bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimating returns to soil conservation adoption in the northern Ethiopian highlands
Authors: Kassie Menale , Pender John , Yesuf Mahmud , Kohlin Gunnar , Bluffstone Randy , Mulugeta Elias 
Published: February 2008

AbstractLand degradation in the form of soil erosion and nutrient depletion presents a threat to food security and sustainability of agricultural production in many developing countries. Governments and development agencies have invested substantial resources to promote soil conservation practices as part of an effort to improve environmental conditions and reduce poverty. However, limited rigorous empirical work has been done on the economics of soil conservation technology adoption. This article investigates the impact of stone bunds on value of crop production per hectare in low and high rainfall areas of the Ethiopian highlands using cross‐sectional data from more than 900 households, with multiple plots per household. We have used modified random effects models, stochastic dominance analysis (SDA), and matching methods to ensure robustness. The parametric regression and SDA estimates are based on matched observations obtained from the nearest neighbor matching using propensity score estimates. This is important, because conventional regression and SDA estimates are obtained without ensuring that there actually exist comparable conserved and nonconserved plots on the distribution of covariates. We use matching methods, random effects, and Mundlak's approach to control selection and endogeneity bias that may arise due to correlation of unobserved heterogeneity and observed explanatory variables.We find that the three methods tell a consistent story. Plots with stone bunds are more productive than those without such technologies in semi‐arid areas but not in higher rainfall areas, apparently because the moisture conserving benefits of this technology are more beneficial in drier areas. This implies that the performance of stone bunds varies by agro‐ecology type, suggesting the need for designing and implementing appropriate site‐specific technologies.
“WILT” OR “CROWN‐ROT” DISEASE OF CARNATIONS CAUSED BY FUSARIUM SP.
Authors: BIJL PAUL A. VAN DER 
Published: February 2008

SUMMARY

The disease in the carnation here commonly referred to as “Wilt” or “Crown‐rot” is caused by a fungus belonging to the genus Fusarium.
The disease usually shows as a wet rot of the stem just below the soil. The lower leaves turn a sickly colour, are usually more erect and soon the whole plant is dead.
This fungus was isolated from diseased carnations; grown in the laboratory and when inoculated into healthy plants produced the disease.
The organism grew well on all culture media, producing usually a greyish growth. Along the glass of the tubes and the bottom of Petri dishes, it showed shades of grey, yellow, brown and red.
The fungus grows best at 25o‐30o C, with something in favour of the latter temperature. No growth at 0o C. or 40o C. At 15o C. growth less vigorous than at 25o C.: at 37o C. it remains feeble. The fungus is not killed by incubation at 0o C.; cultures from 0o C. and 37o C. transferred to 30o C. showed a vigorous growth. No growth occurred in cultures transferred from 40o C. to 30o C.
The organism appears to be strictly aerobic.
It withstands high degrees of acidity but less alkalinity.
Conidia vary in size in different media and range between 14.85‐37.95μ× 3.3‐6.6μ, hyaline, fusiform to nearly straight, on some media (banana) very small; 2–6 celled.
Experiments were carried out in the laboratory with various disinfectants and fungicides; these experiments serve to act as a guide for experiments on the treatment of infected soil.
Field experiments carried out with the object of finding whether the application of quicklime or formalin solution to diseased soils would have any beneficial effect, tend to show: (a) the plot treated with formalin was no better than the control plots; (b) on the whole, the plots treated with quicklime fared a little better than the controls, but further experiments would be necessary.
It is urged that the spread of the disease should be prevented as far as practicable by: (a) growing one's own cuttings; (b) obtaining cuttings from healthy vigorous plants only; (c) laying Guttings in in healthy ground; (d) pulling up and destroying all plants showing any evidence of disease,
Diseased soil should be submitted to a judicious process of crop‐rotation for a few years, and all attempts made to prevent the fungus spreading from diseased to healthy areas.
The question of the existence of varieties more or less immune from the disease has thus far not received attention, though it is a problem well worth serious consideration, and the breeding of disease‐resistant varieties may yet be the ultimate solution.
“REVERSION” AND RESISTANCE TO “BIG BUD” IN BLACK CURRANTS.
Authors: LEES A. H. 
Published: February 2008

SUMMARY.

Reversion is characterised by four symptoms:

“running off” of the fruit,
unusual amount of lateral wood growth,
sharp pointed leaves,
long, thin, internodes.

It is associated with and apparently caused by a check to the terminal growth through change of the terminal wood bud into:

a big bud,
a killed bud or blind bud,
a fruit bud.

It may also be associated with aphis attack.

Mite resistant varieties revert under conditions 2 (6) and 2 (c).
Seabrook's Black is mite resistant because in normal climates‐and seasons the mite kills the attacked growing point and thus starves itself. This only happens when both climate and variety favour an early and strong continued check to the, growth of the bush.
There is a form of reversion occurring in young bushes before mite or aphis are present. This form is at present unaccountable.
A COPPER EMULSION AS A FUNGICIDE.
Authors: WORMALD H. , WORMALD L. K. 
Published: February 2008

Summary. An emulsion containing the equivalent of 0.4 per cent. copper sulphate, (CuSO4. 5H2O) can be made by mixing solutions of copper sulphate and soft soap, and this exhibits preventive action against the attacks of the potato blight fungus.In conclusion, we should like to thank Dr Eyre, who indicated the possibility of preparing an emulsion by the method adopted, and at whose suggestion the above experiments were carried out.
STUDIES IN BACTERIOSIS II1.: A BROWN BLOTCH DISEASE OF CULTIVATED MUSHROOMS.
Authors: PAINE. SYDNEY G. 
Published: February 2008

SUMMARY.A disease of cultivated mushrooms is described in which patches of a chestnut brown colour so disfigure the pileus as to render the affected crop quite unmarketable.The disease is identical with that described in America by Tolaas, but left unnamed by him.The cause of the disease is a small bacterial parasite which may possibly be a strain of Pseudomonas fluorescens and may prove to be identical with the organism which produces Pear‐blossom Blight.Until its identity is established by further experiment it seems well to give it a distinguishing mark, and the name Pseudomonas Tolaasi is suggested.
INVESTIGATION OF THE NATURE AND CAUSE OF THE DAMAGE TO PLANT TISSUE RESULTING FROM THE FEEDING OF CAPSID BUGS.
Authors: SMITH KENNETH M. 
Published: February 2008

SUMMARY.There are several species of Capsid bugs which normally feed on the leaves and fruit of apple trees but only one causes any damage, i.e. Plesiocoris rugicollis. This species produces the death of the tissue surrounding each puncture in the leaves made in feeding and on the fruit produces great distortion and “russeting.”There are three possible explanations of this damage:

A purely mechanical injury produced by the insect's stylets in process of sucking.
The possibility of the bug acting as a “carrier” of bacteria and by injecting these into the plant along with the saliva so sets up a pathological state.
The injection of some secretion from the salivary glands which has a violently toxic effect on the plant tissue.

It was found impossible to reproduce by mechanical means the injury resulting from the feeding of P. rugicollis, also the fact that the other species of Capsid bug feed in a similar manner and produce no injury militates strongly against the theory of mechanical injury only.As regards the second theory, no bacteria could be discovered in microtome sections of either damaged plant tissue or the salivary glands of the bug, and all attempts to reproduce the damage by means of bacteria failed.The third theory was proved to be the correct explanation by several experiments and observations.Experiments were made to try and reproduce the bug injury with various dilute poisons; in most cases a very similar appearance was produced in the foliage, but the attempts were unsuccessful in the fruit itself with the exception of the very great retarding effect in the growth of the fruit, which is one of the results of the bug injury.By feeding the bugs on slices of potato instead of apple the same effect was produced, but on a magnified scale. The salivary glands of P. rugicollis and of Lygus pabulinus, a bug harmful to potato foliage, when placed on a freshly cut slice of potato in a petri dish, produced a violent reaction which killed much of the tissue surrounding the glands. The same experiment was carried out with the glands of one of the harmless apple‐feeding bugs Psallus ambiguus, these had no effect whatever on the potato. When the salivary glands of P. rugicollis were pricked into apple buds, the shoots were killed within 24 hours. The salivary glands of P. ambiguus when similarly treated had no effect. Observations were made showing the rate of exudation of sap from the bug's puncture in the potato and these are given for P. rugicollis and Lygus pabulinus. A list of common plants and fruit trees with their various reactions to the feeding of harmful bugs is also given.
THE HABITS OF THE GLASSHOUSE TOMATO MOTH, HADENA (FOLIA) OLERACEA, AND ITS CONTROL.
Authors: LLOYD Ll. 
Published: February 2008

SUMMARY. H. oleracea is not a normal pest of tomatoes grown under glass, and where it has become established as such it is still in some respects ill adapted to a greenhouse life on a tomato diet. The larvae eat the fruit because many of them are unable to survive on the foliage alone. In spite of this weakness, it has become a serious pest because the species is a prolific one and, once having entered a greenhouse, it usually becomes a prisoner there. In a normal year there are two complete generations and a partial third, and the moths are present in the houses continuously from February to October.Spraying the young plants with arsenate of lead largely controls the first brood of larvae, but not entirely, because moths of the first flight of the year are still emerging when it is not practicable to use a poisonous spray on the plants. The plants should be sprayed three times when the larvae appear early: (1) when the seedlings are in pots; (2) just after planting out; (3) about a month before fruit picking begins. The last operation is the most important and the two previous ones may be omitted if there are no signs of larvae feeding.Systematic moth trapping must be done throughout the growing season, because it will reduce the numbers of moths which pass out of the houses, and these, or their offspring blunder into the same or neighbouring greenhouses; and also because it is the most effective form of control when spraying is not practicable, and will reduce the infestation to a very great extent. Sixty jars baited with ale, treacle and 1 per cent, sodium fluoride should be used to each acre of glass. The dead moths should be removed frequently, and the jars should be rebaited every third week.Broken fruit must not be allowed to lie about in the houses as the moths feed on this and become more prolific.Many full grown larvae may be trapped in sacks placed about the houses. The sacks should be collected and dipped in boiling water every third week.Pupae should be destroyed in the winter.Special baskets should be kept for fruit picking, and those from the markets should never be allowed in the houses.The pest spreads rapidly through areas where the nurseries are congested owing to the escape of moths from the infested houses. It may be introduced into isolated localities by means of market baskets, or by plants purchased from infested nurseries. On its first appearance every method of control should be applied at once, as attempts to check it by picking off the larvae by hand in trade nurseries have almost invariably ended in failure.
A QUANTITATIVE ANALYSIS OF PLANT GROWTH: PART I.
Authors: BRIGGS G. E. , KIDD FRANKLIN , WEST CYRIL 
Published: February 2008

SUMMARY.The series of articles of which this is the first instalment, constitutes an attempt to formulate methods for the quantitative analysis of plant growth and to apply these methods to data which have been lying dormant in the literature for 40 years.In the present chapter the relative growth‐rate curve, which is the weekly percentage increase in dry‐weight plotted against time, and also the leaf‐area ratio curve, that is, the leaf‐area in sq. cms. per g. plotted against time, have been employed. And as a typical example of an annual plant maize has been selected since data are given by Kreusler for this plant grown in four successive years.The first noteworthy result of this analysis is the demonstration of the fact that the growth‐rate varies greatly in magnitude at different periods in the life‐cycle of a plant such as maize in a perfectly definite manner.Fig. 9 gives the generalised form of the growth‐rate curve for maize throughout its life‐cycle. Although the broad form is that of a Sach's grand period curve, it must be noted that it is not a grand period curve, since the grand period curve as denned by Sachs is the curve of the actual increment per unit of time plotted against time and not of relative increment, that is, increment per unit of matter per unit of time plotted against time. On the broad form of the relative growth‐rate curve for maize are superposed three secondary features, an initial fall, and two subsidiary maxima on the descending limb.In this generalised curve the initial period A‐B is the period before the assimilatory organs are able to counterbalance the loss in dry‐weight due to respiration, and the rate of growth is consequently negative or nil. The phase B‐C corresponds to a phase in morphological development during which the leaf‐area per unit dry‐weight increases to a maximum. The phase C‐F covers the remainder of the life‐cycle of the plant during which the leaf‐area per unit dry‐weight is continuously decreasing. The subsidiary maxima D and E coincide with the time of the record of the appearance of the male and female flowers respectively. The minima X, Y which precede these maxima, correspond with the earliest stages of flower development, and are possibly due to increased respiration during that period.The incidence of the maxima is controlled by environmental conditions—not by the environmental conditions operating at the time, but by those obtaining at some previous stage in the life‐history of the plant.The fact that the curve for leaf‐area per unit dry‐weight throughout the season (which has been calculated) shows a correspondence with the growth‐rate curve indicates that the physiological basis for increased and decreased relative rate of growth is a corresponding change in the assimilating area per unit dry‐weight. This point will be dealt with in the next chapter.Evidence from the quantitative analysis of plant growth for maize indicates that the seedling leaves do not perform their normal assimilatory function till some time after their appearance.
ON THE OCCURRENCE IN BRITAIN OF THE CONI‐DIAL STAGE OF SCLEROTINIA MESPILI SCHELL
Authors: WORMALD H. 
Published: February 2008

SUMMARY.This article records the occurrence, in the spring of 1920, of the conidial form of Sclerotinia Mespili Schell. on the leaves of medlar trees in four localities in Kent and one in Somersetshire.Mycelium obtained from dead flowers which had remained on the tree from the previous year gave rise to cultures similar to those obtained from conidia taken from infected leaves but the Sclerotinia stage of the fungus was not observed.
A QUANTITATIVE ANALYSIS OF PLANT GROWTH: PART II.
Authors: BRIGGS G. E. , KIDD FRANKLIN , WEST CYRIL 
Published: February 2008

SUMMARY.In this chapter we have continued our analysis of the results of the experiments on the growth of maize carried out by Kreusler and his co‐workers. The rate of growth has been expressed per unit leaf‐area instead of per unit dry‐weight as in the last chapter. The term “Unit Leaf Rate” is used for the weekly rate of increase of dry‐weight in mgs. per sq. cm. The Unit Leaf Rate, instead of undergoing a perfectly definite type of variation, as does the Relative Growth Rate, fluctuates about a mean value. The larger fluctuations which occur in the values for Unit Leaf Rate calculated for the later phases of the life‐cycle have been attributed mainly to sampling errors.Correlations between Unit Leaf Rate and various environmental factors have been determined.The general evidence is that the Unit Leaf Rate is correlated more closely with temperature than with any of the other environmental factors.By allowing for respiration on the basis of our own experimental results values for the real assimilation were arrived at. These also show a closer correlation with temperature than with light.The values for assimilation determined from the Unit Leaf Rate are of a lower order than those determined by the “half‐leaf” method, but much higher than those determined by the “gasometric” method.Finally, the authors wish to express their indebtedness to Dr F. F. Blackmail for his stimulating criticism and help in this and in the previous chapter.
ON FORMS OF THE HOP (HUMULUS LUPULUS L. AND H. AMERICANUS NUTT.) RESISTANT TO MILDEW (APHAEROTHECA HUMULI (DC.) BURR.). IV
Authors: SALMON E. S. 
Published: February 2008

SUMMARY.

Several forms of H. Lupulus with yellowish‐green (“golden”) leaves exist. One form (T) has proved persistently immune to mildew both in the greenhouse and in the open. A second form (9) has proved slightly susceptible when grown in the greenhouse. A third form (3) is susceptible in the greenhouse and in the open. This ♂ form appears to be the one found originally in Germany and described under the name of H. Lupulus aureus. No account of the origin of any ♀“Golden hop” hag been found in horticultural literature.
Certain seedlings raised from the immune ♀“Golden hop” (the ♂ parent being unknown) possess green leaves and are immune to mildew when grown in the greenhouse.
Different seedlings of the wild hop (H. Lupulus) have distinctive physiological or “constitutional” characters, which are constant under the same environment. These characters confer immunity or susceptibility, or intermediate grades of susceptibility, on the respective seedlings. The immunity is retained by the plant after four years' residence in the manured soil of the hop‐garden.
Certain seedlings of the wild hop which show persistent immunity when grown in the greenhouse show some degree of susceptibility when grown in the open. The susceptibility shown is usually very slight. There is some evidence that this breaking down of immunity is due to the effect of certain climatic conditions.
In the great majority of cases, the greenhouse conditions do not have the effect of making seedlings of the wild hop immune to mildew. In the case of some seedlings extreme susceptibility is shown under greenhouse conditions.
The phenomenon of semi‐immunity is shown by certain seedlings of various origins.
A form (8) of H. americanus Nutt., obtained from the United States, has proved immune to mildew under greenhouse conditions. Under the same conditions several American cultivated varieties proved susceptible.
STUDIES IN BACTERIOSIS. V: FURTHER INVESTIGATION OF A SUGGESTED BACTERIOLYTIC ACTION IN PROTEA CYNAROÏDES AFFECTED WITH THE LEAF‐SPOT DISEASE
Authors: PAINE SYDNEY G. , BERRIDGE EMILY M. 
Published: February 2008

Summary

The production by the cells of Protea cynaroídes of a bacteriolysin against the organism which produces a leaf‐spot disease, suggested in a former paper, has not been confirmed.
The bacteria enter the leaf by way of the stomata; the local lesions produced are prevented from spreading by the development of wound cork.
The causal organism succumbs very readily to the desiccation to which it is subjected owing to the cells which it attacks being cut off by the wound cork from their water supply.
PRELIMINARY OBSERVATIONS ON THE HABITS OF OSCINELLA FRIT, LINN.1
Authors: CUNLIFFE NORMAN 
Published: February 2008

Summary.

The adult frit‐fly is prevalent in the field throughout the year except for the period November to April.
There are periods of high prevalence, which are probably limited by meteorological conditions.
High prevalence seems to be associated with high temperatures and emergence with rainfall, and should not be associated with any particular brood or generation.
It is very probable that normally four generations are produced in one year and that the fly is double‐brooded.
The periods between the emergence of successive generations are about 50 days in spring, 35 days in summer and 230–250 days in winter.
Arrhenatherum avenaceum, Festuca pratensis, Lolium italicum, Lolium perenne and Poa annua can be utilised as host plants in the summer and Alopecurus myosuroides, Arrhenatherum avenaceum, Hordeum pratense, Lolium italicum and perenne in the winter.
In captivity, the longevity of the imago averages 50 days in spring and in summer.
Ploughing‐in and rolling would only control the pest on heavy land.
Nitrogenous manures are not likely to repay the cost of application on average land in England.
The following Hymenopterous parasites are recorded, for the first time, as attacking frit‐fly: Chasmodon apterus, Nees, Psichaera (Först.) spp., Aphidius granarius and Dicyclus fuscicornis, Walker.
STUDIES ON THE APPLE CANKER FUNGUS
Authors: WILTSHIRE S. P. 
Published: February 2008

SUMMARYThe infection of the apple stem by the canker fungus through the leaf scare is described.The fungus appears to enter through small cracks which appear in the leaf scar tissues, in the autumn immediately after defoliation and in the spring when the buds are swelling.The possibility of preventing this infection by disinfecting the leaf scare by fungicides is discussed and results of preliminary trials recorded.
BIONOMICS OF WEEVILS OF THE GENUS SITONA INJURIOUS TO LEGUMINOUS CROPS IN BRITAIN1
Authors: JACKSON DOROTHY J. , SITONA HISPIDULA F. , THUN S. SULCIFRONS , HERBST S. CRINITA 
Published: February 2008

SUMMARY.

1.Sitona hispidula is common throughout Great Britain upon clover and lucerne.
The adults eat the leaves and the larvae damage the roots.
Sitona sulcifrons is frequently abundant upon “seeds” clover and the larvae feed upon the root nodules.
Sitona crinila frequents tares, clover, lucerne, etc., but is rarely sufficiently common to cause injury.
The adults of S. hispidula are either fully‐winged or brachypterous and two forms of brachypterous wings have been observed in S. sulcifrons.
The life‐history of these three species has been investigated in Britain for the first time.
There is only one generation in the year.
The adults live 12 months.
The period of oviposition and the length of the egg, larval and pupal stages varies according to the species.
The Braconids Perilitus rutilus Nees, P. cerealium Hal., P. aethiops Nees, Pygostolus falcalus Nees and a species of Liophron are recorded for the first time as parasites of the adult beetles.
The fungus Botrytis bassiana (Balsamo) Montagne attacks these species of Sitona.