bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variation in the virulence of Verticillium dahliae from strawberry
Authors: TALBOYS P. W. 
Published: February 2008

SUMMARYIsolates of V. dahliae from strawberry, tested in 1968 against cv. Cambridge Vigour, showed differences in virulence; in cvs Talisman and Cambridge Favourite there were no significant differences between plants that were inoculated and those that were not. Evidence from this experiment, and from an earlier non‐replicated experiment with Cambridge Favourite, in which differences of virulence had been apparent, showed that environmental factors can cause variations in disease development that are of similar magnitude to those attributable to genetic variations in host and parasite.
A comparative study of Phialophora radicicola, an avirulent fungal root parasite of grasses and cereals
Authors: BALIS C. 
Published: February 2008

SUMMARYThe biology and infection‐behaviour of a typical isolate of Phialophora radicicola Cain have been compared with those of a representative isolate of Ophiobolus graminis (Sacc.) Sacc. Both species can utilize a nitrate source of nitrogen and both require thiamine and biotin for growth on inorganic nitro‐gen; P. radicicola, but not O. graminis, was able to synthesize biotin when grown on asparagine as a nitrogen source. The pH range for good growth of P. radicicola in nutrient solution was narrower than that for O. graminis, and its growth rate on agar was only one‐third. P. radicicola was the more active decomposer of cellulose, and its cellulolysis adequacy index was I.66 as com‐pared with a value of 0.33 for 0. graminis. In agreement with prediction from Garrett's (I966) hypothesis on the cellulolysis adequacy index, saprophytic survival of P. radicicola in wheat straw was shortened by additional soil nitrogen, which prolongs survival of O. graminis.P. radicicola was found to spread ectotrophically over the roots of wheat, oats and barley by runner hyphae indistinguishable from those of O. graminis, but cortical infection caused no necrosis and no discernible check to growth of the infected cereals, nor any significant decrease in grain yield of inoculated wheat grown to maturity. Pre‐existing infection of wheat roots by P. radicicola retarded spread of infection by O. graminis; inoculation of several grass species with P. radicicola reduced the extent of infection by O. graminis of wheat following the grasses.
Local redistribution of fungicides on leaves by water
Authors: HISLOP E. C. , COX T. W. 
Published: February 2008

SUMMARYLocal redistribution of various fungicides applied as large or small droplets to detached broad‐bean leaflets was examined by laboratory bio‐assay with Botrytis fabae and by leaf‐printing techniques. The results showed that fungicidal particulate and soluble material will spread in water from the initial deposits and that the protected areas on leaves inoculated after washing were often much greater than on unwashed leaves. The extent of redistribution was related to the inherent toxicity, physical form, duration of weathering and tenacity of the fungicides. The effects of formulating copper oxychloride and zineb fungicides with surface‐active agents and adhesives seemed due to differences in the tenacity of the deposits. Results indicated that similar types of redistribution would occur in the field, but the possible importance of the electrokinetic theory of redistribution was not proven.
Fungitoxic action of dimethirimol and ethirimol
Authors: BENT K. J. 
Published: February 2008

SUMMARYThe systemic fungicides dimethirimol and ethirimol were shown to be toxic to spores of Erysiphe graminis and Sphaerotheca fuliginea, in germination tests in vitro. Toxicity of dimethirimol to spores of Botrytis fabae, Phytophthora infestans, Puccinia recondita, Uncinula necator and Venturia inaequalis was relatively feeble or absent. When applied in foliage sprays or in root treatments, both compounds inhibited the emergence of germ tubes from powdery mildew spores on cucumber and barley plants. The specific disease control shown by these fungicides can be explained by their direct fungitoxic action.The effects of dimethirimol and ethirimol on powdery mildew infections and on spore germination were greatly decreased by the presence of riboflavin in the light. A rapid photo‐chemical interaction between riboflavin and dimethirimol was demonstrated. Marked reversals both of disease control and of fungitoxicity were also given by folic acid, and it is suggested that folic acid overcomes a metabolic block induced in powdery mildew fungi by the fungicides.
Tests of dibutyltin compounds as potato blight fungicides
Authors: McINTOSH A. H. 
Published: February 2008

SUMMARYDibutyltin dicarboxylates were about one‐tenth as effective as fentin acetate in controlling potato haulm blight (Phytophthora infestans) in laboratory tests on detached leaflets, but were less phytotoxic. Tributyltin acetate was no more effective than dibutyltin diacetate; dioctyltin dichloride was ineffective.
Pollen release by diploid and tetraploid sugar‐beet plants
Authors: SCOTT R. K. , LONGDEN P. C. 
Published: February 2008

SUMMARYPollen released during three summers at Broom's Barn, Suffolk, by diploid and tetraploid multigerm sugar‐beet plants was caught by automatic volumetric spore traps and by glass funnels situated in the crop. Tetraploids produced on average 66% as much pollen as diploids, their pollen grains were larger and they needed drier air to release pollen, the concentration of which increased more slowly early in the day and was particularly small on dull, damp days. Pollen catches from diploids and tetraploids decreased at a similar rate with increasing distance from the pollinators. The germination of fruits harvested from male‐sterile plants among the pollinators was consistently less with a tetraploid than with a diploid pollinator, but was not affected by distance of the male‐sterile plants from either pollinator.
The cuticles of some Angiosperm leaves and fruits
Authors: HOLLOWAY P. J. , BAKER E. A. 
Published: February 2008

SUMMARYThe cuticles of twenty‐four species from a wide range of mono‐ and di‐cotyledonous plants were examined by chemical methods. The cuticles differ markedly in the amount and composition of the surface wax, in the thickness of the cuticular membrane, and in the content and composition of the cutin of the membrane. Fruits usually have heavier wax deposits and much thicker membranes than leaves. No direct relationship exists between surface waxiness and thickness of the membrane. Alkanes and primary alcohols are prominent in many of the surface waxes; triterpenoids occur less frequently. The cutin content of the membrane varies considerably; a delicate membrane tends to have a low content of cutin in which fatty acids are prevalent, and a well‐developed membrane a higher content of cutin more rich in hydroxy‐fatty acids. 10,16‐Dihydroxyhexadecanoic acid is often an important constituent of cutin; 9,10,18‐trihydroxyoctadecanoic acid is most prominent in the cutin of thicker membranes. The possible influence of the variations in cutin acids upon the structure of cutin and the taxonomic implications of wax and cutin composition are discussed.
Some effects of barley yellow dwarf virus on spring and winter cereals in field trials
Authors: DOODSON J. K. , SAUNDERS P. J. W. 
Published: February 2008

SUMMARYThe tolerance of spring and winter cultivars of wheat, barley and oats to infection by barley yellow dwarf virus (BYDV) was examined in field tests. Sererely affected plants were stunted and grain yields were considerably reduced. These changes in infected spring barley cultivars were associated with decreases in both ear length and number and sizes of grain. Most barley and oat cultivars were more susceptible than wheat cultivars. Yield losses decreased with successively later dates of inocultaiton, the yield response being characteristic of the tolerance of individual cultivars. Differences between tolerant and susceptible cultivars were insignificant in most cases where infection occurred after growth stage 7.Individual seedling symptoms assessed in April and May were more closely related to each other and to yield losses than those recorded in March and June. The incorporation of seedling symptoms into indices of infection permits estimates of decrease in yield to be made by applying the formulae,DY = (LC+LA+SH)/3to barley cultivars andDY = 1.7 × (LC+LA+SH)/3 ‐ 7to oat cultivars. Thus decreases in grain yield (DY) can be related to decreases in seedling height (SH) and increases in percentage of leaf area discoloured (LA) and intensity of discoloration (LC).Plot symptoms of infection, scored on a 0–7 scale, offered a more convenient method of assessment than individual seedling symptoms. Plot scores (PA) were closely correlated with other seedling symptoms and with decreases in grain yield (DY), and can thus be used to estimate yield losses by substituting into the formula, DY = 14PA (April)‐8. This formula was found to be applicable to all cereal cultivars examined in N.I.A.B. trials, there being no distinction between wheat, barley and oats.
Environmental factors influencing the infection of wheat by Puccinia graminis
Authors: BURRAGE S. W. 
Published: February 2008

SUMMARYGermination rate and total germination of Puccinia graminis uredospores were directly related to pustule age and duration between spore collections. Partial drying of the spores enhanced germination rate; keeping them for 18 h at 100% r.h. reduced both rate and total germination. Spores germinated in polystyrene dishes between 4 and 29 °C and optimally between 15 and 23 °C Light (3 cal/cm2/h) had little effect on germination on moist surfaces but inhibited germination on the leaf. In Hybrid 229/8 wheat this effect was more pronounced than in var. Little Club. The number of primary infections increased linearly with duration of surface wetness with a narrow temperature optimum at 23.5 °C.Two phases of infection could be distinguished: germination (requiring darkness and capable of taking place over a wide temperature range) and penetration (requiring light and slightly higher temperature than for germination). Stomatal closure caused by subjecting the plants to water stress led to proporational reductions in infection. The results are discussed in relation to dew formation.
Some chemicals to prevent stump colonization by Fomes annosus (Fr.) Cooke
Authors: PHILLIPS D. H. , GREIG B. J. W. 
Published: February 2008

SUMMARYIn tests to find a replacement for creosote, widely used for painting conifer stumps to prevent colonization by Fomes annosus, the best all‐round results were given by sodium nitrite. This has therefore been introduced in the forest, though, as it is poisonous to man and to animals, urea or disodium octoborate (‘Polybor’) may be used instead where labour cannot be well controlled, or there appears to be a danger to unattended livestock or to water supples.
Lethal bole rot disease of coconut in East Africa
Authors: BOCK K. R. , IVORY M. H. , ADAMS B. R. 
Published: February 2008

SUMMARYA lethal bole, rot disease of coconut, caused by Marasmiellus cocophilus Pegler, sp. nov., reaches epidemic proportions in several areas along the coasts of Kenya and Tanzania.The first symptoms noticed on palms 8 or more years old are a frond wilt and a crown rot, but these follow a primary bole rot. Highest mortality is among seedlings and young palms up to 8 years old.Where the disease occurs sporophores are sometimes common on exposed roots, dead seedlings and the soil surface where diseased palms have been dug out. The fungus appears to be a persistent colonizer of coconut debris in the soil.Mycelial cultures from infected bole tissues and from sporophores were highly pathogenic to seedlings, and slowly invaded older tissue. M. cocophilus reaches the inner bole tissues only through the roots, and wounding of roots of their aerenchymatous protuberances is important in infection.Seedlings may become infected through roots damaged during transplanting from nurseries to the field; movement of seedlings from affected areas is one certain method of dispersal.Suggested control measures are: (1) selection of seedlings in nurseries and subsequent transplanting should be as early as possible; (2) seedlings should be transplanted very carefully, and damaged roots pruned and disinfected; (3) seedlings should never be taken from affected areas; (4) periodic soil sterilization of nurseries; and (5) no cultivation should be done between palms, especially where disease is present.
Comparison of the biology of Myzus persicae Sulz. resistant and susceptible to dimethoate
Authors: BANKS C. J. , NEEDHAM P. H. 
Published: February 2008

SUMMARYApterous Myzus persicae resistant to dimethoate reproduce for the same length of time as susceptible aphids, but the resistant ones reproduce significantly faster during the first 10 days of adult life (especially during the first 5 days). Thereafter, they reproduce more slowly, and eventually the susceptible aphids produce approximately the same number of larvae. Resistant aphids die significantly younger. Resistant aphids as larvae develop faster than susceptible ones and are significantly heavier when they first become adult. The resistant aphids do not excrete faster during the first few days but, as they produce more larvae during the first 10 days of adult life and have developed faster, they probably feed faster during development and early adult life or obtain more nutritious food.Resistant aphids were at least as effective as susceptible ones in transmitting sugar‐beet mosaic and pea mosaic viruses, and plants showed symptoms sooner when resistant aphids were the vectors.
Needle nematodes (Longidorus spp.) and stubby‐root nematodes (Trichodorus spp.) harmful to sugar beet and other field crops in England
Authors: WHITEHEAD A. G. , HOOPER D. J. 
Published: February 2008

SUMMARY Longidorus attenuatus produces galls at the tips of roots of field crops, including sugar beet, growing in alkaline, sandy soils in eastern England. L. elongatus produces similar, but often larger, galls on the roots of sugar beet and other crops in sandy soils in the W. Midlands and in Fen peats. Trichodorus spp. cause ‘stubby root’ of sugar beet and can feed on many field crops. Seven species of Trichodorus were found in sandy soils in eastern England. L. attenuatus, L. elongatus and Trichodorus spp. aggregate around roots and stunt sugar beet and other crop plants. L. attenuatus is commoner below plough depth than in the topsoil, whereas T. cylindricus, T. pachy‐dermus and T. anemones are more abundant in the topsoil. These nematodes cause some forms of ‘Docking disorder’.
The effect of D–D, chloropicrin and previous crops on numbers of migratory root‐parasitic nematodes and on the growth of sugar beet and barley
Authors: WHITEHEAD A. G. , FRASER JANET E. , GREET D. N. 
Published: February 2008

SUMMARYThirty‐three gal D–D or chloropicrin/acre (371 l/ha) injected during winter into well‐drained, sandy soils controlled Longidorus attenuatus, Trichodorus spp. and other migratory root‐parasitic nematodes and resulted in greatly increased yields of sugar beet for at least 3 years; 2 years of bare fallow was less effective than soil fumigation. Trichodorus spp. multiplied more on sugar beet than on barley, whereas L. attenuatus multiplied more on barley and clover than on sugar beet.
Variations in the resistance to Heterodera rostochiensis of potatoes derived from Solarium tuberosum ssp. andigena and S. multidissectum
Authors: PARROTT D. M. , TRUDGILL D. L. 
Published: February 2008

SUMMARYThe proportion of larvae from ten populations of Heterodera rostochiensis Woll. that became female was determined on five potato clones containing genes for resistance derived from S. tuberosum ssp. andigena., on three with genes from S. multidissectum and on four with genes for resistance from both sources. Variations in the resistance of the clones bred from andigena, especially to two of the populations, suggest the presence of more than one gene for resistance.
Host range and some properties of potato mop‐top virus
Authors: HARRISON B. D. , JONES R. A. C. 
Published: February 2008

SUMMARYPotato mop‐top virus (PMTV) was transmitted by inoculation of sap to twenty‐six species in the Solanaceae or Chenopodiaceae and to Tetragonia expansa; species in eleven other plant families were not infected. The virus was cultured in inoculated leaves of Nicotiana tabacum cv. Xanthi‐nc or in N. debneyi. Diagnostic local lesions were produced in Chenopodium amaranticolor. In winter, ten solanaceous species were slowly invaded systemically but the first leaves infected were those immediately above inoculated leaves. When transmitted to Arran Pilot potato by the vector Spongospora subterranea, PMTV induced all the main types of shoot and tuber symptoms found in naturally infected plants. Isolates of PMTV from different sources differed considerably in virulence.PMTV‐containing tobacco sap lost infectivity when heated for 10 min at 80 °C, diluted to 10‐4, or stored at 20 °C for 14 weeks. Infectivity was partially stabilized by 0·02% sodium azide. When sap was centrifuged for 10 min at 8000 g, infectivity was mainly in the sediment. Infective sap contained straight rod‐shaped particles about 20 nm wide, with lengths up to 900 nm and crossbands at intervals of 2·5 nm. Many of the particles were aggregated side‐to‐side, and the ends of most seemed damaged. The slight infectivity of phenol‐treated leaf extracts was abolished by pancreatic ribonuclease. The present cryptogram of PMTV is R/*:*/*:E/E:S/Fu.
The long‐term survival of some plant viruses preserved by lyophilization
Authors: HOLLINGS M. , STONE OLWEN M. 
Published: February 2008

SUMMARYSeventy‐four viruses were tested for survival after lyophilization of infective sap and subsequent storage in vacuum‐sealed ampoules at room temperature. Fifty‐seven viruses survived at least i year and 19 of them over 10 years. The best results were obtained from host plants not containing inhibitors of infection or potent phenol oxidase systems. Purified preparations were also lyophilized. Lyophilization offers many advantages for maintaining a culture collection of sap‐transmissible viruses.
The resistance and tolerance of different cocoa varieties to cocoa swollen‐shoot virus in Ghana
Authors: LEGG J. T. , KENTEN R. H. 
Published: February 2008

SUMMARYThe resistance and tolerance to infection with cocoa swollen‐shoot virus (virulent strain A) of forty‐five and thirty‐eight cocoa progenies respectively was estimated using a manual inoculation method. Resistance was estimated from the proportion of inoculated seedlings which developed symptoms, and tolerance from the severity of these symptoms during a 4‐month period. Resistance was found among Nanay, Iquitos and Scavina, all Upper Amazon types; and an inter‐Nanay cross was outstandingly resistant and offers scope for improvement by breeding. Some Amazon‐Amazon and Trinitario‐Amazon progenies snowed tolerance, especially those with Trinitario T9/21 as a parent. Some progenies seem sufficiently promising for field testing to select varieties suitable for planting in those areas in Ghana where swollen‐shoot disease is epidemic.
Host range, properties and purification of raspberry bushy dwarf virus
Authors: BARNETT O. W. , MURANT A. F. 
Published: February 2008

SUMMARYRaspberry bushy dwarf virus (RBDV) was found in all plants of Lloyd George raspberry with bushy dwarf disease and occurred occasionally in plants of some other cultivars. It was transmitted by inoculation of sap to fifty‐five other species in twelve families of flowering plants and infected most of them symptomlessly. It caused systemic symptoms in some species of Amaranthaceae, Chenopodiaceae and Cucurbitaceae, and necrotic local lesions in some Leguminosae. It did not induce bushy dwarf disease when returned to Lloyd George raspberry. Chenopodium quinoa was used for propagating the virus and Vigna cylindrica for local lesion assay. In C. quinoa sap, RBDV lost infectivity when diluted 10‐4, heated for 10 min at 65 °C or stored for 4 days at 22 °C. Preparations made by twice precipitating the virus at pH 4·8 and resuspending it at pH 7·0, followed by ultracentrifugation and exclusion chromatography in columns of 2 % agarose beads, contained isometric particles about 33 nm in diameter, which sedimented as two components, with sedimentation coefficients of 111 and 116S. Only a few particles, all of them disrupted, were seen in preparations mounted in phosphotungstate, but the particles were well preserved in uranyl formate provided that they were first dispersed in a saxlt such as MgCl2 instead of distilled water. Many particles were oval in outline as though distorted during drying.No serological relationship was detected between RBDV and twenty‐four other isometric viruses nor between RBDV and the filamentous virus apple chlorotic leafspot, to which it was previously thought to be related. An isolate of loganberry degeneration virus was serologically indistinguishable from RBDV.
Evaluation of some coccinellid species for the biological control of aphids in protected cropping
Authors: GURNEY BARBARA , HUSSEY N. W. 
Published: February 2008

SUMMARYFour species of Coccinellidae, Adalia bipunctata (L.), Coccinella septem‐punctata L., Coelomegilla maculata de G. and Cycloneda sanguinea L., were compared as predators of aphids on cucumbers and chrysanthemums. In laboratory feeding tests C. maculata and C. sanguinea proved the most voracious but the former could not remain on cucumber foliage long enough to be effective. The fecundity of C. sanguinea was the highest of those studied and a satisfactory laboratory rearing technique has been developed for this species.
The curative activity of non‐ionic surface‐active agents against some powdery mildew diseases
Authors: EVANS E. , MARSHALL J. , COUZENS B. J. , RUNHAM R. L. 
Published: February 2008

SUMMARYEight non‐ionic surfactants of the general formula RO(C2H4O)nH were examined as fungicides for the control of various powdery mildew diseases. Those based on the condensation products of cetyl and oleyl alcohol with ethylene oxide were effective only as curative fungicides, having very little protective potential. This activity was greatest in products with n= 6–10. The most effective derivative, having eight ethylene oxide units, was particularly active in greenhouse tests against Sphaerotheca fuliginea on cucumber, S. pannosa on roses, and Podosphaera leucotricha on apples at concentrations which were not damaging to these crops. Although this compound caused damage to apples in the field it was effective against rose mildew and apple mildew, and its purely curative action gave a level of control equal to the standard dinitro compounds, which are capable of acting as either protectant or curative fungicides. This suggests that the dinitro‐compounds also probably act mainly in a curative fashion against these diseases in the field.
Tests of fungicides against Alternaria brassicicola and studies on some factors enhancing attack by the fungus
Authors: CHANNON A. G. 
Published: February 2008

SUMMARYWhen various fungicides were sprayed on detached cabbage cotyledons in the laboratory and on young plants in the glasshouse, propineb and mancozeb at 0·2 % a.i. consistently gave good protection against subsequent infection by spores of Alternaria brassicicola. Copper oxychloride, zineb, thiram and maneb showed promise in the laboratory, but were less successful in the glasshouse. Two fentin compounds were active at low concentrations against the fungus but were phytotoxic.Increased pathogenicity of A. brassicicola in the presence of cabbage pollen and of downy mildew infection in the laboratory is reported.