bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seed and soil: sources of inoculum for the colonisation of the foliage of solanaceous hosts by Pseudomonas solanacearum
Authors: MOFFETT MELDA L. , WOOD BARBARA A. , HAYWARD A. C. 
Published: February 2008

SUMMARY Pseudomonas solanacearum was transmitted from contaminated seed to the cotyledons of capsicum (Capsicum frutescens) at 92, 73 and 60% r. h. and to the cotyledons of tomato (Lycopersicon esculentum) seedlings at 92% r. h. Subsequent epiphytic colonisation of the true leaves of capsicum occurred at 92 and 73% r. h. An increase in the population on capsicum cotyledons was detected at 92 and 73% r. h. but only at the higher r. h. was an increased population of P. solanacearum associated with the colonisation of the true leaves. Lesions developed on the true leaves of capsicum at 92% r. h. Transmission of P. solanacearum from capsicum seeds was affected by inoculum concentration, occurring at an infestation level of ∽ 103 propagules seed‐1 but not at 50 propagules seed‐1. Pseudomonas solanacearum was detected on the cotyledons of capsicum held at 98% r. h. after germination of seed in soil infested with 2 × 108 propagules g‐1 soil; lesions were detected on cotyledons 11 days after planting and invasion occurred in 10 stems and one root of the 20 seedlings sampled. The movement of the pathogen from the soil to the seedlings was affected by the level of soil infestation. Pseudomonas solanacearum was detected in four pairs of cotyledons, two stems and one root of the 36 seedlings sampled from soil infested with 107 propagules g‐1 soil but it was not isolated from seedlings sampled from soil infested with 105 or 4 × 103 propagules g‐1 soil. Leaf and stem prints demonstrated the epiphytic nature of this organism on the cotyledons and stems of seedlings.
A possible virus cryptic in carnation
Authors: LISA VITTORIA , LUISONI E. , MILNE R. G. 
Published: February 2008

SUMMARYSmall isometric virus‐like particles were found in low concentration in apparently healthy carnations of the Mediterranean, miniature and Chinese type but not in eleven Sim cultivars tested. Most carnations containing these particles were from Italy but some were from France and the USA. The particles were not transmitted by grafting or by mechanical inoculation but were seed‐transmitted to a large proportion of seedlings. Antisera to partially purified particles were obtained. The particles did not react with antisera to twenty‐eight isometric plant viruses or virus‐like particles but were serologically related to similar particles found in carnations in England, Holland and Israel. When negatively stained, the particles were isometric with a diameter of about 29 nm and a rounded rather than angular profile, but without clear substructure; some particles were penetrated by the stain. The particles remained intact in neutral sodium phosphotungstate. After isopycnic centrifugation in CsCl solution, preparations of particles formed a main band of mean density 1.377 g/ml and other fainter bands that varied in intensity and position in different preparations. In thin sections of carnations, no virus‐like particles or cytological abnormalities were observed.
Observations on the population dynamics and vertical distribution of trichodorid nematodes in a Scottish forest nursery
Authors: BOAG B. 
Published: February 2008

SUMMARYThe population dynamics of Trichodorus primitivus, T. velatus and Paratrichodorus pachydermus was followed between April 1974 and March 1977 in a forest nursery growing young Sitka spruce (Picea sitchensis) trees. Soil samples taken at 10 cm intervals between 0–50 cm indicated that nematode and root distribution were not correlated and numbers of T. velatus were greatest between 0–29 cm and T. primitivus between 30–49 cm. After 3 yr trichodorid numbers between 0–19 cm had increased and those between 40–49 cm had decreased.The sex ratio of T. primitivus and T. velatus males to females was 1:1.6 and 1:1.5 respectively while for P. pachydermus it was 1:1.0. The ratios of adults to larvae varied with depth, the proportion of T. primitivus and T. velatus larvae increasing with depth but for P. pachydermus the greatest larval to adult ratio was in the top 10 cm.No consistent seasonal fluctuations were observed in the populations of all three species although larval numbers were proportionally greater than adult numbers in the summer and autumn of 1975 and 1976.
An analysis of the epicuticular wax of Chenopodium album leaves in relation to environmental change, leaf wettability and the penetration of the herbicide bentazone
Authors: TAYLOR F. E. , DAVIES L. G. , COBB A. H. 
Published: February 2008

SUMMARYThe fine‐structure, epicuticular wax and contact angle characteristics of Chenopodium album leaf surfaces have been examined with respect to the control of this weed by the herbicide bentazone. Epicuticular wax analysis and contact angle measurements suggest a relative impermeability to bentazone (BAS 35107H), that may be enhanced by the inclusion of the oil adjuvant Actipron (BP Oil Ltd) to the formulation. Under different regimes of light, temperature and relative humidity the chemical composition of the epicuticular wax layer remained relatively constant, whereas herbicide efficacy was greatly altered. These findings are discussed in relation to the mode of action and penetration of bentazone in this species.
Uptake of 32P labelled phosphate by clover and ryegrass growing in mixed swards with different nitrogen treatments
Authors: GOODMAN P. J. , COLLISON M. 
Published: February 2008

SUMMARY Lolium perenne cv. S.23 and Trifolium repens cv. Olwen were sown together in 1975, fertilised then and in 1976, and finally given nitrogen doses of either 50, 100, 200 or 400 kg/ha (as N) combined with 0.64 times as much potassium (as K2O) in 1977. As nitrogen increased, grass yield increased, but clover decreased. Grass roots absorbed more 32P than clover roots, and nitrogen increased this difference. Grass roots bore more mycorrhiza than clover roots. The difference in 32P uptake between grass and clover was less in June and July than in August. Clover roots took up most phosphate from the upper layers of soil, while grass absorbed 32P rather uniformly down to 25 cm. It was concluded that optimum fertiliser placement for clover growth was a surface dressing in the early season.
Biochemical changes in tomatoes stored in modified gas atmospheres. I. Sugars and acids
Authors: GOODENOUGH P. W. , THOMAS T. H. 
Published: February 2008

SUMMARYDuring long‐term storage in modified gas atmospheres (MGA), some of the biochemical changes occurring in tomato fruit, cv. Sleaford Abundance, were compared with those in fruit of some Israeli cultivars which had been selected for firmness and slow ripening. The MGA used in the experiments did not succeed in completely restricting changes in sugars and acids during storage, although colour change was prevented. This separation of processes is discussed in relation to the practice of long‐term storage and its implications for fruit flavour.
Biochemical changes in tomatoes stored in modified gas atmospheres. II. Isoenzymes involved in glycolysis and the citric acid cycle
Authors: GOODENOUGH P. W. , THOMAS T. H. 
Published: February 2008

SUMMARYA comparative study of the isoenzymes involved in sugar and organic acid metabolism was made during long‐term storage of Sleaford Abundance, a poor storing tomato cultivar, and several breeding lines selected for fruit firmness or retarded ripening. Of the enzymes investigated, major changes occurred in hexokinase, enzymes of the hexose monophosphate shunt, NADH and NADPH dehydrogenase during storage but no major differences in the patterns of enzyme change were detected between cultivars.
Alate aphid (Homoptera: Aphididae) species and their relative importance as field vectors of soybean mosaic virus
Authors: HALBERT SUSAN E. , IRWIN MICHAEL E. , GOODMAN ROBERT M. 
Published: February 2008

SUMMARYA technique was developed and deployed in central Illinois to trap and assay aphid alatae for incidence of soybean mosaic virus (SMV) transmission among naturally occurring transient aphid populations downwind of a field of infected soybean. In a 2‐yr study, 1709 alate aphids were trapped alive and assayed, 4.2% of which transmitted SMV. Five species of aphids accounted for more than 93% of the transmissions: Aphis craccivora Koch, Macrosiphum euphorbiae (Thomas), Myzus persicae (Sulzer), Rhopalosiphum maidis (Fitch), and Rhopalosiphum padi (L.). At least 55 additional species were assayed, five of which transmitted only once. Others did not transmit. Because virus infection during the early growth stages of soybean increases the loss of yield and the percentage of seed‐borne virus, vector species that tend to fly middle to late spring are, from an economic point of view, more important in the spread of SMV. R. maidis flew in mid‐ to late summer and in autumn. R. padi was not abundant at any time of year and its transmission efficiency was low. M. persicae tended to fly in mid summer. Two species (A. craccivora and M. euphorbiae) which had major flights in late spring and early summer and relatively high transmission efficiencies are potentially important in the economic spread of SMV in central Illinois. A third species, Aphis citricola Van der Goot, may also be important because it flies in late spring and laboratory data suggest it is a relatively efficient vector of SMV. A. citricola was not assayed by our technique because we trapped in the morning and this species appears to fly later in the day.
Phenological and geographical relationships between catches of pea moth in sex‐attractant traps
Authors: PERRY J. N. , MACAULAY E. D. M. , EMMETT B. J. 
Published: February 2008

SUMMARYTraps containing a sex attractant of the pea moth (Cydia nigricana) were used to monitor numbers of male moths in individual fields in south‐eastern and eastern England from 1976 to 1978 at 16 or more sites/yr. Data concerning catches at different sites on several occasions over the flight season, and dates on which a ‘threshold catch’ was achieved were examined, and were related weakly to site locations within areas. Area spray warnings, based on trap catches at a few sites within a large area, provide a less reliable indication of the need to spray than on‐site monitoring (two traps) in each pea field. On‐site monitoring may be improved by specialist interpretation of trap catches.
Effects of Didymella applanata and Botrytis cinerea on axillary buds, lateral shoots and yield of red raspberry
Authors: WILLIAMSON B. , HARGREAVES A. J. 
Published: February 2008

SUMMARYThe viability of axillary buds and the growth and potential yield of lateral shoots at nodes of red raspberry (Rubus idaeus) infected naturally by Didymella applanata or Botrytis cinerea were measured on excised nodes, decapitated nursery canes or on canes from fruiting plantations. In comparison with lesion‐free nodes, buds at infected nodes were smaller and fewer of them were capable of growth when excised and ‘forced’, although the difference in growth between infected and uninfected nodes decreased during late winter. After February, those buds at infected nodes which were capable of forced growth did so as early and with a similar growth rate as those at lesion‐free nodes. In April, 70% of buds at infected nodes were capable of growth compared with 94% of those at lesion‐free nodes.When nursery canes of cv. Mailing Delight were decapitated above infected nodes the emergence of lateral shoots from the terminal infected node did not differ significantly from that at lesion‐free nodes. On a range of farm sites in Scotland the emergence of shoots at infected nodes in the cropping region of canes was significantly poorer than from uninfected nodes but substantially better at infected nodes of cv. Glen Clova than at those of cvs Mailing Jewel and Mailing Orion. It is suggested that cv. Glen Clova is relatively tolerant of spur blight and cane botrytis. The length and potential yield of laterals which developed at infected nodes in the cropping region of canes in these three cultivars did not differ significantly from those at lesion‐free nodes. In all tests there was no significant difference in growth at nodes infected by D. applanata and B. cinerea which may indicate a common mechanism for suppression of buds.
The prevalence of viruses of honey bees in Britain
Authors: BAILEY L. , BALL BRENDA V. , PERRY J. N. 
Published: February 2008

SUMMARYAdult individuals of honey bee colonies in Britain are commonly infected with several small RNA viruses. Black queen cell virus and bee virus Y are the commonest and occur most frequently about June, together with Nosema apis with which both viruses are intimately but independently associated. Bee virus X is less common than bee virus Y and showed no pronounced seasonal fluctuations in local surveys, but was detected mostly in winter and early spring. Sacbrood virus occurred in adults of most local colonies in summer, chronic paralysis virus and cloudy wing particle occurred commonly but without seasonal variations and acute paralysis occurred commonly throughout the active season of bees but does not multiply sufficiently to cause overt disease. Slow paralysis virus was rare.
The role of Anthocoris species (Hemiptera: Anthocoridae) in the integrated control of the damson‐hop aphid (Phorodon humuli)
Authors: AVELING C. 
Published: February 2008

SUMMARYField studies in 1974, 1975 and 1976 investigated integrated control of the damson‐hop aphid Phorodon humuli on hops. After the aphicidal effects of an early‐season soil drench of mephosfolan had declined, natural enemies controlled the aphids for the remainder of the season. Anthocorid bugs, particularly Anthocoris nemoralis, were the most abundant predators. In each year a rapid decline in aphid numbers occurred in mid‐ to late‐July, coinciding with the peak numbers of fourth and fifth instar larvae and adults, the most voracious anthocorid stages. Aphids in the cones remained under control for the rest of the season in 1974 and 1975, and increased in 1976 but damaging numbers did not develop. When predators were excluded by caging mephosfolan‐treated bines, high aphid densities developed on the leaves, and the cones were heavily infested. Plants not treated with an insecticide were almost completely defoliated by late‐July. Heavily infested ‘missed bines’, due to uneven uptake of mephosfolan, attracted large numbers of anthocorids, which later dispersed into the surrounding plants.
Action of mephosfolan on anthocorid predators of Phorodon humuli
Authors: AVELING C. 
Published: February 2008

SUMMARYIn glasshouse and field studies, soil drenches of the systemic insecticide mephosfolan were applied to hop plants to control the aphid Phorodon humuli, and to study the toxicity to anthocorid predators. The mortality of Anthocoris nemorum and A. nemoralis eggs in the leaf tissues increased with the dosage of mephosfolan while A. confusus eggs, which were laid in the petioles and veins, appeared to be unaffected at the dosages used, up to 2 g a.i./plant. Mortality of A. nemorum eggs, which were laid mainly in the leaf margins, was higher than in A. nemoralis eggs, which were laid mainly in the interveinal areas. For both species mortality was highest for the eggs laid in the leaf margins, and susceptibilities appeared similar. It is suggested that mephosfolan becomes unevenly distributed within the leaves, being most concentrated in the leaf margins and least concentrated in the veins and petioles. No species showed any preference when offered mephosfolan‐treated and untreated leaves for oviposition, and the oviposition rates were unaffected by various mephosfolan dosages. Oviposition rates, larval mortality and duration of larval development were unaffected when specimens of each species were reared from eclosion to maturity on a diet of either mephosfolan‐killed or heat‐killed P. humuli.
The effect of sprays of thiophanate–methyl on cane diseases and yield in red raspberry, with particular reference to cane blight (Leptosphaeria coniothyrium)
Authors: WILLIAMSON B. , HARGREAVES A. J. 
Published: February 2008

SUMMARYSpur blight (Didymella applanata), cane botrytis (Botrytis cinerea) and cane blight (Leptosphaeria coniothyrium) were studied in two consecutive seasons in unsprayed raspberries and in plots sprayed with thiophanate‐methyl in the first season alone, (a) twice pre‐harvest, (b) twice post‐harvest, or (c) twice pre‐ plus twice post‐harvest. Pre‐harvest, but not post‐harvest sprays, gave moderate control of both spur blight and cane botrytis; both diseases occurred mainly on the lower halves of canes, the latter being the less common.Cane blight occurred at the base of canes where they were wounded by old cane stubs. In the first year it was severe; 37% of canes died before harvest in the unsprayed plots. The three spray programmes all decreased cane death due to cane blight and they all increased yield by c. 45% even in those plots sprayed post‐harvest where spur blight was severe and not controlled. Clearly this last disease, despite its high incidence, had no effect on potential yield in this experiment. In the second year cane blight was common but less severe and the incidence of its lesions was reduced similarly by all programmes, but only 4% of canes died in control plots.Analysis of the potential yield and the sizes of lesions caused by L. coniothyrium in canes inoculated at fortnightly intervals in the previous year showed that potential yield loss occurred only when lesions girdled canes. A bimodal distribution in the lesion sizes, measured by length or girdling, indicated some endogenous control of lesion development which might explain the marked differences in the effect of cane blight on potential yield in two seasons.
The effect of pH on host plant ‘preference’ for strains of Rhizobium trifolii using fluorescent ELIS A for strain identification
Authors: JONES D. GARETH , MORLEY SUSAN J. 
Published: February 2008

SUMMARYThe effect of pH on host plant ‘preference’ for strains of R. trifolii was studied using the fluorescent ELISA technique. Four white clover cultivars were compared growing at pH 5, 6 and 7 inoculated with 1:1 mixtures of two strains of R. trifolii, CP3B and R4. The growth of these two bacterial strains was also studied at the same pH levels in pure culture. At pH 5, in pure culture, CP3B grew very well but R4 failed to reach the log phase. CP3B also produced the majority of nodules at this pH (86%). At pH 7, in pure culture, R4 grew better than CP3B and also produced 66% of the nodules in the nodulation experiment. However, there was good evidence of host cultivar ‘preference’ with cv. Milkanova having no nodules inhabited by CP3B at pH 7 but cv. S100 having 32%.The results are discussed from the point of view of the establishment of white clover in acid soils and the usefulness of the fluorescent ELISA technique for Rhizobium strain identification is also emphasised.
Purification of carrot red leaf virus and evidence from four serological tests for its relationship to luteoviruses
Authors: WATERHOUSE P. M. , MURANT A. F. 
Published: February 2008

SUMMARYCarrot red leaf virus (CRLV) was purified from infected chervil by centrifuging whole plant extracts at low speed and incubating the resuspended pellets with Driselase; the digest was then treated with 1% (v/v) Triton X‐100 and the virus concentrated by centrifugation twice at high speed through a layer of 20% sucrose. The preparations (about 1 μg virus/g tissue) contained isometric particles c. 25 nm in diameter which formed a single u.v.‐absorbing component in sucrose density gradients. Chervil seedlings exposed to aphids (Cavariella aegopodii) that had been injected with or had fed on fractions from the u.v.‐absorbing zone developed typical symptoms of infection with CRLV. CRLV particles had a sedimentation coefficient (s20,w) of 104 S, buoyant density in CsCl of 1.403 g/cm3 and A260/A280 of 1.62. Antiserum with a gel‐diffusion titre of 1/512 was obtained from a rabbit injected intradermally with 100 μg purified virus. CRLV was detected by immunosorbent electron microscopy and enzyme‐linked immunosorbent assay in extracts of the petioles and leaf midribs of infected chervil and in groups of five to 20 viruliferous C. aegopodii.Analysis of antiserum/virus reactions by density gradient centrifugation showed that CRLV is distantly related to all luteoviruses tested; its relationships were closest to barley yellow dwarf virus (RPV strain), and perhaps also to beet western yellows virus, more distant to tobacco necrotic dwarf, potato leafroll and bean leafroll viruses, and very distant to barley yellow dwarf (MAV strain) and soybean dwarf viruses. Some of these relationships were detected by double diffusion in agarose gels and by electron microscopy of antiserum/virus mixtures. Immunosorbent electron microscopy detected all these relationships but suggested that CRLV was more closely related to tobacco necrotic dwarf and potato leafroll viruses than to barley yellow dwarf virus (RPV strain).The results show that CRLV should be considered a definitive member of the luteovirus group, and provide confirmation of recent evidence that potato leafroll virus is a luteovirus.
A study of sugar beet growers' pest control decisions
Authors: MUMFORD J. D. 
Published: February 2008

SUMMARYThe results of a survey of sugar beet growers are reported which provide subjective information on farmer perceptions of the hazard from pests and diseases on sugar beet, the control methods available and used, farmers' estimates of the costs and effect of controls, their objectives for pest control, and their attitudes to advice. In addition, objective information from research and field observations on losses and control methods is provided. The basis of pest control decisions and implications from comparisons of subjective and objective perceptions of the various problems and solutions are discussed.
A solution culture method for observing the development of clubroot symptoms on young brassica plants
Authors: CRUTE I. R. , BUCZACKI S. T. , STEVENSON KAREN 
Published: February 2008

SUMMARYA method which allows the sequential observation of gall development on young brassica plants following infection by Plasmodiophora brassicae is described. Plants were grown under controlled conditions in solution culture contained in specimen tubes and their development and subsequent symptom production closely paralleled that in a soil/peat mixture. The method should prove useful for studying the biology of the disease.
Methods for inoculating field crops with mycorrhizal fungi
Authors: HAYMAN D. S. , MORRIS E. J. , PAGE R. J. 
Published: February 2008

SUMMARYFour methods were compared for inoculating red clover with selected mycorrhizal fungi when sown in a field containing an indigenous mycorrhizal population. The largest amount of mycorrhizal infection (around 65% of root length infected) was obtained by placing inoculum with the seeds in furrows. The inoculum used was standard soil inoculum from stock plant cultures spread by hand or the same inoculum concentrated to about one seventh by wet‐sieving, and then fluid‐drilled. The effectiveness of multiseeded pellets (seeds stuck onto pellets of soil inoculum) applied broadcast was more variable, infection ranging widely around an average of 30%. Applying both soil inoculum and seeds broadcast produced just under 10% infection, similar to that in the controls given autoclaved inoculum. Seedling establishment, in contrast, was‐better where seeds were applied broadcast than in furrows. It seemed therefore that multiseeded pellets might be the best compromise for achieving reasonable infection in most plants, but fluid drilling had the advantages of greatly reducing the amount of inoculum needed and of readily combining seeds and inoculum in a single carrier.