bluuebunny/crossref_metadata_2025_split huggingface dataset:
Methods of analysing data to compare effects on populations of carrot fly (Psila rosae) larvae on carrots of treatments with exponentially‐increasing doses of granular insecticide formulations
Authors: PHELPS KATHLEEN , THOMPSON A. R. 
Published: February 2008

SUMMARYEffects of insecticide treatments were assessed by comparing the percentages of undamaged carrot roots on insecticide‐treated and untreated check plots. A dose‐response relationship based on a log‐log transformation was derived and illustrated with data for six insecticides from two field experiments.Formulae are provided for estimating doses corresponding to given levels of decrease in the numbers of carrot fly larvae. Guidance is given on sample sizes needed and constraints on the accuracy of the estimates are stated. Examples are given of the use of the dose‐response relationship to compare insecticide treatments within and between experiments.
Effects of heavy metal salts on susceptibility of rice seedlings to brown spot disease
Authors: GIRI D. N. , SINHA A. K. 
Published: February 2008

SUMMARYHeavy metal salts, known to induce phytoalexin production in different plant species, were used at dilute concentrations (10‐3 to 10‐5 M) in different treatments to control brown spot infection in rice seedlings caused by Drechslera oryzae. Foliage sprays, root‐dips for 24 h at the time of transplanting, or seed soaking for 24 h provided moderate to substantial protection to rice seedlings, at different stages after treatment, against artificial inoculation with the pathogen or natural infection under field conditions and mostly caused significant reductions in symptoms. Of the three methods, greatest and most durable protection was achieved with the wet seed treatment. The number of successful infections was appreciably reduced in most treatments and some also inhibited lesion expansion. Ferric chloride and nickel nitrate were the most effective and mercuric chloride the least effective of the chemicals tested. There was no fungitoxicity in leaf diffusates from 3‐ and 5‐wk‐old seedlings that had been treated with heavy metal salts and only mild toxicity in that from untreated, inoculated seedlings. However, treated seedlings inoculated at the 3‐and 5‐wk stages produced leaf diffusates with significantly greater toxicities which were in proportion to their abilities to resist attack.
Olive latent ringspot virus, a newly recognised virus infecting olive in Italy
Authors: SAVINO V. , GALLITELLI D. , BARBA M. 
Published: February 2008

SUMMARYA manually transmissible virus, for which the name olive latent ringspot virus (OLRV) is proposed, was isolated from a symptomless olive tree. The virus was mechanically transmitted to test plants. Purified preparations of OLRV contained three classes of isometric particle, c. 28 nm in diameter, with sedimentation coefficients of 525 (T), 975 (M) and 1325 (B) and containing 0, 30 and 43% nucleic acid respectively. At equilibrium in CsCl gradients, the buoyant densities of T and M components were 1–29 and 1–43 g/cm3 respectively, whereas B component separated into two sub‐components with buoyant densities of 1–51 g/cm3 (BJ and 1–52 g/cm3 (B2). Particle preparations contained two species of single‐stranded RNA with mol. wt 1–40 times 106 and 2–65 times 106, both necessary for infectivity. The coat protein of OLRV, dissociated under strong denaturing conditions, separated into four components in polyacrylamide gel electrophoresis. Over 75% of the protein was found in a band with mol. wt 57 600, but all four components were recognised as oligomers of a monomeric form with mol. wt 14 300. OLRV was serologically unrelated to 26 different isometric plant viruses including 17 recognised nepoviruses. Its properties strongly indicate that it is a hitherto undescribed member of the nepovirus group.
The identification of the potato cyst nematodes Globodera rostochiensis and G. pallida by isoelectric focusing of proteins on polyacrylamide gels
Authors: FLEMING C. C. , MARKS R. J. 
Published: February 2008

SUMMARYIsoelectric focusing on thin layers of polyacrylamide gel was used to separate proteins from the potato cyst‐nematodes Globodera rostochiensis and G. pallida. General protein patterns could be used to identify the two species, even from. single cysts. Staining for the enzyme phosphoglucomutase (PGM) also produced species specific patterns and the presence of PGM variation among G. pallida populations was revealed. The potential of isolectric focusing as a routine research and advisory tool in nematology is discussed.
Control of stem nematode, Ditylenchus dipsaci Coat race‘), by aldicarb and resistant crop plants
Authors: WHITEHEAD A. G. , TITE D. J. , FRASER J. E. 
Published: February 2008

SUMMARYAldicarb at 1.5 or 4.5 kg ha‐1 applied around the seeds at sowing greatly increased the yields of a range of crop plants in soil heavily infested with stem nematode (Ditylenchus dipsaci, ‘oat race’). Yield responses could be largely explained by stem nematode control in onions, field beans, peas, Manod oats and maize but not in wheat, Maris Tabard oats, lucerne or sugar beet. Aldicarb lessened stem nematode attacks and lessened stem nematode increase in host plants.The supposedly resistant oat Manod was susceptible, whereas Maris Tabard was resistant, as were Peniarth, Pennal, Panema, Pennant, Maris Quest and Milford, whose resistances derive from Grey Winter. Maris Tabard outyielded resistant Panema, Peniarth and Pennal and susceptible Maris Osprey and Manod on infested soil. ‘Tulip root’ is not an infallible guide to susceptibility of oats to stem nematode. We advocate using a mixture of nematode populations in breeding for resistance to stem nematodes.
A novel bioassay for herbicides used in wild oat control and for the assessment of their interactions with other xenobiotics
Authors: TAYLOR H. F. , LOADER M. P. C. , NORRIS S. J. 
Published: February 2008

SUMMARYA bioassay is described which uses young oat seedlings to determine the activity of wild oat herbicides alone and in mixtures with other xenobiotics.Test solution (10 μl) was pipetted into the first leaf sheath of the oat seedlings, and 24 to 48 h later, basal shoot sections were removed and cultured for 24 h on agar. The inhibition of leaf growth from these sections, compared with control sections, was an assessment of herbicidal activity. Marked inhibition occurred when as little as 0–5 to 1 ‐0 μg of either diclofop‐methyl or diclofop had been applied to each plant. Wheat and barley seedlings were unaffected by 12 μg of these herbicides, reflecting their known selectivity in cereal crops.The assay was used to evaluate the antagonisms of diclofop‐methyl and diclofop activity by 2,4‐D, MCPA, 2,3,6‐TBA and also related ‘non‐auxins’ (3,5‐dichloro‐phenoxyacetic acid and 2,3,5‐TIBA). Diclofop‐methyl was compatible with the 1‐methylheptyl ester of (4‐amino‐3,5‐dichloro‐6‐fluoro‐2‐pyridyl)oxyacetic acid (Dowco 433).The test allows the simultaneous examination of herbicidal responses and related metabolic changes in the oat tissue. As the procedure uses small amounts of chemical, it is suitable for 14C tracer studies and other investigations for v/hich research chemicals are not freely available. The use of the test with other species and other herbicides is discussed, and possible applications for screening for crop safeners and investigations on crop tolerance are suggested.
Screening for resistance to potato cyst nematodes using bioluminescent photometry
Authors: STOREY R. M. J. , MARKS R. J. 
Published: February 2008

SUMMARYThe measurement of the adenosine triphosphate (ATP) content of cysts by bioluminescent photometry has been used as a screen for assessing the resistance of five potato clones to Globodera rostochiensis Rol and G. pallida Pa3. The multiplication rates (Pf/Pi) of the nematodes are based on the ratio of ATP levels for the cyst inoculum and their progeny. These have been compared to the corresponding ratios based on conventional visual counts of eggs and juveniles. The use of recoverable standard volumes of cysts to inoculate pots has allowed an assessment of the unhatched proportion (Cp) of juveniles from the parental cysts by both methods and an estimate of the corrected multiplication rate (P/P^l‐Cp)). This is an accurate assessment of resistance for a clone and the use of standard inocula and the ATP method will enable the criterion adopted for establishing resistance to be measured rapidly and precisely.
Bud‐eating by bullfinches, Pyrrhulapyrrhula in relation to the chemical constituents of two pear cultivars
Authors: GREIG‐SMITH PETER W. , WILSON MICHAEL F. , BLUNDEN CHRISTINE A. , WILSON GILLIAN M. 
Published: February 2008

SUMMARYDamage to pear trees of the cultivars Conference and Doyenne du Cornice caused by Bullfinches feeding on the flower buds was measured during January‐April 1981. Bud‐eating was concentrated on trees near woodland, and occurred at a steady rate within each row, though progressively more rows were attacked. Levels of total soluble protein, free amino acids, starch, glyeeride‐glycerol, fructose, glucose and phosphorus were low until mid March, when the amounts per bud (and concentrations of starch and total soluble protein) rose sharply, coinciding with an increase in the size of buds. Sucrose did not occur at detectable levels. Conference buds contained significantly higher concentrations of fructose and free amino acids than Cornice. The implications for understanding bullfinches' bud‐feeding habits are discussed.
Alarm pheromone secretion by insecticide‐susceptible and ‐resistant Myzus persicae treated with demeton‐S‐methyl; aphid dispersal and transfer of plant viruses
Authors: RICE A. D. , GIBSON R. W. , STRIBLEY M. F. 
Published: February 2008

SUMMARYThe insecticides demeton‐S‐methyl and pirimicarb induced cornicle secretion, and thereby alarm pheromone release, in Myzus persicae. Secretion was earliest in young and insecticide‐susceptible aphids.In laboratory experiments to assess the behavioural significance of this effect, demeton‐S‐methyl applied to colonies of R1 (moderately resistant) aphids killed the majority, but caused the remainder to disperse. The timing and degree of dispersal depended on the size and composition of the colonies. Beet yellows virus was transferred by dispersed aphids, but less frequently when recipient indicator seedlings were treated with demeton‐S‐methyl. R2 (strongly resistant) aphids soon dispersed from colonies containing susceptible nymphs (which secrete alarm pheromone early) and transmitted readily even to treated seedlings.The non‐persistent potato virus Y was transferred by dispersed R: aphids and no protection was afforded by treatment of the seedlings.
Leafhopper transmission of Rhynchosia little leaf, a disease associated with mycoplasma‐like organisms in Jamaica
Authors: DABEK A. J. 
Published: February 2008

SUMMARYLittle leaf disease of Rhynchosia minima (RLL) in Jamaica is reported for the first time. The presence of phloem‐restricted MLO in diseased but not healthy plants, the remission of symptoms induced in RLL‐affected plants with soil drenches of tetracycline, but not penicillin, and the transmission of disease‐associated MLO to R. minima test plants, suggests that RLL has an MLO aetiology. RLL is vectored by the cicadellid leafhopper Ollarianus balli, for which R. minima represents the specific field host. Healthy colonies of O. balli produced from eggs oviposited on the RLL‐immune weed Asystasia gangetica suggest that RLL is not transovarially transmitted. O. balli acquired the RLL agent after access to infected plants for 5 days (shorter feeds were not tried), and there was a maximum latent period in the leafhopper of 21 days. Of the O. balli collected from heavily‐infected field stands of RLL, 35% transmitted the disease, while, of those reared on RLL in captivity for 14–16 days, 56% transmitted. Male and female O. balli transmitted equally efficiently, while nymphs were less frequent vectors. O. balli also infected Cajanus cajan, an important small scale subsistence crop in Jamaica, and Catharanthus roseus. It did not, however, transmit coconut lethal yellowing (CLY) disease to test palms after natural or deliberate acquisition‐feeding on RLL, acquisition‐feeding on CLY‐affected palms, or, after injection with CLY‐affected phloem exudate. There was thus no evidence that RLL is related to CLY or that O. balli can act as a vector of CLY.
A new plant virus from the high jungle of the Eastern Andes; Solanum apical leaf curling virus (SALCV)
Authors: HOOKER W. J. , SALAZAR L. F. 
Published: February 2008

SUMMARYA previously undescribed plant virus, Solanum apical leaf curling virus (SALCV), was found in cultivated potato and indigenous wild solanaceous plants in an area of high jungle near San Ramon, Peru. Symptoms in potato consisting of red, purple or pink discoloration, curling, crinkling and dwarfing of apical leaves develop soon after infection. Symptoms from tuber‐borne infection may also include dwarfing and stunting, dormancy may be prolonged and sprouts may be filiform producing small plants with very thin stems. The virus is transmissible by grafting, but was not transmitted through seed, by aphids or leafhoppers tested, nor by mechanical inoculation of sap. Infected Datura tatula and D. stramonium, the most useful indicator hosts, developed yellowing of the small veins of newly formed leaves followed by distortion, dwarfing, and cupping of subsequently formed leaves. Tomato, Solanum nigrum, Nicandra physalodes and Nicotiana benthamiana were also infected experimentally. N. physalodes, Solanum basendopogon, D. tatula and Physalis peruviana were naturally infected in the field.Antiserum produced in rabbits was suitable for ELISA which detected SALCV in a range of graft‐inoculated and naturally infected plants. Most virus particles in purified preparations and those trapped on antiserum sensitised grids treated with infective sap were c. 52 times 17 nm and consisted of three quasi‐isometric units in a straight chain. This particle morphology although novel, suggests possible affinities with geminiviruses.
Onion pollination by blowflies and honeybees in large cages
Authors: CURRAH LESLEY , OCKENDON D. J. 
Published: February 2008

SUMMARYThree experiments to investigate the effect of pollination by blowflies (Calliphora and Lucilia spp.) and honeybees (Apis mellifera) on seed yield and crossing level were made using a mixture of plants from two open‐pollinated cultivars of onions (Allium cepa) in breeders' cages.No consistent differences were found between pollinators. In two experiments, fly pollination gave significantly higher yields than bee pollination but in the third, bee pollination gave slightly more seed. Crossing between cultivars, assessed by progeny testing on one cultivar, varied between 22‐7 and 55‐9%. Differences in crossing level attributable to the pollinators were not consistent and were not or only just statistically significant, but there were significant and substantial differences between the experiments themselves. Where more umbels were produced by the red‐bulbed cultivar than by the yellow, higher crossing levels were found in the yellow cultivar. The highest crossing levels were found in the only experiment where insects were not introduced until peak flowering time, but where seed yield was comparatively low. Crossing levels were lowest where the umbel numbers were approximately equal.Individual umbels studied showed that while seed set was usually heaviest at and just before the mid‐flowering date, this period could correspond with the lowest levels of crossing during the flowering period, particularly if flowering of the two cultivars was not completely synchronous.In field plots, approximately 75% of crossed seeds sown survived to give harvestable bulbs, but fewer than 50% of selfed seeds did so. In an experiment in which crossing levels from different pollinators were similar but survival levels differed significantly, it was deduced that bees performed more crossing within a cultivar than flies.
Stem‐boring Diptera in perennial ryegrass in relation to fertiliser. I. Nitrogen level and form
Authors: MOORE D. , CLEMENTS R. O. 
Published: February 2008

SUMMARYThe effects of applying nitrogen to a perennial ryegrass sward were studied in relation to the size and nature of populations of dipterous stem‐bores. Two levels of both ammonium sulphate and calcium nitrate were applied to the sward. Larvae were more numerous in the plots treated with high levels of nitrogen regardless of the form applied. Also, there were more larvae in the plots treated with ammonium sulphate than in those treated with calcium nitrate. A limited range of stem‐borer species predominated. These were Oscinella vastator, two forms of O. frit and Geomyza tripunctata. Stem‐borer species were distributed differently between plots receiving high and low nitrogen levels; G. tripunctata occurred almost exclusively on plots receiving high nitrogen applications while O. vastator was more frequent in those receiving low levels of nitrogen.
Isolates of raspberry bushy dwarf virus differing in Rubus host range
Authors: BARBARA D.J. , JONES A.T. , HENDERSON S.J. , WILSON S.C. , KNIGHT V.H. 
Published: February 2008

SUMMARYIsolates of raspberry bushy dwarf virus (RBDV) occurring in the field at East Mailing Research Station (EMRS), and an isolate from raspberry seed imported from the USSR, were found to differ from the Scottish type isolate (D200) of RBDV in that they infected red raspberry cultivars that are resistant, possibly immune, to isolate D200. Of several red raspberry, blackberry and hybrid berry cultivars and EMRS raspberry selections graft‐inoculated with these recently discovered RBDV isolates only two raspberry cvs (Haida and Rannaya Sladkaya) and one EMRS selection did not become infected.Differences in the conclusions reached in two previous studies on the inheritance of resistance to RBDV in raspberry can be explained by the use of virus isolates that differed in Rubus host range.
Cherry leaf roll virus in the female gametophyte and seed of birch and its relevance to vertical virus transmission
Authors: COOPER J. I. , MASSALSKI P. R. , EDWARDS MARY‐LOU 
Published: February 2008

SUMMARYELISA detected cherry leaf roll virus (CLRV) in infected birch leaf sap diluted 1/320 in buffer, in extracts of one infected leaf with nine healthy leaves and in leaf sap frozen for 2 wk. Similarly, ELISA detected CLRV in mixtures of one infected bud with four virus‐free buds. Intensive bioassays and ELISA showed that in some trees CLRV was restricted to only a few branches whereas in others it occurred throughout the tree. The prevalence of CLRV in unmanaged birch populations in Britain was less (3%) than in Midlands street trees (17%).In CLRV‐free birch trees that received pollen from infected ones, ELISA indicated that antigen was introduced into, and multiplied within, the embryos but not the seed coat or the pericarp/wings. In one instance, antigen was detected in a branch of an experimentally pollinated tree but not in those parts of the crown that had been exposed to open pollination. The proportion of seed germinating after crosses in which both parents were CLRV‐free was greater than when either or both parents were infected but the largest difference occurred with infection in the female parent. Few embryos seemed to escape invasion with CLRV when the maternal tissue was naturally infected. Overall, seed transmission ranged between 0 and 38% (mean 17%) when only females in a cross were infected, and between 11 and 75% (mean 30%) when only the males were infected. Assuming no selective advantage that would help infected plants to achieve reproductive age, we found that CLRV would be lost from a birch population within two generations if transmitted only through seed.Embryos in seeds from CLRV‐infected birch that received CLRV‐free pollen differed from their healthy counterparts in being shrunken and suspended in a loosely fibrillar matrix that contained numerous virus‐like particles in tubular inclusions. In two trees, CLRV‐free pollen tended to fertilise a greater percentage of ovules than did CLRV‐infected pollen. Seedlings derived from infected seed and cuttings from naturally‐infected trees grew less rapidly than their healthy counterparts.In still air, most birch pollen liberated from a height of 3·5 m fell within 3 m of the drop zone and none was detected 10 m from the source. Field observations on the patterns of virus spread as measured by seedling infection were consistent; about 3% of seedlings from a tree 6·9 m away from the nearest source of inoculum were infected but no infected seedlings were detected in more distant trees, even though each was experimentally infectible with CLRV and pollen from the infected tree germinated on their stigmas.
Production of polysaccharide‐degrading enzymes by saprophytic fungi from glyphosate‐treated flax and their involvement in retting
Authors: BROWN AVERIL E. , SHARMA H.S.S. 
Published: February 2008

SUMMARYThe fungi present on glyphosate‐treated flax plants were isolated. Cladosporium herbarum, Epicoccum nigrum, Botrytis cinerea and yeasts occurred most frequently immediately after glyphosate treatment but as retting progressed the frequency of occurrence of Fusarium culmorum, Alternaria alternata and a Phoma sp. increased. Many of the fungi isolated from retting flax were also present as epiphytes on healthy flax stems. Glyphosate was shown to be fungitoxic in vitro but it had only a very slight effect on fungi colonising the flax. The application of sucrose and urea to flax 1 wk after glyphosate treatment resulted in more rapid fungal colonisation of the stems, but did not significantly enhance retting.When grown on sterilised flax stem sections, fungi known to be saprophytic on flax produced polysaccharide‐degrading enzymes. All seven fungi tested produced polygalacturonase, pectin‐lyase and xylanase. The greatest cellulase activity was present in stem tissues inoculated with F. culmorum and the Phoma sp. while no cellulase was detected in tissue inoculated with B. cinerea, a Mucor sp. or a Penicillium sp. Extracts from flax inoculated with the cellulolytic fungi caused the solubilisation of native cellulose. Pectinases, xylanase and cellulase were also detected in naturally‐colonised senescing and dead flax stems. Stems which had been treated with a sucrose solution tended to contain the greatest enzyme activity.
Reasons for poor establishment of direct re‐seeded grassland
Authors: MARSHALL A. H. , NAYLOR ROBERT E. L. 
Published: February 2008

SUMMARYThese experiments suggest a number of causes for the poor establishment of direct reseeded grass. An adequate supply of moisture to the seed is of prime importance and burial of trash in drill slits may impair this supply by preventing seed/soil contact directly or by preventing closure of the drill slit.Management techniques which aim to reduce the burden of trash in areas to be sown by direct drilling, usually result in improvements in emergence. This is achieved by improved seed/soil contact, reduced evaporation of water from an open drill slit and lowered probability of phytotoxic leachates being produced. It is possible that benefits might be achieved were it possible to select for sowing seed of proven high vigour, i.e. seed that establishes well in poor conditions.