more effectively.
Tomato fruit bronzing
Authors: JENKINS J. E. E. , WIGGELL D. , FLETCHER J. T. 
Published: February 2008

SUMMARYTomato fruit bronzing occurs in green fruits and produces variable symptoms in ripe fruits. The bronzing is caused by brown necrosis of the fruit wall, mainly at the calyx end of the fruit, which is also the most severely affected part. Field observations and experiments showed that bronzing is closely associated with infection of the plant with tobacco mosaic virus (TMV) and some other factors, notably rank or ‘soft’ growth. Symptoms occur within a short time of infection with TMV and affected fruits are produced over a relatively short period on any one plant. The symptoms in a particular fruit remain constant and do not get progressively worse. Plants systemically infected with TMV do not subsequently produce bronzed fruits. This disease can be distinguished from some other tomato fruit disorders such as blotchy ripening and appears to be similar to a disorder in the U.S.A. called internal browning.A second type of bronzing in green fruits is less common but symptoms are more severe. In this case the necrosis of the fruit wall is not particularly associated with the calyx end and it gets progressively worse so that the fruit is often unsaleable; a characteristic symptom is a series of dark lines radiating from the stylar end of the fruit. Affected fruits are produced on a particular plant over a long period of time and are not associated with infection of plants with TMV.A histological examination of both types of bronzing is reported.
Seed bacterization and biological activity of bulbiformin
Authors: SINGH PRITAM , VASUDEVA R. S. , BAJAJ B. S. 
Published: February 2008

SUMMARYThe production of bulbiformin by Bacillus subtilis has been observed on the seed coats, spermatosphere and rhizosphere of bacterized pigeon‐pea seeds sown in sterile and unsterile soils. The importance of different nutrients as a base for bacterization in enhancing the antibiotic production has been established. Maximum antibiotic activity was observed in the treatments where bacterization had been made in molasses solution supplemented with groundnut cake. The rate of antibiotic production reached a peak after 15–18 days. Relatively less antibiotic was synthesized under natural unsterile soil conditions.It is shown that the antibiotic produced as a result of bacterization becomes systemic in plant tissue and provides a protective zone around the roots of pigeon‐pea seedlings. Appreciable reduction in the incidence of pigeon‐pea wilt has been obtained through seed bacterization.
Effects of daylength and temperature on ear size in S. 24 perennial ryegrass
Authors: RYLE G. J. A. 
Published: February 2008

SUMMARYThe size of the inflorescence of plants of S. 24 perennial ryegrass (Lolium perenne L.) grown in the glasshouse increased as daylength or temperature decreased. The larger ears had more spikelets and more florets in each spikelet. An increase in the number of axillary primordia accumulated at the shoot apex before spikelet initiation, together with the development of more spikelets after spikelet initiation, accounted for the larger number of spike‐lets. The number of florets per spikelet appeared to be determined by the balance between factors which controlled the rate of spike development and those which controlled the availability of metabolites during the same period.
Spraying arabica coffee for the control of coffee berry disease
Authors: WALLIS J. A. N. , FIRMAN I. D. 
Published: February 2008

SUMMARYThree sprayers were used in each of three field trials to apply 8.4 g. of Perenox† per tree in a range of spray volumes from 0.2 to 1.7 1.Copper deposits and conidial inoculum potential were determined on sample branches. The critical sampling zone was between the fifth and eighth node proximal to the youngest node flowering in the current season.The low‐volume treatments were as effective as the highest (standard) volume in terms of copper deposit, reduction in inoculum potential and the number of diseased fruit, and in increasing the yield of coffee in the first year of the trials.
Studies on plant growth‐regulating substances XIX. Stability of 2,3,6‐trichlorobenzoic acid in wheat plants and in the rabbit and mouse
Authors: BALAYANNIS P. G. , SMITH M. S. , WAIN R. L. 
Published: February 2008

SUMMARYGas chromatography has been used in an investigation of the uptake and persistence of the herbicide 2,3,6‐trichlorobenzoic acid (TBA) in wheat plants. In addition, the capacity of the compound to pass through the alimentary tract of the rabbit and the mouse has been studied. The chemical was found to be present at harvest both in seeds and straw following its uptake by the roots or when applied as a spray at the stage of growth normally recommended for selective weed control. Some 17.6% of the acid fed to the rabbits and 2.7% of that fed to mice was recovered in the acidified extracts of the excreta.
Pea seed infection by Mycosphaerella pinodes and Ascochyta pisi and its control by seed soaks in thiram and captan suspensions
Authors: MAUDE R. B. 
Published: February 2008

SUMMARYApparently normal pea seeds from pods bearing lesions of Mycosphaerella pinodes were often internally infected with the fungus. When infected seeds were sown in sterile grit almost all the seedlings showed disease lesions, at or below soil level, 4–6 weeks after sowing.Seed infected with Ascochyta pisi gave only 40% infection of seedlings: these showed lesions on the stem and first two leaves within 4 weeks of sowing.Infection of seeds by both pathogens could be eradicated by soaking the seeds for 24 hr. in 0.2% suspensions of thiram or captan at 30d̀C. In laboratory or greenhouse tests these treatments did not check germination, but in the field the captan treatment reduced emergence.The treated seeds became fully imbibed but could be dried and stored: the thiram treatment was used for semi‐commercial treatment of quantities of seed up to 3 cwt.
Fungicidal activity and chemical constitution: XIII.* Active components of commercial formulations containing dinocap
Authors: BYRDE R. J. W. , CLIFFORD D. R. , WOODCOCK D. 
Published: February 2008

SUMMARYSix isomers, isolated from the mixture of dinitrophenols obtained by the hydrolysis of commercial formulations containing dinocap, were tested in the greenhouse against apple mildew caused by Podosphaera leucotricha.The two most active compounds were 4‐(Ié‐ethylhexyl)‐ and 4‐(Ié‐propylpentyl)‐2,6‐dinitrophenols, which appear to account for most of the antimildew activity of the mixture. The crotonate of the latter phenol was considerably more effective than dinocap itself, but both crotonates were less effective than the corresponding free phenols.Little evidence of synergism between two ethylhexyldinitrophenols was obtained.
The action of nabam, metham‐sodium and other sulphur compounds on Heterodera schachtii cysts
Authors: CLARKE A. J. , SHEPHERD AUDREY M. 
Published: February 2008

SUMMARYWhen used in tests against eggs of Heterodera schachtii, sodium ethylenebisdithiocarbamate (nabam) solutions break down to give a number of compounds, some being hatch‐inhibiting and others hatch‐stimulating. The compound mainly responsible for the hatch‐stimulating activity of nabam solutions is ethylenethiuram monosulphide. Stored solutions of sodium ethylenebisdithiocarbamate lose activity because the ethylenethiuram monosulphide disappears.Zinc and manganese ethylenebisdithiocarbamates were more active hatching agents than equimolar mixtures of zinc or manganese sulphates with nabam. Hatch stimulation was least with a zinc sulphate/nabam mixture of mole ratio 1.5:1, in which the dithiocarbamate ion became largely replaced by the sparingly soluble zinc dithiocarbamate. Increasing the zinc concentration in the mixture increased hatching because of the hatching activity of the zinc ion.Nabam solutions containing manganese sulphate were inactivated because the manganese ion catalysed decomposition to the hatch‐inhibiting carbon disulphide.Sodium N‐methyldithiocarbamate (metham‐sodium, Vapam), which readily decomposed in aqueous solution, was toxic to, and prevented the hatching of, H. schachtii. Methylisothiocyanate, the major decomposition product, was toxic to H. schachtii at concentrations greater than 0.1 mM.
Effects of photoperiod in growth cabinets on the growth of leaves and tillers in three perennial grasses
Authors: RYLE G. J. A. 
Published: February 2008

SUMMARYLong photoperiods provided in growth cabinets and consisting of a conventional extended photoperiod or of a ‘light‐break’ in the middle of a long, dark period, generally increased leaf length and sometimes leaf width and consequently the rate of expansion of leaf surface, but decreased rate of leaf production and tillering in vegetative plants of S.37 cocksfoot (Dactylis glomerata L.), S.215 meadow fescue (Festuca pratensis Huds.) and S.24 perennial rye‐grass (Lolium perenne L.) compared with short photoperiods. All plants received the same total amount of light each day. These effects were observed both in single plants and in plants grown close together to simulate sward conditions. The total dry weight of plant material was greater in long than in short photoperiods.
Aphids from mangold clamps and their importance as vectors of beet viruses
Authors: HEATHCOTE G. D. , COCKBAIN A. J. 
Published: February 2008

SUMMARYMangold clamps are over‐wintering sources of the aphid‐transmitted beet mosaic, beet yellows and beet mild yellowing viruses, and of several species of aphid, three of the most common in clamps being Myzus persicae, Rhopalosiphoninus staphyleae tulipaellus and R. latysiphon. This study attempted to assess the relative importance of the different species in spreading viruses from clamps.Compared with M. persicae, R. s. tulipaellus and R. latysiphon are seldom trapped in flight, except near large infestations. Alatae of M. persicae and R. s. tulipaellus become common in clamps in April, but few fly below 15d̀ C., a temperature seldom reached in eastern England in early spring. Flight muscle autolysis, which occurs later in R. s. tulipaellus and R. latysiphon than in some aphid species, also probably prevents many alatae in clamps from flying. We confirmed the importance of clamps as sources of beet viruses, the percentage of infected plants decreasing with increasing distance from infested clamps. M. persicae is shown to be a better vector of beet viruses than the other clamp aphids, and is probably responsible for most virus spread from clamps. R. s. tulipaellus did not transmit beet mosaic virus, but it is a fairly efficient vector of beet yellows and beet mild yellowing viruses, and, although we did not find this species on sugar beet in the field, it probably spreads these viruses from clamps. R. latysiphon did not transmit any of the viruses, and the role of Macrosiphum euphorbiae, Aulacorthum solani and Myxus ascalonicus is probably small.
The relation between damage caused by insect pests and boll rot associated with Glomerella cingulata (Stonem.) Spauld. & von Schrenk (Colletotrichum gossypii Southw.) on Upland cotton in Uganda
Authors: LEAKEY C. L. A. , PERRY D. A. 
Published: February 2008

SUMMARYThe conidial form of Glomerella cingulata found on cotton bolls in Uganda was avirulent on undamaged bolls at normal humidity but formed a latent infection which became aggressive when the bolls were put in a saturated atmosphere. Mechanical damage and injury caused by insects feeding were associated with extensive rotting by the fungus at normal humidity.The taxonomy of the fungus is discussed.
Varietal response in wheat to water supply in the field, and male sterility caused by a period of drought in a glasshouse experiment
Authors: BINGHAM J. 
Published: February 2008

SUMMARYField experiments in 1961 and 1962 with four winter wheat varieties (Professeur Marchal, Cappelle‐Desprez, Hybrid 46 and Holdfast) compared three water regimes: irrigation to prevent the soil water deficit exceeding 2 in.; shielding from rain; and normal rainfall. The experiments were done on soils selected for their liability to drought. Grain yield was decreased by water deficit; the effects differed between varieties, but the varietal differences were not consistent in the 2 years.In glasshouse experiments, plants of Cappell‐Desprez were subjected to drought for 3–4 days during ear development and subsequently watered normally. When this treatment preceded pollen meiosis by a few days many of the lower florets of each spikelet were male‐sterile but female‐fertile. Also there was often proliferation, within the spikelet, of normally fertile florets above the male‐sterile ones, showing that the number of florets formed may increase until a late stage in ear development.The results of the field experiment suggested that grain yield was restricted by the capacity of the grains as sinks for photosynthates. If so, a genetic improvement in grain yield could be obtained by breeding for an increase in number of florets per spikelet.
The antifungal activity of thiosemicarbazides in vitro and their systemic activity against cucumber scab Cladosporium cucumerinum
Authors: PLUIJGERS C. W. , SIJPESTEINN A. KAARS 
Published: February 2008

SUMMARYThe antifungal activity of a number of thiosemicarbazides was studies. The position and nature of substituents in thiosemicarbazide seem to be of great influence on growth‐inhibition. High activity was found for 1‐aryl substituted thiosemicarbazides, particularly derivatives, In systemic tests against cucumber scab, PTS and a number of its substitution products showed considerable activity.
The fungitoxicities of cuticular and cellular components of citrus lime leaves
Authors: MARTIN J. T. , BAKER E. A. , BYRDE R. J. W. 
Published: February 2008

SUMMARYCuticular and cellular components of leaves of Citrus aurantifolia Swingle were tested for toxicity to Gloeosporium limetticola Clausen, responsible for the withertip disease. Cuticular waxes isolated from mature, resistant leaves showed little activity. A dimethoxy furocoumarin, isopimpinellin, isolated from the cellular components, was highly toxic, and ester and acidic fractions obtained from both young susceptible and mature resistant leaves showed some activity. The contents in the leaves and the toxicitiesin vitroof the active constituents suggest that they may contribute, to an important degree, to the defence of the leaf against G. limetticola.
The distribution of diosgenin in Dioscorea spp
Authors: BAKER E. A. , MARTIN J. T. , WILSON APHRA P. 
Published: February 2008

SUMMARYThe distribution of diosgenin in Dioscorea deltoidea Wallich and D. sylvatica Ecklon at successive stages of growth is described. Diosgenin occurs in the cotyledon‐endosperm of the dormant seeds, and in the tubers, roots, stems and leaves of plants from the seedling stage onwards. It accumulates in the tubers of seedlings grown in daylight, but not in those of seedlings grown in darkness. Actively growing aerial tissues such as leader shoots appear to be the sites of formation from which the diosgenin is translocated to the tubers. The diosgenin is evenly distributed throughout the tubers.
Studies on the aphid, Cavariella aegopodii Scop: On secondary hosts other than carrot
Authors: DUNN J. A. , KIRKLEY JEAN 
Published: February 2008

SUMMARYOf the eleven cultivated species of Umbelliferae heavily attacked in the field by Cavariella aegopodii Scop., chervil (Anthriscus cerefolium) attracted so many alates that it was killed before a population of alienicolae developed. Carrot was next in order of alate preference and coriander (Coriandrum sativum) and caraway (Carum carvi) were last. Despite its lack of attraction, caraway proved more lastingly suitable as a host and eventually supported the largest population of alienicolae.Of the wild umbellifers tested, wild carrot, Daucus carota ssp. carota, was the species most preferred by the incoming alates and hemlock (Conium maculatum) the least. On hemlock, also, there was little colonization.Although a sequence of wild umbellifers supported C. aegopodii through most of the year, few were suitable winter hosts; the apterae hibernated largely on carrot crops.In spring, cow parsley (Anthriscus sylvestris) was one of the hosts first colonized by immigrant C. aegopodii and carried winged alienicolae before the end of June. The main development of winged alienicolae on Anthriscus and other wild Umbelliferae, however, was in July.The possible role of the wild umbelliferous hosts of C. aegopodii in the spread of motley dwarf virus to carrots is discussed.
Verticillium wilt of the hop: the survival of V. albo‐atrum in soil
Authors: SEWELL G. W. F. , WILSON J. F. 
Published: February 2008

SUMMARY Verticillium albo‐atrum was apparently eradicated from soil in which dicotyledonous plants were suppressed. In one field experiment V. albo‐atrum was not recovered after 4 years of weed‐free grass cover; in the same period soil infectivity reduced to very low levels under two bare fallow treatments. Where weeds developed after single annual cultivations soil infectivity declined from the initially high level but finally increased. In three observation trials in which hop plants were used to detect V. albo‐atrum after grass‐cover treatments, soil infectivity was very low after 2 years and apparently nil after 3–5 years.Grass cover effectively stabilizes infested soil; it may be used for limiting spread from primary disease outbreaks, and also as a short‐term treatment to reduce the infectivity of soil to be re‐planted with resistant varieties.The frequent incidence of V. dahliae hop infections in one trial indicated that this fungus was not amenable to control by grass cover treatment and hence may be ecologically distinct from V. albo‐atrum.
Host/parasite relationships between tomato and pathogenic isolates of Verticillium
Authors: GRIFFITHS D. A. , ISAAC IVOR 
Published: February 2008

SUMMARYA close relationship was established between the virulence in the field of six isolates of Verticillium and their ability to penetrate and colonize sterile tomato seedlings grown in culture. The highly pathogenic species V. albo‐atrum and V. tricorpus rapidly colonized host tissue in culture, host reactions being absent or only slight. V. nigrescens and V. nubilum, mild pathogens, penetrated sterile roots more slowly and caused host reactions. The variation in pathogenicity in the field between two isolates of V. dahliae suggests that they are different physiological strains, but they induced no difference during the first stages of invasion‐reaction of sterile seedlings. Hyaline variants of all these isolates were less pathogenic than the original parent types.Variations in temperature from 25° C. (near optimum for the growth of both tomato plants and the fungi) caused changes in host reactions. Ability to penetrate was not affected within the pH range 4.0–8.0, but at extreme values (3.2, 9.4 and 10.0) all isolates entered without any host reaction. Variations in nitrogen supply to the pathogens induced modifications in their ability to penetrate, whereas changes in supply of nitrogen to the seedlings had no apparent effect upon host/parasite relations.The effects of simultaneous contact of non‐pathogenic and pathogenic isolates with seedling roots suggested that resistance of host tissue was controlled by the growing tip.
The survival on chrysanthemum roots of epiphytic mycelium of Mycosphaerella ligulicola
Authors: CHESTERS C. G. C. , BLAKEMAN J. P. 
Published: February 2008

SUMMARY Mycosphaerella ligulicola has been shown to survive as epiphytic mycelium on the root surface of chrysanthemum cuttings: such survival could continue throughout the life of the glasshouse crop. Symptomless surface colonization of roots of cuttings could be induced in non‐sterile soil from an inoculum of (a) mycelium and sclerotia or (b) conidia (Ascochyta state); the colonization could spread upwards over the root surface.After 12 weeks survival as an epiphyte on chrysanthemum roots the fungus was still pathogenic to unrooted cuttings.Although the root surfaces of twelve other plants could be colonized by M. ligulicola the fungus survived on these roots for not more than 8 weeks.
Studies on sharp eyespot disease of cereals: Effects of the disease on the wheat host and the incidence of disease in the field
Authors: PITT D. 
Published: February 2008

SUMMARYGreenhouse and field experiments showed that sharp eyespot disease can reduce establishment in wheat seedlings. Increasing disease severity caused a decrease in height and dry weight of surviving seedlings. Infection by the pathogen caused a reduction in tillering. Experiments also showed that a high incidence of disease can cause a reduction in the yield of grain of mature plants, but the disease level necessary for such effects is far higher than that usually encountered in the field.Survey work in the East of Scotland in 1963‐65 showed a high percentage of crops infected with the disease. But even in 1964, a year of comparatively high disease incidence, there were few crops with a level of infection as high as that shown to affect yield.