bluuebunny/crossref_metadata_2025_split huggingface dataset:
Separation of three Rubus‐feeding species of aphid — Sitobion fragariae (Wlk.), Macrosiphum funestum (Macch.) and Amphorophora rubi (Kalt.) (Hemiptera: Aphididae) — by electrophoresis
Authors: LOXDALE H. D. , BROOKES C. P. 
Published: February 2008

SummaryFour species of aphid infest wild and cultivated blackberry (Rubus fruticosus agg., R. lachiatus, etc) and other Rubus species in Britain and Continental Europe, ‐ Sitobion fragariae (Walker), Macrosiphum funestum (Macchiati), Amphorophora rubi (Kaltenbach) and Aphis ruborurn (Bösrner). The nymphs, especially the early instars, of the first three species are fairly difficult to differentiate morphologically. However, they can clearly be separated using electrophoresis. The present paper describes diagnostic enzyme/isoenzyme banding patterns which allow differentiation of the first three species as apterous and alate adults and their instars using two enzymes ‐ carboxylesterase (EST) and phosphatase (PHOS).
Field dissipation of the pyrethroid insecticide/acaricide biphenthrin on the foliage of peach trees, in the peel and pulp of peaches, and in tomatoes
Authors: PAPADOPOULOU‐MOURKIDOU E. , KOTOPOULOU A. , STYLIANIDISM D. 
Published: February 2008

SummaryBiphenthrin was applied in the field to peach trees and tomato plants at rates of 2 and 4 g of biphenthrin a.i., 100 e.c. Talstar (Anon., 1983; FMC, USA)/100 litres of water. During the experimental period, three to four applications were made to peach trees and four to tomato plants at 14‐day intervals. Samples from peach foliage, peaches and tomatoes were collected at set post‐application dates and analysed for biphenthrin residues by GLC.The foliar residues of biphenthrin ranged from 65±1 (maximum to 25± 1 (minimum) ng/cm2 and from 101±52 (maximum) to 35±7 (minimum) ng/cm2 at the low and high rates of application, respectively. The residues of biphenthrin in the peach fruit peel ranged from 1016±367 (maximum) to 247±44 (minimum) ng/g for the low rate and from 2845 (maximum) to 368±15 (minimum) ng/g for the high rate of application. The maximum amount of biphenthrin residues measured in the peach pulp was 47±10 ng/g while at 21‐day after the third application and at 7‐day after the fourth application the residues present were at levels lower than the detection limit (1 ng/g) for the method applied. In whole tomatoes the residues of biphenthrin ranged from 119±14 (maximum) to 31±2 (minimum) ng/g. Plots of 1nC versus t, where C is the amount of biphenthrin ng/cm2 of peach leaf surface or per gram of fruit tissues and t is the post‐application time in days, were constructed and the persistence half‐lives of biphenthrin were calculated.
A cotyledon screen for resistance to scab (Cladosporium cucumerinum) in cucumber (Cucumis sativus) seedlings
Authors: VAKALOUNAKIS D. J. , WILLIAMS P. H. 
Published: February 2008

SummaryAn efficient protocol for differentiating cucumber (Cucumis sativus) seedlings resistant and susceptible to scab (Cladosporium cucumerinum) has been developed by examining the interacting factors of spore density and cotyledon growth stage. The procedure permitted both resistant and susceptible plants to be recovered. Seedlings were grown at 20°C and inoculated 1 day after emergence by placing a 5 μl inoculum droplet (2 × 106 spores/ml) on the newly expanded cotyledons. Seedlings were incubated in a darkened dew chamber for 48 h at 20°C and 100% r.h., and then grown for 6 days at 20°C. Plants could be rated as resistant or susceptible 8 days after inoculation.
Fungitoxic effects of extracts from some West African plants
Authors: AWUAH R. T. 
Published: February 2008

SummaryExtracts from five West African plants were evaluated in vitro for fungitoxicity against Ustilago maydis, Ustilaginoidea virens, Curvularia lunata and Rhizopus sp. Steam distillate from leaves of Cymbopogon citratus completely inhibited the growth of all four fungi, and hot water extracts from fresh leaves of Ocimum gratissimum and Chromoleana odorata, and dry fruits of Xylopia aethiopica, reduced radial growth by 10–60%. A hot water extract from dry fruits of Monodera myrstica was ineffective as a fungitoxicant.
Susceptibility of four hedgerow shrubs to a range of herbicides and plant growth regulators
Authors: MARSHALL E. J. P. 
Published: February 2008

SummaryCrataegus monogyna, Prunus spinosa, Fraxinus excelsior and Sambucus nigra, common woody species of hedgerows, were grown in pots and treated in June with half and full recommended rates of 15 herbicides and three plant growth regulators. C. monogyna was affected by fewest compounds, while the other three species showed differing tolerances. The wild‐oat herbicides, diclofop‐methyl, flamprop‐m‐isopropyl and difenzoquat did not adversely affect the shrubs. Plant growth regulators used at rates recommended for cereals and grassland had only minor effects. Clopyralid killed only S. nigra, while mecoprop, fluroxypyr, chlorsulfuron, metsulfuron‐methyl and glyphosate caused significant damage to most species. Height of C. monogyna was increased after treatment with diclofop‐methyl, difenzoquat, ethofumesate, mefluidide and chlormequat.
Further studies on resistance to Leptosphaeria coniothyrium in the red raspberry and related species
Authors: JENNINGS D. L. , BRYDON E. 
Published: February 2008

SummaryRubus pileatus and its F1 hybrids with raspberry (R. idaeus) were resistant to cane blight (Leptosphaeriu conioth‐yriurn), but little resistance was obtained in subsequent backcross generations apart from a hybrid identified in the second backcross. Two hybrids from backcrossing R. coreanus to raspberry also showed resistance. R. pileatus and its F, hybrids produced hard growth, unlike that of raspberries, which may have been associated with a form of resistance that could not easily be transferred to commercial raspberry cultivars. Some of the genotypes used as parents showed intermediate levels of resistance and it is possible that the highly resistant genotype identified in the second backcross arose from a recombination of genes for resistance. Plants with pubescent canes (gene H) were up to 20% more resistant to mycelial inoculation than those with non‐pubescent canes (gene h), and the percentage of machine‐harvester inflicted wounds with disease symptoms that resulted from natural infection was also less in genotypes with pubescent canes. Many genotypes with intermediate levels of resistance suffered only limited damage from mycelial inoculation and so there are good prospects for breeding cultivars with an effective resistance, despite the limited value of R. pileatus as a donor species.
Leaf and root degeneration in early maturing onions: A physiological disorder
Authors: RABINOWITCH HAIM D. , ZIG URI 
Published: February 2008

SummaryThree onion cvs., four sowing dates, two plant densities and two photoperiod regimes were employed to elucidate the factor(s) responsible for leaf and root degeneration which occur frequently in crops of early maturing onions in the Arava valley, Israel, causing heavy economic losses. It was found that the symptoms developed in early maturing genotypes which showed the abnormal sequence of early bulbing in the autumn, followed by the reversal of bulbing later in the season. At this time of season root regrowth is restrained due to low soil temperatures and therefore mineral and water supply to the sprouting foliage is likely to be limited. These interpretations appear to be correct for the problem has been avoided in several seasons by the prevention of early bulbing by sowing later, by keeping population density at standard rates, and by the prevention of mineral deficiency by application of extra nitrogen.
Phytotoxicity of methyl bromide on chrysanthemum cuttings
Authors: HELYER N. L. , LEDIEU M. S. 
Published: February 2008

SummaryThe phytotoxicity of methyl bromide gas on chrysanthemum cuttings was investigated in relation to gas concentration, length of exposure, temperature, and variety and age of cuttings. Concentrations of 10.5 to 13.5 g/m3 for 4 to 5 h produced a concentration time product (CTP) of 54 g h/m3 which is suitable for safe fumigation of most varieties of chrysanthemum. Length of exposure was not critical up to 5 h. However, fumigations of cuttings which were more than 3 wk old generally caused excessive phytotoxicity and therefore cannot be recommended. There was less damage at temperatures of between 14 and 16°C than at higher temperatures. A table of predictions from a fitted regression equation is included to demonstrate the increased susceptibility of chrysanthemums at higher temperatures and ages of cuttings.
A method for in vitro production of conidia of Elsinoe veneta and the inoculation of raspberry cultivars
Authors: WILLIAMSON B. , HOF LYSBETH , McNICOL R. J. 
Published: February 2008

SummaryConidia of two isolates of Elsinoe veneta were consistently produced in vitro by a 3‐stage culture system in which sparsely sporulating microcolonies produced on corn meal agar were used to ‘seed’ Czapek‐Dox V8 juice agar. E. veneta then sporulated on this medium if dises were floated mycelium uppermost on sterile distilled water for 24 h at 25°C. Both isolates also produced microconidia in vitro.Only the growing apices of raspberry canes were susceptible to infection. Of 12 genotypes inoculated in the glasshouse, a red raspberry derivative of Rubus coreanus, EMRS 2769/9, was the most resistant and the black raspberry selection SCRI 815286 and cv. Malling Delight were the most susceptible. Of four red raspberry cultivars inoculated in the field cv. Malling Orion was the most susceptible. Inoculated flowers and developing fruits produced malformed fruits because infected drupelets were smaller or slower to ripen than uninfected ones.
Purification and some particle properties of anthriscus yellows virus, a phloem‐limited semi‐persistent aphid‐borne virus
Authors: HEMIDA S. K. , MURANT A. F. , DUNCAN G. H. 
Published: February 2008

SummaryAnthriscus yellows virus (AYV), a phloem‐limited virus transmitted in the semi‐persistent manner by the aphid Cavariella aegopodii, was purified by treatment of leaf extracts with cellulasc, followed by differential and sucrose density gradient centrifugation. ‘The preparations contained isometric particles c. 29 nm in diameter which were unstable unless stored in buffer at pH 8.0 containing 1 mM CaCl2,. The particles sedimented as two components, ’full‘ nucleoprotein particles with A260/A280= 1.83 containing about 42% nucleic acid, and ’empty‘ protein shells with A260,/A280= 0.73; their buoyant densities in CsCl solutions were 1.52 and 1.27 g/cm3. Respectively. Yields of ihe nircleoprotein particles were c. 1.75 mg/kg leaf tissue. The particles contained a single species of RNA, of mol. wt 3.6 × 10 “(10 000 nucleotides). Particle protein preparations contained four electrophoretic species, of mol. wt (× 103) 35.0, 28.3, 23.3 and 22.3.C. aegopodii did not transmit AYV from purified preparations. A rabbit injected with AYV preparations produced antibodies that coated AYV particles in electron microscope tests, but gave variable reactions in immunosorbent electron microscopy (ISEM), depending on the composition of the medium. No reactions were obtained in enzyme‐linked inimunosorbent asjay (ELISA). No serological relationship was detected in ISEM between AYV and any of 10 viruses that resembled it in one or more properties.
Host ranges and serological properties of eight isolates of parsnip yellow fleck virus belonging to the two major serotypes
Authors: HEMIDA S. K. , MURANT A. F. 
Published: February 2008

SummaryIsolates of parsnip yellow fleck virus (PYFV) from parsnip (P‐121), celery (CV506 and CV065) and Heracleum sphondylium (Hs2) were serologically close to each other but distant from isolates from carrot (Dc2 and Dc5) and Anthriscus sylvestris (A‐421 and As2), which were in turn close to each other serologically. The two groups of isolates also differed from each other in host range. Minor differences in immunological reactions and in host range and symptomatology were observed between isolates in each group. Particles of all eight isolates had similar RNA and protein compositions. The data confirm that PYFV isolates fall into two major serotypes, those from parsnip, celery and H. sphondylium belonging to the P‐121 serotype and those from carrot and A. sylvestris belonging to the A‐421 serotype.
The comparison of isolation techniques for nematophagous fungi from soil
Authors: BAILEY F. , GRAY N. F. 
Published: February 2008

SummaryUsing a single soil, a comparison was made of six well‐known techniques for the isolation of nematophagous fungi. Each technique was tested for its ability to isolate the fungi present with regard to the number of species recovered, the number of plates needed to be 95% sure of isolating all the species possible and the amount of soil required. The advantages and disadvantages of each method are discussed. The results show that specific techniques are required for the isolation of endoparasites and predators respectively. The soil sprinkling technique and the Baermann funnel technique are shown to be the most efficient methods overall, with six and seven replicates required for 95% probability of isolating all the predator and endoparasite species respectively.
On insect‐plant associations in agriculture and the selection of agents for weed biocontrol*
Authors: DENNILL G. B. , MORAN V. C. 
Published: February 2008

SummaryHokkanen & Pimentel (1984) proposed a novel approach for the selection of biocontrol agents. They advocated the selection of agents from a relative of the weed plant rather than from the target weed species itself. The new relationship that such agents would have with the weed would be characterised by a relative lack of homeostasis compared with the old herbivore‐plant associations traditionally used in weed biocontrol, and would consequently be more effective. There are few examples to support these contentions because of the traditional use of old herbivore‐plant associations in weed biocontrol.In the present study, herbivore‐plant associations in agricultural situations, which are analogous to agent‐weed associations, are examined to assess the potential of new associations for weed biocontrol. The herbivores on 14 introduced crop plants which have salient similarities to the major weeds in the south‐western Cape were surveyed: (a) 68% of the 188 insect and mite herbivores are indigenous species in new associations with these host plants, and (b) of the five most damaging pests on each of 13 of the crop plants, 53% are in new associations with the plants. Of the 40 most important agricultural pests in South Africa, 58% are in new associations, confirming these results. About 50% of the insect and mite herbivores in new associations with their host plants are oligophagous, indicating that new associations are not necessarily characterised by polyphagy and hence unsafe for use in weed biocontrol.We conclude that new associations between herbivore species and host plants have strong potential in weed biocontrol because (a) their frequency in agriculture indicates that they can easily be established in weed biocontrol situations, (b) they are as damaging as old associations and (c) they are not necessarily unsafe as regards host specificity. We therefore advocate the use of both the classical approach and that of Hokkanen & Pimentel (1984). Our support for Hokkanen & Pimentel (1984) is, however, based on evidence and rationale clearly different to theirs, and we provide novel guidelines, which can be routinely and practically applied in the selection of agents for weed biocontrol.
Lipid profile of Pleurotus sajor caju
Authors: NAIR N. G. , SONG C. H. , JIANG J. Y. , VINE J. H. , TATTUM B. , CHO K. Y. 
Published: February 2008

SummaryThe lipid profile of Pleurotus sajor caju was studied in relation to mycelial and sporophore growth and different cultural factors. The growth was characterised by lipid synthesis during mycelial growth and utilisation during sporophore growth. The degree of instauration increased during mycelial growth and decreased during sporophore formation. The fatty acid composition of mycelium and sporophore was similar, linoleic acid (C18:2) being the most dominant acid in both. C:N ratio had a significant (P<0.05) positive effect on mycelial dry weight; however, per cent total lipids was similar. Non‐polar lipids became more unsaturated as the temperature was raised from 10° to 25°C and pH from 3.0 to 6.0, but declined when the cultures were aerated. Mycelial dry weight increased significantly (P<0.05) when the liquid medium was supplemented with lipids. In general, fatty acids with carbon chain length C16 and C18 stimulated the growth of mycelium. Supplementation of solid substrate (cotton seed hulls) with safflower oil, soybean oil or rice bran significantly (P<0.05) increased the yield of sporophores. Total lipids and ratio of non‐polar to polar lipids were not affected by lipid supplementation.
Relationships between indices of seed maturity and carrot seed quality
Authors: STECKEL JOYCE R. A. , GRAY D. , ROWSE H. R. 
Published: February 2008

SummaryCarrot seeds cvs Chantenay and Amsterdam were harvested on several occasions from crops grown in 1985 and 1986, from the time they had reached or were close to their maximum dry weight and were starting to turn brown.Maximum seed dry weight occurred approximately 40–45 days after flowering (DAF) in both cultivars. Maximum germination (International Seed Testing Association 14‐day count) occurred 40 and 55 DAF in cvs Chantenay and Amsterdam, respectively, but the maximum 7‐day count and the minimum coefficient of variation of embryo length did not occur until 60 DAF in cv. Chantenay and 55 to 65 DAF in cv. Amsterdam. Percentage germination was negatively and linearly related to seed moisture content, chlorophyll a + b content in the seed coat and seed distortion, measured on a modified tensile‐testing machine, the relationships accounting for 77, 71 and 64% of the variance in the 7‐day germination count, respectively. The corresponding values for the 14‐day count were 63, 61 and 50%. A simple field test for monitoring seed maturity is proposed.
The effects of different external nitrate concentrations on growth of Phaseolus vulgaris cv. Seafarer at chilling temperatures
Authors: ANDREWS M. , LOVE B. G. , SPRENT J. I. 
Published: February 2008

SummaryThe effects of different applied nitrate concentrations (1 to 50 mol m3) on growth of Phaseolus vulgaris cv. Seafarer at temperatures around 15°C was examined. Total plant dry weight and carbon content decreased sharply with increased applied nitrate 1 to 10 mol m‐3 then decreased slightly with further increases in applied N. Total plant reduced ‐N content increased sharply with increased applied nitrate concentration from 1 to 5 mol m‐3, changed little with increased applied nitrate from 5 to 25 mol m‐3, then increased when applied nitrate was increased from 25 to 50 mol m‐3. Nitrate concentration in all tissues increased sharply with applied nitrate increased from 1 to 10 mol m3 and showed a further increase at 50 mol m3 applied nitrate.Fresh weight to dry weight ratio for all leaves and specific leaf area for all secondary leaves increased sharply with applied nitrate concentration from 1 to 5 mol m‐3 then decreased with applied nitrate 25 to 50 mol m3 Secondary leaf chlorophyll concentration decreased sharply when applied nitrate increased from 1 to 5 mol m‐3 but increased with applied nitrate from 25 to 50 mol m‐3. Initially, the rate of leaf extension was greater at 20 mol m‐3 applied nitrate than 1 mol m‐3 applied nitrate.It is proposed that decreased growth with increased applied nitrate in the range 1 to 10 mol m‐3 is due to increased leaf damage caused by a greater rate of leaf expansion.
A procedure for isolating Pyrenochaeta terrestris from onion roots
Authors: AWUAH R. T. , LORBEER J. W. 
Published: February 2008

SummarySurface sterilised stelar tissues from onion roots exhibiting typical pink root symptoms were plated on water agar and incubated under cool white fluorescent light (CWFL) for 12 h day‐1 at 20°C. After 4–5 days, the plates were examined with the 10† objective of a compound microscope and tissues producing conidia of Fusarium spp. were discarded. Sub‐cultures of isolates suspected to be Pyrenochaeta terrestris, grown from Fusarium‐negative tissues, were transferred to chloroamphenicol‐amended (500 ppm) corn‐meal (CCMA) agar plates and incubated at 24°C under CWFL for a further 10–14 days. Cultures with setose pycnidia were identified as P. terrestris. Plates were again scanned for conidia of Fusarium spp., and cultures negative for Fusarium spp., but not producing pycnidia, were suspected to be P. terrestris. These were compared with known isolates on CCMA. On this medium growth of P. terrestris was slow, producing appressed, pinkish colonies which were circular with a smooth margin. All isolates of P. terrestris isolated by the procedure caused pink root of onion when tested, whereas none of the Fusarium spp. isolated produced the disease. However, a mixed inoculums of P. terrestris and Fusariurn solani produced typical pink root symptoms.
The overwintering of cereal aphids on Gramineae in southern England, 1977–1980
Authors: HAND S. C. 
Published: February 2008

SummaryCereal aphids were sampled monthly on graminaceous host plants on farmland in Hampshire, UK from September 1977 to April 1980. Sitobion avenae overwintered anholocyclically on most types of Gramineae, particularly seedling grass crops and small‐grain cereals. S. fragariae was probably mainly holocyclic on Rubus spp. Large summer populations of Metopolophium dirhodum were probably derived from holocyclic colonies on roses. M. festucae (subsp. cerealium) appeared to overwinter only anholocyclically, and was found mainly on mature grass crops and grasses in hedgerows. Rhopalosiphum padi was the most numerous species in autumn and overwintered anholocyclically in all three winters studied. R. insertum and R. maidis were rare and did not appear to survive the winter anholocyclically on graminaceous hosts.
Validation of models that predict the peak density of grain aphid (Sitobion avenue) and yield loss in winter wheat
Authors: CARTER N. , ENTWISTLE J. C. , DIXON A. F. G. , PAYNE J. M. 
Published: February 2008

SummaryAphid counts and yield results from a three‐year field trial of the effectiveness of insecticides applied at various growth stages of winter wheat, were used to test the accuracy of the predictions of the Entwistle and Dixon (1986, 1987) models for forecasting aphid damage and population growth. In general, the peak aphid populations of Sitobion avenae and damage were not accurately predicted but the spray recommendations, which would have resulted from the predictions, would have been correct in each of the three years; one outbreak and two non‐outbreak years. In particular the effectiveness of early spraying was over‐estimated because the persistence of the effect of insecticides was over‐estimated. It is recommended that further work be done on the rate of development of aphid populations following application of insecticides.