bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE RELATIVE RESISTANCE OF SOME WHEAT VARIETIES TO TILLETIA CARIES (DC.) TUL. (—T. TBITIGI (BJERK.) WINT.)
Authors: WESTON W. A. R. DILLON 
Published: February 2008

SUMMARYSome factors influencing the relative susceptibility of a wheat variety to Tilletia caries are recorded, and it is shown that infection varies with the spore load and with the date of sowing. The relative resistances of certain wheat varieties to bunt when contaminated separately with Little Joss bunt, their own bunt and bunt spores from other varieties are shown.Rye is susceptible to Tilletia caries, but no infection is recorded on Hordeum nudum and Avena nuda.Hybridization experiments between resistant and susceptible wheat varieties are described.The general trend of the experiments indicates that several of the so‐called immune or highly resistant varieties are susceptible when they are contaminated with bunt spores that are produced on those varieties. They indicate that the passage of the pathogen through the host increases the virulency of the disease. These phenomena are accounted for because Tilletia caries is not a single system of one identity but is composed of physiologic forms and the passage of the parasite through the host increases the virulency because this process leads to the selection of a particular form or forms well adapted to the environmental conditions. It is thought that resistance depends not on one single factor but on at least three, namely, the physiologic form of the parasite and its environment, and the strain of the host and its environment.
ON ATOMARIA LINEARIS STEPHENS (COLEOPTERA, CRYPTOPHAGEDAE) AND ITS LARVAL STAGES
Authors: NEWTON H. C. F. 
Published: February 2008

SUMMARY

A brief survey is made of the history and habits of Atomaria linearis Stephens, the Pigmy Mangold Beetle, and some new observations recorded.
The egg and the external structure of the larva are described for the first time.
STUDIES UPON THE COPPER FUNGICIDES
Authors: MARTIN HUBERT 
Published: February 2008

SUMMARY

The initial product of the interaction ol cupric sulphate and calcium hydroxide solutions, at ordinary temperatures, is the 4CuO. S03 basic sulphate.
With amounts of calcium hydroxide in excess of 0–75 equivalent, the 4CuO. S03 salt is slowly decomposed with elimination of the sulphate radicle and the formation of a blue hydrated cupric oxide or cupric hydroxide, a product called, for convenience, the hydroxide.
The cupric hydroxide formed retains, by adsorption, part of the sulphate radicle. Direct evidence by analysis of the precipitate, which might be considered to indicate the formation of a basic copper‐calcium complex, is therefore unreliable.
In the analogous interaction of calcium hydroxide with cupric chloride, the formation of cupric hydroxide in the presence of amounts of calcium hydroxide in excess of 0–75 equivalent, is indicated by the dehydration of the precipitate to form nigger brown hydrated cupric oxide, and by the definite point of inflection on the hydrogen‐ion concentration curve which corresponds to equimolecular amounts of calcium hydroxide and cupric chloride.
The hydrogen‐ion concentration curve for the cupric sulphate‐calcium hydroxide reaction shows that permanent alkalinity is not‐reached until equimolecular amounts of calcium hydroxide have been added.
The cupric hydroxide, formed from the 4CuO.SO3 basic sulphate by the action of calcium hydroxide, is stabilised by adsorbed sulphate ions. If the adsorbed sulphate and excess calcium hydroxide be removed by continued washing with carbon dioxide‐free water, the Bordeaux mixture precipitate undergoes dehydration to form the nigger brown hydrated cupric oxide.
Dehydration of the Bordeaux mixture precipitate when sprayed upon foliage, is therefore prevented by some chemical or physical change of the precipitate which occurs on drying.
Dehydration is not prevented by physical changes which occur on drying.
Carbon dioxide is a factor in the process whereby dehydration is prevented.
It is suggested that the formation in situ of the protective copper‐containing deposit by the action, primarily, of carbon dioxide, accounts for the excellent adhesive properties of the Bordeaux mixture precipitate; that inertness towards the chemical changes which occur after spraying may be the cause of failure of some Bordeaux substitutes; that these changes may profoundly affect the value of sedimentation tests as criteria for the fungicidal efficiency of various Bordeaux mixtures.
STUDIES IN THE PHYSIOLOGY OF VIRUS DISEASES IN PLANTS
Authors: CALDWELL JOHN 
Published: February 2008

SUMMARYIt has been shown that the symptoms induced by aucuba or yellow mosaic of tomato in certain other members of the Solanaceae (notably N. glutinosa and D. stramonium) differ markedly from those in tomato. Neither formation of intracellular inclusions nor systemic infection occurs in these plants. In N. glutinosa, the symptoms appear only on the rubbed portion of the leaves and little multiplication of the virus takes place. In D. stramonium, although no mosaic symptoms appear on the host, the virus travels through the tissues and can infect susceptible grafts. Holmes' work on the use of N. glutinosa as a ready means of demonstrating the presence of the virus agent in a juice has been confirmed and amplified.It has also been shown that it is possible to inject the intercellular spaces of the leaf of N. glutinosa with virus juice and that no infection occurs unless cells have been ruptured.
“BREAKING” IN TULIPS. II
Authors: CAYLEY DOROTHY M. 
Published: February 2008

SUMMARYThe results of the second series of bulb manipulation experiments have confirmed previous results as to the infectious nature of the agent or virus which brings about “breaking” in tulips.“Breaking” can be transmitted by grafting and plugging bulbs with tissue from “broken” bulbs, but injections with filtered sap expressed from “broken” bulbs have given negative results.All attempts to induce parrotting by grafting have been unsuccessful.There appears to be no correlation between the type of “break” of the transmitter and the type of “break” induced.Transmitters vary in potency on different hosts, and different hosts vary in degree of susceptibility towards the same transmitter. Tulipa species have been observed to “break” naturally under garden conditions, and “breaking” has also been induced in the same by grafting with “broken” garden varieties.The bi‐colour variety Keizerskroon has been proved not to be an infectious “break,” but a true bi‐colour; “breaking,” however, can be induced in the red areas of the perianth by grafting with other “broken” varieties.The effect of the virus on the colour plastids and the distribution of the anthocyanin sap pigment is discussed.It is suggested that a knowledge of the translocation of the virus in the bulb is of practical importance to bulb growers.The experiments indicate the importance of aphis control by means of spraying in the growing season and the advantage to be gained by lifting and storage under aphis‐free conditions in the autumn.In conclusion, my thanks are due to Sir D. Hall for information with respect to the initial “breaking” of Zomerschoon and the “breaks” in Tulipa species, and to the laboratory assistant E. F. Emarton for taking the photographs for the plates and for his valuable help in the manipulation of the large number of bulbs treated.
THE CONTROL OF TOMATO‐LEAP MOULD
Authors: BEWLEY W. F. , ORCHARD O. B. 
Published: February 2008

SUMMARY

Tomato‐leaf mould may be held in check by attention to atmospheric temperature and humidity.
Varieties resistant to this disease are known, but they are not suitable for commercial work. Attempts are being made to breed varieties combining resistance with crop excellence.
The disease has been controlled by spraying with salicylanilide paste, sold under the name of “Shirlan Paste,” combined with a sul‐phonated oil sold as Agral I.
The above spray mixture has also proved effective against certain other diseases.
STUDIES IN BACTERIOSIS
Authors: LACEY MARGAHET S. 
Published: February 2008

SUMMARYDiseases of potato tubers, lettuces and seeds of Medicago lupulina caused by bacteria belonging to the green‐fluorescent group are described and the identity of the pathogens is discussed. The cultural characters of thirty‐six strains isolated from various plant lesions are given and compared with those of thirty‐two known species of the green‐fluorescent group, and a discussion on cultural variations follows.
THE OPERATION OF INTERSPECIFIC COMPETITION IN CAUSING DELAYED GROWTH OF GRASSES
Authors: CHIPPINDALE H. G. 
Published: February 2008

SUMMARY

An explanation is provided of the causation by L. italicum of delayed establishment in F. pratensis, Phleum pratense and Poa trivialis.
The presence of seeds or seedlings of L. italicum is not detrimental to the germination of the other species under conditions thought likely to occur in the field, except in the case of Poa trivialis, the seeds of which grass are extremely susceptible to the presence of carbon dioxide and hence to root‐respiration.
Under certain conditions, seedlings of L. italicum inhibit completely the growth of seedlings of the other three grasses, the latter being deprived of light and soil nutrients. At the same time, seedlings suffering suppression in this way are remarkably persistent and are capable of immediate recovery on the removal of competition.
The significance of this behaviour, ecologically and to agricultural practice, is discussed.
The effeet of different physical factors on germination in the same four species of grass is described. The action of low temperatures in depressing the germination of F. pratensis, Phleumpratense and Poa trivialis to a greater extent than that of L. italicum is considered an important factor in interspecific competition.
THE INSBCTICIDAL PROPERTIES OF TEPHROSIA MAGROPODA HARV. AND OTHER TROPICAL PLANTS
Authors: TATTEKSFIELD F. , GIMINGHAM C. T. 
Published: February 2008

SUMMARY

Preliminary data is reported as to the insecticidal properties of three tropical fish‐poison plants (Tephrosia macropoda Harv., Mundulea suberosa Benth. and Neorautanenia (Rhynchosia) fisifolia C.A.Sm.).
A list is given of other plants (most of them known to be fish poisons) from many different countries, which have been tested but appear to have little or no toxicity to Aphis rumicis L.
Extracts of the stems of black Haiari (Lonchocarpus sp.) are shown to be toxic as contact insecticides to young larvae of two species of moths. Older larvae are much, more resistant.
All the plants so far tested which are toxic both to fish and to insects are members of the natural order Leguminosae.
A STUDY OF PAXILLUS PANU0IDE8 FR. AND ITS EFFECTS UPON WOOD
Authors: FINDLAY W. P. K. 
Published: February 2008

SUMMARY

An account is given of the occurrence and distribution of Paxillus ?panuoides Fr.
The fruit bodies of the fungus produced naturally and on artificial media and the appearance of the fungus in culture are described and the microscopic details of the hyphae figured.
The effect of temperature, of different hydrogen‐ion concentrations and of antiseptics upon the growth of the fungus are examined.
The growth of the fungus upon sawdust and upon blocks of sound and of already partially decayed wood are investigated and a description given of the details of the hyphae in the cells of the wood and their effect upon the walls thereof.
Means of recognising decay caused by P. panuoides and suggestions for controlling damage by this fungus are given.
THE INFLUENCE OF ENVIRONMENTAL CONDITIONS ON THE DEVELOPMENT OF THE ANGULAR LEAF‐SPOT DISEASE OF COTTON
Authors: STOUGHTON E. H. 
Published: February 2008

SUMMARYExperiments carried out in the Rothamsted control chambers on the influence of atmospheric humidity on the angular leaf‐spot disease of cotton, resulting from spray inoculation of young plants, show that high humidities favour the development of the disease. Maximum infection occurs at humidities exceeding 85 per cent, and at humidities below this the degree of infection decreases rapidly.The relation of these results to the experiments on the influence of air temperature is discussed, and it is concluded that the importance of humidity is mainly physical in nature, by affecting the time during which the infection droplets persist.
THE TOXICITY OF THE VAPOURS OF VOLATILE ORGANIC COMPOUNDS TO THE “RED SPIDER” MITE (TETRANYCHUS TELABIUS L.)
Authors: READ WILFRID H. 
Published: February 2008

SUMMARY

With the exception of methyl formate the toxicity towards the “red spider” mite of the normal aliphatic alcohols and their formates at first increases as the series is ascended.
Methyl formate is an exception to the above rule and is the most toxic of the formates tested.
The normal compounds are more toxic than their isomers, the toxicity decreasing with increased branching of the chain.
The above decrease is greatest when the branching is at the a position to the hydroxyl or carboxyl group.
The relative effects of the compounds on plants are similar to their effects on the mite, but the differences due to molecular structure are more pronounced.
Control of the mite cannot be obtained on tomato plants without injury by the use of any of the substances tested.
THE CHLOROTIC DISEASE OF THE HOP. III
Authors: SALMON PROF. E. S. , WARE W. M. 
Published: February 2008

SUMMARY

Three further cases of the occurrence of the chlorotic disease of the hop, hitherto known from only one hop‐yard (of the Fuggle variety) in Worcestershire, are recorded from hop‐yards in the same county on the varieties Fuggle, Early Bird and Tutsham.
The chlorotic disease has been transmitted by grafting to the commercial varieties Tutsham,. Cobbs and Mathon. With one doubtful exception, all the affected plants showed as well the symptoms of mosaic disease.
The chlorotic disease has been transferred by grafting to three new seedling varieties (M. 45, p. 13 and GG. 45).
In three instances, individuals of symptomless mosaic carriers (of two varieties), to which chlorotic disease had been transmitted by grafting or budding, exhibited eventually marked symptoms of mosaic disease.
Two further cases are recorded of the appearance in scions of chlorotic symptoms in the same year in which the scions were grafted on the infected stocks.
VIRUS DISEASES IN RELATION TO COMMERCIAL SEED POTATO PRODUCTION
Authors: WHITEHEAD T. , CURRIE J. F. , DAVIES W. MALDWYN 
Published: February 2008

SUMMARY

Under a scheme, begun in 1927, and supported by a special grant from the Ministry of Agriculture since 1928, an attempt is being made to test the value of certain localities in North Wales for the production of seed potatoes.
Evidence is produced to show that out of fifteen farms originally selected for this purpose, eight have maintained their stocks without increase of virus diseases, three have shown only a slight increase, whilst four have been discarded from the scheme. Replicated yield trials at the College Farm proved that seed mixed from these eleven farms was equal to Scotch “stock” seed, and the value of this Welsh seed was confirmed by trials in a number of Welsh counties in which it was tested against ordinary T.S. Scotch seed.
Concurrently with this, a study has been made of the aphid population on the potato crops at these centres, which has led to the following conclusions:

The absence of increase of virus diseases, and of leaf‐roll in particular, at the more successful centres is not due to the scarcity of aphides, nor to the absence of known vectors of the diseases, such as Myzus persicae. Neither can it be attributed to the non‐infective condition of the aphid vectors present at these centres since representative samples, taken from potato crops, transmitted leaf‐roll to healthy plants under glass. With one exception no transmission occurred with any of the species of aphides when taken from apparently healthy plants in a partially diseased crop. In samples taken from leaf‐roll plants transmission only occurred when they included Myzus persicae.
The accumulated data suggest that the maintenance of health in potato stocks is influenced not merely by the relative abundance of aphides, but rather by the relation between the date of maximum infestation and the stage of maturity of the foliage. The more successful centres, each year, showed either a delayed maximum infestation and/or the foliage was cut down earlier than at the less successful centres. The relative movement of aphides within the crops at the different centres is certainly of importance, but this is conditioned by many factors which are still under investigation.
THE APPEARANCE AND BEHAVIOUR OF PIGMENT IN THE SUFFOLK BREED OF SHEEP
Authors: BOYD EVLYN 
Published: February 2008

SUMMARYThe results of a microscopic study made of the colour transition shown by the fleece of the Suffolk from birth to maturity are given. It is demonstrated that the physical structure of the fibre cuticle obviates the possibility of pigment inclusions.An explanation for the sporadic occurrence of coloured fibres in an otherwise white 3eece is attempted, and it is pointed out that, however else the pigmentary system of the Suffolk sheep may be stimulated, thresholds of irritation conditioned by temperature need not he considered as possible stimuli.
STREAK IN TOMATOES ASEPTICALLY GROWN
Authors: SMITH J. HENDERSON 
Published: February 2008

SUMMARY.From the necrotic tissues of tomato plants suffering from streak, a virus disease, it is possible regularly to obtain bacteria which belong to one or both of two definite types. The same bacteria are to be found in tobaccos infected with the same disease.If the plants are grown from sterile seed under aseptic conditions throughout and inoculated with bacteriologically sterile virus‐holding streak juice, these bacteria do not appear although the plants develop well‐marked signs of the disease.“No evidence has been found that the bacteria are derived from the virus or the virus from the bacteria.
ZONE LINES IN PLANT TISSUES I. THE BLACK LINES FORMED BY XYLABIA POLYMORPH A (PERS.) GREV. LN HARDWOODS
Authors: CAMPBELL ALEX. H. 
Published: February 2008

SUMMARY.A brief account is given of the literature on zone lines in wood, and a preliminary attempt is made to classify the zone lines into groups in order to provide a basis for systematic research and to facilitate the statement of results. A single fungus, X. polymorpha, suspected of causing black lines in hardwoods, is dealt with morphologically and culturally. The development and stromatal production of the fungus on artificial media and wood blocks are described. X. polymorpha is established as a black line producing fungus by its production of black lines in inoculated wood blocks. The morphology of the black lines is described in detail and their actual formation has been observed in cotton‐wool. As a result the Suggestion is made that the black lines are the marginal zones of entostro‐mata in the substratum comparable to those occurring in the Diaporthe. The black lines produced by the genera Nummularia, Ustulina, Hypoxylon and Daldinia in the substratum are stated to be of similar structure and significance.An account is given of a X. polymorpha black line superimposed upon the zone line formed by the attack of Fomes applanatus on beech wood. The confusion existing in the literature on the zone lines of F. applanatus is partly attributable to this not uncommon phenomenon. The value of zone lines as criteria in the diagnosis of wood rots is discussed and some of the difficulties in the identification of a zone line in a typical rot are pointed out.
THE NITRIFICATION PROCESS IN SOILS AND BIOLOGICAL FILTERS
Authors: BARRITT N. W. 
Published: February 2008

SUMMARY.

An extensive review of the literature on nitrification shows that the workers in this subject may be divided into three groups, viz. (a the Winogradsky or purely autotrophic group, (b those who include growth in organic media, (c those who exclude autotrophic growth.
The process of nitrification in soils and filter beds is essentially the same and the organisms concerned exhibit the same cultural characteristics, viz. autotrophic growth in purely mineral solution containing carbonates and low thermal death‐point (56° C).
In the absence of carbonates heterotrophic organisms can supply the necessary carbon, dioxide by the decomposition of organic matter, a process which accounts for nitrification in acid soils and filter beds. In the absence of a salifiable base the oxidation of ammonia is arrested by the formation of free acid and at a pH of 5.5 the nitrous acid is spontaneously oxidised to nitric acid.
The inhibitive action of organic matter on nitrification can be accounted for by accumulation of carbon dioxide and ammonia and deficient aeration. Removal of any of these factors results in increased nitrification.
Increased nitrifying power of soil after passage through earthworms is recorded and accounted for.
The restrictive influence of Winogradsky's ideas on autotrophism ara discussed, and the possibility of nitrifying bacteria being a phase in the life cycle of heterotrophic organisms is suggested.
THE EFFECT OF SOME ‐CHEMICALS ON GERMINATION IN COCKSFOOT (DACTYLIS QLOMERATA L.)
Authors: CHIPPINDALE H. G. 
Published: February 2008

SUMMARY.

Attempts to accelerate the germination of cocksfoot seeds by treating them with solutions of several chemical compounds have been unsuccessful.
A pronounced acceleration of germination can be produced by soaking the seeds in water and drying for an indefinite period before sowing.
No evidence has been obtained that with any condition of the soil is such treatment undesirable.

The author wishes to thank Professor R. G. Stapledon, to whom he is indebted for criticism and at whose suggestion the work was begun.
GIB BE BELLA SAUBINETII (MONT.) SACC. ON BRITISH CEREALS III. OCCURRENCE UNDER NATURAL CONDITIONS.
Authors: BENNETT F. T. 
Published: February 2008

SUMMARY. Gibberella Saubinetii (Mont.) Sacc. occurred in its perfect stage under field conditions on wheat ears in 1932. The meteorological conditions are compared with those of a season when perithecia were not developed outdoors.Single ascospore growths in culture are normally of the Fusarium type, with a characteristic modification on salts‐glycerine agar. The ascigerous type of growth may arise from ascospores developed under abnormal conditions.
AN INVESTIGATION OF TOMATO VIRUS DISEASES OF THE MOSAIC “STRIPE,” STREAK GROUP
Authors: AINSWORTH G. C. 
Published: February 2008

SUMMARY.Virus diseases of tomato of the mosaic, “stripe,” streak type as occurring in glasshouses in the British Isles have been examined.Ordinary or mild mosaic (tomato mosaic) has been identified with true tobacco mosaic and found not to be implicated in most of the “stripe” disease.The symptom picture generally known as “stripe” may be due to several causes, and in this paper the diseases have been distinguished as follows: stripe when attributed to Bacillus lathyri, glasshouse streak when caused by a single virus (the most frequently occurring form), and streak when due to a mixed virus infection (typically tomato mosaic and potato mosaic).Descriptions are given of tomato mosaic, glasshouse streak, and streak, and they are compared with each other and with spotted wilt.The author wishes to express his best thanks to Dr W. F. Bewley for helpful criticism and advice.The work has been carried out with the aid of a grant from the Empire Marketing Board.