bluuebunny/crossref_metadata_2025_split huggingface dataset:
ON THE BIOLOGY OF THE APPLE SAWFLY, HOPLOGAMPA TESTUDINEA KLUG.
Authors: MILES HERBERT W. 
Published: February 2008

SUMMARYThe biology of the apple sawfly, Hoplocumpa testudinea Klug., has been under observation for several years in the north‐west of England. Mating and oviposition are described and an account is given of the position of the eggs on the host plant. Usually the eggs are found under the epidermis of the upper surface of the receptacle within the calyx ring, and often within the bases of the stamens.The incubation period normally varied from 8 to 15 days. During this period the eggs increased slightly in size, and the majority ruptured the epidermis of the receptacle and so became partly exposed within the calyx ring.The larvae emerge from the eggs on the outside of the fruitlet and proceed to penetrate it either from within The calyx ring, or by passing over the calyx on to the side of the receptacle and tunnelling in from that position. It appears that the larvae seek the ovary but numbers never reach it, and at this stage there may be some mortality among the larvae.Larvae which reach the ovary feed for a short time on the developing seeds and at about the third instar migrate to older fruits. Circular or ribbon scars appear to be caused by the wanderings of first instar larvae in their first penetration of the fruit.The larvae are described. They have five instars and a growth ratio of about 1.4. They measure 9–11 mm. when mature.The larvae over‐winter in cocoons, the majority of those under observation were constructed a t a depth of 3–9 in. in the soil. The pupal period lasts 3–4 weeks.Notes are given on infestation by apple sawfly in relation to variety and date of blossoming of a number of apple varieties, and the significance of details of the biology of the species on control measures is discussed.
ON THREE NEW VIRUS DISEASES OP HYOSCYAMUS NIGER
Authors: HAMILTON MARION A. 
Published: February 2008

SUMMARY

The source and general character of three new virus diseases occurring in Hyoscyanzus are described under the names of Hyoscyamus virus (Hy.) 11, 111 and IV. They have a host range of various solanaceous plants not including any variety of potato.
Hy. I1 and 111 are non‐flterable (through L 3) and are transmitted to and from all their hosts except tomato by tEe aphid Myzus persicae. Hy. I11 survives for a relatively short period as clarified juice. Hy. II and Hy. III have many characters in common and are probably closely related.
Hy. IV is a different type of Virus, flterable through an L 3 candle and no insect vector has yet been found for it.
Problems arising from consideration of the data so far accumulated are submitted and discussed.
LIGHTNING STORMS AND THEIR SIGNIFICANCE IN RELATION TO DISEASES OF (1) COCOS NUCIFERA AND (2) HEVEA BRASILIENSIS
Authors: SHARPLES A. 
Published: February 2008

SUMMARY.

This investigation proves that lightning is a factor of the first importance in the causation of disease on coconut palm plantations in Malaya.
The “bud‐rot” symptoms occurring in Malayan coconut palm plantations are produced entirely by lightning or the after‐effects thereof. No evidence of the presence of a Phytophthora has been obtained.
Lightning has been proved to be of some importance in the causation of disease on rubber plantations.
The typical effects on rubber plantations are described, and attention is specially directed to the association of claret‐coloured bark canker at the collar of trees slightly affected by lightning.

The writer wishes to acknowledge the considerable help rendered by his colleague, Mr H. Gunnery, in the preparation of photographs and recording of field work. Thanks are also tendered to Mr H. T. A. Biddle‐combe for great assistance in the coconut investigations and to Mr G. Shelton‐Agar for similar assistance in connection with the work on rubber plantations.
ON THE USE OF THE PRIMARY LESIONS IN QUANTITATIVE WORK WITH TWO PLANT VIRUSES
Authors: SAMUEL GEOFFREY , BALD J. G. 
Published: February 2008

SUMMARY.The precautions which, should be observed in practical application of Holmes's local lesion method in quantitative work with tobacco mosaic have been examined. The aim has been to obtain results with the greatest statistical significance consistent with the use of reasonably small numbers of plants. The adoption of a standard method of inoculation, and the comparison of viruses on opposite halves of the same leaves, were found to be the most important points to observe, and a method of work has been outlined.Tomato spotted wilt forms necrotic primary lesions on the leaves of tobacco of a character suitable for quantitative work, and a number of the results obtained with tobacco mosaic have been checked with this virus.Applications of the method are discussed. It is shown that rapid comparison of virus concentrations from different sources should be possible after further work has been done on dilution curves. An illustration is also given of the application of the method in plotting the curve of “ageing,” or change in virulence with time, of the expressed virus of tomato spotted wilt. This curve was found to be of the logarithmic type.
THE INFLUENCE OF ENVIRONMENTAL CONDITIONS ON THE DEVELOPMENT OF THE ANGULAR LEAF‐SPOT DISEASE OF COTTON
Authors: STOUGHTON R. H. 
Published: February 2008

SUMMARY.1. Experiments on the influence of variations in the environmental conditions on the bacterial disease of cotton plants caused by Bacterium malvacearum are described.2. A regular diurnal variation in soil temperature is shown to have the same effect on primary infection of seedlings as a constant temperature near the mean of the fluctuations.3. The mean soil temperature at the time of sowing and for the first few days of germination is the chief controlling factor in primary infection, other factors being equal. Subsequent variations in the soil temperature have little effect on the incidence of the disease.4. The amount of disease resulting from infection of the seed, i.e. primary infection, is higher at soil moisture contents approaching saturation than at normal moisture contents in a given type of soil.5. The amount of primary infection at a given soil temperature and moisture content varies with the type of soil.6. A regular diurnal variation of air temperature has the same effect on secondary infection resulting from spray‐inoculation of young plants as a constant temperature near to, or slightly above, the mean of the variations.7. Other things being equal, the amount of infection resulting from spray‐inoculation depends upon the mean temperature prevailing during the incubation period of the disease, the actual temperature at the time of inoculation being unimportant.8. Atmospheric humidity is a conditioning factor in secondary infection only during a short period (less than 48 hours) following inoculation. Its importance lies in its control of the time during which the infection droplets persist. Once penetration of the tissues has been effected variations in the external humidity have little direct effect.9. Plants kept in total darkness are relatively resistant to infection.10. Plants grown in continuous light are no more susceptible than those grown under a daily period of 17 hours' illumination of approximately 1200 foot‐candles.11. The time of inoculation in relation to the period of illumination does not appear to have any marked effect on the amount of infection.12. The relations of the whole series of experiments on the influence of environmental conditions are discussed.
STUDIES ON PENICILLIUM CHBYSOOENUM THOM, IN RELATION TO TEMPERATURE AND RELATIVE HUMIDITY OF THE AIR
Authors: GROOM PERCY , PANISSET THERESE 
Published: February 2008

SUMMARY.(i) Germination and viability of conidia of P. chrysogenum.1. Conidia were found to germinate in moist air on glass in atmospheres ranging in relative humidity from 100 to 81 per cent, and in temperature from 1 to above 35 but below 40° C, with the optimum temperature lying near 25° C.2. At constant temperature the latent period of germination generally shortened as the relative humidity of the air rose, and when liquid or gaseous water was replaced by 2 per cent, malt agar.3. The latent period of germination in water of conidia from old cultures (120 or 210 days old) tended to be longer than that of conidia from young cultures (3 days old). Variations in the intrinsic characters of the conidia caused irregularity in the results which was not shown when the conidia were germinated on 2 per cent, malt agar.4. Conidia were exposed for periods up to 136 days to atmospheres of temperatures 20 and 30° C. and of relative humidities 72–6, 26 and 0 per cent, (approx.). The percentage germinations in water and on agar within 24 hours, and in water, after submersion for periods up to 216 hours, were determined. No correlation was found between the length of exposure of conidia to various atmospheres and the ultimate germination in water, though during the first 24 hours of germination on agar and in water increased length of exposure generally resulted in decline in percentage germination.5. Exposure of conidia to atmospheres of 0–100 per cent. R.H. and 1–100° C. showed that conidia possess considerable powers of resistance to heat for temperatures up to 30° C. in atmospheres of relative humidity 0 and 26 per cent, and can live in the latter for more than 129 days; at temperatures above 40° C. the time required to kill the conidia at the same temperature falls with rise in relative humidity, and at the same relative humidity falls with rise in temperature.
THE ECOTYPE CONCEPT IN RELATION TO THE REGISTRATION OF CROP PLANTS
Authors: GREGOR J. W. 
Published: February 2008

SUMMARY.

The ecotype concept as formulated by Tuxesson (1922) postulates the existence, in the wild, of sub‐specific units–ecotypes–which result from the environmental fractionation of a larger population. Details are given of the occurrence of these units in nature.
While the wild ecotypes are not strictly comparable with the agricultural crop units yet the general principles underlying this concept have a definite agricultural application. Suggestions are made for a standard system of crop classification which embodies data relating to the environmental preferences of its units. Two units of agricultural significance are discussed: (1) the agrotype, or ultimate crop unit, and (2) the agro‐ecotype, or groupof agrotypes possessing similar environmental preferences. The measures necessary for the administration of the scheme are briefly outlined.
THE MOVEMENT OF TOBACCO MOSAIC VIRUS IN ITS HOST
Authors: GRAINGER J. 
Published: February 2008

SUMMARY.1. Experiments on the rate of spread of the virus of tobacco mosaic in the leaves and stems of Nicotiana tabacum L. show that it moves at a logarithmic rate, beginning slowly and later accelerating. The spread seems to be independent of mechanical carriage by the transpiration or translocation streams, and can certainly take place in parenchyma.2. The virus multiplies in tissue near to the point of inoculation at a logarithmic rate portrayed by an S curve which is also typical of the growth of living organisms and of the rate of accumulation of the catalyst in an autocatalytic reaction.3. Naturally produced water of guttation from diseased tomato plants does not carry virus infection, but the application of high pressures ruptures the cells of the leaf and gives an infectious liquid.The author desires to express his sincere thanks to Prof. J. H. Priestley, of Leeds University, for many helpful suggestions and advice, and to Prof. J. Johnson, of the University of Wisconsin, for help in the initial stages of the work. The work has been financed entirely by grants from the Yorkshire Cancer Research Fund.
THE BIOLOGY OF OAT SMUTS
Authors: SAMPSON KATHLEEN 
Published: February 2008

SUMMARY.The paper deals with microscopic observations on the invasion of a selection of A. strigosa orcadensis by two biological species of U. Kolleri, which differ by nearly 100 per cent, in their capacity for producing smutted panicles on this host. Under certain prescribed experimental conditions both strains enter the oat plant with equal facility, but one is retarded in development and fails to reach the growing apex before the tissues of the primary node become lignined, with the result that the panicles produced are not infected.The results are discussed in relation to the problem of the inheritance of resistance to smut in oats.
FUSARIUM SPECIES ON BRITISH CEREALS: FUSABIUM NIVALE (FR.) CES. (=?CALONECTBIA GRAMINICOLA (BERK. & BR.) WR.)
Authors: BENNETT F. T. 
Published: February 2008

SUMMARY.1. F. nivale (?Calonectria graminicola) was commonly present along with one or more other species of Fusarium on the basal parts of oats and perennial rye‐grass that had failed in a field. The pathogenicity of the other species of Fusarium being known from previous investigations, that of F. nivale remained to be ascertained.2. In wheat, barley, oats and rye, this fungus causes some loss of plants before or after brairding, and it acts as a continuous check on the growth of established plants sown and grown under adverse conditions, whether infection arises from contaminated soil or seed; good growing conditions largely counteract the effects of contamination.3. F. nivale also attacks ears and grain, preventing grain formation or causing discoloration of formed grains; whilst possible thus to reduce the yield and market value, such attacks are rare in the field.4. The chief result arising from contaminated soil or seed in practice is a general reduction in vigour, a condition more likely to be attributed to causes other than the true one.5. Perennial and Italian rye‐grasses on contaminated soils are reduced first in growth; subsequently, the former is largely killed off by the end of the season, but in the field this stage would be reached in the second season.6. F. nivale grows vigorously within the range of normal summer shade temperature, its optimum being 20–21° C.; it grows slowly at 0–1° C, and in its vegetative state withstands winter conditions, as well as exposure to temperatures as low as – 20° C.; it ceases growth, and loses vitality within a few days, at 32–33° C.7. In culture the fungus grows on media of hydrogen‐ion concentration from 2–5 to 13, the optimum being 6–5 to 6–9; its conidia do not germinate in media more acid than pH 5–0 to 5–2. Neither the existence nor the pathogenicity of the fungus is appreciably affected by the acid or alkaline condition of soils within ordinary field ranges.8. Comparative cultural studies of the British and Continental strains of F. nivale show that they differ consistently and significantly in size of conidia, and in form and rate of growth on certain selective media. These morphological and physiological differences are accompanied by difference in pathogenicity, the Continental strain, so far as has been tested, being more virulent toward cereals and less virulent toward grasses than the British strain.The writer tenders thanks to Dr G‐. H. Pethybridge for helpful criticism of this paper.
OBSERVATIONS ON GROWTH IN LARVAE OF PLODIA INTERPUNCTELLA HUBN.
Authors: MILES MARY 
Published: February 2008

SUMMARY.Studies on larval growth in four series of P. interfunctella of different provenience, maintained at 21° C. and fed on walnuts, have shown that:

Six larval stadia was usual but development might be accelerated so that larval life was completed in five stadia or retarded so that seven stadia were required.
Number of larval stadia was associated with rate of growth at ecdysis, larvae growing rapidly at each ecdysis having fewer stadia than those growing more slowly.
Duration of larval life was associated with number of stadia and rate of growth at ecdysis, five‐stadia larvae tending to complete larval development in less time than six‐stadia and seven‐stadia larvae.
Duration of the final larval stadium has considerable influence on duration of larval life, and the tendency for the final larval stadium to be prolonged was most pronounced in larvae having seven stadia.
Prolongation of the final larval stadium was frequently followed by failure to attain imaginal development.
Rapid growth and reduction in number and duration of larval stadia are associated with the vigour necessary to pass successfully the several phases of metamorphosis.
Variation in number of larval stadia, rate of larval growth and duration of larval life are the result of acceleration or retardation of physiological processes.

Full details of number and duration of larval stadia, measurements of the width of the head capsule in successive instars and the growth ratios for 74 larvae have been filed at the Department of Economic Entomology, British Museum.
SOME CECIDOMYIDAE ATTACKING THE SEED OF DACTYLIS QLOMERATA L. AND LOLIUM PERENNE L.
Authors: METCALFE MAKGOT E. 
Published: February 2008

SUMMARY.1. Three species of Cecidomyidae have been observed destroying grass seed on the Park Grass Plots at Harpenden: two species attacking Dactylis glomerata, and the third L. perenne. Of the two species on D. glomerata one has been identified as Gontarinia dactylidis (H. Lw.), the other is described for the first time as Dasyneura dactylidis sp.n. The species present on L. perenne is also a new species and is described as G. lolii sp.n.2. All three species of midges are single brooded at Harpenden, the larvae overwintering in the soil. D. dactylidis emerges between May 21st and June 6th, C. dactylidis between June 3rd and 24th and C. lolii between May 31st and June 26th. The damage is done by the larvae which feed on the ovary, singly in the case of D. dactylidis, collectively in the other two cases. Parasitism by certain Hymenoptera in 1932 was respectively 42–3, 11–6 and 0–75 per cent.3. It has not been found possible to cause attack by C. dactylidis on F. rubra or L. perenne. Similarly no infestation by C. lolii was produced on F. rubra, Dactylis glomerata or Alopecurus pratensis. It appears probable that these gall midges are specific in their attack.4. In a brief discussion of control methods it is suggested that delaying the flowering of the grasses either by grazing sheep or by clipping, or by very early cutting to prevent the development of young larvae, might prove effective.
STUDIES UPON THE COPPER FUNGICIDES
Authors: MARTIN. HUBERT 
Published: February 2008

SUMMARY.1. To overcome difficulties encountered in the application of Bordeaux mixture as a fine mist‐like spray, two modifications are proposed which may be applied in larger quantities after the manner of an insecticidal wash. By this means the application of the protective fungicide is made easier and more rapid, the wear on the spray pumps may be reduced and difficulties due to the lack of carrying power of the spray are removed. Further, the incorporation of a contact insecticide with the protective fungicide becomes possible, with resultant saving of labour and of time in the routine spraying of fruit and hops.2. The modifications of Bordeaux mixture proposed are (1) the incorporation of concentrated sulphite lye in the Bordeaux mixture, (2) the glyceride oil emulsion produced by the use of Bordeaux mixture as emulsifier. As examination of the amounts of copper retained on foliage after spraying showed that the presence of oil improves the retention of spray deposit, the content of copper sulphate and lime of the oil‐Bordeaux emulsion was reduced to half that of the Bordeaux mixture used in comparisons of fungicidal efficiency by field trials.3. The results of field trials show that, under the conditions prevailing in 1931 and 1932, (i) the modified Bordeaux mixtures, applied in heavy amounts, proved as effective as lighter applications of Bordeaux mixture for the control of potato blight, apple and pear scab. In one trial, in which vegetable oil of high free‐fatty acid content was used, the fungicidal efficiency of the oil‐Bordeaux emulsion was below that of Bordeaux mixture containing double the amount of copper sulphate and lime; (ii) the application of large quantities of the modified Bordeaux mixtures did not cause greater leaf injury or fruit russeting than Bordeaux mixture used in smaller amounts; (iii) combinations of nicotine with the modified Bordeaux mixtures gave washes of insecticidal efficiency equal to that of nicotine‐soap wash; (iv) as a result of the use of a spray of larger volume, the application of the modified Bordeaux mixtures was easier and more rapid than that of Bordeaux mixture.4. A method is described for the estimation of copper retained on sprayed foliage.
THE EFFECT OF RUBIDIUM SULPHATE AND PALLADIUM CHLORIDE ON THE GROWTH OF PLANTS
Authors: BRENCHLEY WINFRED E. 
Published: February 2008

SUMMARY.1. Comparisons have been made between the action of rubidium sulphate and palladium chloride on the growth of barley, wheat, oats peas and beans in complete nutrient solutions.2. Over a wide range of concentrations rubidium sulphate was not found to exercise either a beneficial or a harmful action on the growth of any of the species tested. The germination of the seeds was likewise not affected.3. No benefit was derived from palladium chloride, but at a comparatively low concentration a harmful action occurred which became more intense with increasing concentration. Stunting of the main root and laterals was a characteristic feature of this toxicity. With the lower concentrations the check was temporary, and the roots eventually made normal growth, as good as that in the control plants. With increasing amounts of pallahum chloride the poisoning effect became more persistent, until a concentration was reached which did not allow of any root or shoot recovery.4. The tolerance of palladium varies with the species, as was indicated b. the measure of recovery. Barley appeared to be the least, and oats the most sensitive of the three cereals tested. Peas responded at much the same concentrations as barley, but broad beans made so complete a recovery from the initial checking that the dry weights were ultimately not reduced even by the strongest concentration tested, the plants being indistinguishable from the controls.5. The effect of palladium poisoning was similar whether the seeds were germinated in the presence of palladium or whether the seedlings were not introduced to it until they were about a week old.