bluuebunny/crossref_metadata_2025_split huggingface dataset:
Decreased severity of potato common scab after foliar sprays of 3,5 ‐dichlorophenoxyacetic acid, a possible antipathogenic agent
Authors: MCINTOSH BY A. H. , BATEMAN G. L. , CHAMBERLAIN K. , DAWSON G. W. , BURRELL M. M. 
Published: February 2008

SUMMARYGlasshouse tests on the potato cultivars Majestic and Maris Bard measured the effects of single early foliar sprays of ring‐substituted phenoxyacetic acids (0.9 × 10–3 M) on the incidence of potato common scab, caused by soil‐borne Streptomyces scabies.The most effective compound was 3,5‐dichlorophenoxyacetic acid (3,5‐D), which decreased scab by about 90%; its action was preventative, early sprays being more effective than late However, it slightly decreased yield, and increased the number of tubers per plant and the proportion of deformed tubers. The trichloro‐ and tetrachloro‐ acids containing the 3,5‐dichloro‐ group also decreased scab, though to lesser extents; the most active of these was the 2,3,4,5‐tetrachloro‐ acid, which had the same side effects as 3,5‐D. The herbicide 2,4‐D almost halved scab incidence, but seriously decreased yield. Other acids tested had little or no effect on scab.In tests against S. scabies in culture, 3,5‐D was no more toxic than other disubstituted acids which were inactive, or weakly active, against the disease in vivo.3,5‐D may be an ‘antipathogenic agent’, preventing scab development by altering tuber metabolism.
Use of Clq enzyme‐linked immunosorbent assay to detect plant viruses and their serologically different strains
Authors: TORRANCE BY L. 
Published: February 2008

SUMMARYClq was prepared from bovine serum using a simple method involving repeated dialysis at low ionic strength in the presence of chelating agents (yield c. 3 mg/100 ml serum). It was viable when stored at ‐18°C for up to 2 months, and at 4°C for at least 10 wk in a storage buffer containing 10% sucrose. When used in Clq ELISA this test was as sensitive as the direct double antibody sandwich form of ELISA (direct ELISA) in detecting purified potato virus Y (PVY), with a limit of detection in both methods of c. 15 ng/ml, and slightly more sensitive in detecting purified cocksfoot mild mosaic virus (CMMV), with limits of detection of c. 15 ng/ml and c. 15–60 ng/ml respectively.Using an antiserum to one strain of each virus, Clq ELISA readily detected strains of PVY, CMMV, Andean potato latent virus (APLV) and barley yellow dwarf virus (BYDV). This included detection of APLV‐Hu by APLV‐Caj antibodies and CMMV(G) by PMV(S) antibodies, neither of which system gives detection in direct ELISA. Clq ELISA was therefore less specific than direct ELISA in detecting serologically different virus strains.Virus detection by Clq ELISA was inhibited when sap of tobacco, Nicotiana clevelandii and Setaria italica was used at low dilution. Inhibition by N. clevelandii sap was alleviated by using increased concentrations of virus specific antibody to detect APLV and plum pox virus. Also, extracting APLV infective N. clevelandii or CMMV infective S. italica saps in a minimum of buffer, centrifuging at low speed and diluting the supernatant before testing, partially overcame the inhibition. The inhibitory substance(s) in sap may act by preventing the binding of Clq to virus‐antibody aggregates. Sap of wheat, oat and barley did not appear to have an inhibitory effect and BYDV was readily detected in naturally infected field grown plants of these species.
Black tea manufacture.
Authors: CLOUGHLEY J. B. , ELLIS R. T. , HARRIS N. 
Published: February 2008

SUMMARYTea shoots were comminuted by four commercial processing systems representing both orthodox, and the more intensive, unconventional methods. Greater amounts of endogenous flavanols were oxidised and higher levels of the flavin class of pigments were produced, during the fermentation of the unconventionally processed leaf. Detailed comparison of quality and all the other aspects affecting market value, demonstrated that the unconventional systems produced a more valuable product. The results are related to the characteristic tissue damage associated with each disruption technique.
Control of pearl millet downy mildew by seed treatment with metalaxyl*
Authors: WILLIAMS R. J. , SINGH S. D. 
Published: February 2008

SUMMARYThree formulations of the systemic fungicide metalaxyl were tested in various seed treatments for the control of pearl millet downy mildew in three field experiments with downy mildew‐susceptible pearl millet hybrid NHB‐3. Uniform, high levels of sporangial inoculum of the causal fungus, Sclerospora graminicola, were provided throughout the growth of the test crops from inoculated infector rows of NHB‐3, planted earlier between the test plots. Significant reductions in downy mildew were obtained with all fungicide treatments. Best control was obtained when seed was soaked in a 0.5% aqueous solution of a liquid formulation (mean infection index of 9.8% compared with 94.8% in the untreated check). The degree of control with the wettable powder formulations was directly related to fungicide dosage, and there were no significant effects of application method. Simple dusting of seed at 2 g a.i./kg, a rapid and simple operation requiring small quantities of fungicide and no special application equipment, gave a high level of control (infection index of 12.6% compared with 78.9% in the untreated check). In two experiments grain yields from all the treated plots were significantly greater than from the untreated plots (means of 1234 and 1534 kg/ha for treated plots compared with 485 and 743 kg/ha, respectively), and in the third, the treatment with the least downy mildew gave significantly more grain than the untreated check (1228 compared with 727 kg/ha).
Inhibition of development of Meloidogyne incognita by root and foliar applications of oxamyl
Authors: WRIGHT DENIS J. , WOMACK NICHOLAS 
Published: February 2008

SUMMARYOxamyl (2.5 μg cm‐3sand) applied to the roots of cucumber seedlings significantly reduced the number of vermiform second stage juveniles of Meloidogyne incognita which developed into swollen forms for at least 30 days. However, when cucumber seedlings containing nematodes were removed from oxamyl‐treated sand 10 days after the pesticide was applied and placed in clean sand a large proportion of the juveniles had become swollen after a further 18 days. This suggested the effect of oxamyl on nematode development was reversible.A single foliar application of oxamyl (25–100 μg) in distilled water was also found to significantly reduce development of second stage juveniles to saccate forms However, the use of various adjuvants with a threshold foliar treatment (25 μg oxamyl) failed to significantly improve its activity.
A simple procedure for the efficient estimation of potato cyst nematode larvae in lactophenol‐treated roots
Authors: MARKS R. J. , McKENNA L. A. 
Published: February 2008

SUMMARYCounts of potato cyst nematode larvae in whole roots of potatoes may be readily made by liberating the larvae from lactophenol treated roots into water using a blender, removing root debris by filtration and counting larvae directly in water. The method obviates the health hazard associated with high levels of phenolic fumes when counting intact root systems or pieces directly in lactophenol and is also considerably faster and more efficient.
The effect of cold storing pre‐germinated lettuce seeds on radicle development and seedling emergence
Authors: WURR D. C. E. , DARBY R. J. , FELLOWS JANE R. 
Published: February 2008

SUMMARYThe effects on radicle development and seedling emergence of cold storing batches of pre‐germinated lettuce seeds for up to 7 days at 0 or 2 °C were investigated in three experiments. Cold storage tended to delay emergence and increase its spread in time. Separate batches of pre‐germinated seeds gave different mean radicle lengths and different patterns of emergence and it is likely that small differences in mean temperature during germination were responsible since the length of radicles after germination was linearly related to accumulated day‐degrees during the germination period. This suggests that germinating seeds over a period during which a required number of day‐degrees is accumulated may produce radicles of the same length for different sowings.The elongation of radicles during cold storage was also linearly related to accumulated day‐degrees. At 2 °C it appeared that the longer radicles elongated faster than the smaller ones and this may account for cold storage tending to increase the spread of seedling emergence when the pre‐germinated seeds were sown into compost.
Effects of cold storage of germinated vegetable seeds prior to fluid drilling on emergence and yield of field crops
Authors: FINCH‐SAVAGE W. 
Published: February 2008

SUMMARYGerminated seeds of five vegetable crops were stored at 1 °C in aerated water or humid air for periods of up to 15 days and then fluid drilled in the field. Viability of germinated seed was maintained in carrot and parsnip for a minimum of 15 days, salad onion for 9 days, lettuce for 6 days and cabbage for 3 days. When salad onion, lettuce and cabbage seeds were stored for longer than these times there was a reduction in the number of seedlings emerging. In species where storing seeds for up to 15 days caused a reduction in emergence an adjustment to the seed rate related to the length of storage can be made to achieve the desired population and still retain the advantages of fluid drilling pre‐germinated seeds. This is possible because with one exception (an increase in the variation of salad onion stem diameters) the performance of plants from all stored germinated seeds after emergence was similar to plants from freshly germinated seeds.
Influence of environmental conditions on spore dispersal and infection by Septoria nodorum
Authors: JEGER M. J. , GRIFFITHS ELLIS , JONES D. GARETH 
Published: February 2008

SUMMARYIn field experiments using healthy trap plants it was found that pycniospores of S. nodorum were dispersed from diseased wheat plants whenever rain fell and occasionally in the absence of rain. Of two spring wheats tested, cv. Kolibri seemed a better ‘source’ plant and cv. Maris Butler a better ‘receptor’ when rainfall was light, but this difference was not apparent when rainfall was heavy.On 44 occasions, plants of Kolibri and M. Butler were also exposed to natural conditions immediately following artificial inoculation with S. nodorum. Infection of plants occurred on 10 occasions and was associated with the following minimum conditions: r.h, at inoculation >63%; and in the following 24 h, minimum temperature <6°C, at least 4 h with r.h. >90% and not more than 4 h with r.h. >60%.
Disease measurement in a study of apple scab epidemics
Authors: JEGER M. J. 
Published: February 2008

SUMMARYAn epidemic of apple scab in an unsprayed planting at East Mailing was monitored during the summer of 1979. Different rates and patterns of scab development on six apple cultivars were observed. Of several disease measures investigated the number of colonies/extension shoot best represented the epidemic.More comprehensive disease measurements on leaves, fruits and shoots were made toward the end of the summer. Cultivar differences were demonstrated for all disease measures investigated. The proportion of leaves with scab (incidence) and the number of colonies on leaves (intensity) were the measures with the lowest coefficients of variation. Consistent relationships between incidence and intensity were obtained.The implications of these findings for studies concerned with fungicide evaluation, cultivar susceptibility, disease—quality loss relationships and monitoring for disease management are discussed.
A comparison of the effectiveness of the four British virus vector species of Longidorus and Xiphinema
Authors: TRUDGILL D. L. , BROWN D. J. F. , ROBERTSON W. M. 
Published: February 2008

SUMMARYThe frequency with which the four virus‐vector species of longidoroid nematodes occurring in Britain transmitted their associated plant viruses were compared in a series of experiments using a standard procedure. In these tests Xiphinema diversicaudatum proved an effective vector of British isolates of arabis mosaic virus and strawberry latent ringspot virus and Longidorus attenuatus of an isolate of tomato black ring virus from England. In comparison, isolates of raspberry ringspot virus and tomato blackring virus from Scotland and of raspberry ringspot virus from England were transmitted much less readily by their respective vectors, L. elongatus and L. macrosoma. These differences in ability to transmit virus were not related to differences in feeding access on the virus source‐ or bait‐plants, in the extent to which virus was retained within the nematode feeding apparatus or in the frequency with which virus was recovered from Longidorus in concurrent slash tests. Three Scottish isolates of raspberry ringspot and tomato black ring viruses were transmitted equally infrequently by two populations of L. elongatus and the frequency with which virus was transmitted was not greatly increased when the species of source or bait plants was changed.
Growth, survival and reproduction of the bird‐cherry aphid, Rhopalosiphum padi, on its primary host
Authors: LEATHER S. R. , DIXON A. F. G. 
Published: February 2008

SUMMARYFundatrices died when caged on senescent leaves of bird cherry on which oviparae thrived. Fundatrigeniae had more ovarioles and a higher reproductive rate than fundatrices. Oviparae developed and matured eggs on unfurling leaves but they took longer to reach maturity and grew more slowly than when reared on senescent leaves. Fundatrices and oviparae in addition to having an intrinsic preference for bird cherry over other plants did better on particular growth stages of their primary host.
Control of subterranean clover red leaf virus in broad bean crops with aphicides
Authors: JOHNSTONE G. R. , RAPLEY P. E. L. 
Published: February 2008

SUMMARYTrials at three sites in north‐western Tasmania monitored the spread of subterranean clover red leaf virus into and within broad bean crops with movement of its vector, Aulacorthum solani. Records indicated that almost all infections within the crops resulted from secondary spread by apterae following the establishment by migrant alatae of a very few foci of infestation and infection soon after crop emergence. Spread of the virus within the crops was reduced by sprays of demeton‐S‐methyl. Incidence of infection in sprayed plots at harvest was 23%, 13% and 23% at the three sites compared with 80%, 31% and 84% respectively, in unsprayed plots. Yield increases as a result of spraying were 980, 420 and 540 kg/ha.
A strain of cassava latent virus occurring in coastal districts of Kenya
Authors: BOCK K. R. , GUTHRIE E. J. , FIGUEIREDO GINA 
Published: February 2008

SUMMARYA strain of cassava latent geminivirus (CLV) was isolated from mosaic‐affected cassava plants from coastal districts of Kenya. This virus (CLV‐C) did not infect Nicotiana clevelandii, a diagnostic host of the type strain (CLV‐T); experimental host range was very restricted and CLV‐C only infected N. benthamiana and N. rustica out of several solanaceous hosts readily infected by CLV‐T.CLV‐C was also isolated from naturally infected Jatropha multifida (Euphorbiaceae) and Hewittia sublobata (Convolvulaceae).CLV‐C was propagated in N. benthamiana with difficulty and only those isolates derived from cassava plants infected with severe mosaic symptoms were maintained more or less successfully; these sources usually contained a higher concentration of CLV than plants with mild symptoms. Symptom variants generally remained unchanged when grafted into a highly susceptible South American cassava variety.CLV‐C and CLV‐T seemed to occur respectively only in coastal and western districts but their ranges overlapped in central Kenya where they could have been introduced in infected material.CLV‐C could be purified satisfactorily with the method used for CLV‐T but only after modifying the procedure by substituting phosphate for borate in the extraction buffer, n‐butanol for n‐butanol/chloroform in clarification of extracts, and phosphate for borate buffer when resuspending concentrated virus.A virus serologically indistinguishable from CLV‐T was isolated from mosaic‐ affected material obtained from Nigeria; East African and Nigerian isolates were essentially similar in host range and symptomatology. In gel‐diffusion serology tests, pronounced precipitation spurs developed between CLV‐T and CLV‐C indicating that the isolates were related but not identical serologically.Symptoms typical of cassava mosaic disease appeared in only three of 105 plants in experiments on transmission of CLV‐C and CLV‐T by whiteflies, when attempted acquisition of either clarified CLV‐infective sap or purified CLV was made through ‘Parafilm’ membranes. Because it is possible that the three infections resulted from contamination, they cannot constitute proof of transmission. The presence of CLV in relation to the etiology of cassava mosaic thus remains unresolved.
The patterns of growth, assimilation of 14CO2 and distribution of 14C‐assimilate within vegetative plants of Loliumperenne at low and high density
Authors: COLVILL KAY E. , MARSHALL C. 
Published: February 2008

ABSTRACTThe patterns of growth, assimilation of 14CO2 and distribution of 14C‐labelled assimilate were followed for 12 wk from sowing in individual plants of Lolium perenne grown in miniswards at either low (500 plants m‐2) or high (5000 plants m‐2) density. At the latter density, plants were characterised by a 50% reduction in RGR, by the production of fewer tillers, especially second‐ and third‐order tillers, and by a reduction in mean tiller weight. All the green and senescing leaves of each tiller assimilated 14CO2 and the overall assimilatory capacity of a tiller was directly related to its dry weight. At both densities the plant consisted of a main shoot and established tillers with comparable assimilatory activities and a range of developing tillers that assimilated relatively small amounts of 14CO2. As each successive primary tiller developed it was supplied with assimilate from the main shoot and the degree of support was inversely proportional to the dry weight of the tiller. At both densities it was concluded that the first primary tiller could be regarded as an independent assimilatory unit when it reached a dry weight of about 25 mg even though some import of main shoot assimilate continued until the tiller was double this weight. The supply of assimilate to the root system was greatly reduced at both densities compared with previous observations on plants grown singly.
Far‐ultraviolet sensitivity and photoreactivation of Hirsutella thompsonii
Authors: TUVESON R. W. , MCCOY C. W. 
Published: February 2008

SUMMARYThe far‐ultraviolet (FUV; 200–300 nm) sensitivity of four pathotypes of Hirsutella thompsonii, representative of three separate taxonomic varieties of the species, was investigated. The UV inactivation curves for the four strains were indistinguishable. A mutant exhibiting enhanced conidiation derived from the HTF‐72 strain was more FUV sensitive than the four wild type strains (fluence enhancement factor ≅ 1.5). All strains were capable of efficiently photoreactivating FUV damage by a process which appeared to enzymatic.
Serological studies on cassava latent virus
Authors: SEQUEIRA J. C. , HARRISON B. D. 
Published: February 2008

SUMMARYParticles of cassava latent virus (CLV) were purified by a method that yielded up to 3 mg per 100 g of systemically infected Nicotiana benthamiana leaf. Specific antiserum was prepared and used for enzyme‐linked immunosorbent assay (ELISA), which detected purified virus at 5 ng/ml. As estimated by ELISA, CLV antigen reached a greater concentration in leaves of N. benthamiana plants kept at 20–25 °C than in those at 15 °C or 30 °C. CLV was also detected in leaf extracts of naturally infected cassava plants kept at 25 C but its concentration was only 1–7% of that in comparable extracts from N. benthamiana. Staining sections of N. benthamiana leaves with fluorescent antibody indicated that CLV particle antigen accumulates in the nuclei of many phloem cells and of some cells in other tissues.In tests on mosaic‐affected cassava plants of Angolan origin, three plants were found in which CLV could not be detected by either ELISA or immunosorbent electron microscopy, or by transmission to indicator plants. This suggests that the mosaic symptoms were caused by a pathogen other than CLV, but no such agent was detected by electron microscopy of leaf extracts.Three kinds of serological test indicated that CLV is related to bean golden mosaic virus. Evidence was also obtained of a distant relationship to beet curly top virus but none was detected to four other geminiviruses.
Selection for immunity in swede (Brassica napus) to infection by turnip mosaic virus
Authors: TOMLINSON J. A. , WARD C. M. 
Published: February 2008

SUMMARYFully heritable immunity to turnip mosaic virus (TuMV) was found in swede (Brassica napus) cvs Ruta Otofte and Bangholm. Attempts to ‘break’ this immunity were unsuccessful. The reactions of two immune lines of cv. Ruta Otofte to cauliflower mosaic virus, clubroot (Plasmodiophora brassicae) and powdery mildew (Erysiphe cruciferarum) were unchanged compared with the unselected parent line. A symptomless response to TuMV inoculation (possibly immunity) was also found in cv. Acme but not in the clubroot resistant cv. Marian. The percentage of plants which gave a symptomless response to TuMV inoculation differed greatly between cultivars and some seed stocks.
Pathology and properties of tulip virus X, a new potexvirus
Authors: MOWAT W. P. 
Published: February 2008

SUMMARYTulip virus X (TVX), a previously undescribed mechanically transmissible virus, causes chlorotic and necrotic lesions in leaves and streaks of intensified pigmentation in tepals of tulip plants. The virus infected 22 of 42 other plant species in 10 of 14 families, but most host species were infected only erratically. TVX is best propagated in Chenopodium quinoa and assayed in C. amaranticolor. Spindleshaped inclusions were observed in epidermal cells of C. amaranticolor leaves. Leaf extracts from C. quinoa contained flexuous filamentous particles measuring c. 495 ×13 nm. The extracts were infective after dilution to 10‐9, after heating for 10 min at 60 °C but not at 65 °C, and after storage at c. 20 °C for 30 days or at ‐20 °C for 6 months.TVX particles were purified (500 μg/g C. quinoa leaf) from tissue extracts in 0.067 M phosphate buffer containing 10 mM EDTA at pH 7, by twice precipitating the virus with 8% polyethylene glycol in 0.2 M NaCl followed by differential centrifugation. The virus particles have a sedimentation coefficient (s20, w) of 102 S. They contain a protein of mol. wt c. 22 500 and a nucleic acid that, when glyoxalated, migrates in agarose gel like single‐stranded RNA of mol. wt 2.05 × 106. TVX particles tend to aggregate, and evidence was obtained that a 118 S component which was consistently observed in purified preparations and in infective sap is an end‐to‐end dimer. A distant serological relationship was found between particles of TVX and those of viola mottle and hydrangea ringspot viruses, but no serological relationship was detected to nine other potexviruses. TVX is considered to be a distinct and definitive member of the potexvirus group.