bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE TRANSMISSIOK OF STREAK DISEASE OF MAIZE BY THE LEAFHOPPER BALCLUTHA MBILA NALIDE
Authors: STORES H. H. 
Published: February 2008

SUMMARYIn the absence of transmission of streak disease by the seed, the wide occurrence of this disease in maize in South Africa is accounted for by infection of the plants at some period after their appearance above ground. It has been shown that plants may be protected from infection by growing them in a greenhouse or under wire‐gauze of not less than 32 meshes to the inch.A number of insects have been tested as possible vectors of streak disease, and positive results have been obtained with a jassid, Balclutha mbila Naude. In four cases out of five, to each of which were introduced three or four adults of this species, collected on streak‐diseased maize, the disease developed in every plant. The plants hi three similar cages, to which no jassids were introduced, remained healthy.In experiments in which single individuals of Balclutha mbila, collected upon streak‐diseased maize, were allowed to feed upon single leaves of the experimental plants, the disease resulted in 46 out of 48 plants. One jassid lived for five months and carried the disease to eight separate plants. No loss of the power of infection occurred in any jassid tested, in spite of periods of starvation in some cases or of feeding on apparently immune plants in others. Certain individuals, collected upon streaked maize were incapable of causing any infection under similar conditions.Jassids reared upon healthy maize were incapable of infecting plants with streak disease. But after feeding upon a diseased leaf for a week, 26 per cent. of the males and 86 per cent of the females, out of a total of 62 individuals, became infective.Negative results were obtained in trials of Aphis maidis Fitch, Peregrinus maidis Ashmead and a number of undetermined jassids and fulgorids.Field observations showed that Balclutha mbila was to be found, although infrequently, whenever a field of maize, recently infected with streak disease, was thoroughly searched. It is held therefore to be the agent of spread of the disease in the field.
STUDIES IN BACTERIOSIS. XIII: A SOFT ROT OF POTATO TUBERS DUE TOBACILLUS CAROTOVORUSAND A COMPARISON OF THE CULTURAL, PATHOLOGICAL AND SEROLOGICAL BEHAVIOUR OF VARIOUS ORGANISMS CAUSING SOFT ROTS
Authors: LACEY MARGARET S. 
Published: February 2008

SUMMARYAn internal soft rot of potato tubers caused byB. carotovorusis described. Various strains ofB. phytophthorus, B. solanisaprusandB. carotovorusare compared with respect to their cultural, pathological and serological behaviour, and the differences seem sufficient to warrant their continued separation into distinct species.
THE VIABILITY OF THE WINTER SPORANGIUM OF SYNCHYTRIUM ENDOBIOTICUM (SCHILB.) PERC., THE ORGANISM CAUSING WART DISEASE IN POTATO
Authors: GLYNNE MARY D. 
Published: February 2008

SUMMARYA staining method for testing the viability of the winter sporangia of Synchytrium endobioticum is described. The sporangial contents are pressed out into acid fuchsin or after treatment by a strongly alkaline reagent into methylene blue. The staining reactions have been correlated with the results of infection experiments in pots. Sporangia which, like the controls stain faintly, produce a high percentage infection and are therefore alive. Those which stain deeply and rapidly produce no infection and are presumably dead. There is an intermediate group in which some sporangia stain deeply and some are intermediate in reaction. This group tends to give less infection than the controls.A method whereby sporangia which have been treated in soil may be extracted without affecting their viability is described. The method depends on the difference in specific gravity of sporangia which has been determined as about 1.17 and of soil which is in the region of 2.5. The sporangia are extracted by means of chloroform (sp. gr. 1.5 approx.), which does not affect their viability.A study of the relation of temperature, time and viability shows that treatment for 5 minutes at 90°C., 15 minutes at 80°C., 1 hour at 70°C. and 8 hours at 60°C. have a similar effect in killing all the sporangia.
THE EFFECT OF SOME SOIL CONDITIONS ON NODULE FORMATION ON CROTALARIA JUNCEA (L.)1
Authors: GANGULEE N. 
Published: February 2008

SUMMARYFrom pot culture experiments in the greenhouse it has been shown that the formation of nodules on the roots of Crotalaria juncea is affected significantly by variations in the texture, moisture content and reaction of the soil, all other conditions being kept uniform. Nodule formation was increased by higher moisture content, by increased coarseness and by reduced hydrogen ion concentration.
NOTE ON THE OCCURRENCE OF DISEASED SHOOTS ARISING FROM POTATO‐TUBERS INFECTED BY PHYTOPHTHORA INFESTANS
Authors: SALMON Professor E. S. , WAKE W. M. 
Published: February 2008

SUMMARY

A résumé is given of the work of those investigators who have recorded the occurrence of diseased shoots arising from potato tubers infected by P. infestans.
An experiment is recorded in which of 25 naturally infected tubers planted early in April in pots in the greenhouse, 2 produced by May 16th short diseased shoots, which developed conidiophores and spores. These shoots, doubtless infected ab initio by mycelium growing from the tuber, were closely similar to those which have been described by de Bary and other investigators.
A probable case of secondary infection was observed on a leaf on one of the healthy shoots of a plant which produced a diseased shoot.
STUDIES ON THE LUCERNE NODULE ORGANISM (B. RADICICOLA) UNDER LABORATORY CONDITIONS
Authors: GANGULEE N. 
Published: February 2008

SUMMARYIt is observed that on whatever media the organism is growing, whether in liquid or agar or in soil, the various stages of the life‐cycle are found to occur simultaneously, but in varying proportions. The soil conditions, such as aeration, temperature and the presence of certain salts, are among the factors that determine which of the stages shall be in predominance. The relative efficiency of liquid and solid media in bringing about the predominance of a particular form was also studied.In the main, the existence of the five stages in the life‐cycle of the organism observed by Bewley and Hutchinson is confirmed; but evidence is obtained to show that under very favourable conditions the motile cocci (“swarmer”) can emerge directly from the banded rod stage, developing flagella even, before their emergence, and therefore missing out the non‐motile (“pre‐swarmer”) stage.The appearance of coccoid bodies is observed to have been accelerated in the presence of saccharose, mannite and phosphates (in agar media) and also in soil extract alone. Short rods are elongated cocci and they tend to persist in media containing the ingredients mentioned above.The formation of “pre‐swarmers” has been ascribed to unfavourable conditions, such as deficiency of food, or excess of calcium carbonate in the media, or inadequate aeration. A closer study of the morphological variations, however, shows that the banded rods are associated with such conditions.Comparing the morphological variation with the number of organisms in a given time, it appears that changes in morphology are accompanied by marked alterations in the bacterial activity. The percentage increase of cocci and short rods in soil is found to be correlated with an increased total number of organisms.The writer wishes to acknowledge his indebtedness to Mr P. H. H. Gray for giving him much valuable advice and criticism in the course of the investigation.
THE GROWTH OF YOUNG MICE ACCORDING TO SIZE OF LITTER
Authors: PARKES A. S. 
Published: February 2008

SUMMARY

Four hundred and seven young albino mice produced in 66 litters had an average weight of 1.41 gm. at birth and of 7.14 gnu at weaning time (3 weeks old).
These average values vary very considerably, but uniformly according to size of litter. Individuals from litters of 2 and litters of 10 averaged respectively 1.0 gm. and 1.6 gm. at birth, and 4.45 gm. and 11.75 gm. at weaning time. Individuals from the intermediate sizes of litter grade fairly evenly in between these extremes. The whole growth during suckling is in fact inversely proportional to the size of litter.
Growth during suckling is characterised by the active phases in the first and third weeks respectively and a comparatively stagnant period in between.
These results can all be explained on a basis of differential nutrition.
A QUANTITATIVE EXAMINATION OF THE TOXI‐CITY OF 3:5‐DINITRO‐O‐CRESOL AND OTHER COMPOUNDS TO INSECT EGGS, UNDER LABORATORY AND FIELD CONDITIONS
Authors: GIMINGHAM C. T. , MASSEE A. M. , TATTERSFIELD F. 
Published: February 2008

SUMMARY

The toxicity of 3: 5‐dinitro‐o‐cresol and its sodium salt to eggs of the moth Selenia tetralunaria Hüfn, has been determined quantitatively under controlled conditions in the laboratory. The figures obtained confirm earlier results and show (a) that these compounds have a very high toxicity to insect eggs, and (b) that the sodium salt of dinitro‐o‐cresol is only slightly less toxic than dinitro‐o‐cresol in the uncombined state. The relationship between concentration and toxicity is expressed by means of diagrams.
Preliminary laboratory experiments indicate that dinitro‐o‐cresol is also highly toxic to insect eggs of a more resistant type than those of S. tetralunaria.
Spray fluids containing dinitro‐o‐cresol or the sodium salt showed a high efficiency against eggs of the Hop‐Damson Aphis (Phorodon humuli Schr.) on plum trees on a larger scale under field conditions. The trees sprayed with these compounds remained almost free from aphides during the following spring when the control trees were badly infested.
A quantitative method for judging the results of the field experiments was worked out. This involved recording details of large numbers of eggs on selected shoots on sprayed and control trees before and after spraying, a numerical measure of the effect of the various treatments being thus obtained. The method gave consistent and reliable results.
The spray fluids containing dinitro‐o‐cresol and its sodium salt had a marked general cleansing effect on the trees. No injury to the trees was observed.
YIELD STUDIES IN OATS: THE EFFECT OF THE PRE‐TREATMENT OF THE PARENT CROP UPON THE SEED PRODUCED, ITS GERMINATION AND SUBSEQUENT GROWTH
Authors: JONES MARTIN G. , TINCKER M. A. H. 
Published: February 2008

SUMMARY

The effect of the parent crop husbandry in the case of oats has been traced upon the seed, its germination and early growth and yield.
The beneficial effects of seed grading by weight are again emphasised, but it has been demonstrated that such mass selection does not cause an improvement of the seed qualities in every respect. More subtle characteristics than weight have a predetermining effect.
The relationship between environmental conditions and panicle characters has been discussed.
In spring oats grown under Welsh conditions the importance of establishment, which can be roughly gauged by laboratory tests, is emphasised. Heating the seed samples appears to be a suitable method by which further information can be obtained as to the seed's vigour.
It seems that an index to yield is likely to be found in this direction. Seed vigour is correlated with yield.
Plant to plant variation is so wide between spaced individuals that little indication of the graminaceous plant's capabilities were discernible in seedling behaviour.
OBSERVATIONS ON THE INSECT CARRIERS OF MOSAIC DISEASE OF THE POTATO.
Authors: SMITH KENNETH M. 
Published: February 2008

Summary.

An account is given of some preliminary experiments with insects as transmitters of potato mosaic disease. The various types of insect‐proof cage which have been used in these experiments are described.
The following insects were used in the inoculations:Aphididae. Myzus persicae. Macrosiphum gei (=solanifolii). Myzus Circumflexus. Aleurodes, White‐fly. Asterochition vaporariorum. Capsidae. Calocoris bipunctatus. Lygus pabulinus. Typhlocybidae, Leaf‐hoppers. Zygina pallidifrons. Eupteryx auratus.
The aim of the experiments is definitely to identify what insects of those normally attacking the potato are disseminators of virus disease.
Infected insects were placed both upon the sprouts of tubers and upon the haulm; the latter is the only satisfactory method for insects other than aphides.
Successful transmission of mosaic disease was obtained in 1925 by means of the aphides Myzus persicae and Macrosiphum gei. Some evidence of infection by means of Aslerochiton vaporariorum (greenhouse white‐fly) and the leaf‐hoppers Zygina pallidifrons and Eupteryx auratus wars also obtained; further work with these insects is required before definite conclusions are drawn. The capsid bugs Lygus pabulinus and Calocoris bipunctatw failed entirely to transmit the disease.
RHIZOCTONIA “FOOT‐ROT” OF THE TOMATO1
Authors: SMALL T. 
Published: February 2008

Summary.

A “foot‐rot” disease of young tomato plants from Guernsey caused by Rhizoctonia solani has been investigated.
The disease is least prevalent on dry open soils; it is most severe at temperatures ranging from 16°C.‐20°C
The degree of infection was increased by stable manure; slightly decreased by ammonium sulphate; apparently unaffected by lime, potassic and phosphatic manures.
Soil sterilisation by heat was the most effective and reliable means of controlling the disease. During the season the disease was checked by uspulun.
Control methods are suggested.
A STUDY OF HYLEMYJTA (CHORTOPHILA) RRAS‐SICAE BOUCHE, THE CABBAGE ROOT FLU AND ITS PARASITES. WITH NOTES ON SOMX OTHER DIPTEROUS PESTS OF CRUCIFEROUS PLANTS
Authors: SMITH KENNETH M. 
Published: February 2008

Summary.A detailed account is given of the life history and parasites of Hylemyia (Chortophila) brassicae, the cabbage root fly. The various stages are described and figured. The egg is deposited in the vicinity of the roofs of Cruciferous plants, in the heads of cauliflowers, and in autumn on the leaves and cut stem of Brassicas. The period of the egg stage lasts from 3 to 5 days, the larva when full grown is smooth, white in colour, and possesses a caudal corona of well‐defined tubercles, one pair of which is bifurcate and serves as a means of identification. The maggots feed in the roots of Cruciferous plants, or in the heads of cauliflowers and turnips, while late in the autumn they may occasionally be found tunnelling in the midrib of Brassica leaves. The larval period lasts from 19 to 25 days. The puparium is reddish brown in colour and measures about 7 mm. in length. The length of the pupal stage is very variable and may occupy from an average of 16 days to 69 days. Pupation takes place in the soil in proximity to the plant. The adult is a dark grey insect somewhat resembling the home fly but is more bristly.There are three generations in the season; as a general rule hibernation is in the soil in the pupal stage.Four other types of larvae found associated with those of H. brassicae in Cruciferous plants are described, the most important being Phytomyza rufipes Meig.A detailed description of the parasites of H. brassicae is given; these are the larva of the Staphylinid beetle Aleochura bilineata Gyll., the Cynipid Cothonaspis rapae Westw., the Braconid Dacnusa stramidpes Halid. and the Anthomyid fly Phaonia trimaculatu Bouché, the larvae of which are carnivorous and feed upon H. bassicue larvae. There are also described a Proctrotrupid, Emllonyx Eigatus Nees., which is parasitic upon the larva of Abochara bilinmta Gyll. and a Tachinid fly, One& agilis Meig., which is associated with H. brassicae, although the exact relationship has not been determined.An unusual form of parasitism of the adult fly by some kind of micro‐organism is also figured and briefly described.
INVESTIGATIONS ON THE CONTROL OF WIREWORMS
Authors: MILES HERBERT W. , PETHERBRIDGE F. R. 
Published: February 2008

Summary.A study of the wireworm problem in Great Britian shows that this pest is especially important in areas devoted to intensive agriculture and commercial horticulture.In addition to most farm crops, strawberries, various flowers and tomatoes me particularly susceptible to wireworm attack and because these crops 60 often occur on new land, losses due to the activities of the pest are frequent, and serious. The nature and extent of wireworm attack, both in the field and in glasshouses, is described herein.Examination of weeds growing in infested fields indicate that wire‐worms are found in numbers at the root of some plants such as couch‐grass, Agropyrum repens, and yarrow, Achillea millifolium, while very few occur at the roots of pants like chickweed, Stelkria media, gout‐weed, Chenopodium album and annual nettle, Urtica urens.Field observations on the movements of wireworms in the soil throughout the autumn, winter and spring indicate that there is a definite downward migration in autumn and an upward migration in spring. Correspondingly wireworm activity in the surface soil was noted to be at its height in September and October, and March, April and May.Expehents on the use of baits as a means of assembling wireworms, indicated that large numbers will collect to baits such as wheat, oats, and bran, and moreover these baits can be used to attract wireworms from the roots of crop plants, on which they are feeding. Because of the seasonal movements of wireworms, baiting is best carried out in autumn or spring.Calcium cyanide in granular form has been found to be highly toxic to wireworms and used, in connection with the baiting, at the rate of 2–3 Ib. per 100 yd. of bait row, destroyed 75–100 per cent. of the wire‐worms assembled.Based on the results of experiments conducted in Lincolnshire, Hertfordshire, and West Sussex, during the years 1925 and 1926, and involving 10,000 wireworms, recommendations are made for the control of wireworms by means of baits and the use of calcium cyanide.
THE BIOLOGY OF THYSANOPTERA WITH REFERENCE TO THE COTTON PLANT: 1. THE RELATION BETWEEN DEGREE OF INFESTATION AND WATER SUPPLIED
Authors: WARDLE ROBERT A. 
Published: February 2008

Summary.

Experiments concerning the degree of infestation of Thrips tabaci upon cotton plants under glasshouse conditions suggest that the infestation factor, or number of thrip stages per 100 sq. cm. of foliage surface, varies inversely with the weight of water supplied.
Plants receiving excessive water supply have a lower infestation factor and a lower number of thrip stages per leaf as compared with plants receiving sufficiency of water supply; plants receiving insufficient water supply have a greater infestation factor than plants receiving sufficiency of water supply but have not necessarily a greater number of thrip stages per leaf; owing to their smaller foliage area however they suffer more from thrip attack.
Irrigation is more effective in influencing the degree of thrip infestation than is rainfall.
Irrigation on a flat soil surface is more effective than irrigation on a furrowed soil surface.
The effect of excessive water supply does not appear to be due to mechanical removal of thrips stages from the foliage, nor an injurious effect of soil moisture or atmospheric moisture upon thrips stages, nor alteration of the osmotic concentration of cell sap, although all three factors may operate slightly.
It is suggested that one factor concerned is the influence of heavy water supply upon the texture of certain soils, in promoting surface caking which will act inimically to soil pupating species of Thysanoptera.
ANTAGONISM OF MICRO‐ORGANISMS AS THE CONTROLLING FACTOR IN THE: INHIBITION OF SCAB BY GREEN‐MANURING
Authors: MILLARD W. A. , TAYLOR C. B. 
Published: February 2008

Summary.

The “preferential food theory” as an explanation of the action of green manure in the control of scab is criticised.
Experiments are described in which potatoes are grown in series of pots containing soil only or soil mixed with grass cuttings. In each series the pots were inoculated with two Actinomyces species—the one, A. scabies (Thaxter) Güssow emend. M. and B., a virulent scab producer; the other, A. praecox, an obligate and prolific saprophyte. In Exp. 1, the inoculum of A. scabies was made to decrease and that of A. praecox to increase along the series. In Exps. 2 and 3 the inoculum of A. scabies was kept constant, and that of A. praecox was gradually increased along the series of pots.
In the absence of the saprophytic Actinomyces species, grass alone exerted no inhibitory action on scab.
A reduction of scab was obtained in all pots whether of soil or soil mixed with grass to which an inoculation of A. praecox had been given. This reduction was most marked in the case of the maximum inoculation with A. praecox.
Counts of the two Actinomyces species were made from soil samples taken from the pots during and after growth of the potato crops, and from these it was found that the presence of the saprophytic species had exerted a very strong depressing effect upon the parasitic species. This depressing effect was most marked after a whole season's growth as shown by Exp. 3. Here, on the millionth dilution platings from a pot inoculated with A. scabies alone, 225 colonies grew but no colonies of this species were found on the plates of the same dilution in the case of three pots to which inoculations of A. praecox had also been given.
The inhibitory effect of A. praecox on A. scabies is not due to the setting up of an unfavourable soil reaction but is probably caused by a starving out of the weaker organism in competition for the available food supply of the soil.
It is suggested that the beneficial effect of green manuring on scab under field conditions is due to similar competitive action and that in this competition the bacteria as well as the Actinomyces may play a part.
The cases in which green manuring has apparently failed to inhibit scab have been considered from this fresh point of view.
ON THE CONTROL OF GLASSHOUSE INSECTS WITH CALCIUM CYANIDE
Authors: MILES.M.Sc. HEEBERT W. 
Published: February 2008

Summary.Experiments on glasshouse fumigation with calcium cyanide in Great Britain during 1925–26 indicate that this material is a satisfactory source of hydrocyanic acid gas, and can be used to control a number of the usual pests infesting glasshouse plants. Trialeurodes vaporariorum Westw. was held in check with dosages of 1/12–1/5 oz. per 1000 cu. ft. and effectively controlled with dosages from 1/4–3/4 oz. per 1000 cu. ft. according to the conditions prevailing.At least six species of greenhouse aphides were controlled with dosages varying from 1/1 oz. to 1/2 oz. per 1000 cu. ft.Thrips, of which four species were dealt with, were more difficult to control, apparently only the adults being affected by the hydrocyanic acid gas. Dosages of 1/3 to 11/2 ozs. per 1000 cu. ft. killed varying percentages of the adults and a series of fumigations were found to give satisfactory control.
THE EFFECT OF SOIL STORAGE AND WATER CONTENT OX THE PROTOZOAN POPULATION
Authors: CUTLER D. WARD , DIXON. A. 
Published: February 2008

Summary.

Experiments are described showing that it is possible to conduct laboratory experiments on micro‐organisms in stored soil, providing the surface of the soil is large relatively to its volume.
Experiments on the influence of moisture on the soil protozoa show that active forms are found in soils containing a very low per centage of water.
The flagellate Cercomonas crassicauda was found to excyst and reproduce in air‐dried soil brought to 1/6 the water‐holding capacity. The numbers of the bacteria also in this experiment nearly doubled their numbers in 24 hours.
Four common soil protozoa were found to behave normally in soil of 1/2 and 1/3 the water‐holding capacity, which previously had been air‐dried and then brought to the desired water content
Field soils having water contents of 6 per cent, in one case and 4 per cent. in another corroborated the laboratory experiments In all of these samples active Cercomonas were found, other protozoa being present only in the form of cysts.