bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE BIOLOGICAL DECOMPOSITION OF PLANT NATERIALS: PART IX. THE AEROBIC DECOMPOSITION OF HEMICELLULOSES
Authors: NORMAN A. GEOFFREY 
Published: February 2008

SUMMARY.1. The decomposition of the hemicelluloses of plant materials occurs rapidly under normal aerobic conditions. Since a number of fungi have been shown by analyses of pure culture rots to be active in fermenting this group, as well as cellulose, some seventy common fungi, mostly Aspergilli and Penicillia, were tested as to their ability to utilise on agar plates the crude hemicellulose from oat straw.2. All of the fungi tested grew reasonably well on the hemicellulose medium, the majority at least as well as on glucose, and a number better than on that sugar. In some cases there was production of a cleared zone round the colony due to an exo‐enzyme. It is likely that ability to ferment hemicelluloses will be found to be a general property of common fungi.3. From soil, manure, and straw, twenty aerobic bacteria were isolated capable of utilising hemicelluloses. Three of these were thermophilic forms. Their morphological characters and biochemical reactions were determined.4. All the organisms utilised a very wide range of sugars and poly‐saccharides; one group produced some acid and gas, the remainder little. Differentiation was obtained on saccharic acid and certain disaccharide acids.5. Five of the mesophilic organisms agreed closely with the description of Achromobacter ubiquitum (Jordan). The remainder were aerobic spore‐formers, though not all Gram‐positive. The negative forms may represent new species.6. None of the organisms in pure culture could validly be described as active in decomposing the isolated hemicellulose, or that in situ in straw.7. Fungi seem to be more active and important in the natural decomposition of hemicelluloses than bacteria, unless when working in association the rather restricted individual fermentative powers of the latter are considerably enhanced.
OBSERVATIONS ON THE BIOLOGY OF THE LYCTUS POWDER‐POST BEETLES, WITH SPECIAL REFERENCE TO OVIPOSITION AND THE EGG
Authors: PARKIN E. A. 
Published: February 2008

SUMMARY.1. The life history and habits of the Lyctus powder‐post beetles have been described and the sex ratio determined.2. External sex characters are given for six species reared from timber at the Forest Products Research Laboratory, Princes Risborough.3. The male and female reproductive organs of various species are briefly described.4. An account is given of copulation and oviposition.5. A detailed description is given of the egg of different species, before and after being laid.6. The changes in form which probably occur as the egg passes from the calyx to the exterior are described, and evidence is given to support the statements made.7. The period of incubation of the egg has been determined and observations are recorded on embryonic development and the eclosion of the larva.8. Special attention is given to the modification of Fisher and Clarke's pore‐size theory to fit the results of the present investigation.
ON THE BIONOMICS AND STRUCTURE OF SOME DIPTEROUS LARVAE INFESTING CEREALS AND GRASSES: II. OPOMYZA GERMINATIONIS L
Authors: THOMAS. I. 
Published: February 2008

SUMMARY.In the laboratory, the larval food plants of Opomyza germinationis L. are, oate, wheat, barley, Lolium perenne, L. italicum, Dactylis glomerata, Festuca rubra, Poa trivialis and Cynosurus cristata. In the field, only a few larvae were found in the cereals, the chief host plants being the grasses. The injury is similar to that caused by the larva of Oscinella frith.There are three larval instars and pupation takes place inside the host plant near the ground. Adults emerge in mid‐June and live until early November.In the laboratory eggs were laid in September and October either on the plants generally near the ground level or on the soil near the seedlings.A description is given of the three larval instars, the egg and the puparium.
The Physiology of Potato Leaf‐Boll
Authors: WHITEHEAD T. 
Published: February 2008

Summary.1. A comparative study of the rates of respiration, as measured by the weight of carbon dioxide evolved, has been made with healthy and leaf‐roll infected potatoes at all stages in the life cycle, under anaerobic as well as aerobic conditions.2. Except for a short period covering the end of dormancy of the tuber to the first unfolding of the leaves, the infected plant respires at a much lugher rate than does the healthy one. This is true also when the conditions of light, temperature, and external carbon dioxide approximate to those present in the field.
The Effect of Mosaic Disease Upon Certain Metabolic Products in the Tobacco Plant
Authors: CORDINGLEY H. , GRAINGER J. , PEARSALL W. H. , WRIGHT A. 
Published: February 2008

Summary.1. Analyses of healthy leaves and of leaves infected with mosaic disease (N. tabacum) show that the diseased leaves contain higher proportions of nitrogen and lower proportions of carbohydrate, these differences being apparently increased during photosynthesis.2. In leaves kept in the dark for 68 hours, carbohydrate losses are similar but fall chiefly on insoluble carbohydrate in healthy leaves and on disaccharides in the diseased leaves.3. In diseased leaves, protein breakdown is retarded and insoluble substances are less readily hydrolysed.4. The diseased leaves resemble older leaves in their metabolism.
The Movement of Tobacco Mosaic Virus Within the Plant
Authors: SAMUEL GEOFFREY 
Published: February 2008

Summary.By means of extensive cutting‐up test's on tomato plants inoculated with tobacco mosaic the following points have been determined:1. Confirming the work of Holmes, there is no movement of virus from the inoculated leaf for the first 3 or 4 days. This period is slightly less or considerably more according to the greater or less activity of growth of the plant.2. When the virus passes out from the inoculated leaf it travels first to the roots of the plant with such speed that it can seldom be intercepted at intervening positions.3. Usually about a day later it travels with equal rapidity to the top of the plant.4. In the earliest stages of entering the stem virus particles may be separated by considerable distances (at least several centimetres), since successive samples taken from the stem may yield lengths of 21/2 cm. (the length of the cuttings) free from infection. interspersed irregularly between portions containing the infection.5. The presence of developing fruit trusses on the stem may cause part of the virus to travel upwards as far as these trusses at the same time that the initial downward movement is occurring.6. The virus enters developing fruits at the same time as it travels through the stem, whereas adjacent leaves remain uninfected for days or weeks.7. In pot plants, after the initial rapid infection of the developing leaves at the top of the plant. the more mature leaves become successively invaded from the top downwards and from the bottom upwards until the plant is completely invaded by the virus. Complete invasion occurs very quickly in small vigorously growing plants; it may take 3 weeks or more in medium sized plants (Text‐fig. 2); and as much as 2 months in large fruiting plants (Text‐fig. 3).8. Complete invasion never occurs when large field plants of tobacco or tomato bearing a number of mature leaves are inoculated. The mature leaves remain free from virus, apart from a limited movement along the mid‐ribs, for periods of more than 3 months following inoculation (Text‐fig. 4).
Aphides as Vectors of “Breaking” in Tulips. II.
Authors: D.I.C. A. W. McKenny HUGHES, 
Published: February 2008

Summary.

Three types of “breaking” are distinguished—full, “self and “clotted.”
The evidence points to “full break” being the product of two viruses.
“Self breaking” may be selectively transmitted by the aphis vectors Myzus persicae Sulz and Macrosiphum gei Roch.
“Self break” tulips only transmit “self breaking.”
“Clotting” is an expression of “full break” in certain varieties.
Anuraphis tulipae B. de Fonsc. is a definite vector in the bulb store but not on the growing plant.
At a certain stage of growth tulips cease to be susceptible to infection.
Some Common Species of the Genus Thrips (Thysanoptera)
Authors: SPEYER E. R. 
Published: February 2008

Summary.1. The economic importance of the Thysanoptera as an order of insects and the necessity for a revision in the classification of the order are pointed out.2. The past confusion between some common and destructive species of the genus Thrips is unravelled and the reasons for this confusion are set out.3. The range of variation, within the species, of characters which have in the past been used for the separation of species in the genus Thrips is illustrated, this relating especially to measurements of the antennal joints and of setae upon the body. New structural characters of true specific value, especially relating to the chaetotaxy of the abdomen, are illustrated by examples.4. Variation in colour and the shape of the head are referred to.5. Characters of a constant nature for the species and of value in determination are set out, together with some account of the abdominal structure.6. Quick and reliable methods for the mounting of specimens for microscopic examination are given.7. Specific characters, which enable them to be distinguished from one another, and from other species, are given for some common British species of the genus Thrips.8. A general account of the biology and a more detailed account of that relating to some common species is given.9. Lines upon which a sounder classification of the Thysanoptera than at present exists are outlined.
Some Factors Affecting the Inactivation Rate of the Virus of Tomato Spotted Wilt
Authors: BALD J. G. , SAMUEL GEOFFREY 
Published: February 2008

Summary.Tomato spotted wilt inoculum stirred in the process of inoculation lost its virulence more rapidly than inoculum standing undisturbed.The rate of inactivation of the virus was increased by bubbling air through the inoculum.When all but traces of free oxygen were excluded by bubbling nitrogen through the inoculum loss of virulence was slightly delayed but the final rate of inactivation was practically unchanged.The addition of two oxidising agents, chloramine T and hydrogen peroxide, increased the rate of inactivation.Of six reducing agents tested, one, sodium sulphite, retarded inactivation very markedly. In one experiment at a temperature of 22° C. the virus remained active for more than 36 hours in a 0.2 per cent, solution of the anhydrous salt while control inoculum prepared at, the same time with distilled water was completely inactivated in less than 5 hours.Sodium nitrite retarded inactivation slightly.The remaining four reducing agents—ferrous sulphate, tannic acid, hydroquinone and cysteine hydrochloride—hastened inactivation, but the oxidation‐reduction potentials existing in the virus‐containing systems were not known.These results are briefly discussed in their bearing on the possibility that the normal rapid inactivation of spotted wilt virus which occurs in the standing juice is due to an oxidation reaction.
The Physiology of Virus Diseases in Plants: Vi. Some Effects of Mosaic on the Metabolism of the Tomato
Authors: CALDWELL JOHN 
Published: February 2008

Summary.The literature dealing with the effect of virus diseases on the metabolism of the host plants is briefly summarised. Results are presented of work which has been carried out on the aucuba or yellow mosaic in tomato. The effect of time of inoculation has been studied in some detail. It has been found that the plant is generally reduced by the disease, and that the carbohydrate and dry‐matter content of the diseased plants is less than that of the controls. The stage of development of the plant is not apparently affected by the disease; the diseased plants, though reduced in size, have the same number of leaves and flower trusses as the controls. The nitrogen content is not materially affected by the disease. The effect of the disease on the respiratory mechanism of the host tissues has been examined, and it has been established that the CO2, output of these tissues is higher than that of the controls. This is found when the output is expressed in mg. of CO2, per three‐hour period in terms of the initial fresh weight, the residual dry‐matter content or of the residual nitrogen content. The higher CO2, output is also found ill respiration in oxygen or in nitrogen. This has been attributed to all increase in the efficiency of the enzyme system of the diseased plants.
The Sheep Blowfly Problem in North Wales
Authors: DAVIES W. MALDWYN 
Published: February 2008

Summary.1. Early writings indicate that attack by sheep blowflies was common and well known in the early sixteenth century, prior to the establishment of sheep farming in North Wales.2. A survey of North Wales has shown thatLucilia sericataMg. isthesheep blowfly of the province. In two advanced cases only were larvae ofCalliphora erythrocephalaMg. present, and then only in small numbers.3. Sheep are attacked from May until October. The degree of attack as indicated in a summary of seasons regarded as severe was as follows:Upland districts—10–15 per cent. of sheep attacked;Lowland districts exposed—20–25 per cent.;Lowland wooded—35–40 per cent.4. The complete absence of parasitism among larvae taken fromlivingsheep was a signscant result of the survey. Such a source of unparasitised larvae will mitigate success in the biological control of blowflies.5. The life history ofLucilia sericataunder North Wales conditions has been investigated. Four generations are recorded. The normal mode of hibernation is in the prepupal stage, which hibernates in late September or October and returns to the soil surface from mid‐March onwards, when the soil temperature at 8 in. approaches 45° F. and when in the upper layers is slightly higher.6. Shepherds, normally, “rub out” larvae from infested sheep, assuming that starvation and death results in the soil. Over 90 per cent, of such larvae produced imagines, and such infestations are pure cultures ofLucilia sericataMg. with an absence of competitive secondary species. Experiments, combined with a morphological study, showed that at the temperature of the sheep's body, larvae attain the third instar in 24 hours. They are then only half‐size, but can successfully produce imagines despite subsequent starvation. The present practice, therefore, should be changed, and a larvicide applied before the larvae are removed from the wool.7. There is clear evidence of the greater susceptibility of lambs to attack, and the factors involved are being studied.8. Observations have been made on the relative susceptibility to attack of six different breeds of sheep and their crosses. The degree of attack ranged from the Wiltshire breed, which is only rarely attacked, to the Southdown breed, which is frequently subject to heavy infestations.
THE INSECTICIDAL PROPERTIES OF SOME EAST AFRICAN PLANTS. I
Authors: WORSLEY R. R. Le G. 
Published: February 2008

Summary.A number of East African plants, mostly indigenous, has been tested for insecticidal value as contact poisons.No new insecticide equal in toxicity to nicotine has been discovered.Two plants, Cassia didymobotrya and Barringtonia racemosa, have toxic properties slightly less than half that of nicotine used as sulphate. The plants, which grow dd, should be of value for making insecticides on those farms where they are already growing: they would not, however, be worth cultivating. No definite chemical compounds were obtained from these two plants.The toxicity of extracts of Tephrosia vogelii has been found to be of the same order as that of nicotine in the form of sulphate, and these extracts should be able to replace nicotine in all sprays against soft‐bodied insects such as aphis and thrips.Nearly all parts of this plant contain tephrosin, the seeds having the largest content at 0.35 per cent., whilst the leaves contain 0.18 per cent. Methods are given for the easy extraction of tephrosin from the various parts of the plant. The product obtained has been called “crude tephrosin ” by the author, and in this form is suitable for the preparation of insecticides.Crude tephrosin contains about 20 per cent. of a substance crystallising in he yellow needles with a melting‐point of 227° C., which is probably dehydrodeguelin and is non‐toxic. The remaining 80 per cent, forms white tabular crystals with a melting‐point of 187° C., and is undoubtedly identical with Hanriot's tephrosin. So far it has resisted separation into two or more constituents, either by repeated recrystal‐lisation or by oxidation. This crystalline substance accounts for the toxicity of the crude tephrosin and of the plant itself.Resins were obtained from most parts of the plant but, contrary to Tattersfield's results, they were found to be only slightly toz.It is considered that in view of the fact that Tephrosia vogelii grows both widely spread and vigorously in East Africa it should be able to replace the use of nicotine almost entirely. On a small scale home‐made solutions could be easily and cheaply prepared, and the extraction of crude tephrosin on a larger scale is also worth consideration.9. As a paraffin spray agarnst Antestia and Lygus, Tephrosia vogelii extracts proved useless compared with pyrethrum, but as a domestic spray against flies, mosquitoes, etc., paraffin extracts were found to be as effective as pyrethrum and should be able to replace it, at least for local use.10. The finely powdered pod of T. vogelii has some value as an insect powder, due probably to the tephrosal in it, but cannot compare with pyrethrum powders.11. The seeds contain 12 per cent. of fixed oil from which a soft soap can be made, suitable, according to preliminary tests, for a spreader but not for domestic purposes. The oil is a non‐drying one.12. Further work on many of these points is continuing.
THE EFFECT OF ENVIRONMENTAL CONDITIONS UPON PYRETHRUM (CHRYSANTHEMUM CINERARIAEFOLIUM). II.
Authors: MARTIN J. T. , TATTERSFIELD F. 
Published: February 2008

Summary.The effects of light, temperature and dormancy upon pyrethrum have been studied. The partial shading of the plant during the five months preceding flowering resulted in the production of smaller flowers with a reduced pyrethrin content.The successful flowering of the plant was largely dependent upon the relative temperatures experienced throughout the year. A dormant period, dependent upon sufficiently low winter temperatures, was shown to be necessary for the normal production of large numbers of flowers.
AN APPARATUS FOR TESTING CONTACT INSECTICIDES
Authors: TATTERSFIELD F. 
Published: February 2008

Summary.A description is given of the design of two atomisers for use in quantitative laboratory spraying for testing contact insecticides.Tables and graphs are given showing the weights of spray delivered by each form upon known areas placed in different positions inside the spray jars, and an examination is made of the change in the distribution of the spray with the progressive closure of the orifice and increase in the distance from the orifice of the surface sprayed.
POTATO BLIGHT (PHYTOPHTHORA INFESTANS) INVESTIGATIONS IN JERSEY. PREVENTION OF DISEASE IN EXPORT PRODUCE
Authors: SMALL T. 
Published: February 2008

Summary.

In Jersey the loss due to potato blight (Phytophthora infestans) in crops grown for export may be divided into:

Loss in transit caused by contamination of the tubers by spores at digging time and by packing tubers which are infected, but not obviously, when dug.
Loss in the field, which includes diseased potatoes left on the ground at harvesting time.

These losses, excepting those caused by contamination, occur when the disease on the haulms has reached an advanced stage before harvesting. The remainder occurs when disease is active on the haulms at digging time.
It is shown that blight may spread from diseased or contaminated tubers during transit and that there is little or no danger in using barrels which have previously contained diseased produce.
Ventilation or fumigation of the packages reduced the disease in transit.
Control methods are suggested and discussed.
SOME OBSERVATIONS UPON THE “RED SPIDER”, TETRANYCHUS TELARIUS L., ON HOPS AND ITS CONTROL, WITH NOTES ON SOME PREDATORY INSECTS
Authors: JARY S. G. 
Published: February 2008

Summary.

Treatment of the soil around hops in November, with crude naphthalene at the rate of 300 lb. per acre, did not prevent infestation by Hop Red Spider in the following summer.
Examination of hop poles showed that large numbers of mites may hibernate in deep cracks in the poles.
h emulsion containing 5 per cent. of a high‐boiling neutral tar oil, sprayed with force into the cracks of poles, killed the great majority of mites. It was1 more effective in this respect than an emulsion containing 5 per cent. of a semi‐refined petroleum oil.
Of a number of washes applied in the summer to infested hops, emulsions of a highly refined (water‐white) petroleum oil at 1 and 2 per cent. oil concentrations, were effective in killing the mites. Lime sulphur a t concentrations of 1 in 30 and 1 in 60 also gave a complete control. A Derris wash of 0.0056 per cent. rotenone content appeared to give a complete control at the second applicabion whereas it failed to do so at the first. 'There is evidence that the toxicity of a Derris wash of the type used increasies up to a point with time after water is added to the powder. Liver of sulphur and colloidal sulphur a t the concentrations used showed no marked toxicity and the two spreaders used were also non‐toxic.
The petroleum‐oil emulsions and lime sulphur caused some injury to foliage when applied in late June and the first three weeks in July.
Lime sulphur caused no injury to foliage or “burr” on the varieties Fuggles, Cobbs and Early Birds, when applied during late July and early August, a t concentrations ranging from 1 in 60 to 1 in 150. Concentrations smaller than 1 in 100 were not markedly toxic to the mites, but at 1 in 60 and 1 in 80 lime‐sulphur wash was completely effective in killing all forms other than eggs.
Notes are added on three insect predators of the Hop Red Spider.
STUDIES ON APHIDES INFESTING THE POTATO CROP
Authors: DAVIES W. MALDWYN. , WHITEEEAD T. 
Published: February 2008

Summary.

Field observations show that migrating alatae are the main source of the initial infestation of Myzus persicae Sulz. on the potato crop. They arrive in quantity, during June and July, from various cruciferous plants on which they have hibernated, or to which they migrated in early spring.
In 1934 the main migration at a selected centre occurred during a week which contrasted with other periods, since the wind, which was slight, changed from the north‐west to the south‐east, tbe temperature rose from about 67d̀ F to 80d̀ F. and the relative humidity dropped from 68 to about 30 per cent.
The hot, dry conditions not only facilitated flight but also greatly increased the proportion of alatae by causing the cruciferous weeds to wilt and die, when alate forms were produced in abundance.
The proportion of alate M. persicae was found to be much higher in a district where virus infection of the stocks had been rapid compared with a district where such was negligible.
The proportion of migrating alate M. persicae infected with virus diseases, in a district where the spread is rapid, proved to be particularly small. In eighty‐one experiments involving 1178 alatae only four instances included vectors; possibly only a single vector in each of the four experiments.
It is concluded that the introduction of virus diseases into a healthy stock by migrating alatae is slight, but this small amount is subsequently spread by apterous forms moving within the crop.