bluuebunny/crossref_metadata_2025 huggingface dataset:
SOME REMARKS ON THE METHODS FORMULATED IN A RECENT ARTICLE ON “THE QUANTITATIVE ANALYSIS OF PLANT GROWTH.”
Authors: FISHER R. A.
Published: February 2008

Summary

The methods of calculation formulated by Briggs, Kidd and West for the analysis of plant growth are inaccurate, (i) in introducing a large exaggeration when the plant is increasing in mass, (ii) in applying to periods of varying length a method of calculation which thereby becomes self‐inconsistent.

The correct measure for the mean value of the relative growth rate over any period, long or short, is that advocated by Blackman under the name of the “efficiency index.”
ON THE FUNGUS FLORA OF GLASSHOUSE WATER SUPPLIES IN RELATION TO PLANT DISEASE1
Authors: BEWLEY W. F. , BUDDIN W.
Published: February 2008

Summary

Nursery waters in the Lea Valley have been examined and some shown to be an important source of disease.

Contaminated waters may be purified by filtering, boiling and by addition of certain chemicals.
THE CONTROL OF THE GREENHOUSE WHITE FLY (ASTEROCHITON VAPORARIORUM) WITH NOTES ON ITS BIOLOGY1
Authors: LLOYD LL.
Published: February 2008

The insect exhibits partial adaptation to a temperate climate, the egg and adult being resistant to considerable cold.

The wide range of its food plants is indicated.

The adults are gregarious and show marked colour reactions. The life is long and the fecundity great. Parthenogenesis occurs and only male offspring result from this; mating is the rule and produces offspring of both sexes.

The incubation period of the egg varied from 8 to 117 days according to temperature, and the duration of the scale stage from 17 to 43 days.

The occurrence of A. sonchi Kotinsky in England was noted.

The attacks of the pest on tomatoes mainly make it of great economic importance. Specialisation in tomato growing to the exclusion of other crops is a useful precaution and other precautionary measures are indicated.

Fumigation is the only effective method of treating infested plants. Naphthalene and tobacco preparations give little relief. Tetrachlor‐ethane is a good fumigant, but is too costly for trade growers.

Cyaniding is the best method of treatment. The dose of sodium cyanide varies from one‐quarter to one‐tenth ounce per thousand cubic feet of greenhouse space, according to the type of greenhouse and the condition of the plants. Long fumigations with these small doses are more effective than short fumigations with larger quantities.

The precautions necessary to avoid damage to the plants are given, avoiding daylight during fumigation and having the roots of the plants dry being the most important.
OBSERVATIONS ON THE ENSHEATHED LARVAE OF SOME PARASITIC NEMATODES.
Authors: GOODEY T.
Published: February 2008

The eggs of Graphidium strigaswm and Trichostrongylus retortae‐formis give rise, under suitable cultural conditions, to larvae which finally become ensheathed and wander from the culture medium.

A new and easily manipulated method of experimentation for skin infection work is described, in which skin from a young freshly killed animal, rat or mouse, is stretched over a hole in a piece of sheet‐cork and pinned in position. The cork is floated on N saline at 37oC. and care is taken to ensure that the saline comes into contact with the underside of the skin. A drop containing the larvae to be tested is placed on the upper surface of the skin. The saline is contained within a suitable glass jar and the whole can be placed on the stage of a binocular dissecting microscope and the surface of the skin examined at any moment.

By this method it was found that ensheathed larvae of Necator americanus leave their sheaths and penetrate the skin when the drop of water containing them is allowed to evaporate and become sufficiently shallow to enable them to obtain a purchase against the surface of the drop. These larvae are very actively motile at 37oC.

Ensheathed larvae of G. slrigosum and T. retortaeformis do not penetrate the skin under exactly the same experimental conditions. They are not actively motile at 37oC. but become coiled and quiescent at this temperature. Their temperature for optimum* activity is shown to be between 22oand 25oC.

Ensheathed larvae of N. americanus cannot resist desiccation in air at room temperature and cannot revive on being moistened, whereas the larvae of G. strigosum and T. retortaeformis can withstand air desiccation and are easily revived on being remoistened. It is shown that the ensheathed larvae of these two species are more resistant to plasmolysing agents than the ensheathed larvae of N. americanus.

The sheath surrounding the larvae in all three species named in the foregoing paragraph is composed of a very resistant substance whose composition is not known. It is not true chitin since it is readily soluble in 5 per cent, caustic soda.
LEAF CHARACTER IN REVERTED BLACK CURRANTS
Authors: Lees A. H.
Published: February 2008

A means is indicated whereby reverted leaves may be identified even in very slight cases or where the leaves have almost regained normality.

This method depends (a) on counting the number of submain veins running from the midrib to points in the margin, and (b) on observation of the margin points, which also may if necessary be reduced to t numerical basis.

That reverted leaves may be produced by artificial means, but that this reversion is of a temporary character. In each case examined the plant appeared to be under a special stimulus to growth.

Cases in the field were examined in detail in three respects, namely (a) leaf vein number, (6) mite infected buds, and (c) leaf margin. Three classes could be distinguished: (o) normal healthy, (b) simple reverted, and (c) mite infected (reverted). These corresponded with three facton which appeared to be acting: (a) seasonal factor, (b) reversion factor, and (c) mite factor. Furthermore, since “oak leaf” is an advanced stag of reverted leaf and is always associated with mite, the chances an that reverted leaves when found without “oak leaf” owe their existence in some way or other to the mite factor either patently or latently.
“SLEEPY DISEASE” OF THE TOMATO1
Authors: BEWLEY W. F.
Published: February 2008

1. “Sleepy Disease” or “Wilt” of tomatoes may Joe caused by one of two fungi, Fusarium lycopersici or Verticittium albo‐atrum.

Massee's “diplocladium stage” of F. lycopersici has been shown to be V. albo‐atrum.

The wilt producing fungi attack the roots and grow up through the vascular bundles into the stem, leaves and sometimes the fruits. The wood of a diseased plant is a light or dark brown colour.

The average temperature is a “limiting factor” in determining which fungus is active. F. lycoperstci grows best at an average temperature of 27‐8‐28‐9oC. If the temperature remains constantly much below this, little infection results. V. albo‐atrum develops well at temperatures from 15‐6‐24‐0oC, being most active at 2M‐22‐8oC. Above an average temperature of 25oC. little infection occurs.

The average temperature conditions existing in glasshouses in this country are generally too low for F. lycopersici and consequently it is rarely found as a cause of tomato wilt. The relatively low temperatures are favourable to V. albo‐atrum, which accordingly is the most important cause of wilt.

Wilted plants soon die under conditions of low temperature, but if the average temperature be raised above 25oC, they recover and will bear a crop so long as the high temperature is maintained. When the temperature again drops, wilt reappears and death results.

V. albo‐atrum from tomato readily induces wilt in the potato, eggplant, snapdragon, cotton, pepper plant and cucumber, and produces a stunted condition of the sycamore and elm.

A number of different strains of V. albo‐atrum have been isolated which vary in their rate of growth, the amount and rate of production of microsclerotia, and in colour production; but no evidence has been obtained^to show that there may be different strains restricted to different varieties of tomatoes.

In pure culture the fungus has been shown to produce a large number of enzymes and there are strong indications that substances of a toxic nature play an important part in producing wilt.

There is a distinct relation between hardness of growth and susceptibility to wilt; the harder growing varieties and plants suffering from starvation or a severe check in the young stages being most susceptible to attack. Most varieties of tomatoes cultivated in this country are susceptible to Vertidllium, but Manx Marvel has proved to be practically immune and Bides' Recruit highly resistant.

Certain cultural devices, including regulation of the temperature and shade, have been devised which assist “wilted plants” to recover.

Further investigations upon soil sterilisation and the production of resistant varieties are in progress.
BIOLOGICAL STUDIES OF APHIS RUM WIS LINN. REPRODUCTION ON VARIETIES OF VICIA FABA.
Authors: DAVIDSON J. , FISHER R. A.
Published: February 2008

The reproduction of Aphis rumicis was tested on 18 varieties of field beans and the results compared with the reproduction on Prolific Longpod broad beans.

The aphids used in the experiments were the offspring from one Fundatrix.

The experiments were all carried out under similar conditions. Five plants of each variety were tested, and the total number of aphids produced on each plant, from one a. v. ♀, in 14 days was counted.

The mean values of infestation for the varieties range from 37 to 1037, vide Tables I and II.

These mean values allow of the varieties being grouped into classes representing various grades of susceptibility, ranging from 98 per cent. to 3 per cent, vide Table III.

Vicia narbonensis has a very low susceptibility. The results obtained indicate that resistance or susceptibility may be largely determined by genetic factors in the plant.
STUDIES IN BACTEEIOSIS. VIII
Authors: PAINE SYDNEY G. , BEWLEY W. F.
Published: February 2008

The organism which produces “Stripe” disease of the tomato is shown to be the cause of a number of “Streak” diseases of other plants, namely sweet pea, culinary pea, broad bean, french bean, red clover, lucerne, lupin, vetch, sainfoin and potato.
THE HEALING OF WOUNDS IN POTATO TUBERS AND THEIR PROPAGATION BY CUT SETS
Authors: PRIESTLEY J. H. , WOFFENDEN LETTICE M.
Published: February 2008

The sequence of events during the healing of the cut surface of a potato tubei is carefully traced.

Apart from unessential colour changes, the first process in the healing of the tuber is the deposit of a fatty “suberin” layer, formed by the oxidation and condensation of fatty substances depositing from the sap drying up in the tissues at the cut surface.

The condition essential to the formation of this layer is access of oxygen.

If the cut surface is exposed in a moist atmosphere the layer is continuous; in a dry atmosphere, especially in sunlight, the layer may not be continuous.

This layer forms within 24 to 48 hours. A few days later cork is formed below this suberin deposit as the result of cell divisions in an actively dividing layer, the cork phellogen.

The essential factors promoting the activity of this phellogen appear to be the accumulation behind the blocked surface of sap containing substances diffusing from the vascular bundles, and the production of an acid reaction just below the blocked surface by the anaerobic conversion of sugars into fatty acids.

The activity of the cork phellogen may be roughly estimated by the numbeT of layers of cork produced. Comparative data are presented for a number of varieties of potato which show that Majestic, King Edward VII and Bishop are particularly deficient in this important activity connected with the healing of wounds.

The bearing of these facts as to the process of wound healing is considered in relation to the practice of propagation by potato sets and two practical conclusions drawn. (1) Potato tubers should not be cut in sunlight or left in too dry a place. (2) The practice of liming potato sets appears to be without justification so far as its use in promoting the healing of the wound is concerned.
STUDIES IN BACTERIOSIS. IX
Authors: PAINE SYDNEY G. , LACEY MARGARET S.
Published: February 2008

The “streak” disease of beans (Chocolate Spot Disease) is caused by B. lathyri.

Moist and warm conditions are responsible for the appearance of the disease in epidemic form.

The disease is spread by wind, black fly, and the bean beetle.

Methods of control are suggested.
EFFECT OF WEIGHT OF SEED UPON THE RESULTING CROP
Authors: BRENCHLEY WINIFRED E.
Published: February 2008

Field experiments, especially in America, nave indicated that, with annual plants at least, better crops are usually obtained by the use of heavy seed in preference to light, whether equal numbers of bushels or equal numbers of seeds are sown per acre.

Water culture experiments with peas and barley have shown that there is a steady and considerable rise in the dry weight of the plants as the initial weight of the seed increases. This occurs both with a limited and abundant food supply.

The efficiency index (rate per cent, increase per day) falls gradually as the weight of the seed rises. With prolonged periods of growth this tends ultimately to counterbalance the initial advantage gained by plants from the heavier seeds, but with annual crops as cereals, peas, etc. harvesting occurs before this equilibrium is reached, leaving the advantage with the heavier seeds.

The relative development of shoot and root is to some extent influenced by the initial weight of the seed, but may vary with the species and with the amount of available food.

The results lend support to the growing agricultural practice of advocating the use of large heavy seed, especially with annual crops. The advantage in the case of perennials would appear to be less, if any, but this has not been determined by laboratory experiments.
THE KILLING OF BOTRYTIS CINE RE A BY HEAT, WITH A NOTE ON THE DETERMINATION OF TEMPERATURE COEFFICIENTS
Authors: SMITH J. HENDERSON
Published: February 2008

The spores of Botrytis cinerea were exposed to the action of hot water at temperatures ranging from 31oC. to 50‐3oC, the proportion of spores surviving at different times determined, and the results plotted for each temperature. These give a series of approximately symmetrical sigmoid curves, all exactly alike one another except for the change in the speed of killing at different temperatures. The curves are superimposable on adjustment of the time scale, and in this respect they differ from the curves obtained with phenol, where the shape changes from an S to a J shape as the strength of phenol is increased, eventually becoming logarithmic.

The shape of the general curve agrees excellently with a recognised type of frequency distribution, and the observations at all the temperatures examined fall closely on the curve of this distribution.

The effect of temperature on the velocity of the reaction is unusually great, and is well expressed by the formula of Arrhenius, if the temperature is reckoned from 0oC. instead of the absolute temperature.

By combination of the formula for the curve and the formula for the velocity‐temperature relationship it is possible to express completely for the spores of Botrytis the whole of the killing process for any temperature within the Mmits studied under the conditions and with the strain used in these experiments.

It is pointed out that in the estimation of temperature coefficients comparison of the times taken to reach a constant result give more accurate and consistent values than comparison of the results reached in constant time.
APPLES ATTACKED BY THE LARVAE OF THE DOCK SAWFLY (AMETASTEGIA (TAXONUS) GLABRATA, FALLEN)
Authors: PETHERBIDGE P. E.
Published: February 2008

The larva of the dock sawfly, Ametastegia glabrata, Fallén, which is a leaf feeder usually found on docks and polygonums, injured apples in East Norfolk by boring small holes into the flesh in which to pupate. They made from one to six holes in each fruit. They were kept in check by keeping the orchard clean.
FURTHER OBSERVATIONS ON THE PREVALENCE AND HABITS OF OSCINELLA FRIT, LINN.
Authors: CUNLIFFE NORMAN
Published: February 2008

Observations on the prevalence of the imago of Oscinella frit in the field have been made during the period 1919 to 1922.

The annual cycle consists of three generations: Generation III swarms from the end of April to the middle of June, with a maximum about May 26; Generation I from the end of May to the middle of August, with a maximum about July 15; Generation II from the end of July to the beginning of September (or longer) with a maximum about August 19.

Although meteorological variations during the period 1919 to 1922 were apparently very diverse, they were not sufficiently diverse to affect the prevalence periods of the fly on the crop materially; the prevalence curves of the different years show a remarkable similarity. This may be due to the fact that the larva is an internal feeder.

As the periods of maximum prevalence are not displaced from year to year, it would appear that the fly population is determined by the total number of host plants and not by the cultivated plants alone.

The larva exhibits a strong tendency to attack those regions of the plant which are in receipt of abundant supplies of sap.
NOTE ON THE ECONOMIC VALUE OF THE NEUROPTERA, WITH SPECIAL REFERENCE TO THE CONIOPTERYGIDAE
Authors: WITHYCOMBE C. L.
Published: February 2008

The Neuroptera as a whole are distinctly beneficial to man. Three families of economic importance are represented in Britain; the Coniopterygidae, Hemerobiidae, and Chrysopidae.

The Coniopterygidae are far more common in England than is generally supposed. In general facies they resemble Aleurodidae, but can easily be distinguished.

The eggs are laid generally at the edges of leaves. Larvae are top‐shaped, with small head and mouthparts. They are predacious. After two moults a flat, circular cocoon is spun.

Larvae of Conwentzia are very beneficial on oaks in England, where they prey upon small Rhynchota, such as Phylloxera, and mites.

They would seem to lend themselves particularly well to employment economically and might be introduced to peach houses in England.

Six imagines of Conwentzia released upon a pear tree infected with Bryobia praetiosa K., resulted in roughly one thousand individual cocoons at the end of the season 1921.

Conwentzia could probably be introduced successfully into other countries where the genus does not exist. Parasites must be rigidly guarded against.

The Hemerobiidae are more often found in woods than elsewhere in Britain. Some shew preference to conifers, others to deciduous trees. Boriomyia subnebulosa Steph. is common in orchards and gardens near London.

The larvae of Chrysopidae differ from Hemerobiidae by possessing throughout life a trumpet‐shaped empodium, and generally setigerous tubercles.

As in Hemerobiidae, larvae, according to species, shew preferences to different trees.

Chrysopa prasina Burm. is a valuable check upon Chermes, on conifers; C. tenella Schn., and C. septempunctata Wesm., on Eriosoma lanigerum Hausm., of apple; while C. phyllochroma Wesm., probably does valuable work in bean‐fields in some parts.
THE DENSITY OF UNICELLULAR ORGANISMS
Authors: ALLISON R. V.
Published: February 2008

By measuring the rate of fall of certain unicellular organisms of known diameter under appropriate conditions, their density has been calculated by the formula of Stokes.

According to this method the average ansity of algal cells studied is 1.098 and that for the cysts of Gonostomum sp. 1.057.

The density of the algal cells was found to vary greatly between the larger and smaller sizes, while that for cells intermediate was fairly constant. In the case of protozoan cysts the total variations in average density was much less marked.

It was found that during maturation, the cysts of a certain species of Colpoda decreased to one fourth their original volume, while their average density increased from 1.04 to 1.06.

Since many of the 4‐day cysts of Colpoda sp. excysted during or shortly after the measurement of their density, the average density, 1.042, for this group is thought to represent quite accurately the density of the young animals in this early stage.

By the application of the formula of Hehner and Richmond to the density values so obtained, a tentative value has been derived for the actual dry matter of the cells studied.

It has been found by calculation upon this basis that the dry matter of the young cysts (4‐day) of Colpoda sp. amounts to 10.6 per cent. while at the later stage (20‐day) it is 15.1 per cent.

It appears that 64.3 per cent, of the total dry matter of the cyst and 76.2 per cent, of the water content are lost during maturation. With regard to the total percentage of loss in terms of either constituent, it has been found that water represents 90.9 per cent, and dry matter 9.1 per cent, of the total loss respectively.
THE MULBERRY “BLIGHT” IN BRITAIN
Authors: WORMALD. H.
Published: February 2008

The occurrence of bacterial Mulberry “Blight” in Sussex and Kent is here recorded.

It has been found on well‐established trees, on “stools,” and on young trees during the first and second years after removal from the stools.

The bacterium causing the disease has been isolated from lesions on the leaves and this has been found to conform to descriptions of Bacterium mori Boyer and Lambert.
THE ACTION OF SOME ORGANIC COMPOUNDS UPON THE CUCUMBER‐HOUSE WOODLOUSE
Authors: SPEYEE E. R. , OWEN OWEN
Published: February 2008

With a view to the winter control of the cucumber woodlouse the action of a number of compounds has been tested. Observations are described on the effects due to contact, vapour and mixing with the soil.

The organism of the animal is not affected in a similar manner by different compounds. p‐Cresol and p‐Nitrophenol are less active than the corresponding ortho‐compounds and both nitro‐phenols are less active than phenol.

Certain compounds show a maximum activity shortly before their disappearance from the soil. Phenol and the cresols were the most active compounds tested. Naphthalene ceases to act in the soil on the fourth day after mixing.
A ROOT DISEASE OF THE TOMATO CAUSED BY COLLETOTRICHUM TABIFICUM (HALLIER PRO PASTE) PETHYBRIDGE
Authors: BEWLEY W. F. , SHEARN J.
Published: February 2008

A root disease of the tomato, due to Colletotrichum tabificum (Hallier pro parte) Pethybridge, has been investigated and described.

The pathogen is considered to be identical with Rhizoctonia tabifica Hallier, Vermicularia varians Ducomet, Sclerotium setosum Bewley and Shearn, and possibly Colletotrichum solanicolum O'Gara.
INVESTIGATION OF THE STRUCTURE OF REVERTED BLACK CURRANTS
Authors: RIDLER WINIFRED F. F.
Published: February 2008

GENERAL CONCLUSIONS AND SUMMARY.

No actual qualitative differences in structure have been observed between normal and reverted plants of Ribes nigrum; those that have been observed being rather quantitative, i.e. differences in degree only, e.g. amount of gum present, and variations in the amount of wood and medullary ray tissue.

Briefly the main differences showing to a greater or lesser extent practically all through the plant are a reduction in the amount of wood, and a consequent increase of medullary ray tissue, coupled with a tendency to produce more gum in the revert plant than in the normal.

On the whole, it is very difficult to correlate the morphological evidences of the disease with any of the anatomical differences observed, as the latter seem quite inadequate to account for the comparatively large morphological effect.

The general reduction in the amount of wood present, does not seem sufficient to account for the generally smaller and more unhealthy appearance of the revert bush; nor in the petiole even combined with a certain amount of blocking by gum, can it be held to account entirely for the typical reverted leaf. with fewer veins and reduced leaf surface. In the case of the fruit, although the vascular system is reduced, there seems no reason why some of the ovules at, least should not develop. It is probable that there is some physiological factor at work causing hypertrophy and abortion.

My thanks are. due t o Mr A. H. Lees, who has supplied me with all material and given much valuable help and advice. I also thank 31r F. Summers and Professor O.V. Darbishire for their advice and interest in the work.
SOME OBSERVATIONS ON THE GROWTH OF RHIZOCTONIA CROCORUM (PERS.) DC. IN PURE CULTURE
Authors: BUDDIN W. , WAKEFIELD E. M.
Published: February 2008

The organism dealt with in this paper is that which has been commonly known in this country as Rhizoctonia violacea Tul. but until satisfactory proof is forthcoming of a spore stage of the organism it should be known by its valid prior name, Rhizoctonia Crocorum (Pers.) DC.

The methods used for isolation of the fungus in pure culture are described and some account given of preliminary inoculation experiments with the re‐isolation of the parasite.

It is shown that growth of R. Crocorum will occur on a very wide range of sterilised artificial material when in pure culture.

No spore form has occurred in any of the large number of cultures which have been grown.

Some notes are given on difficulties arising in temperature relation work from differences in the “internal condition” of the organism under varying conditions, and it is shown that the optimum temperature for the growth of the organism in culture on meat‐malt extract agar as measured by the increase in diameter of colonies is in the neighbourhood of 25.5° C. This optimum temperature probably explains the geographical distribution of the severe attacks of the organism in the field.
OBSERVATIONS ON THE LIFE HISTORY OF TAPEWORMS OF THE GENUS MONIEZIA
Authors: JENKINS J. R. W.
Published: February 2008

The period during which lambs may become infected with Moniezia spp. is not confined to the Spring, but may extend at least until August.

Sheep as well as lambs may become infected.

Neither the distribution of the genus nor the fauna of infected farms has been of guidance in discovering the life history.

Examination of the intestinal contents of lambs which had become heavily infected shortly before death gave negative results.

Attempts to produce infection of possible intermediate hosts by feeding with mature proglottides gave negative results.

Five species of Moniezia have been collected at Aberystwyth, and there is every reason to suspect the occurrence of further species.
AN EXPERIMENTAL STUDY OF THE FVNGAL INVASION OF APPLES IN STORAGE WITH PARTICULAR REFERENCE TO INVASION THROUGH THE LENTICELS
Authors: KIDD M. N. , BEAUMONT A.
Published: February 2008

The spores of rot forming fungi on the surface of the apple and in the lenticel cavities have been studied as regards their distribution and number.

The natural modes of entry of apple rot fungi have been described and the relative frequency of their occurrence assessed.

The factors controlling lenticel invasion in storage have been analysed by a new experimental technique.

The literature dealing with lenticel spotting of apples has been reviewed; the cause of spotting has been distinguished as functional rather than fungal and the general name “Lenticel Spot” has been proposed for the disease.
SOME INFECTION EXPERIMENTS WITH LOOSE AND COVERED SMUTS OF OATS WHICH INDICATE THE EXISTENCE IN THEM OF BIOLOGICAL SPECIES
Authors: SAMPSON KATHLEEN
Published: February 2008

1. Infection experiments are described with two spore collections of U. avenae (Pers.) Jens. and U. levis (K. and S.) Magn. obtained from Missouri and from Wales.

2. The results with U. levis indicate that the spore collections under test represent two distinct biological species, thus confirming the conclusion arrived at by Dr Reed(4), working with the same material at Missouri.

3. Forms highly susceptible and resistant to U. levis appear to exist in the sub‐species glabrescens of A. strigosa.
NOTE ON THE BACTERIAL SOFT ROT OF TURNIPS
Authors: WORMALD H. , HBRRIS R. V.
Published: February 2008

A soft rot of turnips in a garden at East Malling was found to be caused by an organism which has peritrichous flagella and has the same group number as Bacillus carotovorus Jones.
ON THE STRUCTURE, LIFE‐HISTORY, ECONOMIC IMPORTANCE AND DISTRIBUTION OF THE COCKSFOOT MOTH, GLYPHIPTERYX FISCHERIELLA, ZELL.
Authors: CHOPRA ROSHAN LAL
Published: February 2008

The Cocksfoot Moth (G. fischeriella, Zell.) is a small moth (wing expansion 71/2‐‐– 81/2 mm., body dark fuscous, front wings coppery brown, with five silvery streaks along the costal margin.

The moth is diurnal in habits, bright warm weather greatly favoun its activities, and on such days from the last week in May till the third week in June it is very common in the field on the nettle and gorse bushes and on flowering stalks of cocksfoot.

The eggs are deposited as a rule singly at the base of a seed in the second and third weeks of June, and hatch in from ten to fifteen days' time.

The larva which does the sole damage is small glassy white when newly hatched, but assumes more and more of green colour as it feeds and grows. When full grown it measures about 6 mm. in length. There are four larval instars altogether.

Immediately after hatching the larva begins to bore into the seed on which it was hatched. The injury takes the form of a small circular bole through which it enters and feeds on the kernel. There is always one entrance hole and only one in each seed which also serves as the exit.

After about four weeks' feeding, when the larva is full grown, it either leaves the food plant and crawls away in search of winter quarters, or remains inside the hollow husk of the seed which previously served 86 its food. In the former case, it spins a small, oval elongate, dirty white, silken cocoon in which it hibernates during the next nine months prior to actual pupation, while in the latter, instead of constructing a cocoon, it simply seals the entrance hole with a thick silken web.

In captivity, under laboratory conditions, a large number of larvae, by cutting small holes, entered the dry hollow stalks of the cocksfoot plants and constructed cocoons therein.

Pupation takes place in April or early in May, the pupal period extending over three or four weeks.

There is only one generation in a year.

As regards the food plants it was found that indigenous plants of cocksfoot were attacked much more heavily than the foreign “nationalities,” as is shown in the following table:

A suggestion is made that the moth selects the panicle on which it lays its eggs, finding the indigenous plants more attractive than those of the foreign nationalities. It appears that the selection is made by the moth rather than by the larva.

Samples of seeds obtained from different places in England, Scotland and Wales showed that the pest was generally distributed all over the island; almost all samples examined were found to have been attacked. The larva is so effectively protected within the seed that no internal parasite was found to attack it.

An effective method of obtaining seeds free from this pest is to place them in an airtight chamber, heat up to 60°C., and leave there for twenty‐four hours. This temperature kills all the larvae, and, on the other hand, does no harm to the germinating power of the seed.
STUDIES ON OSCINELLA FRIT LINN. TBE CORRELATION BETWEEN STAGE OF GROWTH OF STEM AND SUSCEPTIBILITY TO INFESTATION
Authors: CUNLIFFE NORMAN , FRYER J. C. F. , GIBSON GORDON W.
Published: February 2008

Oat plants, of known stage of growth, were exposed to Frit Fly attack at different growth periods, with the result that the susceptibility of the main stem to attack was found to be most marked during the two‐ and three‐leaf stages of growth. In the four‐leaf stage susceptibility decreased and beyond this stage the shoot seemed to be immune relatively. Plants in the early one‐leaf stage showed a certain degree of immunity, due probably to size non‐attractiveness rather than to specific morphological characters.

Considered in conjunction with the constancy of the prevalence periods of the fly, these observations have a certain importance. Thus a practical solution of the Frit Fly problem may be found either by early sowing (as is already well known) or by the selection of a variety which passes rapidly through all stages of growth preceding that described as the “four‐leaved.” The next step in the investigation would appear to be an examination of the different races or varieties of oat, in order to compare their rates of growth up to and including this stage.
NETTLEHEAD IN HOPS
Authors: DUFFIELD C. A. W.
Published: February 2008

Under the name “Nettlehead” two quite distinct diseases, “true” and “false,” have been noticed.

In the case of “False” Nettlehead the bine usually dies away in August and the root system is in a state of decay; in the “True” form the bine remains green though growth is retarded, at the same time the root system remains in an apparently healthy state.

The “True” form is usually to be found starting from the edge of a garden especially where the garden slopes down to a deep ditch or high hedge. “Fahe” Nettlehead, on the other hand, may be found distributed throughout the garden.

The Beet eelworm, Heterodera Schachtii, may be found in all hop gardens, but its presence is not correlated with “Nettlehead.”

“True” Nettlehead has been in greater evidence the year following a bad attack of aphis.
MOISTURE MOVEMENT IN WOOD
Authors: MARTLEY J. F.
Published: February 2008

A number of experiments were carried out on the exchange of moisture between discs of 1/8th inch and 1/16th inch Birch veneer below the fibre saturation point.

It appears from these experiments that the rate of moisture movement in wood below the fibre saturation point is dependent, not only upon the moisture gradient, but also upon the moisture content. But for this limitation, fair agreement was obtained with the law of diffusion. The values obtained for the coefficient of conductivity have no definite significance as they represent mean values over a period.

The rate of moisture exchange between the discs was found to be approximately proportional to the square of their combined thickness and was within 15 per cent, of the demands of the law of diffusion for these particular experiments.

From the few experiments carried out at a higher temperature it would appear probable that the change in the rate of moisture movement with rise in temperature is proportional to the change in the vapour pressure of water.
OBSERVATIONS ON THE BIOLOGY OF TYLENCHUS DIPSACI (KUHN) BASTIAN, AND ON THE OCCURRENCE OF BIOLOGIC STRAINS OF THE NEMATODE
Authors: HODSON W. E. H.
Published: February 2008

The stem eelworm, Tylenchus dipsaci (Kuhn) Bastian, is a severe pest on a variety of crops.

Usual symptoms of attack constitute dwarfing, distortion and frequently chlorosis of the host plant.

The biology of the eelworm is essentially the same in nearly all host plants.

Infection may take place immediately after leaving the previous host, or after a period of enforced quiescence.

Examination of available data indicates that, while biologic strains or races of the eelworm do exist, these strains show varying powers of adaptation to other host plants.
STUDIES ON CARBON DIOXIDE PRODUCTION IN SOIL AND SOLUTION1
Authors: BAL D V.
Published: February 2008

The rate of carbon dioxide production by B. prodigiosus from various sugars has been studied and an account of experiments conducted with a view to finding out the factor or factors responsible in lowering the carbon dioxide production in soil and solution is given.

It is found that B. prodigiosus can decompose glucose and laevulose most readily while sucrose comes next in order. Lactose and maltose are very slightly decomposed.

The amount of carbon dioxide produced is not equivalent to the amount of sugar used up. Other organic products like alcohol, acetone and organic acids are produced.

Carbon dioxide production always attains its highest limit within the first three or four days and then declines rapidly in spite of the presence of sugar and active organisms.

Successive additions of fresh quantities of sugar to solution cultures when the carbon dioxide production has reached its minimum rapidly increase the carbon dioxide formation to a value practically identical with that previously attained.

It appears that exhaustion of total or readily available carbon, formation of an unattackable film on the surface of particles of organic matter, or exhaustion of available mineral constituents is not responsible for lowering the carbon dioxide production in soil.

Additions of organic matter such as glucose' or oil cake to soil after the carbon dioxide production has declined, restores the process practically to the same level as at the start.
NOTES ON THE CONSTITUTION OF AN UNIMPROVED COTTON CROP
Authors: BOLLAND B. G. C.
Published: February 2008

This paper gives an account of the formation of the Cotton Service in Ceara, one of the north‐east states of Brazil, the lines on which the work of improving the cotton crop is to be conducted and some figures showing the composition of the crop prior to any selection.

Owing to the large number of types represented and the long period of time during which cross‐fertilisation has taken place, several years must necessarily elapse before any pure selected strains can be put on the market.
CONCERNING “FAIRY RINGS” IN PASTURES
Authors: ELLIOTT JESSIE S. BAYLISS
Published: February 2008

Observations are made on the growth of three types of fairy rings found in pastures and elsewhere.

Marasmius oreades belongs to a type which causes the death of rings of grass. It behaves as a parasite, destroying grass by means of a toxin.

Comments are made on the views of Shanz and Piemeisel, who consider the death of the grass in certain fairy rings is merely due to a drought produced by the presence of mycelium in soil.
SOME OBSERVATIONS ON WHITE CLOVER, AND A METHOD OF DISTINGUISHING BETWEEN THE SEEDS OF WILD WHITE AND DUTCH CLOVER1
Authors: ADAMS F. M. J.
Published: February 2008

Diagnostic characters which have been found of use in distinguishing samples of wild white from Dutch clover seed:

(a) Frequency with which certain shape types of seed occur in each sample.

(b) Average ratio of long diameter of seed to short diameter.

(c) Area of cotyledon.

(d) Length of petiole of first foliage leaf.

All samples, all individuals of one sample, or of one head of wild white clover, do not give a positive reaction for the cyanophoric test.

Further diagnostic characters at a later stage of growth, (a) prostrate habit, (b) formation of axillary shoots, are characteristic of wild white clover.

Permanence in wild white clover is due to a strongly developed power of vegetative propagation. Dutch clovers are not permanent as they lack this power to different extents.

Loss of permanence in cultivated white clover is due to unintentional selection of the non‐permanent type (by the grower), and to cross‐fertilisation by the non‐permanent or Dutch plants growing in the neighbourhood.
BIO‐CHEMICAL DECOMPOSITION OF CELLULOSIC MATERIALS, WITH SPECIAL REFERENCE TO THE ACTION OF FUNGI1
Authors: REGE R. D.
Published: February 2008

In mature plant materials pentosans form the most important food for micro‐organisms.

The Klober and Tollens method for the determination of pentosans is not specific for these compounds.

While pentosans are easily attacked by micro‐organisms, the other furfurol‐yielding compounds are found to be resistant, and it is therefore essential to get a correct figure for pentosans. A possible method is suggested: to determine the furfuroids in the cellulose obtained by the chlorination method and to deduct this amount from the total furfuroids.

Two factors appear to control the decomposition of ripe cellulosic materials in the presence of assimilable nitrogen. The one is the food, or, better termed, energy factor which is the pentosans, the other is the physical or inhibitory factor which is the lignin. It is found that if the ratio of energy factor to inhibitory factor is above 1, the material is easily decomposed; but if it is below 0.5, the material is very resistant to microbial attack. The prediction of the “decomposability” of a material is thus possible.

Attempts to increase this ratio in resistant materials by the addition of carbohydrates proved unsuccessful. It was concluded that since micro‐organisms obtained their food materials outside the tissues, they did not attack the tissues until the more easily available food‐stuffs were exhausted. Thus the decomposition of the material was actually less than was possible under natural conditions.

Mannose and galactose do not appear to form suitable food for the micro‐organisms concerned in these processes and it is concluded that the pentosan part of the hemi‐celluloses is most important as microbial food.

The study of the relative importance of bacteria and fungi proves that under the conditions of these experiments, fungi play a more prominent part especially during the early stages of such decomposition.

The study on the availability of the nitrogen of the fungal bodies proves it to be of the resistant type. It seems that at later stages of decomposition under natural conditions fungi are decomposed by other organisms.

The ability of certain fungi isolated from such decomposing heaps, to grow at high temperature as well as on purified carbon constituents of plants, and also the presence of almost all the enzymes necessary to hydrolyse the complex carbon constituents, further confirm their importance. The possibility of their activity under natural conditions in manure heaps is strongly suggested.
THE INTER‐RELATION BETWEEN SILICON AND OTHER ELEMENTS IN PLANT NUTRITION
Authors: BRENCHLEY WINIFRED E. , MASKELL E. J. , WARINGTON KATHERINE
Published: February 2008

Under controlled conditions in water cultures soluble silicate was found to have little effect upon the growth of barley if phosphorus were also present, but if the latter were absent a significant increase in dry weight was induced by the silicate.

The addition of silicate caused an appreciable increase in the height of the main shoot, which was most marked in phosphate‐free solutions, becoming less evident as the quantity of phosphate present was increased.

Leaf development was retarded by phosphate deficiency and hastened by the addition of silicate.

A close association exists between the amount of phosphate present, and the effect of silicate upon the rate of tillering and the number of tillers developed.

Soil cultures with barley and mustard in pots with various forms of silicate showed that soluble silicates are more active than glass silicates, tending to cause increase in dry weight with deficient mineral manuring, and in some cases also with complete manuring.

Further soil experiments revealed variations in the response of barley and mustard to silicate on different types of soil. A general improvement occurred with increasing doses of silicate together with various combinations of manures, notably when phosphorus or potash was deficient.

The significance of the results obtained has been examined statistically, and an attempt made to formulate the effect of added silicate in terms of an increase in the efficiency of the superphosphate present.
COMPARISON BETWEEN KAURI PINE AND SWAMP KAURI (AGATHIS AUSTRALIS)
Authors: MARTLEY J. F.
Published: February 2008

Swamp kauri was compared with normal kauri pine wood but no very decided differences between them were discoverable.

No definite structural differences were noted in the microscopic examination.

The shrinkage in swamp kauri was found to be less than in normal kauri when losing moisture under the same conditions.

No differences in hygroscopicity were noted.

The density of the wood substance of swamp kauri is the same or slightly less than that of normal kauri pine.

No mechanical tests were made.
YIELD STUDIES IN OATS
Authors: TINCKER M. A. H. , JONES MARTIN G.
Published: February 2008

A series of correlation studies has been carried out between the seed characteristics and early growth data of a number of Record oats samples; many coefficients of correlation obtained gave values of no biological significance. The influence of “outlying” readings had to be carefully considered as the number of readings was limited. For this purpose dot charts were employed as well as mathematical coefficients.

The results can be summarised as follows:

Generally the total germination figures in a sand test were correlated with field establishment, but within the narrow germination range 85–100 per cent. no correlation with establishment was found.

The amount of available food in the seed as measured by the average dry weight of the caryopses influenced the size and weight of the seedlings produced.

The moisture content of the grain was negatively correlated with the rate of germination, indicating that samples stored with a high water content did not germinate well.

The percentage husk bore no relation to germination.

Ten weeks after sowing the mass of the plants obtained from a given sowing depended primarily upon the number of plants established. Although tillering was well advanced plants possessing additional space did not compensate for low establishment figures at this stage by increased growth.

When the grain was heated for 15 minutes at 75°C. those samples containing a high moisture content suffered more than well dried samples. Indications were also obtained that the following type of sample was particularly susceptible to such injury—artificial heating—

(a) a rapidly germinating sample,

(b) a thin‐husked sample,

(c) a sample with heavy grain.
NOTE ON THE ACTIVITIES OF HUMBLE BEES (BOMBUS) IN NORTH WALES
Authors: WALTON C. L.
Published: February 2008

A short account is given of the species of Humble Bees (Bombi) observed by the writer in North Wales and adjacent districts during the period 1919–27, with notes on their relative abundance and seasonal activities.

The chief economic plants visited by each species are Wed, together with brief mention of those cultivated and wild flowers most favoured.
ON THE PAIR OF SO‐CALLED SENSORY PITS OF THE NINTH ABDOMINAL SEGMENT OF THE WIREWORM (AGRIOTES OBSCURUS LIN.) WITH ADDITIONAL NOTES ON THE INTERNAL ANATOMY
Authors: JAMES H. C.
Published: February 2008

The structural evidence obtained from the study of the pits on the ninth abdominal segment of Agriotes obscurus favours the view that they are a pair of muscular impressions. The hairs lining the pit walls do not possess a nervous supply nor was any special nervous supply traceable to the pits as a whole. No structures which have been associated with sense reception in insects were found in the neighbourhood of the pits. There wm no evidence that the pits are a modified pair of spiracles as was suggested by one miter (6).

With regard to the alimentary canal there are no salivary glands. The oesophagus possesses four ridges which project into its lumen and their muscular nature suggests that they are capable of independent movement.

The mesenteron is devoid of gastric coeca and does not contain a peritrophic membrane of any type.

The digestive fluid is secreted in vesicles which are budded off from the epithelial cells lining the midgut. The contents of the mesenteron has a pH of between seven and eight which is similar to the reaction of its cell walls. The hindgut is a straight tube without clearly marked intestinal and rectal regions and there are no glands of any kind in this part of the gut.

The malpighian tubes are four in number and are generally of a yellow colour, but it is not unusual to find blackened patches in the tubes which are due to dark masses of excretory matter blocking the tube.

The dorsal vessel is non‐septate.

Besides the supra‐ and sub‐oesophageal ganglia there axe 11 nerve massea in the central nerve chain—three thoracic and eight abdominal.

The masses of fat body are characterised by their leaf‐like shape and great length.