bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of tannin content of faba bean (Vicia faba) seed on seed vigour, germination and field emergence
Authors: KANTAR F. , PILBEAM C J. , HEBBLETHWAITE P D. 
Published: February 2008

SummaryDifferences in seed vigour of zero‐ and high‐tannin faba beans were investigated using 25 seed lots of 12 cultivars following earlier reports of poor emergence in the zero‐tannin types. Field emergence ranged from 54–96% indicating differences in seed vigour between cultivars all having high laboratory germination (>91%). Seed from zero‐tannin accessions with poor emergence had a higher incidence of testa and cotyledon cracking, a smaller percentage of hard seeds, more rapid water uptake, a lower percentage of vital staining of cotyledons and a greater leaching of solutes than high‐tannin types. Nevertheless, variation in these characteristics existed between cultivars and lines of both types. Seeds with more cracks in the seed coat and fewer hard seeds imbibed water more rapidly and consequently showed lower levels of vital staining and more cracks in the abaxial surface of the cotyledons. Slower imbibition in polyethylene glycol lessened the incidence of these deleterious characteristics and may provide a practical resolution to the problem of poor field emergence in zero‐tannin lines of faba bean with low seed vigour.
The Biology of the Tospoviruses
Authors: MUMFORD R A. , BARKER I. , WOOD K R. 
Published: February 2008

SummaryThe tospoviruses are a diverse, cosmopolitan and economically important genus of plant viruses. In the recent past, interest in the tospoviruses has been rekindled with the resurgence and expansion of tomato spotted wilt virus and the appearance of new tospoviruses, including impatiens necrotic spot. This renewed interest in the tospoviruses, accompanied with the many recent advances in plant virology techniques, particularly those utilising molecular biology, have resulted in a rapid growth of our understanding of these viruses. This paper provides a review of the tospoviruses, encompassing all the major aspects of their biology, including the recent changes in the classification of the genus and current knowledge on molecular biology, vector relations, control and diagnosis.
The separation of Liriomyza huidobrensis (Diptera: Agromyzidae) from related indigenous and non‐indigenous species encountered in the United Kingdom using cellulose acetate electrophoresis
Authors: COLLINS DOMINIQUE W. 
Published: February 2008

SummaryThe non‐indigenous pest leaf miner Liriomyza huidobrensis and its close relatives L. bryoniae and L. strigata belong to a natural group. These species can be separated from one another by means of protein electrophoresis on a cellulose acetate membrane. The protocol for this diagnostic assay involves staining for two enzymes, glucose‐6‐phosphate dehydrogenase (G6PDH) and leucine‐glycine peptidase (PEP). Other leaf miner species that might also be found under glass, Chromatomyia syngenesiae, C. horticola and the non‐indigenous L. trifolii and L. sativae, are clearly distinguishable from the L. huidobrensis group of species by this assay. The effect of parasitism on L. huidobrensis by Dacnusa sibirica was investigated and shown unlikely to cause misidentification of the leaf miner host. Results obtained from practical use of the assay to identify unknown specimens from ports and nurseries are compared with those obtained from flies kept in laboratory culture and used during development of the assay. No new variation was found for G6PDH. New PEP variation was found for both L. huidobrensis and L. bryoniae but this did not affect the integrity of the assay. A biochemical key to these agromyzid leaf miners is presented.
Density dependence in cereal aphid populations
Authors: MAUDSLEY M J. , MACKENZIE A. , THACKER J I. , DIXON A F G. 
Published: February 2008

SummaryLong sequences of data on the incidence of cereal aphids from five European countries were analysed for evidence of density dependent processes occurring between years. Using a randomisation test (Pollard, Lakhani & Rotheray, 1987), density dependence was revealed in all (16) population censuses of Metopolo‐phium dirhodum, 60% of Rhopalosiphum padi censuses (10 of 17) but only 25% of Sitobion avenae population censuses (4 of 16). Correcting for density independent effects of weather revealed the existence of significant direct density dependence in some populations censuses where it was previously undetected. The implications of density dependence in cereal aphid populations are considered.
Transformation of blueberry without antibiotic selection
Authors: GRAHAM J. , GREIG K. , McNICOL R J. 
Published: February 2008

SummaryTransformation of the blueberry cultivar North Country (Vaccinium corymbosum×V. angustifolium) was achieved using the disarmed Agrobacterium tumefaciens isolate LBA4404, containing a binary vector with an intron‐containing β‐glucuronidase (GUS) marker gene. Plant regeneration was carried out in the absence of antibiotics due to their toxicity to blueberry explants. Agrobacterium contamination was controlled by dipping the explants in antibiotics and rinsing in sterile distilled water. Once regeneration had been achieved, the plantlets were placed on to medium containing the antibiotic ticaricillin at 250 mg litre‐1 to control and try to eliminate any remaining Agrobacterium. Selection of regenerating explants expressing GUS was achieved by growing the plant material for 2 days on a medium containing 4‐methyl umbelliferyl glucuronide (MUG), and examining the medium under UV light to detect fluorescent activity. From the 19 explants showing signs of regeneration, seven produced fluorescent patches on MUG medium. From the selected explants, five plantlets were found to express the GUS gene as detected by fluorometric and histochemical analysis. PCR was used to confirm the presence of the GUS and/or NPTII marker genes after 2 years in culture. Bacterial contamination isolated from plant material (which appeared free of contamination) was examined for GUS activity and analysed using PCR with GUS and NPTII specific primers, but no positive results were obtained.
Common cabbage resistance mechanisms against the diamondback moth: still an open book?
Authors: VERKERK R H J. , WRIGHT D J. 
Published: February 2008

SummaryDespite the extensive research on host plant resistance of Brassica oleracea L. var. capitata (common cabbage) against Plutella xylostella L. (diamondback moth), knowledge of the resistance mechanisms involved remains incomplete. While robust evidence exists for the physical (antixenosis) mechanisms believed to cause resistance in glossy‐leaved breeding lines, the one mechanism proposed in the literature to date (polar leaf extracts causing antibiosis) at best only explains a part of the resistance observed in two partially‐resistant normal‐bloom breeding lines in the field and the evidence is suggestive rather than direct.Evidence from other host plant resistance studies involving P. xylostella is discussed and the other possible mechanisms are considered with the aim of providing a context for further investigations on host plant resistance mechanisms against P. xylostella.
Impact of density of Aphis craccivora (Aphididae) on growth and yield of susceptible and resistant cowpea cultivars
Authors: ANNAN I BILLY , SCHAEFERS GEORGE A , TINGEY WARD M 
Published: February 2008

SummaryImpact of initial density of cowpea aphid Aphis craccivora Koch (Aphididae) at infestation on the growth and yield of aphid‐susceptible cowpea cultivar ICV‐1 and aphid‐resistant cultivar ICV‐12, was investigated. Plants at the seedling, flowering and podding stages of development were infested with five aphid densities consisting of 0, 2, 5, 10 and. 20 aphids per plant and maintained for 22 days. Extended leaf heights of plants and aphid counts were recorded at 7, 12, 17 and 22 days after infestation. Two crop growth parameters (biomass duration and leaf area duration), and two plant yield parameters (number of pods per plant and number of seeds per pod) were recorded. Due to the occurrence of parthenogenesis and changes in population dynamics during infestations, aphid densities were converted into cumulative cowpea aphid‐days, to facilitate data analyses and interpretation. ANOVA indicated that there was significant (P=s 0.05) difference in aphid‐day accumulations between the two cultivars when infested at the seedling stage. Accumulations on cv. ICV‐1 were greater than on cv. ICV‐12. However, no such differences between the cultivars were detected when plants were infested at flowering and podding stages. Therefore, the seedling stage was used for comparisons of the impact of cowpea aphid‐days on the growth and yield parameters of the two cultivars. At the 95% confidence intervals, ICV‐12 plants were consistently taller than ICV‐1 plants. Infested ICV‐1 seedlings showed stunting and other growth deformities which were not observed on ICV‐12 plants. Regression analyses revealed substantial reductions in the growth and yield parameters of ICV‐1 relative to ICV‐12. Overall, cowpea aphid‐days provided a convenient and reliable method for studying the aphid population dynamics and the subsequent impact on plant growth and yield performance.
Inoculum sources of Fusarium oxysporum f.sp. asparagi in asparagus production
Authors: BLOK WIM J , BOLLEN GERRIT J 
Published: February 2008

Summary Fusarium oxysporum f.sp. asparagi (Foa) incites crown and root rot of asparagus which causes early decline of asparagus plantings. The aim of the present study was to identify the main inoculum sources of the pathogen in the Netherlands.As has been reported for foreign seed lots, Dutch seed lots can be infested with Foa at low levels. We found that seed infestation occurs mainly during the seed harvesting process through infested soil adhering to fallen berries.Soil samples from 59 fields without a history of asparagus growing and differing in their distance from asparagus plantings were tested for infestation with Foa, using a bioassay with asparagus as a bait plant. A high correlation was found between the incidence of infestation and proximity to asparagus fields; Foa was found in 69% of the samples from fresh fields in an asparagus production centre, and in only 6% of the samples from fields at a distance of 1 km and more from asparagus fields and outside a production centre.To evaluate planting material as an inoculum source of Foa, 49 lots of one‐year‐old crowns from 23 nurseries were collected and rated for disease symptoms. Infestation was found to be common with only two lots free of symptomatic plants. Most of the lots had more than 75% of symptomatic plants. Although most of the plants were infested, they showed only slight root rot symptoms. The procedure for production of Foa‐free planting material is discussed.Persistence and infestation of asparagus root residues in former asparagus fields was assessed by retrieving the residues from eight former asparagus fields with an asparagus‐free period of one to 25 years, and three fields with a standing asparagus crop. Even after an asparagus‐free period of 25 yr asparagus root residues were retrieved from soil, although at low levels. Mean population densities of Fusarium spp. declined from 2 times 106 to 1 times 105 colony forming units g_1 air‐dry root tissue during the first 10 years and were still > 104 c.f.u. g“1 air‐dry root tissue 20 to 25 yr after asparagus produced was stopped. The population was dominated by F. oxysporum. Eighty‐three of the 112 isolates (74%) of F. oxysporum belonged to the forma specialis asparagi. The proportion of Foa in the population did not decrease in time. It was concluded that persistence of Foa in asparagus root residues is a major reason for its long‐term survival.
Comparison between woody indexing and a rapid hybridisation assay for the diagnosis of little cherry disease in cherry trees*
Authors: EASTWELL K C , BERNARDY M G , LI T S C 
Published: February 2008

SummarySweet cherry (Prunus avium) and sour cherry (Prunus cerasus) trees from orchards in the Kootenay and Okanagan Valleys of British Columbia, Canada were assayed for the presence of little cherry disease by three different methods: Northern blot analysis of double‐stranded RNA, woody indexing for fruit symptoms on sweet cherry cv. Lambert, and woody indexing for foliar symptoms on cv. Canindex 1. Results of the three methods were in agreement for 85% of the samples. Of the 78 orchard trees tested, double‐stranded RNA isolated from 48 trees hybridised with a radiolabeled cloned probe specific for little cherry disease. When the 48 trees were tested by woody indexing, buds from 41 trees induced fruit symptoms on cv. Lambert, but only 32 yielded foliar symptoms on cv. Canindex 1 under the conditions of the experiment. Of the 30 orchard trees that did not yield a positive response to the Northern blot analysis, 26 samples were negative on cv. Lambert and 26 were negative on cv. Canindex 1. Northern blot analysis of the 78 cv. Lambert indicator trees revealed that there was an absolute correlation between the presence of little cherry disease‐associated double‐stranded RNA and the development of typical little cherry disease symptoms on the indicator trees. Reliability of woody indexing of orchard samples was impaired by poor transmission of the disease from the inoculating bud to the indicator tree. Woody indexing with cv. Canindex 1 was particularly prone to a large number of apparently erroneous negative results. Of the three protocols used, diagnosis of little cherry disease by Northern blot analysis was found to be the most reliable and offered a greatly accelerated means of diagnosis.
A review of the pre‐oviposition behaviour of small cabbage white butterfly, Pieris rapae(lepidoptera: Pieridae)
Authors: HERN ALAN , EDWARDS‐JONES GARETH , MCKINLAY RODERICK G 
Published: February 2008

SummaryThis paper reviews the literature concerning the ovipositional behaviour of Pieris rapae (small cabbage white butterfly) and where appropriate considers results from studies involving other butterflies. The paper considers searching behaviour, stimuli utilised in host plant finding and identification and concludes with a general section on the role of learning and prior experience in ovipositional behaviour.
Development of an apparatus and protocol for the efficient isolation of bacteria and yeasts that attach to Botrytis cinerea germlings
Authors: COOK DARRYL W M , LONG PETER G , GANESH SIVA , NEILSON HUGH F 
Published: February 2008

SummaryAn apparatus and protocol for the efficient and consistent isolation of bacteria and yeasts with the ability to attach to germlings of Botrytis cinerea is described. The study focused on minimising microbial contamination by bacteria or yeasts which do not attach to the pathogen B. cinerea but which interact with materials used in the equipment and would otherwise be isolated along with target microbes. After development, the assay reduced the contamination rate to 1–2 cells per 100 added and this was found to be a satisfactory level for the selection of microbial attachers to fungal hyphae. One or more phenotypes of microbes that adhered to B. cinerea germlings were found in 97% of the 70 samples collected from phylloplane washings and processed using this assay.
Control of the mushroom pests Lycoriella auripila (Diptera: Sciaridae) and Megaselia halterata (Diptera: Phoridae) by Steinernema feltiae (Nematoda: Steinernematidae) in field experiments
Authors: SCHEEPMAKER J W A , GEELS F P , SMITS P H , GRIENSVEN L J L D VAN 
Published: February 2008

SummaryThe nematode Steinernema feltiae (Nematoda: Steinemematidae) was tested for its ability to control two main mushroom pests i.e. the sciarid Lycoriella auripila (Diptera: Sciaridae) and the phorid Megaselia halterata (Diptera: Phoridae) in growing‐rooms filled with spawned compost. A clear difference between female and male sciarid control was observed. A nematode application 1 day after casing preceded by an application 1 day before casing on the compost caused an almost complete control (97%) of the F1‐generation of female sciarids. The F2‐generation of females was similarly controlled (95%) by an application 7 days after casing. A dosage of 1 × 106nematodes m‐2was found to be equally effective as higher dosages. Diflubenzuron remained active throughout entire the cropping period with high sciarid mortality rates varying from 72% to 99%.Phorid control was variable and seemed to depend on the presence of sciarids. In one occasion the control rate of F2‐generation phorid larvae was 75% and was possibly caused by the presence of new infective juvenile nematodes recycled in F2‐generation sciarid larvae. Diflubenzuron did not significantly reduce phorid numbers.
Mycocentrospora acerina in carrots; Effects of crop rotation on disease incidence
Authors: HERMANSEN ARNE , AMUNDSEN TERJE , TAKSDAL GUDMUND , DRAGLAND STEINAR , SYNNEVÅG GRY , FLØNES MONS , SUNDHEIM LEIF 
Published: February 2008

SummaryFour experimental sites located in different climatic regions in Norway were inoculated with Mycocentrospora acerina in 1985. In 1986, crop rotation experiments including carrot, barley, grass, red clover, onion and potato, were established at these sites. Incidence of M. acerina on the foliage and the roots of carrots after storage were recorded in 1989/90 and 1994/95.The 3 yr rotation only slightly reduced the inoculum of M. acerina in the soil. Red clover and grass were the most effective crops in reducing the inoculum, potato and barley were less effective, and onion had no effect on the inoculum. Differences in M. acerina infection on carrots between 3, 6 and 8 yr of rotation with barley and grass were not statistically significant.
Production of phytotoxic spore germination liquids by Alternaria brassicae and A. brassicicola and their effect on species of the family Brassicaceae
Authors: COOKE D E L , JENKINS P D , LEWIS D M 
Published: February 2008

SummaryExperiments assessed the susceptibility of Brassica spp. and non‐Brassica spp. in the family Brassicaceae to infection by Alternaria brassicae and A. brassicicola, and determined the sensitivity of the host species to spore germination liquids (SGLs) produced by the pathogens on B. napus leaves. There was a wide range of sensitivity to the pathogens. Brassica spp. were generally more susceptible, and some non‐Brassica spp. (Barbarea vulgaris and Capsella bursa‐pastoris) were immune to A. brassicicola. Measurable damage was caused by SGLs but with significant variation between host species. Non‐hosts and weak hosts also showed necrosis. It was concluded that, in the case of both pathogens, the toxic factors in these SGLs were host‐selective. Selectivity in toxin production was also demonstrated in relation to the host surface or growing medium in which spores germinated. A substantial amount of toxin was produced on all Brassicaceae tested but not on unrelated species (Triticum aestivum, Pisum sativum and Lycopersicon esculentum). Neither pathogen produced measurable amounts of toxin when cultured in Czapek (Dox) broth.
A novel method for detection of viable zoospores of Pythium in irrigation water
Authors: WAKEHAM A J , PETTITT T R , WHITE J G 
Published: February 2008

SummaryA membrane filtration test has been developed for the detection of viable zoospores of Pythium species. Zoospore suspensions were filtered through 5 (m nitrocellulose membranes and the membranes incubated overnight in 0.07 m glucose, rifamycin (30 mg litre‐1) and pimaricin (100 mg litre‐1). Zoospore germlings were detected using a polyclonal antiserum, raised to mycelial surface washings of five Pythium spp., and visualised with Sigma fast red. The assay gave positive results for all Pythium spp. tested and also to zoospores of Phytophthora cryptogea. Of 10 fungal species isolated from commercial irrigation water, two were detected by the polyclonal antiserum in ELISA tests but only one produced detectable zoospore germlings. The latter isolate was later identified as a Pythium sp. Irrigation water samples collected from commercial UK nurseries yielded zoospores of both Pythium and Phytophthora spp. which, using the assay, were positively identified. Results indicated greater sensitivity than was seen with conventional plating methods. This is a test which could be adapted for on‐site use in commercial nurseries.
Role of a novel type of double infection in the geminivirus‐induced epidemic of severe cassava mosaic in Uganda
Authors: HARRISON B D , ZHOU X. , OTIM‐NAPE G W , LIU Y. , ROBINSON D J 
Published: February 2008

SummaryTo study the cause of the current epidemic of severe mosaic in Ugandan cassava, PCR analysis was used to detect and identify African cassava mosaic virus (ACMV), East African cassava mosaic virus (EACMV) and the recently reported recombinant geminivirus (UgV), which is derived from ACMV and EACMV, in leaf extracts from cassava plants grown from cuttings in the glasshouse at Dundee. The cuttings were collected from plants showing symptoms of different severities and growing at different sites in Uganda inside, at the periphery of, and outside, the area affected by the epidemic. ACMV occurred throughout the nine districts sampled but UgV was detected only in the area affected by the epidemic. EACMV was not found in Uganda. Most plants containing ACMV alone expressed mild or moderate mosaic, whereas very severe mosaic developed in most plants containing UgV plus ACMV and a few of those containing UgV only. Very severe mosaic in cassava from southern Sudan was likewise associated with co‐infection by UgV and ACMV. The very severe disease was reproduced by graft‐inoculating geminivirus‐free cassava with UgV plus ACMV; plants inoculated with either UgV or ACMV developed severe or moderate symptoms, respectively. Unlike ACMV, Malawian EACMV did not enhance the severity of symptoms induced by UgV. However, a very severely affected plant from Ukerewe Island, Tanzania, contained ACMV and EACMV but not UgV. UgV attained a much greater concentration in cassava than did ACMV but the opposite occurred in Nicotiana benthamiana. In neither host was total virus antigen concentration affected by co‐infection.Factors affecting the genesis, selection and spread of UgV are discussed. The evidence indicates that UgV is probably of relatively recent origin, that such variants do not appear often, and that the current epidemic has resulted from the rapid spread of UgV to infect plants and to invade regions in which ACMV already occurred. The novel type of virus complex so produced, consisting of an interspecific recombinant virus (UgV) and one of its parents (ACMV), typically has even more severe effects than UgV alone.