bluuebunny/crossref_metadata_2025_split huggingface dataset:
Field evaluation of a tunnel sprayer and effects of spray volume at constant drop size on spray deposits and efficacy of disease control on apple
Authors: Cross J V. , Berrie A M. 
Published: February 2008

SummaryAn air assisted tunnel sprayer (the Noric Joco EX2) incorporating CDA rotary atomisers (Volume Median Diameter (VMD) =c. 140 μm, volume rate = 50 litre ha‐1 forward speed = 3.9 km h‐1) gave at best equal but in some cases significantly poorer control of apple powdery mildew and scab than the standard commercial practice of spraying with an axial fan sprayer with Micron XI rotary atomisers (VMD =c. 90 μm, volume rate = 50 litre ha‐1, forward speed = 7.2 km h‐1). Approximately 30% of the spray volume applied was collected for recycling with the tunnel sprayer. Increasing spray volumes at approximately constant drop size (c. 140 μm) from 50 to 100 to 200 litre ha‐1 with the tunnel sprayer consistently improved efficiency of mildew and scab control. Bulk spray deposits on leaves, and their gross distribution in the tree, was similar with the different spraying methods and volumes. The mean percentage leaf area covered with spray deposit increased with spray volume as did the number of spray deposits per unit area. The tunnel sprayer at 50 litre ha‐1 gave a similar though less variable mean level of cover than the axial fan sprayer at the same volume rate. It gave 2–3 times more cover on upper than on lower leaf surfaces. The axial fan sprayer gave approximately equal cover on upper and lower leaf surfaces.The main limitations of the tunnel sprayer were its slow maximum forward speed and the restricted tree size and shape on which it can be used.
Chemical control of vine weevil larvae on container‐grown hardy ornamental nursery stock 1986–1989
Authors: Cross J V. , Buxton J H. , Jacobson R. , Richardson D M. 
Published: February 2008

SummaryIn a search for alternatives to the former standard aldrin compost incorporation treatment for control of vine weevil (Otiorhynchus sulcatus) larvae on container‐grown hardy ornamental nursery stock, a series of 87 tests of insecticides were done at four experimental centres of the ADAS (Leeds, Reading, Wolverhampton and Wye) from 1986 to 1989. Insecticidally‐treated plants and untreated controls were artificially infested with vine weevil eggs at varying intervals before and after treatment, and the survival of the pest was assessed. Aldrin treatment gave consistent and excellent preventive control of vine weevil larvae for over 2 years. Of the candidate materials tested, a slow‐release granular formulation of chlorpyrifos incorporated into compost at a dose rate of 100 g a.i. m‐3 of compost gave good control for up to 34 wk after treatment (the longest period evaluated) and a micro‐encapsulated slow release formulation of fonofos incorporated at a dose rate of 43.3 g a.i. m‐3 usually gave good control for up to two years (the longest period evaluated). Surface applications of these two organophosphates or of carbofuran granules, though sometimes effective, were unreliable as either preventive or remedial treatments even for short term control.
Tolerance of antibiotic and susceptible cereal seedlings to the aphids Metopolophium dirhodum and Rhopalosiphum padi
Authors: Lamb R J. , Mackay P A. 
Published: February 2008

SummarySome cereal seedlings exhibit antibiotic and antixenotic resistance to the aphids Metopolophium dirhodum (Walker) and Rhopalosiphum padi (L.), because the seedlings contain hydroxamic acids or gramine. The association between tolerance to aphids and aphid antibiosis was investigated for three cereals, Dollarbird wheat Vulcan wheat and Yagan barley. The dry biomass gained by the aphids and the simultaneous reduction in the biomass of the plants (biomass conversion ratio) quantified tolerance. Biomass production and the density dependence of biomass production by the aphids quantified antibiosis more effectively than fecundity. Vulcan wheat, which has more hydroxamic acid than Dollarbird wheat showed the highest level of antibiosis, and the barley was not antibiotic for either aphid. The biomass conversion ratio was a constant; the biomass of an infested plant was reduced by 3 mg for each mg of aphid biomass gained, regardless of aphid species, plant cultivar, or aphid density. The three plants showed no differential tolerance to the aphids, and therefore tolerance is not associated with antibiosis in this case.
Physiological determinants of genotypic differences in carbon isotope discrimination in potato grown in well‐watered conditions
Authors: Jefferies R A. 
Published: February 2008

SummaryCarbon isotope discrimination (A), leaf conductance (gs), photosynthetic capacity, and plant growth were measured in well‐watered, glasshouse‐grown potato plants of clones from a cross made between diploid Solanum tuberosum and Solanum vernei. Clones showed significant differences (P < 0.001) in gs, Δ, stomatal density, root growth, and total dry matter production. Carbon isotope discrimination of genotypes was positively correlated (P < 0.001) with gs. There was no correlation between gs and stomatal density indicating that differences in gs reflected differences in stomatal aperture. Differences in rooting characteristics or in root/shoot ratio did not contribute to differences in gs or A. Genotypic differences in photosynthetic capacity were not statistically significant, and there was no correlation between A and photosynthetic capacity. Total dry matter production and A were positively correlated (P < 0.001) when differences in the time of plant emergence were included in the regression model.It is concluded that differences in A among potato genotypes is largely determined by gs, but confounding of gs and photosynthetic capacity reduces genotypic variation in A compared with that in gs. Total dry matter production is largely determined by processes other than carbon assimilation rate per unit area in individual leaves. Effective use of A as a character for selection in plant breeding depends on elucidating the effects that differences in stomatal characteristics have on crop production both in well‐watered and in water‐limited crops.
A method to test compounds for feeding deterrence towards redlegged earth mite (Acarina: Penthaleidae)
Authors: Ridsdill‐Smith T J. , Jiang Y. , Ghisalberti E L. 
Published: February 2008

SummaryA bioassay, based on a membrane sachet technique, has been developed to identify antifeeding compounds affecting the redlegged earth mite, Halotydeus destructor (Acari: Penthaleidae). The method consists of counting H. destructor numbers on membrane sachets in choice experiments, which was quicker and more efficient than weighing the mites. Five per cent aqueous glucose solution was used as a feeding stimulant, with Tween 80® at 5% concentration as a solubilising agent for water‐insoluble compounds. (+)‐Catechin, rutin, biochanin A, formononetin, chlorogenic acid, and gramine acted as feeding deterrents at 1% concentration. Quercetin (1 %) and azadirachtin (100 ppm) had no significant effect. At lower concentrations (0.01%), compounds showed antifeeding (gramine), phagostimulating (quercetin and chlorogenic acid), or no effects on mite numbers. Dose‐dependent deterrent effects of plant extracts were demonstrated with the bioassay, which could be used for other mites.
Detection of pineapple bacilliform virus using the polymerase chain reaction
Authors: THOMSON K G , DIETZGEN R G , THOMAS J E , TEAKLE D S 
Published: February 2008

Summary.A polymerase chain reaction (PCR) assay has been developed to detect pineapple bacilliform virus (PBV) in extracts from infected plants. Initially, degenerate primers were designed from conserved badnavirus amino acid sequences and used in PCR with partially purified PBV preparations. A 448 bp DNA fragment was amplified from a region in the reverse transcriptase and ribonuclease H genes. The nucleotide sequence of the cloned PCR product indicated that PBV was related to, but distinct from, other badnaviruses. Specific primers designed from the PBV sequence yielded a 403 bp fragment when used in PCR with extracts from infected pineapple plants, but not from plants infected with sugarcane bacilliform or banana streak viruses (genus Badnavirus). The specificity of the PCR product was confirmed by Southern hybridisation using a digoxigenin labelled DNA probe. PBV appears to be present in all pineapple growing areas along the east coast of Australia. PBV was detected in plants grown from seeds, plants propagated through meristem tip culture and in mealybugs which were collected from infected plants. PBV was detected in crown, leaf and root tissue from infected pineapple plants. PCR results of all field‐infected samples were confirmed by immunoelectron microscopy.
Costs and benefits of hydroxamic acids‐related resistance in winter wheat against the bird cherry‐oat aphid, Rhopalosiphum padi L.
Authors: GIANOLI E. , PAPP M. , NIEMEYER H M 
Published: February 2008

Summary.Estimations of infestation by the bird cherry‐oat aphid (Rhopalosiphum padi) as well as measurements of grain yield in 26 Hungarian winter wheat cultivars under field conditions were correlated with the concentration of hydroxamic acids (Hx) in seedlings of those cultivars. The significant inverse relationship between infestation ratings and Hx levels in wheat showed that Hx, despite their decreased accumulation at later plant phenological stages, may be able to confer resistance against aphid infestation in the field. Since no significant relationship was found between grain yield and Hx levels in plants it is suggested that Hx accumulation does not impose a cost to the plant in terms of yield. These findings support earlier claims stressing the potential of Hx as breeding targets for aphid resistance in wheat.
Relationships of wheat quality with climate and nitrogen application in regions of England (1974–1993)
Authors: SMITH G P , GOODING M J 
Published: February 2008

Summary.Region x year means for crude protein concentration (CP) and Hagberg falling number (HFN) from the Home Grown Cereals Authority (HGCA) surveys were modelled using mean daily temperature, rainfall and nitrogen application. A model accounting for 78.6% of the variation in CP incorporated positive coefficients for mean daily temperature (25 June to 15 July), nitrogen applied to the crop, and early summer rainfall (28 May to 8 July), and a negative coefficient for spring rainfall (5 March – 27 May). For CP there was no statistical evidence that fitting one regression for all regions was significantly worse than fitting individual lines for each of the 10 regions. A model describing 67.1% of the variation in HFN incorporated a negative coefficient for August rainfall and positive coefficients for mean June temperature, mean August temperature and nitrogen applied to the crop. There was statistical evidence that fitting separate lines for certain regions was justified.
Radiation interception and modelling as an alternative to destructive samples in crop growth measurements
Authors: WILLIAMS J H , RAO R C NAGESWARA , DOUGBEDJI F. , TALWAR H S 
Published: February 2008

Summary.Growth analysis presently uses destructive samples to detect temporal variations in biomass. The destructive nature of the measurements, their cost, and statistical considerations limit the application of growth studies in many domains of crop science. In contrast radiation interception data are cheap and easy to obtain without destruction of experimental material. Biomass may be modelled as the product of cumulative radiation intercepted by the crop [ΣI] and a radiation use efficiency coefficient [e]. Therefore, in theory, an alternative to destructive samples is provided by measurement of I at intervals during growth and e. The success of this approach depends on the validity of the value of e and its constancy through time. With measurement of I at intervals the mean radiation use efficiency [Σ] can be estimated from the seasonal ΣI and the final harvest data. The Σ can then be used with the time series data for ΣI to estimate the biomass for that plot for any date. To test this approach model‐derived biomass data were compared with data from destructive samples at seven dates for six groundnut germplasm lines grown in water limiting and fully irrigated conditions. The model‐derived data was consistently less than destructively obtained data when the plants were small. This bias was an artifact of the interception measurement technique used not being accurate for small plants. Once plants were tall enough for fractional interception to be measured without substantial error, the nondestructive method effectively described the growth of the well‐watered crops. For the drought treatments, it was less effective. However, by dealing with the phases of growth separately, good correlation between the two methods was achieved. An important assumption in the method is that the final harvest biomass is a realistic reflection of the preceding growth, since the model method forces the estimates of growth to that point. In one germplasm line this assumption was not valid and the model‐based method did not match the sampled biomass data.
Influence of wheat and oat cultivars on the development of the cereal aphid parasitoid Aphidius rhopalosiphi and the generalist aphid parasitoid Ephedrus plagiator
Authors: FUENTES‐CONTRERAS J E , POWELL W. , WADHAMS L J , PICKETT J A , NIEMEYER H M 
Published: February 2008

Summary.The effects of three wheat cultivars and two oat cultivars on the development of the cereal aphid parasitoid Aphidius rhopalosiphi De Steph. and the generalist aphid parasitoid Ephedrus plagiator (Nees) (Hymenoptera: Braconidae) were evaluated in the laboratory. The level of hydroxamic acids, a family of secondary metabolites that can affect the mean relative growth rate of cereal aphids in cereals, were measured in the different cultivars. The parasitoids were reared in Sitobion avenae (F.) (Homoptera: Aphididae), using plants grown under greenhouse conditions. A. rhopalosiphi showed a longer developmental time on wheat relative to oat cultivars. This effect was accounted for by a significant increase in the time from oviposition to pupation (mummy formation), while the duration of the pupal stage remained constant between treatments. No further effects were observed in other variables evaluating A. rhopalosiphi performance, such as adult longevity, adult body weight and secondary sex ratio. The generalist E. plagiator did not show significant differences in any of the variables analysed, both between cultivars and cereal species. Hydroxamic acids levels correlated negatively with mean relative growth rates of S. avenae, but positively with the observed developmental time of A. rhopalosiphi. The results are discussed in terms of tritrophic effects and the development of breeding programmes trying to improve plant resistance to aphids.
Observations on the maintenance and measurement of soil water in simple pot experiments and its effects on seed‐borne Fusarium culmorum seedling blight of winter wheat
Authors: HARE M C , PARRY D W 
Published: February 2008

Summary.A simple method for maintaining and measuring soil water and the relationship between soil water and seed‐borne Fusarium culmorum seedling blight of wheat was investigated under controlled environmental conditions to develop reproducible assay conditions for epidemiological studies and the testing of fungicide seed treatments. For reproducibility, soil matric potential (ψm) was used to define soil water, and a range of watering regimes were tested. Treatments were watered to either a maximum ψm or to maintain a mean ψm in order to establish which parameter best described the effect that soil water had on the incidence of disease symptoms. The severity of disease symptoms was closely related to the mean soil water status and not the maximum ψm value. Watering intervals, ranging from three times a day to once every three days, did not affect this relationship. The percentage of seedlings showing symptoms after emergence (i.e. localised or extensive necrotic lesions) was inversely related to the mean ψm. With increasing soil dryness (mean ψm from ‐0.14 MPa to ‐0.17 MPa) the percentage of seedlings with post‐emergence symptoms decreased from 50% to 20%. However, as the mean ψm changed from ‐0.14 MPa to ‐0.17 MPa the percentage of seedlings dying before emergence increased from 25% to 55% in direct proportion to ψm. Overall the incidence of infection as indicated by the total number of seedlings showing symptoms either before or after emergence remained relatively constant, and was not significantly related to mean ψm.
Transmission of tomato spotted wilt virus by Frankliniella occidentalism median acquisition and inoculation access period
Authors: WIJKAMP I. , WETERING F VAN DE , GOLDBACH R. , PETERS D. 
Published: February 2008

Summary.To quantify the transmission of tomato spotted wilt virus (TSWV) by Frankliniella occidentalis, the median acquisition access period (AAP50) and median inoculation access period (IAP50) were determined. These parameters were established using transmission rates obtained after AAPs and in IAPs which both ranged from 5 to 2560 min. An AAP50 of 106 min was found when larvae acquired virus from TSWV‐infected Impatiens plants. IAP50s of 58 or 137 min, respectively, were calculated when petunia or Datura stramonium leaf disks were used to test the inoculation efficiency of viruliferous thrips. The virus could successfully be acquired or inoculated in periods of 5 min. Transmission reached an optimum after an AAP of 21.3 h (AAPopt) and in an IAP of 42.7 h (IAPopt). These results show that TSWV can be acquired and transmitted efficiently by F. occidentalis in short feeding periods.
Resolution of natural hatching factors for golden potato cyst nematode, Globodera rostochiensis
Authors: DEVINE K J , BYRNE J. , MAHER N. , JONES P W 
Published: February 2008

Summary.The hatching responses of Globodera rostochiensis (golden potato cyst nematode) to purified and partially‐purified preparations of natural (including the potato glycoalkaloids solanine and α‐chaconine) and artificial hatching factors (HFs) were bimodal. At least 10 HFs, mostly anionic, were resolved from potato root leachate by a combination of gel permeation and ion‐exchange chromatography. Whereas potato roots were the principal source of HFs, haulm leachate also contained such chemicals. Root leachate from aseptically‐grown potato plants lacked several HFs which were present in conventionally‐produced leachate.
Control of Chenopodium album by soil application of Ascochyta caulina under greenhouse conditions
Authors: KEMPENAAR C. , WANNINGEN R. , SCHEEPENS P C 
Published: February 2008

Summary.Effects of soil application of Ascochyta caulina spores on seedlings of Chenopodium album and five cultivated plant species were investigated under greenhouse conditions as a part of a study on biological control of C. album.Application of A. caulina spores to soils resulted in disease development on C. album and to a lesser degree on Spinacia oleracea seedlings, but not on Beta vulgaris subspecies vulgaris, Zea mays, Triticum aestivum and Pisum sativum seedlings. Affected C. album seedlings had an abnormal olive‐green colour or necrotic spots on cotyledons and hypocotyls, and were stunted or died. Affected S. oleracea seedlings were pale in colour or had necrotic spots on the cotyledons, but did not die. Time courses of disease incidence and of mortality of C. album could be described by a monomolecular model. Effects of spore density, sowing depth, soil water content, soil type and time of sowing on disease development were examined. Disease incidence and mortality were influenced by spore density, soil water content and soil type, but not by sowing depth. Spores in a moist soil maintained infectivity at least 2 wk. Spore densities of 109 to 1010 spores m‐2 were required for 50% mortality of emerged C. album plants.Aspects of the development of A. caulina into a soil‐applied mycoherbicide are discussed.
Removal trapping to controlArtioposthia triangulata
Authors: BLACKSHAW R P , MOORE J P , ALSTON R. 
Published: February 2008

Summary.Removal trapping was used to try and reduce numbers of the predatory planarianArtioposthia triangulatain polythene tunnels on a nursery and a grass field. Ten months of trapping in the tunnels failed to have any impact upon flatworm numbers but weekly catches reduced over a period of 12 weeks' trapping in grassland. The calculated residual population in the grassland (40 ha‐1) was small in comparison with that estimated from formalin sampling (940 × 1288 ha‐1). A separate field study examined the effect of trap density on catch by spacing traps at 2.5, 5, 10 and 20 m intervals. This showed that the numbers of planarians caught was inversely related to the logarithm of trap spacing. It is concluded that removal trapping is too demanding of resources to be a viable control option for this pest in commercial and agricultural situations.
Phytotoxin production by Alternaria linicola and phytoalexin production by the linseed host
Authors: EVANS N. , MCROBERTS N. , HILL R A , MARSHALL G. 
Published: February 2008

Summary. Alternaria linicola produced a wide range of secondary metabolites when grown in a defined culture medium. Reverse phase chromatography fractions produced disease‐like symptoms on linseed cultivars and a range of non‐host species indicating the presence of phytotoxic components. Characterised via thin layer chromatography, these included the non‐host specific phytotoxins tenuazonic acid, alternariol monomethyl ether, tentoxin and two destruxin‐type compounds (which closely resembled destruxin A and destruxin B). The identity of four of the compounds was confirmed by two dimensional thin layer chromatography and proton nuclear magnetic resonance spectroscopy. In a second experiment, Linum leaf material infected with conidia of A. linicola and blastospores of Melampsora lini was extracted using a facilitated diffusion extraction technique. The resultant extracts contained a number of compounds which were fungitoxic to Cladosporium cladospiroides and, to a lesser extent, Alternaria brassicicola. One such compound corresponded to the phytoalexin coniferyl alcohol. Quantitative differences in the amount of the fungitoxic compounds produced between the inoculated and uninoculated resistant and susceptible host genotype combinations suggested that the production of fungitoxic compounds was greater in response to attempted colonisation. On this basis it is proposed that phytoalexin production is a component of the resistance reaction. The results from these investigations are discussed in relation to recent research on the ecology of the pathogen and the possible roles of phytotoxin production by the pathogen and phytoalexin production by the host on disease development.
Effects of foliar applications of fungicides during plant growth on grain development and grain germinability in spring barley
Authors: COCHRANE M P. 
Published: February 2008

SummaryIn 1990 and 1991 grain samples of spring barley were obtained from plots in which fungal diseases were controlled until ear emergence using fungicide sprays, and from comparable plots which had received no fungicide applications. The grain was stored at 10oC, and tested for germination at intervals during storage. Grain from plots treated with fungicide consistently exhibited more dormancy than grain from untreated plots. In 1992, grain development was monitored from anthesis to harvest‐ripeness in treated and untreated plots of cvs Blenheim, Camargue and Tyne. In cvs Blenheim and Camargue, grains in fungicide‐treated plots had a greater dry weight at harvest‐ripeness, and dehydrated later in development than grains in untreated plots. Neither of these differences was observed in cv. Tyne. Possible interpretations of the effects of fungicide treatment of the parent plant on the physiology of the grain are discussed.