bluuebunny/crossref_metadata_2025_split huggingface dataset:
Susceptibility of the leatherjackets Tipula oleracea and T. paludosa to soil flooding
Authors: MEATS A. 
Published: February 2008

SUMMARYA relation was found between temperature and the survival of larvae of Tipula oleracea and T. paludosa when submerged in tap water alone or on turf growing on a sandy loam flooded with still or disturbed water (experiments with soil always starting with freshly flooded soil). Larvae under water alone usually survived until they starved, whereas larvae submerged on soil died in a relatively short time. The periods of survival at a depth of 25 mm were the same for both large and small larvae of either species at any one temperature. The regression of log.‐log. survival time on temperature was a straight line, mean arithmetic values ranging from about 5 h at 20 °C to 122 h at 0 °C. Survival times at 25 mm were not increased by disturbing the water and the times at greater depths were no different, providing the water was still. If the water was regularly disturbed then the greater the depth the longer the survival time at any one temperature.Survival times in deoxygenated water indicated that lethal conditions may not be entirely due to deoxygenation of the water.
Cocoa canker caused by Phytophthora palmivora
Authors: FIRMAN I. D. , VERNON A. J. 
Published: February 2008

SUMMARYCanker disease of Theobroma cacao L. caused by Phytophthora palmivora (Butler) Butler gives rise to serious damage in Fiji and is common in the S.W. Pacific area. Fusarium decemcellulareBiick (imperfect stage of Calonectria rigidiuscula (Berk. & Br.) Sacc.) was constantly associated with P. palmivora in disorders of cocoa but was not found to be a primary pathogen. Most Amelonado cocoa trees were resistant to canker but there were differences in the reactions of other Forastero and of Trinitario types. The F1 generation of a local Trinitario selection, itself resistant, showed segregation resulting in a proportion of very susceptible plants. Isolates of P. palmivora from black pod, canker and green twigs were equally pathogenic, both to pods and seedling stems. Sporangial dimensions, particularly the length/breadth ratio, differed from those reported elsewhere. It is uncertain whether the reason that cocoa canker is more serious in some countries than others is because of differences in the pathogenicity of P. palmivora strains to bark or the genetic differences of the cocoa grown.
The relationship between nutrients in extracted xylem sap and the susceptibility of fruit trees to silver‐leaf disease caused by Stereum purpureum (Pers.) Fr.
Authors: BEEVER D. J. 
Published: February 2008

SUMMARYXylem sap was extracted from cut branches of stone‐fruit and pip‐fruit trees at different times of the year, and analysed for nitrogen and carbohydrate content. Growth of Stereum purpureum was measured in the different sap samples in vitro. Nitrogen and carbohydrate levels in xylem sap from peach trees were highest in late winter and early spring, and these samples supported most growth of S. purpureum. At full bloom the levels of nitrogen and carbohydrate in xylem sap from stone‐fruits (peach, nectarine, plum, cherry) were several times greater than in sap from pip‐fruits (apple, pear), and the growth of S. purpureum in sap from stone‐fruits was approximately ten times that in sap from pip‐fruits.The results suggest that seasonal variations in susceptibility of stone‐fruits to silver‐leaf disease, and the greater susceptibility of stone‐fruits than of pip‐fruits, are due to differential ability of their xylem saps to support growth of S. purpureum.
Decline and other effects of five virus infections on three varieties of plum (Prunus domestica L.)
Authors: POSNETTE A. F. , CROPLEY R. 
Published: February 2008

SUMMARYThe effects of five different virus inocula on three varieties of plum (Prunus domestica L.) were studied in a field trial of 10 years duration. The viruses causing line pattern, ringspot, prune dwarf and bark split had no effect on the growth of Marjorie's Seedling and Cambridge Gage, and only that causing prune dwarf stunted Oullins Gage trees. However, these viruses diminished the fruit yield of one or more varieties, and prune dwarf virus seriously decreased the yield of all three. Decline disease, probably caused by a strain of Prunus necrotic ringspot virus, developed in Marjorie's Seedling but not in the other varieties. The symptoms first appeared after 5 years and then the trees declined progressively with necrotic ‘incompatibility’ between rootstock and scion.
Identification of viruses isolated from plum trees affected by decline, line‐pattern and ringspot diseases
Authors: SENEVIRATNE S. N. de S. , POSNETTE A. F. 
Published: February 2008

SUMMARYViruses obtained from plum trees infected with either decline, line‐pattern or ringspot diseases were characterized and identified. All the viruses were serologically related to Prunus necrotic ringspot virus (NRSV); those from trees with decline or ringspot were serologically indistinguishable from cherry strains of NRSV but differed in pathogenicity, whereas the virus from trees with line pattern was closely related to apple mosaic virus. When returned from herbaceous hosts to Prunus, line‐pattern and ringspot isolates reproduced symptoms characteristic of the diseased sources. One virus isolate from trees with decline diminished the vigour of young plum trees. Comparison with other investigations shows that at least two unrelated viruses cause plum line‐pattern disease in America and Europe.
Inheritance and effectiveness of genes in barley that condition tolerance to barley yellow dwarf virus
Authors: CATHERALL P. L. , JONES A. T. , HAYES J. D. 
Published: February 2008

SUMMARYTolerance to barley yellow dwarf virus (BYDV) in five Ethiopian barley genotypes was conditioned by major genes which apparently occurred at, or near, the same chromosome locus in each genotype. The genes or alleles differed in effectiveness, one providing a high, three an intermediate and one a low level of tolerance. In plants having a slow rate of growth, the effectiveness of the tolerance genes tended to be masked, but the effectiveness of the gene or allele which provided the highest level of tolerance was masked to a lesser extent than that of genes or alleles providing low or intermediate levels of tolerance.
Field experiments with spring barley resistant to cereal cyst nematode, 1965–1968
Authors: COTTEN J. 
Published: February 2008

SUMMARYTwo bulk populations of spring barley lines differing in respect of a single dominant gene for cereal cyst nematode (Heterodera avenae) resistance were used in trials over 4 years to assess the effect of the nematode on grain yield. On an infested site the resistant lines consistently and significantly out‐yielded the susceptible lines by an average of 9 % over the 4 years. On non‐infested sites, there was no difference in yield between the resistant and susceptible lines.To measure changes in the cereal cyst nematode population under continuous barley cultivation, the resistant and susceptible lines were each sown at the infested site on the same plots for 4 consecutive years. The cereal cyst nematode population declined under both susceptible and resistant barley, but more rapidly under the latter. Migratory nematodes, mostly Pratylenchus minyus, were latterly prevalent on all plots.There was no detectable change in the pathogenicity of the cereal cyst nematode population after 3 years of growing resistant barley.
Aggregation and the transformation of counts of Aphis fabae Scop, on beans
Authors: TAYLOR L. R. 
Published: February 2008

SUMMARYIn several sets of counts of Aphis fabae colonies on bean stems, obtained with different sampling methods, variance was always proportional to the same power of the mean; s2=amb where b= 1.72 and a differed by different sampling methods. The resulting standard transformation for A. fabae on beans, z=x0 2, is marginally more effective than z= log (x+1).
Effects of population density on alienicolae of Aphis fabae Scop.
Authors: SHAW M. J. P. 
Published: February 2008

SUMMARYA technique for rearing aphids in dense populations is described. Apterae were reared in high (‘C’) and low (‘U’) population densities and the proportions of alatae among their progenies were compared. Proportions of alatae were larger among progenies of ‘C’ apterae, and the proportions also increased as the density of the population in which the progenies were reared increased. Progenies of alatae never became alatae.
Epidemiology and control of powdery mildew (Sphaerotheca pannosa) on roses
Authors: PRICE T. V. 
Published: February 2008

SUMMARYIn examinations between September 1966 and December 1968 of 741 specimens of rose species and cultivars, cleistocarps of Sphaerotheca pannosa were found on thirty‐two cultivars, mostly ramblers and old shrub roses, and on nine of these they were found in two or three successive seasons.On stem pieces placed on soil in each of the winters 1966‐7, 1967‐8 and 1968‐9 the number of cleistocarps with asci and ascospores decreased during November and December and rose slightly in January, but none showed dehiscence.Cleistocarps on rose bushes examined during the winters of 1967‐8 and 1968‐9 showed a progressive degeneration of ascospores, and by December none was found.Perennation of S. pannosa in buds was demonstrated by field observations, by inducing bursting of dormant buds on surface‐sterilized shoots and by dissection of dormant apical buds.In field studies in 1968 of the development of mildew, infected buds were noted on 22 March but secondary infections did not appear until 17 April, though viable conidia and susceptible leaf tissue were present during this period. Low temperatures appeared to be partly responsible for this lag. On detached leaves in the laboratory the fungus developed from germination to sporulation in 4 days at 20°, 7 days at 15°, 11 days at 10° and 28 days at 3°. Keeping inoculated detached leaves at 0° for 10 days apparently did not affect the viability of the conidia.In both 1967 and 1968 there were two host growth periods, each culminating in flowering, between May and September; mildew did not develop on the shoots until the second growth phase, then the disease increased logarithmically on shoots and blooms during August and September.The disease on the shoots was effectively controlled in the field during 1968 by applications of ‘Benlate’ (benomyl) or dinocap, but not by methy‐rimol; these fungicides were less effective in controlling mildew on pedicels.Laboratory tests showed that ‘Benlate’ inhibited sporulation of S. pannosa by deforming the conidiophores.
The role of the sexual stage in the over‐summering of Erysiphe graminis DC. f.sp. hordei Marchal under semi‐arid conditions
Authors: KOLTIN Y. , KENNETH R. 
Published: February 2008

SUMMARYThe sexual stage of E. graminis f.sp. hordei was found to be functional in Israel, and adapted to the climate of the region. Cleistothecia serve as the principal, and perhaps the only means for persistence of the pathogen in the host‐less, hot and rainless summer, and induce initial infection on wild and cultivated barleys in late autumn. The cool and rainy weather, which induces germination of seeds of the host in the field, also permits ascospore differentiation and ejection. Details are given of the conditions favouring or delaying cleistothccial maturation during and after the growing season.
Seed treatments with benomyl and other fungicides for the control of Ascochyta pisi on peas
Authors: MAUDE R. B. , KYLE ANN M. 
Published: February 2008

SUMMARYIn three experiments, using laboratory, glasshouse and field tests, seed dressings of benomyl‐1½ (42.4 g) to 2 oz (56.6 g) Benlate 50% w.p. per 28 lb (12.7 kg) of seed‐gave complete control of Ascochyta infection of pea seeds. Mixtures of benomyl and captan and benomyl and thiram were also effective. Carboxin, captan, and thiram used as seed dressings, either singly or in mixtures, did not eliminate the pathogen from peas. Germination, emergence and seedling vigour were not impaired by any dressing.
Effects of temperature and rainfall on the incidence of wilt (Verticillium albo‐atrum) in hops
Authors: TALBOYS P. W. , WILSON J. F. 
Published: February 2008

SUMMARYWilt incidence in certain hop cultivars recorded during 15 years of experiments on a plot infested with a virulent strain of V. albo‐atrum, and over shorter periods on various infested farm sites, was studied by multiple regression analysis in relation to rainfall and soil temperature at various periods during the growing season. In the least‐resistant cultivar, Fuggle, the incidence of wilt was always high, and was independent of rainfall and soil temperature. Wilt incidence in other cultivars showed a negative correlation with mean soil temperature at 20 cm for the period mid‐April to late June; no other single or multiple regression was consistently significant. It was concluded that the commonly observed association of high wilt incidence with wet weather in early summer is attributable to low soil temperature rather than to high rainfall.
The effect of weather on the concentration of pollen within sugar‐beet seed crops
Authors: SCOTT R. K. 
Published: February 2008

SUMMARYThe concentration of pollen in the air within diploid open‐pollinated sugar‐beet seed crops at Broom's Barn Experimental Station increased between 05.00 and 09.00 G.M.T. as relative humidity became less than 90%, was greatest between 09.00 and 11.00, when relative humidity wasc.75%, and gradually decreased towards evening. The average pollen concentration during 24 h periods ranged from 170 to 12400/m3being greatest on fine, windy, dry days after periods of cooler weather. Rain during the morning washed pollen out of the air and damaged developing anthers, but rain in the late afternoon following a sunny morning seemed hardly to affect the pollen catch, while rain at night sometimes caused an immediate temporary increase in pollen concentration. Most pollen was released between 27 June and 31 July in all years (1965‐7); more in the first than in the second half of July. 1965 was cool and damp, 1967 warm and dry, 1966 warm and dry early, and cool and wet late. The total pollen catch in 1965 was 83% and in 1966 31% of that in 1967 but the percentage germination of seed harvested in the 3 years was similar.The total pollen catch on a trap 230 m east of the 1965 crop was c. 1% of the catch within the crop on days with gusty westerly winds and the catch on a trap c. 46 cm above the 1966 crop averaged 78.6% of that at the level of most flowers.
Breeding for mature‐plant resistance to yellow rust in wheat
Authors: LUPTON F. G. H. , JOHNSON R. 
Published: February 2008

SUMMARYIn recent years several varieties of wheat, such as Rothwell Perdix and Maris Envoy, have shown good resistance to yellow rust when first produced, but because their resistance was determined by simply inherited major genes, they have later been severely attacked by newly arising physiologic races of the pathogen. Other varieties, such as Little Joss, Atle and Maris Widgeon, though slightly attacked by several races, have never suffered severe damage even when exposed to high levels of inoculum. The inheritance of this non‐race‐specific type of resistance was studied in a cross between Little Joss and a susceptible but shorter‐strawed variety, Nord Desprez. Resistance appeared to be under complex control. It was found possible to select short‐strawed resistant plants, using simple techniques in the field.
Sites of virus retention in the alimentary tract of the nematode vectors, Xiphinema diversicaudatum (Micol.) and X. index (Thorne and Allen)
Authors: TAYLOR C. E. , ROBERTSON W. M. 
Published: February 2008

SUMMARYElectron microscopy of thin sections of Xiphinema diversicaudatum and X. index fed on plants infected respectively with arabis mosaic and grapevine fanleaf viruses showed that the viruses are retained as a monolayer of particles adsorbed on to the cuticle lining the lumina of the odontophore (stylet extension), anterior oesophagus and oesophageal bulb. During the moult of the nematode the cuticular lining is shed and together with the detached virus particles is ingested into the intestine through the oesophago‐intestinal valve; this supports the limited experimental evidence that viruses transmitted by X. diversicaudatum and X. index are not retained through the moult.
Bacteriophage and serological methods for the identification of Pseudomonas phaseolicola (Burkh.) Dowson
Authors: TAYLOR J. D. 
Published: February 2008

SUMMARYRapid phage and serological methods were compared with biochemical and bean‐pod inoculation tests for the identification of Pseudomonas phaseolicola. Phages II P, 12 P and 48 P were highly specific and did not lyse any of forty‐five other isolates from bean or the sixteen species of Pseudomonas tested. They were also, however, unable to lyse the rough colony forms of P. phaseolicola which were occasionally isolated. Phage 12 S lysed a wide range of Pseudomonas spp., including a proportion of P. phaseolicola isolates, the majority of which were race 2. Serological tests showed that the heat‐labile antigen possessed by P. phaseolicola was common to twelve other species of plant pathogenic pseudomonads. The heat‐stable antigen was more specific and was detected only in P. mors‐prunorum and P. primulae, neither of which occurs on bean. The two races of P. phaseolicola were indistinguishable in serological tests. It was concluded that both phage and antiserum tests provide specific, rapid and easily applied methods for the routine identification of P. phaseolicola isolates from plant and seed material.
The control of common scab of potatoes by irrigation
Authors: LAPWOOD D. H. , WELLINGS L. W. , ROSSER W. R. 
Published: February 2008

SUMMARYIrrigation applied early during tuberization significantly decreased scab on tubers of Majestic, King Edward and Record, but not on Pentland Crown, a resistant cultivar, where tubers had little scab even from the driest soil. There was little benefit from keeping soils wetter than 0.6 in (15.24 mm) soil moisture deficit (S.M.D.) for more than 3 weeks after tuber initiation, and irrigation to 0.8 in (20.32 mm) S.M.D. gave economic control. Irrigating only after the ‘marble stage’ increased yield but the tubers were scabbed. Irrigation did not alter the rate eyes (nodes) separated from the apical bud but speeded the swelling of tubers.
The biology of Peronospora viciae on pea: laboratory experiments on the effects of temperature, relative humidity and light on the production, germination and infectivity of sporangia
Authors: PEGG G. F. , MENCE M. J. 
Published: February 2008

SUMMARYGermination of Peronospora viciae sporangia washed off infected leaves varied from 20% to 60%. Sporangia shaken off in the dry state gave 11–19% germination. Most sporangia lost viability within 3 days after being shed, though a few survived at least 5 days. Infected leaves could produce sporangia up to 6 weeks after infection, and sporulating lesions carried viable sporangia for 3 weeks.Sporangia germinated over the range 1–24 °C, with an optimum between 4 and 8 °C. Light and no effct.The temperature limits for infection were the same as for germination, but with an optimum between 12 and 20 °C. A minimum leaf‐wetness period of 4h was required, and was independent of temperature over the range 4–24 °C. Maximum infectivity occurred after 6h leaf wetness at temperatures between 8 and 20 °C. Infection occurred equally in continuous light or in darkness.After an incubation period of 6–10 days sporangia were produced on infected leaves at temperatures between 4 and 24 °C, with an optimum of 12–20 °C. Exposure to temperatures of 20–24 °C for 10 days reduced subsequent sporulation. Sporangia produced at suboptimal temperatures were larger, and at 20 °C. smaller, than those produce at 12–16 °C. Viability was also reduced. No sporangia were produced in continuous light, or at relative humidities below 91%. For maximum sporulaiton an r.h. of 100% was required, following a lower r.h. during incubation.Oospores wre commonly formed in sporulating lesions, and also where conditons limited or prevented sporulation.The results are discussed briefly in relaiton to disease development under field conditions.
Distribution of aphids in cereal crops
Authors: DEAN G. J. , LUURING B. B. 
Published: February 2008

SUMMARYCereal crops were examined weekly for aphids during 1969. Plants in twenty samples of row 0.3 m long were examined in a sheltered perimeter of a crop and along a transect 36.6 m into the crop. Aphids were usually first found within 1–4 weeks of the first alatae caught in a suction trap operating 12.2 m above ground. When first alatae caught in a suction trap operating 12.2 m above ground. When the first found from 10 to 27% of the 0.3 m lengths sampled contained aphids. Rhopalosiphum padi, first found late in May, were scarce (< 0.53/0.3 m) throughout June and July. Sitobium spp. and Metapolophium dirhodum, which appeared in mid‐June, were more numerous than R. padi; most occurred during the second half of July, and populations decreased just before harvest in early August. Sitobium avenae was more abundant (max. 19.3/sample) than either S. fragariae (0.91) or M. dirhodum (2.51).More aphids occurred in oats (max. 52/0.3 m) during July than in wheat (45), and barley had fewer (6.8). S. avanae was more abundant than M. dirhodum in sheltered areas of barley and wheat, and in exposed areas of the same crop M. dirhodum was commonest. Along sheltered perimeters, the ratio of S. avenae to M. dirhodum was largest in barley (11:1), intermediate in oats (6:1) and smallest in wheat (3.7:1). Sitobium spp. were most numerous on the ears, when most M. dirhodum were on the leaves.Regression analyses of log. S2 on log. m suggested that S. avenae was more evenly distributed within (36.6 m) the field (b = 1.056 + 0.109) than along the sheltered perimeter (b = 1.432 + 0.132), though it seemed similarly distributed along perimeters of barley, oats and wheat. The distributions of M. dirhodum and Sitobium spp. along sheltered perimeters of all crops were apparently similar.
Preliminary studies of an integrated control programme for cucumber pests and an evaluation of methods of introducing Phytoseiulus persimilis Athias‐Henriot for the control of Tetranychus urticae Koch
Authors: GOULD H. J. 
Published: February 2008

SUMMARYPreliminary investigations suggest that, when Phytoseiulus persimilis is used to control Tetranychus urticae, the major pest of cucumbers, the control of other pests and powdery mildew can be effected by means of Encarsia formosa for the control of whitefly (Trialeurodes vaporariorum), bed drenches of gamma‐BHC for thrips control and dimethirimol for the control of cucumber mildew (Erysiphe cichoracearum). The parasite Aphelinus flavipes failed to control an infestation of Aphis gossypii in one trial. A comparison of different methods of introducing Phytoseiulus confirmed that the best results were obtained when an even, artificial infestation of Tetranychus urticae was established on the crop before the introduction of the predator.