bluuebunny/crossref_metadata_2025_split huggingface dataset:
VIRUS DISEASES OF THE POTATO: THE “CARRIER” PROBLEM. ITS RELATION TO SYMPTOMATOLOGY AND COMMERCIAL POTATO GROWING
Authors: WHITEHEAD T. 
Published: February 2008

SUMMARY

Symptomatology, of which a study of “carriers” is regarded as one aspect, tends to be used as a means of segregating “unit” viruses rather than as a means of furthering plant physiological studies. The effects of changes in environmental conditions of growth, acting through the unstable metabolism of a plant upon a virus, have not been adequately studied. Until this is done, the specificity of the reactions said to be due to a unit virus must remain in doubt and, with it, the whole foundation of the biological methods of segregating viruses.
The symptomatological unit is the plant cell, and the clinical picture resulting from infection is the expression of the varying degree to which invaded cells dominate, or are dominated by, a virus. Successive stages in plant dominance are shown by (a) discontinuous or local symptoms; (b) symptomless shoots; (c) individual carrier plants in a variety usually reacting to infection; (d) carrier varieties.
The conditions under which the power to suppress symptoms can be broken down are discussed. Masked symptoms are revealed by relatively slight environmental changes, but the breakdown may be the more difficult to achieve as perfect “carrying” is approached. There is no fundamental difference between “masking” and “carrying”. The conditions under which masking can be converted into carrying are also discussed.
Evidence is submitted to show that a perfect carrier plant is not only unaffected in vigour as a consequence of carrying a virus, but may thereby exhibit a reduced susceptibility to certain other viruses in the field.
Field trials are described in which proof is given that the viruses carried by the varieties King Edward VII (paracrinkle), and Up‐to‐Date (streak and virus X), were not transmitted to intolerant varieties under the most favourable conditions. These carrier varieties are not therefore the serious menace to other varieties they are commonly believed to be.
METHODS OF INVESTIGATING THE BIONOMICS OF THE COMMON CRANE‐FLY, TIPULA PALUDOS A MEIGEN, TOGETHER WITH SOME RESULTS
Authors: BARNES H. F. 
Published: February 2008

SUMMARY

Full‐grown larvae of Tip & paludosa Meigen were obtained by application to the soil of an emulsion of orthodichlorobenzene, and it is suggested that the larvae become non‐susceptible to this treatment about 6 weeks before pupation. The larvae were reared in pota of soil containing germinating and growing wheat.
The adult crane‐flies were kept in glass tubes for longevity trials which showed that on the average the males lived about 7 and the females 4–5 days. Mating and oviposition took place in these tubes.
Twenty‐seven females laid 5408 eggs, averaging 200 each. About 45 per cent of the eggs were laid the day the female emerged and 40 per cent the fist day after. It is believed that these figures are too low as the regular observations stopped a t 7 p.m. G.S.T. and it is suggested that 75 per cent of the eggs are in reality laid by midnight on the actual day of emergence and 10 per cent on the first day after. The eggs were kept damp in solid watch‐glasses which xere stood in water in culture dishes.
It is shown that by the time the peak of crane‐flies on the wing has been reached, the peak of eggs in the soil will already have been passed.
Hatching took place 11–15 days after the emergence of the parent crane‐fly, 2498 hatching from 5408 eggs. The young larvae were kept in Petri dishes and fed on wheat rootlets, clover or chickweed leaves, pieces of cabbage leaves, slices of potato or bran. By the time the 3rd instar was reached about 54 per cent mortality had occurred, chiefly owing to larvae escaping and cannibalism (576 survived out of 1257). This stage was reached in roughly 14 days.
The breeding potential was as follows: 51 per cent of the nearly full‐grown larvae emerged as adults (this figure is low because of the number of larvae escaping); 75 per cent of the available eggs were laid by the females; 46 per cent of the eggs laid hatched, and 46 per cent of the larvae survived the fist two instars. In other words, under the conditions of the experiment, on the average, one female crane‐fly laid 200 eggs, 92 larvae hatched and 44 survived the first two instars.
STUDIES ON AMERICAN FOUL BROOD OF BEES: THE RELATIVE PATHOGENICITY OF VEGETATIVE CELLS AND ENDOSPORES OFBACILLUS LARVAEFOR THE BROOD OF THE BEE
Authors: TARR H. L. A. 
Published: February 2008

SUMMARYVegetative cells ofBacillus larvaehave not produced American foul brood in healthy nuclei even when B dose almost 3000 times greater than an inoculum of spores of this organism capable of causing the disease has been sprayed over the developing brood.A very much smaller inoculum of the spores of B.larvaeis effective in producing American foul brood when the developing larvae of healthy nuclei are sprayed directly with them than when they are fed in syrup to the bees.
A BIOLOGICAL STUDY OF THE FUMIGATION OF EMPTY WAREHOUSES WITH HYDROGEN CYANIDE AND ETHYLENE OXIDE
Authors: POTTER C. 
Published: February 2008

SUMMARYAn account of the fumigation of a number of empty warehouses is given. The fumigation was designed to kill the hibernating larvae of Ephestia elutetta Hb. and Plodia interpunctella Hb. which were present in the fabric of the warehouse. The first sheds were fumigated with “Etox” (ethylene oxide with 10 per cent carbon dioxide), the rest with hydrogen cyanide. An account is given of the factors involved in making a biological test of a fumigation. The effect of the fumigation was studied first by its action on test insects placed in various positions in the warehouse and secondly by an examination of the warehouse to discover how the insects present in situ had been affected. The actual measured concentrations of fumigant are given for the positions where insects were examined. The results are given of a laboratory experiment on the action of hydrogen cyanide on the hibernating larvae of Ephestia elutell and Ploaia interpunctella which amplify the results obtained in the warehouse. An analysis of the results obtained is given together with a summary of the results of other workers.The work here reported was done under the direction of Prof. Munro, in whose department it was carried out. The writer is greatly indebted to Messrs Page & Lubatti for much helpful criticism and advice and for permission to use their figures of gas concentrations.
OBSERVATIONS ON THE EFFECT OF MOLYBDENUM ON PLANTS WITH SPECIAL REFERENCE TO THE SOLANACEAE
Authors: WARINGTON KATHERINE 
Published: February 2008

Summary

In view of the similarity between certain cytological changes induced by virus disease and treatment with molybdenum, pot‐and water‐culture experiments were carried out to determine further the effect of this element on plant growth. Sodium molybdate was used throughout.
Toxic symptoms were produced with the larger dressings of molybdate, injury being shown at much lower concentrations in solanaceous species than in barley.
The shoots of tomato and Solanum nodiflorum turned a golden yellow, and potato tubers a reddish yellow colour when the plants were grown with the larger quantities of molybdate.
These colour changes were shown to be due to the presence of yellow globules of a tannin‐molybdenum compound which had formed within the tissues.
Blue granular accumulations occurred in large numbers in molybdenum‐treated plants. Their distribution was confined to tissues that contained anthocyanin pigment, and their composition was apparently of an anthocyanin‐molybdenum nature.
A STUDY OF CROWN RUST, PUCCINI A CORONATA CORDA, IN GREAT BRITAIN: PHYSIOLOGIC SPECIALIZATION IN THE UREDOSPORE STAGE1
Authors: BROWN M. R. 
Published: February 2008

Summary

Uredospore cultures of Puccinia coronata Corda were established in the greenhouse, on their appropriate hosts, by inoculation with uredoor aecidiospores collected in the field. Their pathogenicity was tested by inoculating the uredospores on to a series of grass genera and oat varieties.
Seven varieties of P. coronata have been distinguished in Great Britain:

All these varieties have previously been identified on the continent of Europe and some have been identified in North America.
Some varieties are confined to a single host genus; others infect several genera.
Four physiologic races were distinguished in the var. avenae: race 6, previously identified in North America and Australia, and races 42, 43 and 44, hitherto undescribed. Races 6, 42 and 44 were obtained in Great Britain and race 43 in Portugal.
Experiments carried out under different conditions of temperature and illumination showed that variation in these conditions had only a slight influence upon the infection type produced.
Marked variation in reaction to the rust was shown by plants of the same species of grass inoculated with the same culture under identical conditions. This was probably due to genetic impurity of the grasses.
There were no clear‐cut differences, either in morphological or pathological characters, between the varieties assigned by Klebahn to P. coronata Kleb. and those assigned to P. coronifera Kleb. (P. Lolii Niels.).
STUDIES ON EUROPEAN FOUL BROOD OF BEES: FURTHER EXPERIMENTS ON THE PRODUCTION OF THE DISEASE
Authors: TARR H. L. A. 
Published: February 2008

SummaryEvidence has been submitted which supports the theory that European foul brood is a single disease caused by Bacillus pluton White. The course of the disease can be modified by introducing cultures of certain secondary invading bacteria into colonies of bees infected with B. pluton.A certain “mass inoculum” of B. pluton organisms is required to induce the disease in healthy colonies.The causal organism is present in virulent form in the rectal ampullae of young bees in affected colonies, but does not appear to exist elsewhere in the bee or to multiply in its intestinal tract.It appears as if B. pluton is a strict parasite which will only multiply in the intestines of young larvae.
SHEEP BLOW‐FLY INVESTIGATIONS: CHEMOTEOPIC TESTS CARRIED OUT IN 1936
Authors: HOBSON E. P. 
Published: February 2008

SummaryAn account is given, of tests on 42 organic substances as repellents for the sheep maggot fly, Lucilia sericata Mg. Repellency was measured by observing the ability of added substances to counteract the attraction of a solution of ammonium carbonate and indole placed in the fleece of a sheep. The substances tested were classified into three groups: (a) repellent at 0.3 per cent (amount added to attractant solution), (b) repellent at 0.9 per cent, (c) not repellent at 0.9 per cent. No substance was found which was repellent at 0.1 per cent.Examination of blow‐flies (L. sericata) trapped when approaching sheep treated with indole and ammonium carbonate, showed that only gravid females are attracted. This chemotropic response depends, therefore, not only on the species, but also on the sex and physiological condition of the fly.The writer wishes to take this opportunity of thanking the Agricultural Research Council for a grant which has entirely financed this work.
NOTES ON THE VIABILITY OF BACILLUS SALMONICIDA EMMERICH AND WEIBEL
Authors: SLACK H. D. 
Published: February 2008

Summary

Observations on Furunculosis of Salmonidae caused by Bocillus salmonicida in brown trout in part of a Hampshire river, over a period of 5 years, showed that the disease was endemic in the area and the epizootics occurred at regular intervals; following spawning and when the water temperature became optimal for the development of the parasite.
While no direct evidence has been found for supposing that the disease was maintained within this area, by living hosts other than salmonid fishes, the possibility that B. salmonicida remains viable for extended periods in natural waters and silt deposits has been investigated.
The results of this investigation tend to show that B. salmonicida can only remain viable in such media when their normal flora and fauna is absent or greatly reduced and that this fact may explain the inconsistency between the observations of Williamson and Plehn on the viability of this bacillus.
A FURTHER NOTE ON FUNGUS ASSOCIATION IN THE SIRICIDAE
Authors: CARTWRIGHT K. St G. 
Published: February 2008

SUMMARY1. Earlier work on the association of Sirex cyaneus with a Basidiomycete fungus has been confirmed. The culture of the fungus closely resembles, but is not identical with that of Stereum sanguinolentum; it is therefore thought that it is a form of S. sanguinolentum.2. The fungus isolated from Sirex gigas has been identified as Stereum sanguinolentum.3. At the moisture content favourable for the development of the larvae, only slow development of the fungus can take place. Under more moist conditiona viporous fungus growth occurs, with apparently fatal results to the lam.4. The fungus is introduced into the wood during ovipition in the cam of both Sirez cyaneus and S. gigaa.5. Fungus was found to be present in glands at the base of the ovipositor in lete stage female pupae.6. A fungus, the culture of which resembles in appearance that of Daldinia con‐centriea, has been related from larval tunnels and from glands in adult females of Xiphydia prolongata.
CROSS‐AND SELF‐FERTILITY IN SAINFOIN
Authors: THOMSON J. R. 
Published: February 2008

SUMMARY1. The number of flowers per raceme is slightly greater in Common than in giant sainfoin.2. Little more than half the flowers set seed under conditions of open pollination.3. When the flowers were protected and left untouched the self‐fertility was found to be 0.98%. When the flowers were artificially self‐pollinated by tripping the self‐fertility was significantly higher, being 5.11%4. Seedlings grown from selfed seed showed poor establishment and reduced vigour.5. Evidence is brought forward which suggests that the phenomenon of seeding year flowering in common sainfoin cannot be due to the fertilization of the parent plants by pollen from giant sainfoin.Thanks are due to the following seeds merchants who supplied samples of seed: Dunn's Farm Seeds, Ltd., Salisbury; Gartons, Ltd., Warrington; A. G. Leighton, Ltd., mtchurch; Sutton and Sons, Ltd., Reading.
INVESTIGATIONS ON THE RUST OF ROSES PHRAGMIDIUM MUCRONATUM FR.
Authors: WILLIABIS P. H. 
Published: February 2008

SUMMARY1. Cross‐inoculation experiments have shown that Rosa laxa and certain varieties of R. canina are not attacked by Phragmidium mucronatum from the cultivated rose, and that the rose is resistant to certain forms of the rusts on briars.2. These differences are correlated with differences in the size of the teleutospores.3. The teleutospores of P. mucronatum require exposure to winter conditions before they will germinate.4. The mycelium of the rust may persist for several years in the stem but there is no evidence of systemic infection.The writer is indebted to Mr Courtney Page for supplying material and for much valuable information, and to Dr W. F. Bewley for helpful criticism and advice.
ON THE CHANGES IN CHEMICAL COMPOSITION ASSOCIATED WITH LARVAL DEVELOPMENT IN THE SHEEP BLOWFLY
Authors: RAINEY R. C. 
Published: February 2008

SUMMARYThe most marked change in composition during embryonic development is the disappearance of fat typical of cleidoic eggs.The chorion probably consists of protein together with gome nitrogen‐poor constituent, perhaps a saturated fat or wax; chitin and other carbohydrates are absent, and ash and moisture contents are low.No great changes in composition occur during the first two larval instars, with the exception of a possible utilization of some reserve protein and carbohydrate while the larvae are establishing themselves on the meat.During the third and last instar, however, a considerable ieduction in moisture content occurs, and an extensive storage of fat takes place, beginning at about the stage at which previous work had shown a marked increase in resistance to starvation. There is also evidence for the accumulation of a large bulk of reserve protein and a smaller amount of reserve carbohydrate during this instar.The most important factor influencing the degree of uneaturation of the larval fat appears to be the nature of the food fat; iodine values show little variation with the state of development, and preliminary observations suggest that the influence of the environmental temperature is small.I wish to record my sincere thanks to Prof. P. A. Buxton for his active interest in this work, and to Dr V. B. Wigglesworth for helpful advice and valuable suggestions. I am also indebted to the Agricultural Research Council for the award of a Research Scholarship which has entirely financed this investigation.
INVESTIGATIONS UPON THE CONTROL OF OAT SICKNESS BY THE ADDITION OF CERTAIN CHEMICAL SUBSTANCES TO SOIL INFECTED WITH HETERODERA SCHACHTII SCHMIDT
Authors: EDWARDS E. E. 
Published: February 2008

SUMMARYAn account is given of pot experiments carried out in triplicate in 1936 and 1937 upon the control of the oat sickness associated with the Root eelworm, H. schachtii. Calcium cyanamide, sodium nitrate, ferrous sulphate, ferric chloride and two forms of ferric oxide were incorporated intimately with infected soil, and quantitative observations were made on the effects of the treatments upon oats grown in the soil in 1936 and1937 with regard to (a) germination, (b) vegetative growth, (c) panicle production and yield of grain, and (a) degree of infestation of the roots by the nematode. The data obtained show that while all the dressings produced better growth of the plants, at least in the first year after application, calcium cyanamide alone yielded significant results. Further, of the treatments tested, only the use of calcium cyanamide at the rate of as much as 100 cwt. to the acre protected the plants completely from oat sickness in both years and, at the same time, apparently eradicated the parasite from infected soil. Unfortunately, such heavy dressings are not a practicable proposition except, perhaps, under special circumstances.
A STUDY OF CROWN RUST, PUCCINI A CORONATA CORDA, IN GREAT BRITAIN
Authors: BROWN M. R. 
Published: February 2008

Summary

Experiments were carried out to determine the relationship between the varieties of Puccinia coronata Corda previously isolated in Great Britain and the two species of Rhamnus, R. Frangula and R. cathartica, which are the alternate hosts of the rust in this country.
The experiments included: (a) the inoculation of seedling plants of the Rhamnus species with sporidia from germinating teleutospores of the different varieties; and (b) the inoculation of a number of grasses with aecidiospores collected in the field on the two species of Rhamnus.
The varieties were found to show a considerable degree of specialization in their relation to the alternate hosts, vars alopecuri, arrhenatheri, avenae, festucae, holci and lolii producing aecidia on R. cathartica only and var. calamagrostidis on R. Frangula only.
The difference in aecidial host relationship of the varieties is not considered to be an adequate criterion for species differentiation, and it is suggested that the use of the names Puccinia coronata Kleb. and P. coronifera Kleb. (P. Lolii Niels.) be discontinued and the rust be designated by the original name P. coronata Corda.
The pathogenicity of the varieties was not altered appreciably by passage through the alternate host and the varieties did not appear to hybridize readily.
SOIL CONDITIONS AND THE TAKE‐ALL DISEASE OF WHEAT
Authors: GARRETT S. D. 
Published: February 2008

SummaryAttempts to produce infection of wheat seedlings by the ascospores of Ophiobolus graminis in a variety of natural soils and in sand have failed. Yet, the ascospores germinate well on nutrient agars, and the resulting agar cultures produce infection as readily as cultures obtained from mycelium.Ascospore infection of sterile wheat seedlings growing in sterilized soil may be obtained without difficulty. The nutrients present in sterilized soil are unnecessary for the initiation of ascospore infection, which occurs as freely as in sterile sand. Ascospore infection is, therefore, considered to be inhibited in unsterilized soils and sand by the antagonism or competition of other soil micro‐organisms.In unsterilized sand this antagonism is not sufficient to hinder infection by agar inoculum, nor does it appreciably impede the progress of infection along the roots. It is suggested, therefore, that microbiological interference with the initiation of ascospore infection is a competitive rather than an antagonistic effect, and is due to assimilation by the general soil microflora of the nutritive substances excreted from the growing and developing roots. Only under sterile conditions is this organic detritus available to the germinating ascospores.The results of these experiments render it unlikely that the ascospores can play any part in the survival and dispersal of the fungus under field conditions.
CONIOPHORA PUTEANA (SCHUM.) KARST. ON LIVING SEQUOIA GIGANTEA
Authors: MACDONALD J. A. 
Published: February 2008

Summary

When a 36‐year‐old tree of Sequoia gigantea was felled it was found to have rotted areas in the wood at the base of the trunk.
One organism only was isolated from wood in these rotted areas.
The general and detailed microscopic characters exhibited by this fungus in culture identify it as Coniophora puteana.
In the present case it seems clear that the fungus was acting as a primary parasite.
ENCHYTRAEID WORMS AND THE BACTERIA BED METHOD OP SEWAGE TREATMENT
Authors: KEYNOLDSON T. B. 
Published: February 2008

SUMMARY OF PARTS I AND II

The flora and fauna of the bacteria bed of a sewage plant are described, and their interrelationships discussed.
A definite cycle in the character and quantity of the Phormidium (Cyanophyceae), the main constituent of the surface growth, is described, the most striking feature of the cycle being the spring off‐loading.
The Enchytraeid worm, Lumbricillus lineatus Mull., is briefly described and its habits observed in relation to the conditions in the bed. The worms feed primarily on the growth of Phormidium, and consequently tend to cluster at the surface, when this is abundant and climatic conditions allow. Cold drives them slightly down, but the off‐loading sends them deeply into the bed, when an increased proportion pass out with the effluent. Drying of the surface in summer sends them down in an erratic manner according to the degree of desiccation.
The cause of the off‐loading of the surface growth in spring is its change from a leathery to a spongy condition. The worms are mainly responsible for this and, therefore, for the off‐loading. The alga rapidly re‐forms (3–4 weeks) upon the pebbles, worms migrating into it again when it is sufficiently thick. The absence of an off‐loading in summer when the growth is again spongy is attributed to the higher rate of regeneration owing to increased temperature and sunlight, which lessens the effect of the worm depredations.
The importance of Lumbricillus lineatus in keeping open a bacteria bed and helping to maintain its efficiency is proved by means of experimental beds. Worms introduced into an inefficient bed with solids rapidly accumulating cleared the medium and allowed active nitrification to commence. If the bed is very badly choked and septic, the worms may be unable to carry out this function. It is probable that all the larger scouring organisms abundant in the bed have this property to a greater or lesser extent.
The mechanism of the spring off‐loading is discussed with special reference to the role of L. lineatus in the Leeds bacteria beds.
The importance of the maintenance of the biological balance by means of the most economic fauna is pointed out.
Finally, the need for more intensive physiological studies is stressed.