bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on the relation between density of Longidorus elongatus and growth of sugar beet, with supplementary observations on Trichodorus spp
Authors: BROWN E. B. , SYKES G. B. 
Published: February 2008

SUMMARY Longidorus elongatus attacks sugar beet on light sandy soils in the West Midlands. Severely damaged plants may die or recover, producing fanged roots. Up to 335 L. elongatus/200 g of soil were found around attacked seedling plants and were often visible to the unaided eye on the roots of freshly lifted plants.Five experiments were made and regressions computed of yield of beet, total numbers of plants and numbers of normal and fanged beet on L. elongatus numbers. Between 24% and 50% of roots per 100 L. elongatus/ 200 g were killed or became fanged. Corresponding figures for loss of plant were between 7.5% and 33%.Estimated loss of yield varied between 0.8 and 7.3 tons (2.0–18.3 t/ha)/acre/100 L. elongatus/200 g, the former where the potential yield was high and the latter where poor growing conditions hindered recovery.Large numbers of Trichodorus occurred in two trial sites and there is some evidence of competition between the two genera. Significant negative regressions for Trichodorus spp. were obtained in one trial suggesting a loss of 12% total and 17% normal roots per 100 Trichodorus spp./200 g.
Serological relationship between cherry leaf roll, elm mosaic and golden elderberry viruses
Authors: JONES A. T. , MURANT A. F. 
Published: February 2008

SUMMARYA virus obtained from plants of Sambucus canadensis imported from North America and another obtained from wild plants of Sambucus nigra growing in Perthshire, Scotland, were serologically identical to golden elderberry virus described from North America. They were serologically related to, but distinguishable from, cherry and rhubarb isolates of cherry leaf roll virus from Europe, and elm mosaic, another virus from North America.
Chemical treatment of soil to prevent transmission of tobacco rattle virus to potatoes by Trichodorus spp
Authors: COOPER J. I. , THOMAS P. R. 
Published: February 2008

SUMMARYOf the chemicals tested in field experiments at two sites on sandy soil in Scotland, D‐D (dichloropropane‐dichloropropene) applied before planting at 200 or 400 Ib/acre (224 or 448 kg/ha) gave the best control of potato spraing disease caused by tobacco rattle virus (TRV); it almost eliminated the disease in the first year and greatly decreased the incidence in the second. Application in the autumn was more effective than in the spring.Methomyl at 8 Ib/acre (9 kg/ha) and dazomet at 150 Ib/acre (168 kg/ha) greatly decreased the spread of TRV in the first year after treatment, but not in the second. These effects were closely related to the nematicidal effects of the chemicals on the nematode vectors (Trichodorus spp.), except that methomyl controlled virus spread more effectively than it killed Trichodorus. When data from plots treated with methomyl are excluded, spraing incidence was more closely correlated with the numbers of Trichodorus found in May than in September. In general, the infectivity of soil, estimated by infection of cucumber bait seedlings with TRV in pot tests, paralleled the incidence of spraing, but bait cucumber roots were infected more readily than potato tubers.Application of D‐D at 200 Ib/acre (224 kg/ha) is probably worthwhile economically when potato cultivars that are susceptible and sensitive to TRV are to be grown on land infested with the virus.
Disk electrophoresis of proteins of Heterodera species and pathotypes of Heterodera rostochiensis
Authors: TRUDGILL D. L. , CARPENTER J. M. 
Published: February 2008

SUMMARYThe proteins extracted by aqueous buffer from the females of six Heterodera spp. were separated into bands by polyacrylamide gel electrophoresis and the patterns compared. Heterodera schachtii and H. trifolii, with lemonshaped cysts, had a similar pattern of bands, differing greatly from that of the round‐cyst nematodes H. virginiae and H. rostochiensis. Ten pathotype A populations of H. rostochiensis had similar patterns, distinguishable from those of twelve pathotype E populations by the absence of two bands and by the presence of another rarely found in pathotype E. Bands from pathotype B populations were indistinguishable from those of pathotype E. No consistent difference was detected between populations of the same pathotype. These results support the suggestion by Jones, Carpenter, Parrott, Stone & Trudgill (1970) that H. rostochiensis Woll. comprises two species.
Fireblight epidemic among Kentish apple orchards in 1969
Authors: GLASSCOCK H. H. 
Published: February 2008

SUMMARYEvidence from field observations and orchard plans indicates that the fireblight epidemic among apples in 1969 followed a critical combination of weather conditions. There is little doubt that diseased hawthorns, situated entirely or mainly to the north‐west of the main lanes of infection, were the source of inoculum. Initial infection was confined to shoots. No blossom infection was seen at any time. Weather data from a nearby meteorological station point to distribution of inoculum having taken place on one of the days 6–10 July when strong winds, rainfall and hailstorms occurred. These days were followed immediately by temperatures above 18d̀C which are considered suitable for infection and for progress of the bacterium within the shoot tissues. The control measures advised were the removal and destruction of diseased parts, the disinfection of pruning implements, the protection of wounded surfaces against infection and the destruction of nearby diseased hawthorns.
Properties of inhibitors of plant virus infection occurring in the leaves of species in the Chenopodiales
Authors: SMOOKLER M. M. 
Published: February 2008

SUMMARYLeaf extracts from twenty‐nine species of the Chenopodiales were shown to inhibit the infection of Phaseolus vulgaris by tobacco necrosis virus. The inhibitors were not lost on dialysis or by storage at ‐ 25 d̀C for 56 days. Partially dry lyophilized extracts kept at ‐ 25 d̀C for 2 years in unsealed screwtopped bottles retained inhibitory activity. The inhibitors in extracts of species of Beta, Halimione and Amaranthus were largely inactivated by heating for 10 min at 60–80 d̀C, but 80–100 d̀C was needed to inactivate those in sap of species of Chenopodium, Atriplex, Basella, Hablitzia, Salsola and Celosia. The extent of this inhibition of infection caused by unheated Chenopodium album sap depended on the virus‐host combination. With heated sap this dependence was changed.The properties of inhibitors from extracts of Chenopodium amaranticolor, C. album, Atriplex nitens and Amaranthus caudatus were compared. Extracts made with water‐saturated phenol were not inhibitory and precipitation tests with 50% acetone, 50% ethanol and 2.5% trichloracetic acid suggested that the inhibitors are protein. Most inhibitory activity was precipitated from extracts by 70–90% saturated ammonium sulphate. Ion‐exchange column chromatography on CM‐Sephadex C‐25 showed that most inhibitory activity and protein was eluted by 0.4 M sodium acetate buffer. Disc electrophoresis indicated that several proteins occurred within the pooled inhibitory fractions. Gel filtration with Sephadex G‐200 suggested that the inhibitors have molecular weights of 25000–38000.The four inhibitors are probably very similar, but not necessarily identical, basic proteins.
The microbiology of moist barley storage in unsealed silos
Authors: LACEY J. 
Published: February 2008

SUMMARYThe microflora of moist barley grain and whole‐crop barley silage stored in top‐unloading, unsealed concrete‐staved silos on six farms in England depended on the initial water content of the grain (23–58%), method of covering the grain, and the rate at which it was unloaded. Fungi and actinomycetes were fewest when the initial water content was more than 30%, and the grain was covered first with a layer of wilted grass, and then a plastic sheet. During unloading, the uppermost layer of grain remained in good condition provided 7.5 cm was removed daily.With an inefficient top‐seal, the top grain heated and became mouldy, as it also did when unloading was slow. As the rate of unloading slowed, heating increased, and a characteristic succession of fungi and actinomycetes developed. With unloading at 7.5 cm/day or more, only yeasts, chiefly Endomycopsis chodatii Wickerham and Hansenula anomala (Hansen) H. & P. Sydow, were abundant, but at slightly slower rates of unloading Penicillium spp. also became common. Both these groups became less common as unloading was slowed further and were replaced, first by Absidia spp. and Mucor pusillus Lindt, then Aspergillus fumigatus Fres., Humicola lanuginosa (Griffon & Maublanc) Bunce, Micropolyspora faeni Cross, Maciver & Lacey, and Thermoactinomyces vulgaris Tsiklinsky as the heating increased. The number of spores (including bacterial cells) that could be removed from samples by blowing air ranged from 0.4–428 times 106/g dry weight of grain. Whole‐crop barley silage contained 2.9–132 times 106spores/g dry weight. Similar species were isolated from whole‐crop silage as from grain. Little moulding occurred deeper than 30 cm below surface of the grain.Concentrations of airborne spores were estimated periodically during two seasons. There were always more airborne spores than is usual in outdoor air. Without disturbance the silos contained 106‐107 spores/m3 air, but when mouldy grain was unloaded concentrations increased to a maximum of 2860times106 spores/m3 air; more than half of these were bacteria and actinomycetes and a quarter Aspergillus flavus Link. Potentially pathogenic fungi and actinomycetes were frequent, particularly when they also occurred in the grain or capping materials for spontaneous heating. Some probably survived in dust deposits and were resuspended during unloading. Airborne spores were frequent around the silos when grain was unloaded and rolled. Workers should wear efficient dust respirators at these times and while inside silos.
The infection of potatoes by Phoma exigua
Authors: ENTWISTLE A. R. 
Published: February 2008

SUMMARYThe pathogenicities of Phoma exigua var. foveata and P. exigua var. exigua were compared by determining the relationship between incidence of infection of whole tubers or tuber pieces and various inoculum levels in soil. In natural soil var. foveata was more pathogenic than var. exigua, but in sterilized soil there were no clear differences between the two. Both varieties were isolated from some lesions derived from inoculum to which only one variety had been added indicating either natural contamination of soil or latent infection in tubers; the proportion of such lesions increased at the lower inoculum concentrations.In studies where potato plants were grown in infested soils, the incidence of stem disease and tuber disease increased at increased inoculum concentrations of var. foveata; var. exigua was not added to the inoculum but was isolated from some lesions, the proportions of such lesions again increasing at lower inoculum concentrations. The infectivity of the infested soil, assessed by a tuber‐baiting method, declined soon after planting but increased prior to harvest.Laboratory studies indicated that in natural soil the infectivity was highest after 2–3 months and lowest after 10 months incubation, but in sterilized soil infectivity was highest after 5 months and lowest after 7 months incubation.
Phenology and fungus‐nematode relations of corky root disease of Douglas‐fir
Authors: BLOOMBERG W. J. , SUTHERLAND JACK R. 
Published: February 2008

SUMMARYSymptoms of corky root disease of Douglas‐fir seedlings include: (I) swollen tap‐ and lateral roots; (2) paucity of lateral roots; and (3) stunted shoot growth. In diseased roots, the primary cortex persisted and enlarged, but secondary vascular tissues, periderm, pericycle and endodermis were reduced. Cylindrocarpon destructans was the fungus most frequently isolated from cortical cells and symptoms were induced by massive inoculum of some isolates but not by dispersed inoculum nor by extracts from cultures. Whereas symptoms first appeared 2 months after seeds sown in May germinated, C. destructans was rarely isolated until 4 months after germination. Relatively more colonies of C. destructans were isolated from corky roots in the winter than in the summer, when Fusarium oxysporum or Mycelium radicis atrovirens were more abundant. Populations of the plant‐parasitic nematode Xiphinema bakeri on roots and in adhering soil were highest 2 months after germination and during the summer, correlating positively with the per cent of tap‐root affected and negatively with numbers of lateral roots.
Transpiration in potato plants infected with Verticillium spp
Authors: HARRISON J. A. C. 
Published: February 2008

SUMMARYPotato plants (cv. King Edward) infected with Verticillium albo‐atrum and with V. dahliae transpired more slowly than healthy plants; this difference increased as the disease progressed. Diurnal fluctuations in transpiration were smaller in infected plants than in controls because infection markedly reduced water loss during the normal daytime peak period. Transpiration at night was unaffected by infection.Both stomatal and cuticular transpiration of single, detached leaves were reduced by infection. A linear correlation was obtained between ‘water saturation deficit’ and transpiration rate in both diseased and healthy plants until the leaves wilted, suggesting that reductions in the stomatal rate are a consequence of the greater water deficits found in diseased plants, the differences in cuticular rates probably being due to anatomical differences between healthy and diseased leaves.Close parallels between transpiration and water deficit indicate that in diseased plants water loss is largely determined by leaf water content. Thus wilting, commonly seen as a symptom of infection, is not the result of excessive water loss but follows a reduction in the supply of water to the leaves.The author thanks Professor I. Isaac of this department and Dr G. C. Evans of the Botany School, Cambridge for their advice. The research was sponsored by the Potato Marketing Board.
The effect of temperature on eyespot (Cercosporella herpotrichoides) in wheat seedlings
Authors: SCOTT P. R. 
Published: February 2008

SUMMARYWhen seedlings of the winter wheat cultivars Cappelle‐Desprez, Champlein and Hybrid 46 were artificially infected with mycelial inoculum of Cercosporella herpotrichoides Fron, the number of leaf sheaths penetrated by the pathogen increased with temperature over the range 6‐18oC. Rate of growth of the pathogen on agar also increased with temperature over this range. Temperature had little effect on differences between cultivars in number of leaf sheaths penetrated.
The relationship between the relative growth rates of the shoot system, number of tillers and mean tiller size in Lolium perenne
Authors: TROUGHTON ARTHUR 
Published: February 2008

SUMMARYThe relative growth rate of the shoot system of Lolium perenne may be considered as being made up of two components, the relative growth rate of the increase in the number of tillers and the relative growth rate of the mean tiller. These three relative growth rates were calculated for twenty‐two clones of Lolium perenne growing in twenty‐eight environments. Analyses of variance showed that differences in the environment were responsible for a greater amount of variation than either differences between clones or the interaction between clonal and environmental influences.For each clone it was possible to calculate relationships between the relative growth rate of the shoot and its two components as they varied with the environments. The relationships held irrespective of the environmental factor(s) which altered to cause the difference in relative growth rates. In all clones an increase in the relative growth rate of the shoot was found to be due to an increase in the relative growth rates of both components. In seventeen clones the relationship between the increments of the two components was constant. In five of the clones an increase in the relative growth rate of the shoot at low values was due more to an increase in the relative growth rate of the number of tillers than to an increase in the relative growth rate of the mean tiller. At high values the opposite occurred.These results are discussed in relation to the theory of ‘nutritive diversion’ and in relation to the proportion of lateral buds which produce tillers.
Uptake and distribution of macro‐nutrients in trees of Coffea arabica L. in Kenya as affected by seasonal climatic differences and the presence of fruits
Authors: CANNELL M. G. R. , KIMEU B. S. 
Published: February 2008

SUMMARYYoung to mature, conventionally managed, single‐stem, deblossomed and fruiting Arabica coffee trees growing in a fertile lateritic clay loam at Ruiru, were uprooted at 2‐ to 3‐monthly intervals between February 1967 and June 1968. Each was divided into ten parts which were dried, weighed, completely ground, and analysed for organic‐N, and total P, K, Ca and Mg.Mature trees took up about 100 g N, 6 g P, 100 g K, 35 g Ca and 10 g Mg each per annum, of which 8‐29 % (depending on the element) would be removed in an average crop of fruits, and 50‐81 % returned to the soil in prunings and fallen leaves. About half the P and K in senescing leaves was returned to the tree.N, K, Ca and Mg uptake by deblossomed trees was relatively rapid when they produced a large post‐drought ‘flush’ of shoot growth in February‐April 1967. Thereafter uptake kept pace with changes in dry weight, and the concentration of N, K, Ca and Mg in the tree parts changed relatively little. By contrast, P‐uptake was relatively rapid over the cool, dry season 1967 (June‐September), when the roots < 1 mm diameter grew rapidly, and during the subsequent Short Rains, but was slow during the hot, dry season 1968 (December‐March) when the surface 2‐3 ft of soil dried out. The concentration of P in the trees changed accordingly, especially in the branches. The flower buds took 39 % of the small total P‐uptake during the hot, dry season 1968.Trees bearing a light or moderate crop of fruits absorbed all the minerals determined more rapidly than deblossomed trees. The fruits on heavily fruiting trees took 89,95,98 and 99 % of the net current increment in Mg, K, organic‐N and P, respectively, but only 39 % of the Ca. All leaves on the fruiting trees became rich in Ca, and most of their woody parts were depleted of P.Mineral uptake in a coffee plantation is compared with that in plantations of other woody perennial crops, and some practical implications are noted in relation to soil and plant factors affecting the mineral nutrition of coffee in Kenya, with special reference to phosphates.
Aphanocladiutn album, a fungus inducing teliospore production in rusts
Authors: BIALI M. , DINOOR A. , ESHED N. , KENNETH R. 
Published: February 2008

SUMMARYThe hyphomycetous fungus Aphanocladiutn album can grow over and around uredia of the rusts Puccinia coronata, P. hordei, P. graminis f.sp. avenae and P. recondita f.sp. triticina when host plants are kept under very humid conditions, but not on such plants not infected with rusts; uredia are adversely affected and telia develop in their vicinity.Plants inoculated with these rusts and with five isolates of A. album (one from a dead insect) showed: (1) much earlier development of telia on detached and non‐detached rusted leaves inoculated with A. album than on corresponding leaves not thus inoculated; (2) telial induction by A. album in some isolates of rust species which hitherto had rarely or never produced telia; (3) precocious telial formation, in comparison with controls, when A. album spores were sprayed on leaves as much as 3 days before and 9 days after rust inoculation, and occasionally after uredia had already matured. As affected leaves remained green until the whole leaf became moribund, senescence is apparently not the factor inducing telia formation.The normal‐appearing teliospores of some isolates were induced to germinate, whereas others did not. Rhamnus palaestina inoculated with basidiospores of one isolate of A. album‐treated P. coronata f.sp. avenae produced pycnia and fertile aecia.The importance of A. album as a working tool in rust research and as a possible means for biological control of rust epiphytotics is discussed.
Infection of cereals by cocksfoot mottle and phleum mottle viruses
Authors: BENIGNO D. A. , A'BROOK JOHN 
Published: February 2008

SUMMARYCocksfoot mottle (CFMV) and Phleum mottle (PMV) viruses are both transmitted by the Chrystomelid beetles Ouletna melanopa and O. lichenis. Both viruses are readily inoculated into some cereals but only CFMV has ever been found causing a natural infection, in one wheat crop. The apparent absence of these viruses from cereals in the field results from inefficient transmission by the vectors and the existence of symptomless tolerance in cereals to both viruses, especially after tillering. In cereals symptom expression is related to virus concentration, and both may be influenced by light intensity and ambient temperature. O. melanopa, which is potentially the most important vector of the viruses to cereals, moves to winter‐sown cereals only when the virus‐tolerant growth stage has been reached, and later to spring‐sown cereals when they too have commenced tillering. Whereas the spread of these viruses within grass crops is increased by cutting and grazing, cereal crops are neither cut nor commonly grazed.
Soil fumigation with methyl bromide: bromide accumulation by lettuce plants
Authors: KEMPTON R. J. , MAW G. A. 
Published: February 2008

SUMMARYLettuce plants grown in beds of soil previously fumigated with methyl bromide accumulated water‐extractable bromide, the amount present in the tissues depending on the concentration of inorganic bromide produced in the soil by the breakdown of the fumigant. Samples of lettuce plants from commercial nursery soils fumigated with methyl bromide at rates of 1–2 lb/ 100 ft2 (49–98 g/m2) gave rise to soil bromide levels of n‐6i/μg/g. The corresponding bromide concentrations in the plants ranged from i‐6 to io‐1 mg/g of dry tissue.The bromide concentrations in whole lettuce plants grown in pots of soil supplemented with 0–5 mg/g inorganic bromide, as potassium bromide, ranged up to 100 mg/g of dry tissue. Bromide taken up from the soil by lettuce plants was located mainly in the outer leaves.Lettuce was relatively insensitive to the presence of bromide in the soil; no phytotoxic symptoms were observed in plants growing in soils containing 5 mg/g inorganic bromide.Implications in relation to possible tolerance limits for the bromide content of lettuce plants are discussed.