bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE PROBLEM OF THE EVALUATION OF ROTENONE‐CONTAINING PLANTS
Authors: TATTERSFIELD F. , MARTIN J. T. 
Published: February 2008

Summary.

Seven samples of Derris root have been examined chemically and the following determinations carried out: rotenone (crude and recrystallised), ether extract, methoxyl content, and dehydro compounds. The importance of using standard methods of analysis is stressed.
Insecticide tests have been carried out and comparisons made between pairs of samples tested on the same day.
When comparisons were made between pairs belonging to different species of Derris, the determinations of rotenone by the present methods, ether extract or methoxyl content did not express accurately the relative insecticidal potencies of the pairs of samples. When comparisons were made between pairs of the same species, all these determinations appeared to give a closer measure of their relative activities.
In our samples, the estimation of the dehydro compounds, or of rotenone plus the dehydro compounds in the resin, gave a better assessment of the relative potencies than the other determinations, whether comparisons were made between samples of the same, or of different species. Further work is, however, needed.
THE INFLUENCE OF SEASON AND OF THE APPLICATION OF LIME ON THE BOTANICAL COMPOSITION OF GRASSLAND HERBAGE
Authors: BRENCHLEY WINIFRED E. 
Published: February 2008

Summary.The botanical composition of the herbage of grassland under constant manurial treatment varies considerably from year to year.With complete fertilisers including nitrogen and minerals the relative proportions of the three main groups of species, i.e. grasses, leguminous and miscellaneous plants, are not usually much affected by season, though the individual species do vary, but with one‐sided fertilisers and on unmanured areas wide fluctuations occur in the percentage of these groups. No correlation can be traced between the annual variations in the yield and the botanical composition of the herbage, except for some suggestion of association between high yield and high percentage of leguminous plants with long‐continued mineral manuring.The variations of individual species occur on all plots. They may be caused by direct or indirect response to season and are much influenced by the type of manuring. It is often difficult to determine whether a marked increase or decrease of a species in any year is due to climatic conditions being beneficial or detrimental to that particular species. It may be that the real effect is on other constituents of the herbage which change so much that the proportion of the species under consideration is radically affected [cf. Alopecurus in 1922). In some cases, especially with organic fertilisers, the main groups and also certain species [as Alopecurus, Arrhenatherum, Dactylis] show a tendency to rhythmic changes with season, rising and falling over a period of years. In other cases the fluctuations are more abrupt and irregular, sometimes being exaggerated in the presence of lime.The application of lime to plots with long‐established manurial treatment does not affect the balance of the three main groups with complete fertilisers, but with one‐sided manures a definite bias in one direction appears sooner or later. Individual species usually respond to lime at once, showing a change of proportion at the first succeeding cut, but under certain soil conditions a delay may occur until a second dressing has been given. It would appear that the maximum effect of liming is reached within a few years from the first application, after which fluctuations with season may again become more obvious.Shade is also a factor which influences the balance of species in herbage. The available data is limited to a single plot, but indicates that certain species may be greatly increased or decreased as a result of shading, whereas the proportion of other species may not be affected.
NOTES ON THE TIMOTHY GRASS FLIES (AMAUROSOMA SPP.)
Authors: BARNES H. F. 
Published: February 2008

Summary.

A short account of the systematic position of the Timothy flies (Amaurosoma armillatum Zett. and A. flavipes Fall.) is given and the literature concerning them is reviewed.
Their distribution is stated and notes are given on their bionomics as observed at Harpenden on material obtained from Slough, Buckinghamshire.
The parasites Microbracon exhilarator Nees and Lamprotatus sp. are recorded.
Efforts have been made to see whether the earliness or lateness of Timothy grass strain has any effect on the incidence of attack. There are indications that a dwarf strain which is an early one is less liable to attack, though this may be due to a varietal resistance rather than to the time of flowering.
It does not appear feasible to get limits of flowering wide enough to cover the period of attack, so that further investigations in this direction need not be pursued.
Indications were obtained that the effect of manuring the grass may be to lower the attack, but further work in this direction ia required.
SHEEP BLOWFLY INVESTIGATIONS
Authors: HOBSON E. P. 
Published: February 2008

Summary.

Various putrefying substances attract Ludlia sericata to oviposit on sheep in the field. Other blowflies do not respond.
Excreta of Ludlia larvae are extremely attractive; faeces from scouring sheep, stale urine and bacterial cultures are also effective.
Ludlia does not oviposit on these substances unless they are placed close to the skin of a live sheep; neither sheep skin, wool, nor other live animals can take the place of sheep.
The attraction is not due to chemical or bacterial changes in the fleece, since actual contact with the skin or wool is not necessary.
It is therefore concluded that the sheep itself plays an essential part in attracting Ludlia. The natural odour may be responsible.
These results are discussed in relation to the origin and control of sheep strike.
THE CHLOROTIC DISEASE OF THE HOP
Authors: SALMON E. S. , WARE W. M. 
Published: February 2008

Summary.In 228 seedlings raised from hop plants affected with chlorotic disease, transmission of the disease occurred in twenty‐eight plants (12.3 per cent.) in the first year and, of the remaining 196 healthy seedlings,1 thirty‐three plants (16.8 per cent.) showed the disease in the second year. Thus, of the 228 seedlings raised, sixty‐one (26.8 per cent.) eventually showed chlorotic symptoms.In the authors' opinion, transmission of the disease was through the seed.
OBSERVATIONS ON THE SHEEP BLOWFLY (LUCILIA SERICATA MEIG.) IN SCOTLAND
Authors: RATCLIFFE F. N. 
Published: February 2008

Summary.

It is suggested thai; a limited temperature tolerance in the early stages of Calliphora erythrocephala, as compared with Lucilia sericata, is the reason for this species not being a serious pest of sheep.
Experiments to discover the numbers of eggs laid by females of Lucilia sericata, and the length of the larval, prepupal, and pupal stages are described.
The detailed records of strikes in an Aberdeenshire flock throughout the 1933 and 1934 seasons are analysed; and the figures shown to agree with results obtained in other parts of Britain.
PREVENTION OF BLIGHT (PHYTOPHTHORA INFESTANS) IN SEED POTATOES
Authors: SMALL T. 
Published: February 2008

Summary.

The loss of seed potatoes through blight (Phytophthora infestans) in Jersey may be subdivided into (a) loss in the field at digging time, and (b) loss in the seed boxes subsequent to harvesting.
It is shown that the loss in the field may be prevented in most seasons by regular and thorough spraying, whilst that in the boxes may be reduced by scorching or removing the diseased haulms before digging, or by immersing the tubers in a fungicide.
TWO VIRUSES OF THE CUCUMBER MOSAIC GROUP ON TOBACCO
Authors: HOGGAN ISMÉ A. 
Published: February 2008

Summary.A “yellow cucumber mosaic virus” is described, which appeared to develop spontaneously during experiments with ordinary cucumber mosaic on tobacco. This form is readily distinguishable from the ordinary cucumber mosaic virus by the conspicuous bright yellow mottling produced on tobacco and other hosts. In modes of transmission, properties and host range, the virus appears to be identical with ordinary cucumber mosaic virus, and is hence regarded as a strain variant of this form.A second virus is described on tobacco which appears to belong to the same general group, although showing differences of greater magnitude from the ordinary cucumber mosaic virus. This form is distinguished chiefly by the milder type of symptoms produced upon various common hosts, and by its somewhat lower thermal death‐point, tolerance to dilution and longevityin vitro.Additional evidence is thus offered of strain variation in the cucumber mosaic group, similar to that already recognised in certain other groups of plant viruses.
ON THE GALL MIDGES INJURIOUS TO THE CULTIVATION OF WILLOWS
Authors: BARNES H. F. 
Published: February 2008

Summary.

The species of gall midges whose larvae live in the stems of willows have been briefly reviewed.
It is pointed out that, in the past, the so‐called “shot hole” midge damage on willow stems and branches has been frequently ascribed to R. saliciperda Dufour without considering either the insect itself or the species of willow.
This study has shown that several species of gall midges are responsible for this type of damage and that, so far as can be ascertained from an examination of cultivated species of willows, with S. fragilis in addition, each species of midge is restricted to one (in one case three) species of willow.
The adults, pupae and larvae of R. saliciperda Dufour, R. triandraperda sp.n., R. purpureaperda sp.n. and R. justini sp.n. have been described.
The bionomics of these species have been worked out. It has been found that, while all multiply by means of unisexual families, the first three species are single brooded but that R. justini sp.n. has two broods a year. R. saliciperda Dufour lives on S. caerulea, S. fragilis and S. alba (Cecconi), R. triandraperda sp.n. will only attack S. triandra, while R. purpureaperda sp.n. and R. justini sp.n. are restricted to S. purpurea.
The nature of the damage caused by the larvae of these midges has been described and control measures have been discussed. Tarring the stubs has been mentioned. It is suggested that cutting down the new growth in May, where practicable, would reduce the midge infestation. This latter treatment has the additional advantage of getting rid of initial caterpillar and frost damage which result in dead terminals and so produce side‐branching close to the stubs. Wild Crack willow (S. fragilis) should be destroyed as it can act as a reservoir for R. saliciperda Dufour.
Keys have been drawn up for the identification of the midges using host plants, larval, pupal and adult female characters.
The following parasites are recorded—Torymidae: Torymu ssp., near auratus Fonsc; Eurytomidae: Eurytoma aciculata Ratz., E. saliciperdae. Mayr.: Pteromalidae: Tridymus salicis Nees; Eulophidae: Pleurotropis? caenus Walk., Tetrastichus flavovarius Nees, T. roesellae De Geer; Platygasteridae: Platygaster cecidomyiae Ratz., P. sp. (?philinna Walk.).
PHYTOPHTHORA INFESTANS (MONT.) DEBARY AND CLADOSPORIUM FULVUM COOKE ON VARIETIES OF TOMATO AND POTATO AND ON GRAFTED SOLANACEOUS PLANTS
Authors: BOND T. E. T. 
Published: February 2008

SUMMARYExperiments are described which are concerned with the possibility of an increase or decrease in susceptibility to pathogenic fungi, induced or transmitted by grafting. Two diseases are investigated, namely, potato blight, caused by Phytophthora infestans (Mont.) dc By., and tomato leaf mould, caused by Cladosporium fulvum Cke.Preliminary inoculation experiments were carried out on eleven large‐fruited varieties of tomato, eight varieties of potato, various small‐fruited tomatoes, and other Solanaceous plants, with the following results: Phytophthora infestans. All the varieties of potato were equally susceptible, but certain varieties only of tomato, viz. Giant Red, Golden Queen. Detached leaves of the currant tomato were also infected. Cladosporium fulvum. Only tomato varieties and certain smail‐fruited tomatoes were susceptible. Giant Red and Golden Queen were particularly susceptible, Stirling Castle and Maincrop were relatively resistant. The currant tomato (Lycopersicum racemigerum Lange or L. pimpinellifolium Dun.) was immune. No support can be given to Schmidt's suggestion that immunity depended on the presence of a substance termed “prohibitin”, capable of inhibiting spore germination. It is suggested that the identity of Schmidt's cultures was mistaken.About fifty grafts were made involving various combinations of resistant and susceptible plants. The grafts were inoculated, in most cases, after new growth had developed from stock and scion. Without exception, the results of these experiments were the same as on the ungrafted material, both stock and scion retaining their characteristic reaction to infection unaltered. Although negative results cannot be conclusive in themselves, they indicate that resistance and susceptibility are either genotypic properties of the protoplasm or else are due to some factor that is not, as such, transmissible from stock to scion or vice versa.
GLOMERELLA PHACIDIOMORPHA (CES.) PET. ON PHORMIUM TEN AX IN BRITAIN
Authors: KINGHOKN W. O. 
Published: February 2008

SUMMARY

Glomerella phacidiomorpha (Ces.) Pet. has been found to be the cause of a disease of Phormium tenax in England. This is the first record of the fungus in Britain.
The fungus is only weakly parasitic, and is of danger only to plants of lowered vitality.
The imperfect fungus Colletotrichum rhodocyclum (Mont.) Pet. is shown to be a conidial stage of Glomerella phacidiomorpha.

I wish to express my indebtedness to Mrs N. L. Alcock, Plant Pathologist to the Department of Agriculture for Scotland, who supplied the material of Phormium tenax, and to Dr M. Wilson, Mycology Department, University of Edinburgh, who supervised the work.
BIOLOGIC STRAINS OF OPHIOBOLUS GRAMINIS SACC.
Authors: PADWICK G. W. 
Published: February 2008

SUMMARY

Isolates of Ophiobolus graminis compared were obtained in England, Canada and Australia from the following hosts: Triticum vulgare, Agropyron tenerum, A. repens and Hordeum murinum.
The optimum for growth of all isolates studied on carrot dextrose agar was in the neighbourhood of 25o C. They varied in their ability to grow at temperatures above and below the optimum.
Isolates vary in type of growth on carrot dextrose agar, the most noticeable difference being in the production of macrohyphae.
Saltation leading to the abundant production of black strands of macrohyphae by a culture producing very few was observed.
There are distinct differences in ability to survive desiccation over calcium chloride or 60 per cent, sulphuric acid. There seems to be some relation between the presence of macrohyphae and ability to withstand desiccation.
Isolates exhibit marked differences in general pathogenicity, but these differences are not specific towards certain hosts. Those causing greatest reduction in length of plants of Triticum spelta also caused greatest injury to T. dicoccum, T. monococcum, T. vulgare varieties and Hordeum vulgare. Conversely, hosts most resistant to one isolate were also those most resistant to the others.
SOME NOTES ON THE MORPHOLOGY OF THE IMMATURE STAGES OF SOME BRITISH CHAFER BEETLES
Authors: FIDLER J. HAVELOCK 
Published: February 2008

SUMMARYFrom the foregoing morphological descriptions of the main genera of the British Melolonthinae, it will be seen how much more closely allied Amphimallus is to Melolontha than is Serica. In nearly all details where the former species differs only slightly from Melolontha, Serica is found to differ more widely. This therefore gives support to the practice of separating this subfamily into the two tribes of Sericini and Melolonthini.Since Scarabaeid larvae other than those of the Melolonthinae are also found damaging crops in the British Isles, a table for the rough identification of the most common genera is appended. All species of the Scarabaeoidea are not however included, and since genera such as Geotrupes and Aphodius may be found at the roots of crops, confusion may occasionally arise in their identification, although they are not known to cause damage to plants. In such cases therefore reference should be made to the foregoing descriptions for exact identification.

(2) Body club‐shaped at caudal end, antennae long with joints of unequal length. 3.
(1) Body thickest at middle, antennae short with joints of equal length.Cetonia.
(4) Spines of radula arranged in two longitudinal rows 5.
(3) Spines of radula arranged in one transverse row Serica.
(6) Longitudinal rows of spines on radula parallel or slightly converging at ends 7
(5) Longitudinal rows of spines on radula diverging especially at caudal end.Amphimallus.
(8) Caudal aspect of mandibles with stridulating area made up of small pits.Melolontha.
(7) Caudal aspect of mandibles with stridulating area made up of transverse file‐like ridges Phyllopertha.
THE DISTRIBUTION AND SAMPLING OF INSECT POPULATIONS IN THE FIELD WITH SPECIAL REFERENCE TO THE AMERICAN BOLLWORM, HELIOTHIS OBAOLETA FABR.
Authors: MARSHALL JOSEPH 
Published: February 2008

SUMMARY

The problem associated with estimation of insect activity is discussed.
A precision experiment, undertaken to investigate the nature of the egg‐laying of the American bollworm, is described. The nature of the distribution is investigated.
Correlation trials between the two counts show that the same portions of the crop retain their relative attraction to the bollworm moth over short periods.
The effect of subdivision of the area on the sampling error is analysed.
Both egg as well as plant number figures per 3‐yard length show a greater variation between than within rows.
Correlation and regression coefficients prove a very close relationship between plant number and eggs laid.
Eliminating the effect of plant number eliminates this greater variation for the first egg‐count figures. In the second count the variation between rows is still significantly greater. The reason for this is discussed.
Considerations affecting the sampling technique developed from the precision data are discussed.
The sampling method is explained and two examples are given. From the analysis of these the system is shown to sample adequately the fields and fulfills the requirements of the survey.
TRIALS OF MERCURIC CHLORIDE FOR THE PREVENTION OF POTATO SICKNESS
Authors: JOHNSON L. R. 
Published: February 2008

SUMMARY

An investigation of the effect on potato sickness of mercuric chloride applied as a soil dressing is described.
It has been found that mercuric chloride applied 3–6 weeks prior to planting has a depressing effect on the early growth of potatoes. The variety Great Scot withstands this effect better than the varieties Majestic and Eclipse. This toxic effect is prevented by applying the chemical 3 or 4 months before planting.
The degree of infestation of the plants by the eelworm is decreased by dressing the soil with mercuric chloride. The reduction in infestation is greater the nearer the application is to the time of planting.
The reduction in eelworm infestation is accompanied by an increased yield of tubers except where plants cannot properly recover from the direct toxic effect due to mercuric chloride.
Evidence has been obtained to show that mercuric chloride does not kill the eggs within the cysts.
Mercuric chloride treatment of soil effectively prevents the fungous diseases common scab and collar rot.

The writer wishes to acknowledge with thanks the assistance given by many of his colleagues, and especially to Mr W. E. Gelling and Mr J. Strachan for their help in arranging the field trials, and to Mr S. Burr and Dr W. A. Millard for their help with the mycological aspect of the investigation.
METHODS OF DETECTING MUSKRATS
Authors: WARWICK TOM 
Published: February 2008

SUMMARYIn this article natural signs left by muskrats and various artificial aids in detection are described and discussed. Houses and the so‐called “push‐ups” are in marshes obvious and characteristic signs. With few exceptions it is hard to state definitely whether food traces found in the field have been made by muskrat or not. Willow shoots and the stems of bulrush (Scirpus) are however bitten off in a characteristic manner. The finding of burrows is very important from the practical standpoint. Where the burrows are not superficial the Fangerstock or probing bar is employed in locating them. The footprints of the muskrat are unmistakable.A method for the identification of muskrat dung is given. This depends on the measurement of the ratio of medulla width to hair width in hairs obtained from the faeces and its comparison with that of similar hairs from water vole and brown rat. Far more hairs of the muskrat lie in the ratio limits 0–30‐0‐50 than do those of water vole and brown rat– the reverse being true of the ratio limits 0–70‐0‐90.
OBSERVATIONS ON THE LIFE HISTORY AND CONTROL OF THE CABBAGE APHIS, BRE VICORYNE BBASSICAE L.
Authors: PETHERBRIDGE F. R. , MELLOR J. E. M. 
Published: February 2008

SUMMARY

A study has been made ofthe life history of Brevicoryne brassicael. in the market‐garden areas of Bedfordshire, Cambridgeshire and Huntingdonshire from November 1933 to October 1935.
There was a variation in the behaviour of this pest in the two years. In 1934 the aphis over‐wintered only as eggs on cultivated cruciferous crops (and particularly Brussels sprouts), whereas observations strongly suggest that in 1935 it over‐wintered both as viviparous females and eggs. The hatching of the eggs was much later in 1934 than in 1935, but the first winged forms were produced at about the same date.
Predators and parasites were fairly abundant but not sufficiently so as to prevent serious damage.
It is suggested that control measures should aim at preventing the aphides from passing from old plants to newly planted ones. Nicotine sprays or nicotine dusts are suitable for this purpose. The pest is difficult to control on ordinary field crops.
STUDIES ON THE APHIDES INFESTING THE POTATO CROP
Authors: DAVIES W. MALDWYN 
Published: February 2008

SUMMARYThe results are given of laboratory experiments on the effect of variation in wind velocity upon the flight of Myzus persicae Sulz.When no wind passed through the experimental chamber, twenty‐five winged aphides averaged 154‐8 flights per minute. The incidence of flight in a range of wind velocities is recorded. Low wind velocities had a marked influence on flight which ceased when the speed of the wind was increased to 3–75 m.p.h.The aphides remained stationary on the glass surface of the chamber when high winds of 20 and 30 m.p.h. passed through the chamber and even when the full force of the wind, equivalent to a gale of 70 m.p.h., passed over them the aphides adhered to the surface with ease. Microscopical observation showed that the aphides possess a small membranous pad between each claw and another at the base of each tarsus; these are adpressed to the surface and facilitate adherence.The literature on the subject of the dissemination of aphides by wind is reviewed and the phenomenon of voluntary migration as compared with involuntary transportation is discussed.