bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some properties of cocksfoot mottle virus
Authors: SERJEANT E. P. 
Published: February 2008

SUMMARYCocksfoot mottle virus (CFMV) was transmitted by manual inoculation of sap to cocksfoot (Dactylis glomerata L.), wheat, oats and barley, but not to nineteen other monocotyledonous and thirteen dicotyledonous plant species. The virus was also transmitted by cereal leaf beetles (Lema melanopa L.). Adult beetles infected plants more frequently than larvae, and remained infective for up to 2 weeks after they had fed on infected plants. Seed from infected cocksfoot and oat plants produced virus‐free seedlings.The infectivity of sap was lost during 10 min. at 65° C., and 2 weeks at 20° C., but survived many months at — 15° C.Purified virus preparations, made by various methods, contained numerous nearly spherical particles, about 30 mμ in diameter. In electron micrographs some of the particles were penetrated by negative stain though most appeared intact. However, all the particles migrated together in a centrifugal (sedimentation coefficient = 118 S) or electrophoretic field. The ultraviolet absorption spectrum, and the phosphorus and nitrogen contents of the virus preparations, were typical of a nucleoprotein containing about 25 % nucleic acid.Serological tests failed to show any relationship between CFMV and eleven other viruses with particles of similar shape and size.
The transmission of European wheat striate mosaic virus by Javesella pellucida (Fabr.) injected with extracts of plants and plant‐hoppers
Authors: SERJEANT E. P. 
Published: February 2008

SUMMARYVirus‐free individuals of the plant‐hopper Javesella pellucida (Fabr.) infected plants with European wheat striate mosaic virus (EWSMV) after being injected at 5° C. with extracts of either plants or hoppers, but extracts of hoppers provided a better inoculum. Hoppers were unable to infect plants until at least 8 days at 20–25° C. after they were injected, and nymphs fed on infected plants similarly required 8 days before they gave infective extracts. Few hoppers survived more than a week after injection with untreated extracts of hoppers or with material sedimented from them by centrifuging the extracts at 8000g, but 60–70% survived injection with purer virus preparations. Injection of the virus seemed harmless, because as many hoppers survived CO2 anaesthesis + injection, whether or not they later infected plants, as survived anaesthesis without injection. Attempts to determine the properties of the virus in vitro gave inconsistent results, but virus from hoppers was still infective after 10 min. at 30° C, 36 hr. at 5° C, precipitation at pH 4.0, storage for several months at ‐15° C, or at a dilution equivalent to 0.0014 g. hopper/ml. The best extraction medium contained 0.2 M‐Na2HPO4+ ascorbic acid + 0.01 M‐DIECA at pH 7.0–7.3. In sucrose density‐gradients, EWSMV sedimented more slowly than tobacco mosaic virus. No specific particle with which infectivity could be correlated was seen by electron microscopy.
The significance of biological races of Ditylenchus dipsaci and their hybrids
Authors: WEBSTER J. M. 
Published: February 2008

SUMMARYPure cultures of six races of Ditylenchus dipsaci derived from a single female, namely, lucerne race (LR), red clover race (RCR), white clover race (WCR), narcissus race (NR), tulip race (TR) and oat race (OR) were inoculated into eight plant species growing in pots. Onion was host to all six races, and tulip to all except RCR, whereas lucerne was susceptible only to LR and slightly to WCR. Hyacinth was not very susceptible to any race. The TR and OR were the most polyphagous. Severe symptoms were not necessarily associated with large nematode populations. Parthenogenesis did not occur. Ten fertile hybrids between races were produced and the host range of five of these was tested. On average the hybrids multiplied less than their parent races and their host ranges showed no relationship to those of their parent races. RCR and TR inoculated together into tulip produced significantly fewer nematodes than did TR alone and more than RCR alone. Mixed populations of races occur in nature which are probably a mixture of parental races, their hybrids and back‐crosses. Repeated back‐crossing of the hybrids with parental types and the slower multiplication of the hybrids is an explanation for the variation in host range of known races and the failure to record new races.
The uptake and adsorption of diquat and paraquat by tomato, sugar beet and cocksfoot
Authors: BRIAN R. C. 
Published: February 2008

SUMMARYExperiments on leaves of tomato, sugar beet and cocksfoot show that uptake of diquat and paraquat, although rapid in the light, is increased by darkness and therefore takes place through the cuticle and not through stomata. Darkness for as little as 4 hr. increased uptake almost twofold.Diquat and paraquat are rapidly and strongly adsorbed both to leaf tissue and to extraneous matter on the leaf surface.Uptake in the field is so rapid that rain immediately after treatment has little adverse effect.
Bacterial canker of poplars in Britain: The cause of the disease and the role of leaf‐scars in infection
Authors: WHITBREAD R. 
Published: February 2008

SUMMARYBacterial canker and die‐back of poplars in Britain is caused by Aplano‐bacterium populi Ridé. Pseudomonas syringae (van Hall), which has been suggested as the causal agent, plays at most only a minor role in canker lesions. It may cause a shoot blight in spring, a distinct pathological condition frequently associated with bacterial canker.Marked variation in infectivity of bacterial slime between seasons and at different dates of collection within one year appears to be the main cause for situations in which varieties, resistant in trials to inoculation with slime, have proved susceptible in the field.Leaf scars afford the main avenues for infection but their infectibility declines rapidly during October. The implications of the temporal separation of availability of natural inoculum and available infection sites are discussed.
Dothistroma needle blight of pines: Effect and etiology
Authors: HOCKING D. , ETHERIDGE D. E. 
Published: February 2008

SUMMARYThe defoliating needle blight of pines caused by Dothistroma pini Hulbary (perfect state Scirrhia pini Funk & Parker) is severely damaging to plantations of Pinus radiata D. Don., P. ponderosa Laws, and P. nigra Am. Symptoms and studies on P. radiata are reported.Disease severity has a linear relationship to stunting in very young trees, and a sigmoidal relationship to losses of height and diameter increments in 3‐year‐old trees, the most rapid losses occurring at disease severities between 25 and 75% blighted foliage. Height, independently of age, reduces disease severity. Maximum infection occurs at 0–5 ft. above ground level, while above 18 ft. there is significantly less attack.Rainfall of less than 1/2 in. weekly has little effect on disease increase and a mean weekly temperature of 65° F. or greater seems to be necessary for large disease increases; but the general environmental relations are too complex to be explained entirely quantitatively from the present data.
Susceptibility of potato tubers to infection by Phytophthora infestans
Authors: LACEY J. 
Published: February 2008

SUMMARY Phytophthora infestans infects King Edward potato tubers more readily through inoculated eyes than through lenticels, but more lenticels than eyes became infected when whole tubers were sprayed with inoculum. The resistance of lenticels but not of eyes increased as tubers aged. The spores did not infect through intact periderm. The likelihood of tubers on plants grown in pots becoming infected by sporangial suspension poured on to the soil increased the nearer the tubers were to the soil surface, the stem, or the side of the pot. Naturally infected tubers, and those sprayed with sporangial suspension, had most eyes infected at the rose end, and most lenticels infected on the middle region of the tuber. Of naturally infected tubers, on which the site of infection could be identified, most were infected through eyes at the rose end.
The multiplication of Longidorus elongatus (de Man) on different host plants with reference to virus transmission
Authors: TAYLOR C. E. 
Published: February 2008

SUMMARYIn pot tests, Longidorus elongatus (de Man) populations increased rapidly on Fragaria vesca, Stellaria media, Mentha sativa and Lolium perenne and slightly on Brassica rapa (turnip var. White globe) and on Ribes nigrum; but on Rubus idaeus populations declined at the same rate as in fallow soil. Raspberry ringspot (RRV) and tomato black ring (TBRV) viruses were readily transmitted by L. elongatus to S. media, TBRV only was transmitted to L. perenne, and M. sativa became infected with neither virus. RRV was transmitted to R. idaeus var. Mailing Jewel, on which the nematode fed but evidently did not reproduce.In a field experiment L. perenne and Fragaria ananassa (strawberry) vars. Huxley and Redgauntlet were shown to be good hosts for L. elongatus and R. idaeus (raspberry) vars. Lloyd George and Mailing Jewel were confirmed as non‐hosts, together with Rheum rhaponticum (rhubarb). Two periods of egg laying were detected each year in the Redgauntlet strawberry plots and these coincided with the growth of young roots during the late spring and autumn.The wide host range of L. elongatus among cultivated plants and weeds, together with its ability to survive long periods without food, precludes the use of crop rotation as a means of control. Chemical soil sterilization is considered the most effective means of control because it can greatly decrease L. elongatus populations and as the nematode multiplies slowly, even on favourable host plants, several years are likely to elapse before populations become large enough to spread viruses effectively from infector plants to susceptible crops.
Soil teachings and the hatching of larvae of the potato‐root eelworm, Heterodera rostochiensis Wollenweber
Authors: ELLENBY C. , SMITH L. 
Published: February 2008

SUMMARYLeachings were taken from fallow soil brought in from an outside plot at monthly intervals throughout a year, and tested for their ability to stimulate hatching of the potato‐root eelworm. Some of the leachings showed stimulatory action, the results indicating a seasonal pattern of activity with a peak in August. As noted previously, this suggests that soil organisms produce substances able to stimulate hatching and that these are probably responsible for the so‐called ‘spontaneous’ hatching.
Selection of aphid prey by Adalia bipunctata L. and Coccinella 7‐punctata L
Authors: BLACKMAN R. L. 
Published: February 2008

SUMMARYLarvae and adults of Adalia bipunctata L. and Coccinella 7‐punctata L. seemed unable to detect and avoid feeding on unsuitable or toxic aphids, e.g. larvae of A. bipunctata fed on the highly toxic Megoura viciae, even when given the choice of a suitable aphid. Apparent preferences were not always for the most suitable food.Field cage experiments demonstrated the preference of adult A. bipunctata and C. 7‐punctata for different habitats, the former ovipositing at the shrub level (4 ft.) and the latter feeding and ovipositing on plants near ground level.
Dothistroma needle blight of pines
Authors: HOCKING D. 
Published: February 2008

SUMMARYIn laboratory and field tests against Dothistroma pini of thirty‐eight commercially available or experimental fungicides several showed high contact activity (notably Blasticidin M), indicating potential eradicant properties. Only triphenyl tin or copper‐based compounds gave good field protection.For protection, two widely spaced annual applications are recommended for an area with two heavy rainfall periods.
Biochemical changes in infection droplets containing spores of Botrytis spp. Incubated in the seed cavities of pods of bean (Vicia faba L.)
Authors: DEVERALL B. J. 
Published: February 2008

SUMMARYInfection droplets containing spores of Botrytis cinerea become inhibitory to the growth of germ tubes of the fungus within 18 hr. of their incubation in bean pods. The inhibition is caused by an ether‐soluble substance, which has been partially purified, and which counteracts the stimulatory effect of sucrose, glucose, fructose, galacturonic acid and several amino acids, which are also present in the infection droplets.Changes in concentration of these substances have been described in the first 24 hr. after placing infection droplets in pods. The only major difference between droplets containing B. fabae and B. cinerea concerns the nature of the ether‐soluble substances produced. Following B. fabae infection a biologically inactive u.v. absorbing substance appears in high yield in place of the antifungal substance formed following B. cinerea infections.
The use of heat to control the rotting of Cox's Orange Pippin apples by Gloeosporium spp
Authors: EDNEY K. L. , BURCHILL R. T. 
Published: February 2008

SUMMARYDipping in warm water successfully reduced the incidence of infection of Cox's Orange Pippin apples by Gloeosporium spp. Treatment of fruit loaded after harvest with spores of G. perennans was most successful if carried out 3–9 days after inoculation; later treatment was less effective. Infection taking place late in the growing season was relatively more susceptible to treatment than infections established on less mature fruit. Steam/air mixtures provided a successful, alternative source of heat; accelerated cooling after treatment with such mixtures did not reduce their effect. Browning of the skin and increased incidence of rotting by Penicillium spp. may follow heat treatment. With liquid cultures heat has a greater effect on germinated than on ungerminated spores and over the range of temperatures used for treating apples results in delayed fungal development rather than eradication.
Inheritance of resistance in maize to the virus of streak disease in East Africa
Authors: STOREY H. H. , HOWLAND AUDRIE K. 
Published: February 2008

SUMMARYMaize plants selected from lines raised in South Africa, and resistant to an East African isolate of streak virus, gave rise on selfing to lines that bred true for resistance through four generations.Heterozygotes from crossing resistant by susceptible lines reacted to infection by inoculation with the vector in a manner intermediate between the parents; neither allelomorph was fully dominant. The F2 generation from the cross segregated in the expected 1:2:1 ratio. Backcrosses segregated 1:1.The evidence is interpreted as showing control of resistance by a major gene, but with modification in details of the reaction attributed to minor genes.
Some effects of cultural treatments on virus diseases of cultivated mushroom, Agaricus bisporus
Authors: LAST F. T. , HOLLINGS M. , STONE OLWEN M. 
Published: February 2008

SUMMARYInoculating crops of a white strain of mushroom with virus‐infected cultures delayed cropping and decreased yields; the effects were progressively less the later that infection occurred, and/or the larger the amount of healthy spawn used.Crops in trays inoculated at a single site usually developed three zones: (1) a barren zone about the site of inoculation, progressively enlarging as the crops aged; and surrounded by (2) a band of stunted mushrooms bordering an outer area (3) of apparently healthy crop, in which a few sporophores might show hard‐gill or watery‐stipe abnormalities. Mycelial isolates taken at different distances from the sites of inoculation grew at different rates, growth being inversely proportional to the virus content of the fruit‐bodies as estimated by electron microscopy and serology. Isolates from virus‐free mushrooms grew rapidly on agar media, producing white fluffy colonies with many coarse strands, whereas those obtained from the few fruit‐bodies near sites of inoculation were brown, adpressed to the medium, and grew very slowly. Between these extremes a continuous range of intermediates occurred, most of which remained constant when subcultured. Isolates taken at successive intervals from the same site in a tray had progressively smaller growth rates.Unsterilized mushroom‐growing equipment (e.g. trays) is thought to carry viruses in infected spores and mycelial fragments which infect later crops without inducing characteristic zones. Instead, cropping of the whole tray declines with each successive flush. Such infection was prevented by heat‐sterilizing the trays between crops.
Persistence and distribution of insecticidal seed‐dressings for control of the wheat bulb fly, Leptohylemyia coarctata
Authors: LORD K. A. , SCOTT G. C. , JEFFS K. A. , GRIFFITHS D. C. , MASKELL F. E. 
Published: February 2008

SUMMARYSamples of plants and soil from two experimental sites, one clay loam and one peaty loam, were analysed chemically to try to explain differing results with γ‐BHC and dieldrin seed‐dressings applied to control wheat bulb fly on different soil types, and to suggest reasons for patchy plant stands and occasional failure to control the pest. Seed dressed with dieldrin yielded more than untreated seed on both sites, whereas seed treated with γ‐BHC yielded as much as seed treated with dieldrin on the clay site, but it yielded less than untreated seed on peat. The chemical analyses showed that the poor performance of γ‐BHC on the peat site could not be explained by its failure to persist, because the soil still contained considerable quantities of γ‐BHC at the time of insect attack. Possible reasons may be sorption of the poison by organic matter making it less available, and deeper sowing, permitting larvae to reach the plants without prolonged contact with the insecticide.Bayer 38156 (O‐ethyl S‐p‐tolyl ethyl phosphonodithioate) and trichloro‐nate (O‐ethyl O‐2,4,5‐trichlorophenyl ethyl phosphonothionate) persisted in soil long enough and were sufficiently toxic to wheat bulb fly to suggest that organophosphorus compounds might provide alternatives to chlorinated hydrocarbon insecticides for control of the fly.Analyses made on seeds dressed at the laboratory for the experiment showed that the amounts of insecticide on seeds were smaller than expected and that the amounts on individual seeds differed greatly. Of ten samples of seeds dressed commercially with y‐BHC, three carried very little insecticide, and the variations in the other seven samples were greater than with experimentally applied dressings.
The toxicity of tributyltin oxide to the wood‐boring beetles Lyctus brunneus Steph. and Anobium punctatum (Deg.)
Authors: BAKER J. M. , TAYLOR JEAN M. 
Published: February 2008

SUMMARYWhen tributyltin oxide (TBTO) was tested by British Standard 3653 against Lyctus brunneus, 0·5 % solution, equivalent to 0·72 g/m2 surface application, gave almost complete protection. Tests to BS 3651, using larvae of Anobium punctatum transferred into fully impregnated wood gave toxic limits of 1·39–2·93 kg/m3 TBTO when benzene was used as diluent. The use of white spirit as diluent gave lower toxic limits, probably due to combined toxic action of TBTO and white spirit residues. TBTO appears to have no contact action against the insects tested.Probit analysis of the test with A. punctatum gave an LD 50 of 0·254 kg/m3 and an LD99 of 3 kg/m3. The advantage of treating results by probit analysis rather than by deriving ‘toxic limits’ is discussed.
Effect of wax and lanolin emulsions on the efficiency of potato‐blight fungicides in laboratory tests
Authors: MCINTOSH A. H. , EVELING D. W. 
Published: February 2008

SUMMARYFour potato‐blight fungicides (copper oxychloride, tetrachloroisophthalo‐nitrile, zineb and fentin acetate) were formulated either by adding emulsions of paraffin wax or lanolin to solid fungicide dispersed in water, or by dissolving the fungicide in wax or lanolin and then emulsifying the solution; all emulsions were non‐creaming and extremely stable. These formulations were compared in the laboratory with commercial wettable powders of the same fungicides for their ability to protect detached potato leaflets against infection by Phytophthora infestans (Mont.) de Bary; in these and in other laboratory tests, the quality of rain‐fastness, or tenacity, was involved directly or indirectly.Most of the wax or lanolin formulations gave better protection than the wettable powders. It is suggested that the wax and lanolin acted as viscous stickers, suitably increasing the rain‐fastness of deposits on leaflets; and that when the fungicide was dissolved in the wax or lanolin before emulsification, the particle size of the dispersed fungicide was extremely small, a quality that increases biological action.
Screening trials of materials for suppressing spore production by Gloeosporium perennans on apple trees
Authors: CORKE A. T. K. 
Published: February 2008

SUMMARYIn a screening trial of thirteen potential spore suppressants carried out in 1965, sporing cankers on Cox's Orange Pippin shoots, induced by inoculation with Gloeosporium perennans in November 1964, were treated at bud‐burst with the test materials. The most effective spore suppressant was dichlo‐fluanid; this, with the next five most effective materials and six additional materials, was used in a second trial in 1966, when the greatest reduction in spore production was obtained with tetrachloro‐o‐cresol.A general trend towards correspondence between spore output from cankers and infection on neighbouring fruits was shown, but this could be modified by a number of factors, including changes in spore viability caused by fungicide treatment.
Observations on the vapour phase activity of some foliage fungicides
Authors: HISLOP E. C. 
Published: February 2008

SUMMARYBy means of a Botrytis fabae/Vicia faba bio‐assay technique it has been demonstrated that phenyl mercury chloride, maneb, mancozeb, dichlo‐fluanid and oxythioquinox protect areas of leaf beyond the visible limits of the fungicide deposits. The evidence suggests that the extended areas of protection are due to the release of fungicidal vapours. For a given dose of mancozeb the area of protection was related to the number of conidia of B. fabae dusted on to the leaves and for a given inoculum density it extended with increasing fungicide dose applied in standard drop sizes. When the same dose of fungicide was applied in increasing volumes of water, producing widening areas of deposit, the area of protection also increased. Fungicide deposits aged on leaves for up to 4 weeks continued to release toxic vapours.Contact between the fungicides and leaves or between fungicides and spores was not necessary for the demonstration of the phenomenon since vapours diffused from deposits on glass and inhibited the germination of spores in water droplets placed at a distance from the fungicide source. For a given distance separating the fungicide and the spores inhibition increased with increasing fungicide dose. For a standard fungicide dose, inhibition decreased with increasing distances between the fungicide and the spores. The fungicidal vapours inhibited the germination of spores of test fungi other than B. fabae.The practical implications of these observations are examined in the light of evidence that vapour phase protection can occur on leaves incubated in large cabinets; on leaves pre‐incubated at unsaturated humidities; and on leaves incubated in a moving stream of air.
Effect of soil fumigants on Fusarium wilt and nodulation of peas (Pisum sativum L.)
Authors: EBBELS D. L. 
Published: February 2008

SUMMARYChloropicrin, dazomet, formaldehyde, and D‐D soil treatments all decreased the incidence of Fusarium wilt in a wilt‐susceptible variety of pea grown in wilt‐infested soil, but only chloropicrin and dazomet gave satisfactory control of the disease. All four fumigants decreased root nodulation, but no adverse effects on plant growth were detected. With dazomet, formaldehyde, and D‐D, decreased nodulation is largely attributed to the extra soil nitrogen mineralized, whereas with chloropicrin the almost complete suppression of nodulation probably reflects the lethal effect of this material on the Rhizobium bacteria.