bluuebunny/crossref_metadata_2025_split huggingface dataset:
FIELD EXPERIMENTS ON THE DETERIORATION OF SCOTCH POTATO SEED IN ENGLAND
Authors: BROWN W. , BLACKMAN V. H. 
Published: February 2008

Summary

An experiment with three varieties of potatoes (Great Scot, Kerr's Pink and King Edward) was carried out during the period 1922–24 in order to test the physiological theory of potato deterioration by determining whether the cropping power was influenced by early lifting or affected by shading the growing plants and so protecting them from overheating. The main results of this experiment were as follows:

In the absence or very limited presence of virus disease, neither early lifting nor shading produced any significant effect on crop yield. All the types of seed (one‐year grown, two‐year grown, early‐lifted, etc.) gave yields which were not significantly different from that of fresh Scotch seed.
When considerable infestation with virus disease was shown, all the types of English‐grown seed showed a significant falling off in yield as compared with Scotch seed. In such cases the falling off in yield was not so great with seed which had been lifted at a very early date. Thus, with virus disease present, an advantage may be gained by early lifting of the seed.
In one case, evidence was obtained that very immature seed is intrinsically inferior in cropping power to seed lifted at the normal time, i.e. apart from the effects due to the unequal distribution of virus disease.
In two cases the greater cropping power of one‐year grown English seed as compared with fresh Scotch seed was demonstrated. This difference is probably to be explained on the ground of the unequal sprouting at the time of planting.
A general correlation was observable between the amount of virus disease present in the various plots and the falling off in cropping vigour.
No effect of a purely physiological nature arising from early lifting or from shading was indicated. Though such an effect could not be disproved, it was clear that it was of minor account and quite subsidiary to the effects of virus disease.

An experiment was carried out over the period 1925–8 to determine whether, by a process of rogueing, the cropping vigour of a deteriorated stock could be restored. The weight tests carried out in 1928 showed that certain English‐grown stocks, some of which were in their seventh year from Scotland, yielded as heavily as Scotch seed.
The experiments were carried out in such a way that the statistical significance of the data obtained could be assessed. In thirty‐three such experiments, where the yield of English‐grown types of seed was compared with that of Scotch seed, the percentage drop in cropping power which was significant varied from 7.0 to 20.0. Over the whole series, the average figure was 11.8 per cent., corresponding to a falling off in yield of about 1.2 tons per acre.

In conclusion we wish to record our thanks, for facilities offered for this work, to the Director of the Rothamsted Experimental Station and to the Principal of the South‐Eastern Agricultural College, Wye, and the Principal of the Harper‐Adams Agricultural College, Newport, Salop.
APHIS AS A POSSIBLE VECTOR OF “BREAKING” IN TULIP SPECIES
Authors: HUGHES A. W. McKENNY 
Published: February 2008

Summary

Myzus persicae Sulz. is suggested as a vector of the virus of transmissible variegation known as “breaking” in tulips.
“Red‐streak break” is associated with Myzus persicae.
Macrosiphum gei Koch possibly carries “break” in a lesser degree and is associated with “white streak.”
Anuraphis tulipae B. de Fonse. and Rhopalosiphoninus tulipaella Theo. have both so far shown negative results.
GIBBERELLA SAUBINETII (MONT.) SACC. ON BRITISH CEREALS
Authors: BENNETT F. T. 
Published: February 2008

Summary

The occurrence of Gibberella Saubinetii (Mont.) Sacc. on wheat and barley grown in England is recorded, but the extent to which it occurs in this country is not known.
The methods by which it was isolated and grown in pure culture are described.
The complete life cycle of this “strain” has been carried through from single‐conidium and single‐ascospore pure cultures.
The diagnostic characters are given, and the identification verified.The writer tenders thanks to Dr G. H. Pethybridge for assistance rendered.(Since writing the foregoing article the writer has isolated G. Saubinettii from the bases of wheat, barley and T. monococcum plants grown in the Eastern Counties. 23/12/29.)
BACTERIAL “BLIGHT” OF WALNUTS IN BRITAIN
Authors: WOEMALD H. 
Published: February 2008

Summary

An organism has been isolated from lesions on leaves, shoots, and fruit of young walnut trees at the East Mailing Research Station, Kent.
This organism was proved to be pathogenic by positive results obtained from inoculation on walnut leaves and shoots.
It corresponds closely to descriptions of Pseudomonas juglandis and is therefore referred to that species.
CARBON DIOXIDE IN RELATION TO GLASSHOUSE CROPS
Authors: SMALL T. , WHITE H. L. 
Published: February 2008

Summary

The effect on the tomato crop of atmospheres enriched in respect of carbon dioxide liberated by two methods with possibilities of commercial application, (1) a fermentation process, and (2) a portable stove, is compared with that of carbon dioxide liberated by acid from sodium bicarbonate.
The concentration of carbon dioxide obtained from the fermentation process was insufficient to give any increase in yield. Using the stove method, which gave a concentration of at least 18 parts per 10,000 for 1.5 hours twice daily, the average increase in crop was 16 per cent. where plants were treated throughout the season and was 9 per cent. where they were treated for the first half of the season only.
Relatively high concentrations of carbon dioxide are shown to be normally present in cucumber houses. It is suggested that, under the weak light conditions prevailing in such houses, the concentration is sufficient for the requirements of the crop.
Mechanical mixing of the carbon dioxide and air is not essential from the standpoint of crop production.
In the case of tomatoes grown in enriched atmospheres, the cultivation of two crops, planted January and June respectively, was not profitable under the experimental conditions.
The stove method of treatment is discussed in relation to commercial practice.
APPARATUS FOR THE GROWING OF PLANTS IN A CONTROLLED ENVIRONMENT
Authors: STOUGHTON R. H. 
Published: February 2008

SummaryAn account is given of the construction of tanks and chambers for the growing of plants under independently controlled soil and air conditions. The plants are grown in soil tins sunk in a water tank, the temperature of which is automatically controlled. Double‐walled glass chambers fit over the tanks, and within these the conditions of temperature and humidity are independently controlled. Artificial illumination is provided by two floodlights over each chamber, with 500‐watt gas‐filled lamps in each providing an illumination of the order of 1000 foot‐candles. The chambers were erected under a grant from the Empire Marketing Board for research on the bacterial disease of cotton.
ON THE CAUSES OE SWARMING IN THE HONEY BEE (APIS MELLIFERA L.): AN EXAMINATION OF THE BROOD FOOD THEORY
Authors: MOBLAND D. M. T. 
Published: February 2008

Summary

The influence of nitrogenous food in the hive is discussed in its bearing on the question of swarming.
Theories of the origin of the brood food are examined.
The division of labour among the bees of various ages is considered in its relation to the brood rearing cycle.
A critical surplus of nurse bees is found to be associated with the formation of queen cells in preparation for swarming.
Eecognised swarm control measures are reviewed in the light of the brood food theory.
Studies On Potato Virus Diseases VIII. On A Ringspot Virus Affecting Solanaceous Plants
Authors: Smith Kenneth M. 
Published: February 2008

SUMMARY.

A ringspot virus affecting solanaceous plants is described. This is the first record of the disease in the British Isles.
The reactions of the following solanaceous plants to the ringspot virus are described S. capsicastrum. S. tuberosum (potato). S. laciniatum. S. nigrum (black nightshade). S. nodiflorum. Lycopersicum (tomato). Nicotiana tubacum (var. (a) White Burley, (b) Virginia). N. glauca. Datura stramonium (jimson weed). Capsicum spp.
The close parallels in the behaviour of the ringspot to the viruses of the potato mosaic group are emphasised. The virus is able to exist in a variety of symptom expressions according to species of host plant and degree of virulence. “Ringspot” is thought to be an alternative symptom expression for a number of mosaic viruses, the development of the ringspot symptoms probably depending upon the degree of virulence of the virus, the type of host plant and the method of infection of that host plant.
A marked difference in receptivity of the various solanaceous plants to the ringspot virus when transmitted by the aphis M. persicae is shown to exist. The virus was transmitted by means of this aphis to D. stramonium and Capsicum and not to the other species.
The phenomenon of temporary recovery of tobacco plants affected with the ringspot in its virulent form is well illustrated. Plants die down and then re‐grow for a period, temporarily symptomlees, only to succumb once more to a severe attack. This may happen two or three times before the plant finally remains in a necrotic and moribund condition.
In no case was the virus transmitted through the seed of affected plants.
Pasture Production In Areas Liable To Infection By Oncopera Intraicata (Walder) In Tasmania
Authors: Nelson Alexander 
Published: February 2008

Summary.The replies to a questionnaire sent out to a large class of sheep owners and pastoralists in Tasmania indicate: (1) that Oncopera intricata (Walker) is a pest of first‐class economic importance in the State of Tasmania, precluding as it does successful pasture production over large areas of the country; (2) that grasses with a mechanism for natural vegetative propagation, e.g. stolons, etc., are likely to persist through a severe attack and by their recovery after the pupation of the grass‐attacking larvae provide some return rather than allow the ground to go out of production or be covered by unprofitable weeds; (3) the replies plus external evidence show that a sward of creeping grasses and clovers will be likely to be most useful.
The Stem And Buld Eelworm, Tylenchus Dipspaci (Kuhn) Bastian. A Further Conteribution To Our Knowledge Of The Biologic Strains Of The Nematode
Authors: Hodson W. E. H. 
Published: February 2008

Summary.1. The significance of the occurrence of biologic strains in T. dipsaci is discussed and reference made to previous work on the subject,2. The technique by which the nematode may regularly be induced to set up an infestation in a favoured host plant is described, as is its application to the experiments made.3. Experimental results obtained when fourteen strains of the nematode, of known history, are given facilities for entering alien host plants are presented in detail.4. The conclusions arrived at are, that biologic strains of T. dipsaci occur, but that these strains are in some cases able to attack more than one host plant. Further, some affinity appears to exist between strains occurring in the narcissus and in the common plantains.5. The practical application of our knowledge, in the event of a crop being attacked by the nematode, is discussed.
Gibberella Saubinetii (Mont.) Sacc. on British Cereals: II. Physiological AKD Pathological Studies
Authors: Bennett F. T. 
Published: February 2008

Summary G. Saubinetii (Mont.) Sacc., the conidial stage of which is known as Fusarium graminearum Schwabe, produces mature perithecia on natural and artificial substrata, given ample moisture and a uniform temperature of 21° to 22°C. British summer shade temperature does not suffice for this.The minimum temperature for the germination of conidia and ascospores is about 6°C. Between 5° and 10°C. both kinds of spores develop mycelia, and the fungus can infect cereal seedlings. The optimum temperature for vegetative growth of the fungus and the production of mature perithecia is about 24° C.; the maximum temperature for growth is about 37°C.In its vegetative and perithecial stages this fungus can withstand prolonged exposure to a temperature range of — 1° to — 20°C. and in its vegetative stage it persists through the winter in this country.Under storage conditions it retains its vitality for at least two years in its vegetative stage, and for at least one year (probably much longer) in its perithecial stage.Heating to 100°C. for five minutes under dry conditions kills G. Saubinetii on or in diseased grains, but this treatment of seed grain is not a practicable way of controlling the disease. G. Saubinetii causes “seedling blight” and “foot rot” of cereals, but is much less virulent than .F. culmorum and F. avenaceum in this respect. All three fungi attack the ears in a similar way, with similar virulence and with similar results. G. Saubinetii occurs throughout England and in Ireland, but full details of its frequency of occurrence in the British Isles have not yet been obtained.
Extracts of Pyrethrum: Permanence of Toxicity and Stability of Emulsions
Authors: Tattersfield F. , Hobson. R. P. 
Published: February 2008

Summary.1. Pyrethrum flowers (Chrysanthemum cineraraefolium) both as whole heads and as powder retain their insecticidal properties at ordinary temperatures and at 28°C. for considerable periods if stored in closed vessels. If exposed to the atmosphere in a thin layer as finely ground powder there is risk of loss of toxicity.2. Alcohol and petroleum extracts of pyrethrum retain their toxicity in temperate climates over many months. Alcohol extracts readily give permanent emulsions when added to water; petroleum extracts require the incorporation of an emulsifier.3. Water‐miscible petroleum extracts of pyrethrum can be prepared by the addition of certain materials, such as ammoniated Agral W.B. and neutral turkey‐red oil.4. A study has been made of the degree of permanence of the active principles in alcoholic and water‐miscible petroleum extracts at ordinary British temperatures and at 28°C. and also in emulsions of these extracts in alkaline spray fluids of varying PH. The active principles proved more permanent than has been usually supposed.5. The readiness with which water‐miscible petroleum extracts disperse in the aqueous phase and the stability of the emulsions formed under a variety of conditions have been investigated.
Experiments on Potato Sickness
Authors: Cheal W. F. 
Published: February 2008

Summary.Following results already published of the effect of inoculations on potato plants with Heterodera schachtii and Corticium Solani in 1928 and 1929, further pot experiments were carried out in 1930 with an additional organism Colletotrichum atramentarium. The results showed a definite effect, the fir& year of inoculation, in those pots where Heterodera schachtii was present.There was not enough evidence to support the view that the absence of Colletotrichum atramentarium in the 1928 inoculations accounted for the slight symptoms of potato sickness produced that year compared with results obtained in 1929 (the second year).
The Formation Of Intracellular Inclusions In Solanaceous Hosts Infected With Aucuba Mosaic Of Tomato1
Authors: SHEFFIELD F. M. L. 
Published: February 2008

SummaryA description is given of the mode of formation of intracellular inclusions produced by aucuba mosaic of tomato in Solanum nigrum, S. nodiflorum, S. lycopersicum, Nicotiana tabacum and Hyoscyamus niger.Soon after infection the rate of streaming of the cytoplasm is increased, then minute particles of protein appear in the cytoplasm which carries them passively about the cell. These particles aggregate and fuse to form large masses which are still carried passively but more slowly about the cell. These fuse until all the protein material is contained in one or occasionally more granular masses. In the three Solanum species examined this mass becomes rounded and it may lose its granular appearance and become vacuolated. In N. tabacum the body does not always round off and in H. nip it very seldom does so but remains as an irregularly shaped granular mass which may, however, become vacuolate.There is no evidence at any time of autonomous movement, the particles and the fully formed body being carried, as are the cell nucleus, mitochondria, etc., of the normal plant, in the cytoplasmic stream.After the spherical body is formed spike‐like crystal appears in the cell.The cell remains at rest for the space of several weeks. Often the rounded inclusion body and the nucleus are juxtaposed, but there is no special significance in this, it is merely the accidental result of the mode of formation of the body. Particles tend to accumulate where number of strands of plasm meet; usually several strands converge on the nucleus.Ultimately the body breaks down giving number of protein crystals. After some months these dissolve. In H. niger the inclusion bodies are confined to the chlorotic areas where they are abundant in all tissues. In the other species studied they are distributed over green and yellow tissues. They are very abundant in the hairs, less so in the epidermis and very rare in the palisade and spongy tissues. In H. niger the development of the palisade tissue is arrested, in the other species the development is not so obviously affected although growth is retarded.These inclusions appear not to be organismal in nature; they seem to be products of reaction of the host cell to the virus, but they may contain the etiological agent of the disease.
Some Experiments On Inoculating Methods With Plant Viruses, And On Local Lesions
Authors: SAMUEL GEOFFREY 
Published: February 2008

Summary.It is shown by means of dilution tests that a light rubbing with virus, in which no visible wound is produced on the leaf, is a more effective method of mechanical inoculation than scratching with a needle in the case of the five viruses: cucumber mosaic, spot necrosis, tobacco ring spot, petunia mosaic, and yellow tobacco mosaic, all inoculated on to tobacco. The contentions of Holmes with regard to inoculating methods with tobacco mosaic are thus extended to these other viruses.Some of these viruses form local lesions of a definite type which may prove to be of value in quantitative work. It is shown that temperature, age of the leaf inoculated, and other factors influence the character and the number of the local lesions formed.The development of the virus in the inoculated leaf (the “primary phase” before systemic symptoms become visible), as well as certain later stages, can be followed particularly well in the case of yellow tobacco mosaic, using the iodine method for demonstrating the areas of normal starch formation (Holmes, 1931). In an area closely corresponding to where the virus has spread, starch formation is inhibited, so that the path followed by the virus shows up as a light‐coloured area in the treated leaves. An intimate relation between the vascular system and the path of travel of the virus is made strikingly evident by this treatment.
The Biology Of Thysanoptera With Reference To The Cotton Plant: VII. The Relation Between Temperature and Relation and the Life Cycle
Authors: MACGILL ELSIE I. 
Published: February 2008

Summary.1. It is found that in the development of T. tabaci the degree of atmospheric humidity is of great importance in the question of the survival of the larva.2. At high temperatures a relatively high degree of atmospheric humidity (over 70 per cent.) is necessary if the insects' are to reach maturity.3. Although temperature has a most marked effect on the length of the life cycle of T, tabaci, the degree of relative humidity appears neutral, neither accelerating nor retarding the development of this insect.
Pyrethrum Flowers: A Quantitative Study Of Their Development
Authors: TATTERSPIELD F. 
Published: February 2008

Summary.

An account is given of the examination of the flowers of pyrethrum plants (C. cinerariafoolium) grown upon a bed in Harpenden. The plants were divided into blocks and randomised, the flowers being harvested from a dozen plants each week over a period of 81/2 weeks, the flower heads ranged from the small bud stage in the first week to the overblown stage in the last week. The categories into which the flowers were divided to indicate maturity are defined and illustrated.
The yield in numbers and weight of heads per plant, the diameters of the receptacles and the content of pyrethrin I and II were determined. There was a considerable amount of variation in all these factors in the flowers from different plants.
A statistical analysis showed in this experiment:

That there was no significant variation in the numbers of the flowers with time, but that position of the plant in the bed had a significant effect.
That the time of harvesting had a significant effect upon the content of the pyrethrins whether taken separately or together and whether expressed in percentages, parts per flower head or parts per plant. The effect due to‐ position was only definitely significant in the case of pyrethrin I when expressed in parts per flower head.
That there was on the different dates a significant correlation between the contents of pyrethrin I and II expressed in parts per flower head or plant.
That there was, for the blocks of material examined, a significant correlation between the contents of pyrethrin I and II, whether expressed in percentages, parts‐per head or parts per plant, but that owing to the heterogeneity of the material the correlation was only significant for individual plants when the pyrethrias were expressed in parts per plant.

The data in this experiment indicate that for the material examined, there is a quantitative development of the active principles in the flower heads from the small bud stage up to the time of maturity of the flowers, which more than keeps pace on the whole with the increase in weight of the flowers. Thus the content of pyrethrins, both relatively and absolutely, rises to a maximum at the maturity of the flowers. The mean percentage content of pyrethrins fell after pollination and the fading of the flowers; this corresponds with the rapid increase in weight of the heads on the formation of seed. There would thus appear to be a loss, which might be serious, both in percentage content of active principles and in yield of flowers if harvested before being fully open. There seems to be no useful purpose served in leaving the flowers to the overblown condition.

I wish to express my great indebtedness to Dr R. A. Fisher and Dr J. Wishart for carrying out the greater part of the statistica.1 analyses incorporated in this paper and for much helpful advice. I am also indebted to Mr J. T. Martin for checking many of the analyses by an alternative method.
THE FILTRATION OF THE VIRUS OF STREAK DISEASE OF MAIZE
Authors: STOREY H. H. 
Published: February 2008

SUMMARYExperiments have been carried out in the feeding of leafhoppers timragh membranes upon the juice of streak‐diseased maize plants after passage through various filters. Tests of these leafhoppers have shown that at a pH of about 6 the virus passes through Chamberland LI, Berkefeld V and N niters, and less freely through Chamberland L3. Hie virus does not pass a Seitz E.K. filter disc.
THE CHLOROTIC DISEASE OF THE HOP. II
Authors: Salmon E. S. , Wake W. M. 
Published: February 2008

SUMMARY

Further experiments are recorded in which the transmission of the recently described chlorotic disease of the hop was obtained by means of grafting and budding.
Transmission was obtained also by rubbing healthy leaves with macerated chlorotic tissue in such a way that.bruising of the lamina resulted.
In all the experiments described, with one exception (see above, p. 6), no symptoms of disease appeared until the year following that in which the inoculations were made.