bluuebunny/crossref_metadata_2025_split huggingface dataset:
Control of slugs with contact‐action molluscicides
Authors: HENDERSON I. F. , MARTIN A. P. 
Published: February 2008

SummaryA number of iron and aluminium compounds were compared as contact‐acting poisons against the slug Deroceras reticulatum, by confining slugs on treated surfaces of glass and wet soil in laboratory tests. Simple metal salts were effective poisons when applied to a glass surface, but were rapidly inactivated when applied to wet soil. Chelation of both metals with organic ligands retarded the rate of attenuation on wet soil. In a field trial D. reticulatum and Arion spp. slugs were killed by a broadcast application of the chelate iron (III) 2,4‐pentanedionate applied at 40 kg a.i. ha‐1.
The effects of lodging and a paclobutrazol — chlormequat chloride mixture on the yield and quality of oilseed rape
Authors: BAYLIS A. D. , WRIGHT I. T. J. 
Published: February 2008

SummaryThe effects of lodging and a plant growth regulator mixture on oilseed rape cv. Ariana were studied in three field experiments. Natural and artificially induced lodging treatments varying in time of imposition and severity were compared to a supported control. A mixture of paclobutrazol and chlormequat chloride was applied either as a spray or as paclobutrazol granules followed immediately by a chlormequat chloride spray.In 1987, severe lodging treatments reduced yield by up to 52%. Yield penalties varied with the time at which lodging was imposed. Yield was inversely correlated with the ground cover of volunteers growing from shed seed under lodged crops.In 1988, two experiments showed increased incidence of disease and decreases in seed yield and quality in lodged crops. Yield reductions were related to the severity of lodging. Lodging decreased oil contents and increased glucosinolate levels. PGR treatments reduced lodging and maintained yield at a level not significantly different to a supported control treatment. Oil contents were also similar in seed from PGR treated and control plots. Glucosinolate levels in PGR treated seed were similar to control levels in one experiment and intermediate to those from control and artificially lodged plots in another experiment.The results are discussed in relation to the use of PGRs to prevent lodging in ‘double zero’ varieties of oilseed rape, and the potential losses from using ground vehicles to apply pesticides after flowering.
Measurement and classification of genetic diversity in okra (Abelmoschus esculentus)
Authors: ARIYO O. J. 
Published: February 2008

SummaryEighteen accessions of okra of diverse ecological background were evaluated for genetic variability through the techniques of coefficient of racial likeness (CRL) and principal coordinate analysis (PCO). The variation patterns among the accessions were classified by using the techniques of metroglyph analysis and single‐linkage cluster analysis. CRL and PCO produced similar results on the diversity of the accessions but the grouping of the accessions by metroglyph analysis and SLCA produced different results. The usefulness of metroglyph analysis depends on the amount of variation accounted for by the two principal characters on which the two co‐ordinate axes are constructed. The techniques are compared.
Influence of drought and flowering on growth and water relations of perennial ryegrass populations
Authors: THOMAS H. , EVANS C. 
Published: February 2008

SummarySpring‐sown (vegetative) and autumn‐sown (flowering) swards of Lolium perenne cvs Melle, Aurora and their hybrid growing in 0.9 m deep bins of soil in the glasshouse were compared, a) as drought progressed from June to August 1986, and b) after cutting, fertilising and re‐watering.During drought, vegetative plants produced more herbage, had initially higher leaf extension rates, had longer and wider leaves, maintained more tillers, had lower mortality, adjusted osmotic potential more effectively and had stomata less sensitive to stress than did flowering plants. On re‐watering, previously stressed flowering plants regrew more slowly than the irrigated controls, whereas previously stressed vegetative plants regrew more rapidly than the controls.Aurora was the most drought‐resistant population, mainly because of low tiller death rates. The hybrid tended to have the lowest leaf water potentials and conductances and grew poorly during drought. Possible underlying physiological mechanisms are discussed.
Uptake of 14C‐gibberellic acid by mature grapefruit (Citrus paradisi Macf.) as affected by relative humidity and method of application
Authors: GREENBERG J. , GOLDSCHMIDT E. E. 
Published: February 2008

SummaryEffects of the method of application and relative humidity on the uptake of 14C‐gibberellic acid (14C‐GA3) by mature grapefruit (Citrus paradisi Macf.) were examined. Uptake was higher when 14C‐GA3 was applied as a ‘drying‐out’ solution than as a ‘non‐drying’ solution. When 14C‐GA, was applied by the ‘drying‐out’ method, which closely imitates field conditions, rates of uptake were very high while the solution was drying out and during the first few hours after drying. Uptake from the dry residue continued in decreasing rates till the end of the experiment (72 h). Uptake from the dry residue was higher when fruits were incubated at 100% than at 50% relative humidity (RH). Transfer of fruits from 50% to 100% RH as late as 48 h after drying still increased the rate of uptake. Drying‐out treatment solutions produced higher uptake rates with neutral (pH 7) as well as acid (pH 4) treatment solutions, and in the presence of triton B‐1956, Triton X‐100 or L‐77 surfactants.
Free amino acid content of phloem sap from Brassica plants in relation to performance of Lipaphis erysimi (Hemiptera: Aphididae)
Authors: WEIBULL J. , MELIN G. 
Published: February 2008

SummaryCultivars of Brassica juncea, B. napus and B. campestris, differing in host‐suitability to the mustard aphid (Lipaphis erysimi pseudobrassicae Kalt.), were analysed for their phloem sap content of free amino acids. Sap was collected from excised mustard aphid stylets and analysed by means of high performance liquid chromatography. Aspartic and glutamic acid were, together with glutamine, the dominating amino acids. All plants had very little glycine, γ‐aminobutyric acid (GABA), methionine and tryptophan in their sap. This amino acid pattern closely resembled that of cereals. The total concentration and the individual composition of amino acids were not found to be related to the level of aphid resistance previously found in the investigated Brassica species. However, one B. campestris cultivar, yellow sarson YSB‐9, on which the aphids were shown to grow more slowly, had less amino acid content than other B. campestris varieties. The slow population growth of aphids on B. juncea, compared to that on B. campestris, is probably due to other than nutritional factors.
Reproductive rate of the Indian mustard aphid (Lipaphis erysimi pseudobrassicae) on different Brassica oilseeds: colmparisons with Swedish strains of mustard (Lipaphis erysimi erysimf) and cabbage aphid (Brevicoryne brassicae)
Authors: RONQUIST F. , AHMAN INGER 
Published: February 2008

SummaryThe reproductive rate of the Indian mustard aphid (Lipaphis erysimi pseudobrassicae), a serious pest on Brassica oilseeds in India, was compared with that of Swedish strains of mustard aphid (L. e. erysimi) and cabbage aphid (Brevicoryne brassicae) on six common Indian and Swedish Brassica oilseed cultivars. There were clear differences between L. e. erysimi and L. e. pseudobrassicae in the relative suitability of the cultivars, emphasisipg the biological differences between these aphids. B. brassicae had similar reproductive rates on all cultivars.In addition, the reproductive rate of L. e. pseudobrassicae was measured on both young and old plants of the six Brassica oilseed cultivars and 14 Indian rai (B. juncea) cultivars. Among the six Brassica cultivars, the reproductive rates were highest on turnip rape and toria (B. campestris), and lowest on yellow sarson (B. campestris) and rai (B. juncea). The ranking of the cultivars was similar for young and old plants. There were no significant differences between the rai (B. juncea) cultivars tested, neither among young nor among old plants. These results from laboratory studies are compared with field data from India on the relative susceptibility of different Brassica oilseed cultivars to L. e. pseudobrassicae.
Factors influencing oviposition behaviour of the sorghum midge, Contarinia sorghicola Coq.
Authors: SHARMA H. C. , LEUSCHNER K. , VIDYASAGAR P. 
Published: February 2008

SummaryVisual stimuli influence the orientation behaviour of the sorghum midge, Contarinia sorghicola Coq. (Diptera: Cecidomyiidae). Yellow, red and white colours are attractive to the midge while blue and black are least attractive. Sorghum panicles covered with blue‐ or black‐coloured bags in a headcage showed maximum midge damage, while the reverse was true for panicles covered with yellow, red, and white coloured bags.Panicles at half‐anthesis with viable pollen and receptive stigmata suffered higher damage than those at the pre‐ and post‐anthesis. Physical removal of anthers and stigmata significantly reduced the oviposition by the sorghum midge. Reduced oviposition/adult emergence was also recorded in male sterile sorghum lines (2219A and 296A) or through chemically‐ (Ethrel) (2‐Chloro ethyl‐phosphonic acid) induced male sterility in panicles of the sorghum cultivar, Swarna. Chemical stimuli from viable pollen and receptive stigmata and to a limited extent physical stimuli, govern the oviposition behaviour of the sorghum midge.Sorghum cultivars IS 12573C, S‐GIRL‐MR1 and IS 2816C showed antixenosis to adult midges. However, these cultivars became susceptible under no‐choice conditions in the headcage. DJ 6514 and IS 12666C were attractive to the adult midges, but showed antixenosis to oviposition under natural and no‐choice conditions. Genotypes with short florets showed antixenosis for oviposition. Ovary and anther breadth and tannin content of grain showed negative associations with oviposition. Cultivar antixenosis to adult midges and oviposition is an important component of resistance to the sorghum midge.
The effectiveness of traps used currently for monitoring populations of the cabbage root fly (Delia radicum)
Authors: FINCH S. 
Published: February 2008

SummarySix different types of traps were compared for capturing adults of Delia radicum. Cone traps caught so few flies that it seems inadvisable for them to be used for monitoring populations of this pest. All the other traps tested were suitable for monitoring D. radicum populations. When expressed on a trap for trap basis, the large 1800 cm2 Canadian traps caught most flies. When expressed as the numbers of flies caughthnit area of trapping surface, most flies were caught in the water traps. Similar numbers of D. radicum, D. platura, syrphids, blowflies and a tachinid, Eriothrix rufomaculatus were caught per unit area on each of three different vertical sticky traps. Although water traps have the advantage that they catch about 5 times as many females D. radicum/unit area as the most effective vertical sticky traps of a comparable size, their disadvantage is that they catch about 10 times as many beneficial syrphids. The reasons why water traps are so effective against D. radicum are discussed, with details of how to convert water‐trap data to sticky‐trap equivalents, and vice versa.
New approaches for restricting spread of potato leafroll virus by different methods of eradicating infected plants from potato crops
Authors: WOODFORD J. A. T. , GORDON S. C. 
Published: February 2008

SummaryExperiments were made at Invergowrie in 1984 and 1985 to compare the spread of potato leafroll virus (PLRV) after removing infected plants by three different methods; conventional roguing, desiccation with diquat, or incineration for 45–60s using a propane gas flame. Potato leaf roll ‘infector’ plants, grown in plots of virus‐free Maris Piper seed potatoes, were artificially infested in June with aphids (Myzus persicae) from a laboratory culture, and removed from the plots after 2 or 3 wk. In both years, natural infestations of potato aphids were scarce during this period. There was no significant difference in the proportion of tubers infected with PLRV in adjacent plants after the neighbouring infector plants had been rogued by hand or desiccated with diquat, but the proportion was considerably reduced following incineration of the infector plants. In 1984, the spread of PLRV in conventionally rogued plots was also significantly reduced by a mixture of deltamethrin plus heptenophos, applied four times from 80% crop emergence, and was almost eliminated by a treatment with aldicarb granules, either at planting, or as a side‐dressing 5 wk later. In 1985, delaying infector removal by 8 days in early July significantly increased the spread of PLRV to neighbouring plants from 2.3% (1 July) to 8.3% (9 July). A single application of deltamethrin plus heptenophos to infectors 1 wk before removal did not significantly decrease spread. Although incineration was quick and effective, the value of this method of eradicating infector plants in seed potato crops is limited because it failed to destroy infected tubers.
The effect of heat treatment and meristem‐tip culture on June Yellows in strawberry
Authors: WATKINS C. A. , McNICOL R. J. , YOUNG K. , JONES A. T. 
Published: February 2008

SummaryBecause there is some evidence that June Yellows (JY) of strawberry may be caused by a pathogenic agent, combinations of heat treatment and meristem‐tip culture that are known to eliminate some viruses from tissues were used in attempts to cure affected Cambridge Favourite strawberry plants from JY. None of 397 propagants derived from JY‐affected plants subjected to various combinations of these treatments were freed from JY. Indeed, all propagants showed more obvious JY symptoms than the parent plants from which they were derived, suggesting that such treatments may be useful for detecting incipient JY in symptomless strawberry stocks.
Distribution of velvet tobacco mottle virus in its mirid vector and its relationship to transmissibility
Authors: GIBB KAREN S. , RANDLES J. W. 
Published: February 2008

SummaryFollowing acquisition by feeding, velvet tobacco mottle virus (VTMoV) was detected in the gut, haemolymph and faeces of the mirid vector, Cyrtopeltis nicotianae, but not in the salivary glands. Virus antigen was detected in the gut and haemolymph for up to nine days following acquisition. Infective virus was detected in the secretions and excretions of the mirids immediately after acquisition and was also detected in the faeces of nymphs after six days. Insoluble nigrosin dye was eliminated intermittently from the gut up to six days after ingestion, in a manner similar to the loss of virus infectivity. Non‐infective mirids were able to inoculate plants from infectious sap deposits on the upper epidermis. An ingestion‐defecation model of insect transmission in which the salivary glands are not implicated is proposed as one explanation for the persistence of transmission in this mirid‐virus association.
Characterisation of a new strain of tobacco necrosis virus isolated from nutrient feeding solution*
Authors: ADAM G. , WINTER S. , LESEMANN D.‐E. 
Published: February 2008

SummaryA virus, isolated from the nutrient feeding solution of a bell pepper culture in a glasshouse, was characterised as a new serotype of tobacco necrosis necrovirus (TNV) and named TNV‐nft. The virus was monopartite and contained a single RNA species and a single coat protein with molecular weights of 1.45± 106 and 2.9 ± 104 daltons, respectively. The particle had an apparent sedimentation coefficient of 110 S and a density of 1.37 g/cm3 in cesium chloride. In decoration tests antiserum prepared against TNV‐nft reacted most strongly with the TNV strains Kassanis A and B, but at lower dilutions it also reacted with all other TNV‐serotypes available. In Ouchterlony tests spur formation occurred with TNV strains Kassanis A and B, indicating that the TNV‐nft strain was serologically distinct. The isolate was not associated with a satellite virus. Cloned cDNA prepared against viral RNA reacted exclusively with the viral RNA band in Northern blots.
Sources of variation in firmness and ester content of ‘Cox’ apples stored in 2% oxygen
Authors: KNEE M. , HATFIELD S. G. S. , FARMAN D. 
Published: February 2008

SummaryThe contribution of various factors to variation in the quality of ‘Cox’ apples after storage in 2% oxygen at 3.3°C was investigated. Within one season variation in the firmness of fruits from different orchards could be largely accounted for by correlations with firmness at harvest and the position of the fruit on the climacteric at the time of harvest. However, different relationships were found between these variables in different seasons. The butyl and hexyl acetate contents of fruit were influenced by season and source of fruit, but little affected by maturity at harvest. Ester content was inversely correlated with fruit firmness after storage. Other factors which were expected to influence the ripening of fruit during storage were found to be unrelated to firmness and ester content. These included the respiration rate of fruit during storage, the resistance of the fruit to gaseous diffusion and its specific gravity. Carbon dioxide production was nearly constant at about 2.3 ml kg‐1h‐1 across seasons, sources and harvest dates. Specific gravity seemed to be particularly affected by season, whereas diffusive resistance decreased with maturity.
Screening for fire blight resistance in apple (Malus pumila) using excised leaf assays from in vitro and in vivo grown material
Authors: DONOVAN ANNE 
Published: February 2008

SummaryThe apple cultivars Greensleeves and Novole and somaclones derived from Greensleeves were tested for resistance to fire blight (Erwinia amylovora) using excised leaf bioassays. Cv. Greensleeves was consistently susceptible to fire blight in in vitro, and in glasshouse and excised leaf bioassays whilst cv. Novole was resistant. Greensleeves somaclones, identified as having intermediate levels of fire blight resistance in glasshouse and in vitro screening tests, also showed intermediate levels of resistance in excised leaf bioassays. The length of leaves and the inoculum concentration employed affected the severity of symptoms observed. Excised leaf bioassays were unsuitable as tests for fire blight resistance using field grown material.
Effects of rotation length, fungicide treatment of seed tubers and nematicide on diseases and the quality of potato tubers
Authors: HIDE G. A. , READ P. J. 
Published: February 2008

SummaryIn 1982 – 88, potatoes were grown in 2‐, 4‐ and 6‐course rotations with spring barley on a field infested with Globodera rostochiensis. Severity of stem canker and black scurf increased with increasing frequency of previous potato crops, and seed tuber treatment with tolclofos‐methyl became less effective in controlling diseases. This suggested that previous crops had increased the amounts of soil‐borne inoculum of Rhizoctonia solani. Oxamyl soil treatment increased stem canker in one year and decreased black scurf in four years.Seed tuber treatment with imazalil or prochloraz decreased stem base infection by Polyscytalum pustulans and skin spot and silver scurf on tubers. Black dot was prevalent on tubers in all years and was not affected by seed tuber treatment or previous cropping. Oxamyl increased black dot and common scab in five years and decreased % tuber dry matter in six years.Cysts of G. rostochiensis were found attached to Désirée but not to Maris Piper tubers in August. At harvest tubers of both cultivars were affected by superficial pitting and its severity was related to soil populations of G. rostochiensis at planting. This damage was controlled by oxamyl. It is suggested that the pitting developed from holes made in the tuber skin at larval invasion.In 1989, Désirée seed tubers and healthy mini tubers were planted in all plots and severity of stem canker and black scurf increased with increasing proximity of previous potato crops and with the number of previous crops. Black dot on stems and tubers was not affected by previous cropping but was much less severe in a plot that had not grown potatoes during the seven years of the experiment. The severity of common scab generally decreased as the number of preceding potato crops increased.
The use of antibiotics to eliminate latent bacterial contamination in potato tissue cultures
Authors: GILBERT JULIE E. , SHOHET S. , CALIGARI P. D. S. 
Published: February 2008

SummaryA simple leaf bioassay was developed to screen for slow‐growing latent bacteria found in potato nodal cuttings. The potato cultures were established to provide a source of sterile leaf tissue for protoplast isolation and the bacteria were only detected after numerous generations in culture. In an attempt to solve this problem cultures were screened before and after various treatments. Two antibiotic mixtures were tested for their efficacy in eliminating bacteria: ABM1 contained penicillin, streptomycin, amphotericin and NaCl while ABM2 contained erythromycin, streptomycin and carbenicillin at various concentrations. Both cocktails, when added to the micropropagation medium, reduced plant growth, induced chlorosis at higher levels and did not eliminate contamination. In terms of protoplast isolation, the only effective treatment was when ABM1 was incorporated into the plasmolysis and enzyme media. It removed contamination at all levels tested and had a differential effect on cell division such that, at low levels of ABM1, protoplasts regenerated successfully.
Study on the factors affecting storage of edible aroids
Authors: AGBOR‐EGBE TOM , RICKARD JUNE E. 
Published: February 2008

SummaryThe effects of temperature (15 °C, 25 °C, 30°C and 24–29°C), relative humidity (45%, 85% and 86–98%) and harvest maturity on the storage behaviour of cormels of the edible aroid species Colocasia esculenta and Xanthosoma sagittifolium were studied. The changes monitored were respiration rates, weight losses, incidence of decay and sprouting. Post‐harvest losses that occurred during storage were influenced by the storage conditions, the state of maturity at harvest and the morphological characteristics of the cormels. When stored under high temperature and humidity more sprouting and decay occurred with C. esculenta cormels than with X. sagittifolium cormels. Less sprouting and decay occurred with Colocasia cormels at high temperature and low humidity than at high temperature and high humidity but higher weight losses were recorded. Wound pathogens were the major cause of post‐harvest deterioration in Colocasia cormels and the causal pathogen of cormel decay was Sclerotium rolfsii.Under conditions of low temperature (15 °C) and high humidity (85%), cormels of both C. esculenta and X. sagittifolium were successfully stored for periods of 5–6 weeks. Similar storage periods were also possible under tropical ambient conditions with the Xanthosoma cultivars used in these experiments. Under the same storage conditions up to 60% decay occurred in the Colocasia cormels indicating the need for post‐harvest fungicide treatment.