bluuebunny/crossref_metadata_2025 huggingface dataset:
SOME ASPECTS OF THE PHYSIOLOGY OF CERTAIN NITRITE‐FORMING BACTERIA
Authors: CUTLER D. WARD , CRUMP. L. M.
Published: February 2008

1. One hundred and four species of bacteria which produce small quantities of nitrite from ammonium sulphate have been isolated from niters receiving waste water from a beet sugar factory, and these bacteria do not differ in their behaviour on carbohydrates from non‐nitrifying bacteria from the same source.

2. Ammonium lactate is the salt of ammonia which is most readily oxidised.

3. In the majority of cases nitrite can also be utilised, by these bacteria in the course of growth.

4. There is a positive correlation between increase in bacterial numbers and the percentage nitrite in a culture during the initial growth period.

5. Nitrite may disappear slowly from solutions at a pH. of 4–8 when the bacteria have been killed by autoclaving; but this is not invariably the case.
THE SEEDLING CHARACTERS OF SOME CULTIVATED BRASSICAE
Authors: ROBSON W. S.
Published: February 2008

A detailed study was made of the morphological characters of the seedlings of some cultivated forms of Brassica, namely, white‐fleshed and yellow‐fleshed swede turnips, winter swede and summer swede rapes, white‐fleshed and yellow‐fleshed common turnips, and winter and summer turnip rapes.

It is shown that there are no constant points of difference between the seedlings of swede turnips and swede rapes, nor between the seedlings of the bulb‐forming turnips and their corresponding leafy turnip rapes.

These investigations were carried out at the Agricultural Botanic Garden and in the Department of Agricultural Botany, University of Reading, under the direction of Prof. Percival, to whom I desire to express my cordial thanks for suggestive criticism and assistance with the illustrations.
EXPERIMENTS BEARING ON THE NATURE OF INTRACELLULAR INCLUSIONS IN PLANT VIRUS DISEASES
Authors: SHEFFIELD F. M. L.
Published: February 2008

The intracellular changes resultant on infection with aucuba mosaic and Hy. III diseases are described and are compared with the cytological effects of tobacco mosaic virus. With the two former viruses, inclusion bodies are formed by the aggregation and fusion of minute particles which appear in the cytoplasmic stream. With tobacco mosaic disease an amoeba‐like body is produced and this persists for some weeks before suddenly disappearing again. It is accompanied by striate material all of which ultimately fuses into one large body.

Attempts have been made to parallel these conditions in healthy cells of Solanaceous plants by treatment with substances known to coagulate protoplasm. Almost all the reagents used induced stimulation of the cytoplasmic stream similar to the initial sign of virus infection. With salts of molybdic acid, all the cytological abnormalities due to aucuba mosaic or Hy. III disease have been imitated. Treatment with lactic acid induces the formation of amoeboid bodies like the X‐bodies of tobacco mosaic, but these bodies persist for only a few hours.

Attempts have also been made to inhibit the formation of inclusion bodies induced by several different diseases in a number of hosts but no success was obtained.

The experiments support the view that the intracellular inclusions of plant virus diseases are essentially products of the host cell.
EFFECTS OF TEMPERATURE AND HUMIDITY ON THE CLOTHES MOTH LARVA, TINEOLA BISELLIELLA HUM. (LEPIDOPTERA)
Authors: MELLANBY KENNETH
Published: February 2008

Methods for breeding clothes moths with very little attention are described.

Experiments were made in which fasting clothes moth larvae were exposed to a number of temperatures (35, 30, 22 and 10° C.), and four humidities at each temperature (0, 30, 60 and 90 per cent.). The rate of loss of weight of the larvae was determined, and al 50 the amount of solid matter lost.

In moderately dry or moderately moist air, the larvae maintained their water balance, but in very dry air the proportion of solid matter in their bodies rase, and in moist air it fell. A considerable amount of dry matter was lost by excretion and the production of silk, in addition to metabolism. These processes were not affected by humidity.

The results suggest that the rate at which water is evaporated from the !arvae is proportional to the saturation deficiency of the air.
ON THE BIOLOGY OF THE MITE, GLYCYPHAGUS DOMESTICUS DE GEER. (TYROGLYPHIDAE, ACARINA)
Authors: HORA A. M.
Published: February 2008

1. A list is given of the mites most commonly found in houses. The most important of these is Glycyphagus domesticus, the furniture mite, and this has been mainly studied during this investigation.

2. An account is given of the occurrence of G. domesticus in houses and the conditions under which it is found.

3. The life history is described. It is characterised by the occurrence of the hypopus, a cyst‐like stage which is found only amongst the Tyroglyphidae.

5. Humidity and temperature have a marked effect on the life of the mite. Tables are given showing the effect of (a) humidity on the adult, (b) humidity and temperature on the hypopus and egg.

6. Some experiments on the effect of carbon tetrachloride and methyl salicylate on the hypopus are recorded.
THE PINEAPPLE BUD MOTHS IN HAWAII
Authors: HERFORD G. V. B.
Published: February 2008

The two most important species of bud moth, in Oahu are Pyro‐derces rileyi Wlsm. and Ereunetis flavistriata Wlsm.

Both species are evenly distributed over the island, the latter being the more common.

They are most numerous in old ratoon fields, where they feed on dead plant tissue. They are also often found on young fruits, where, contrary to certain claims, they appear to do very little damage.

Methods of distribution are discussed; wind is probably the most important factor.

Although often found with mealy bugs, neither species appears to be predacious.

Except when disturbed, the larvae are not molested by ants, but when unfavourable circumstances cause them to wander, large numbers may be killed in this way.

Parasitism is very low. Only two parasites have been reared from several hundred larvae. Predators, principally Sphecoid wasps, carry off many larvae, but being unable to reach the majority are relatively ineffective as a means of control.

Apart from the regular spraying for control of mealy bugs and the knocking down of old ratoon fields, no specific control measures are practised against bud moths, and any further effort would appear to be unwarranted.
Zone Lines in Plant Tissues: Ii. The Black Lines Formed by Armillaria Mellea (Vahl) Quel.
Authors: CAMPBELL A. H.
Published: February 2008

The black lines of Armillaria melleu have been found in the tissues of a number of plants. Isolations were made from the lines and an account of the development of Armillaria mellea in culture is given. Particular mention is) made of the formation of sclerotium‐1il.e bodies in the culture medium and of the development of the rhizomorphs. Pure cultures of the fungus on wood blocks have produced black lines in the substratum similar to those occurring in nature. A short review is given of the nature of the sclerotium, and from a consideration of the formation of the black plates, or lines, as they appear in section, the suggestion is made that they form the limiting layer of sclerotium‐like bodies, which are partly immersed in the substratum. The black lines in the wood are continued at the surface as the black rind of an effused mycelial mass named the black xylostroma. Thus there is formed a body comparable to a sclerotium in that it is completely surrounded by a black rind of bladder hyphae and has a medulla of hyaline hyphae. It is, however, partly immersed in the wood substratum and, in consequence, contains a considerable proportion of host tissues. Further, this body, probably as a result of its immersion in a hard woody substratum, has developed the power of apical growth resulting in the
On the Relation Between the Stage of Development of the Potato Crop and the Incidence of Blight (Phytophthora Infestans)
Authors: BEAUMONT A.
Published: February 2008

The evidence for the common opinion that potato plants above a certain age are on that, account more susceptible to blight than younger ones is based on (1) general field observations, (2) dates of planting experiments, (3) artificial inoculation experiments. The results of such observations and experiments are discussed and summarised, and it is shown that they do not consistently support this opinion; further, it is pointed out that much more careful analysis than is usually employed is needed to interpret the results correctly.

The difference in behaviour towards blight sometimes observed between assemblages of old and young plants appears in reality to be due to variation in “epidemic potentiality,” and not to change in inherent susceptibility with age. It is not necessary to assume the existence of differences in susceptibility between plants of different ages, for the differences in disease intensity and resultant rate of spread will follow from the increasing chances of the occurrence of primary infection foci as the plants become older, and from the greater chances of the environment (particularly the micro‐climate) being suitable for the development of the parasite amongst older than amongst younger plants. Accurate conclusions concerning inherent resistance or susceptibility are possible only from carefully controlled artificial inoculation experiments carried out under uniform optimum infection conditions. Seedlings are often readily attacked so that youthfulness does not confer any degree of resistance on the plant. The results of experiments hitherto carried out with older plants are conflicting, and further study of the problem on carefully planned lines is eminently desirable.
On the Biology of Psylliodes Hyoxcyami Linn. (Chrysomelidae, Coleoptera), The Henbane Flea‐Beetle, with Descriptions of the Larval Stages
Authors: NEWTON H. C. F.
Published: February 2008

1. A severe attack by a flea‐beetle, Psylliodes hyoscyami Linn. on Hyoscyamus niger L. grown as a commercial crop is recorded.

2. The life history and developmental stages of the beetle are described.

3. Suggestions for control are made.

4. The larvae of Lonchaea flavidipennis Zett. (Sapromyzidae, Diptera) has been found associated with the beetle larvae in the damaged stems.
Reviews
Authors: BRIERLEY W. B.
Published: February 2008

Recent Advances in Cytology. By C. D. Darlington.

Recent Advances in Plant Genetics. By F. W. Sansome and J. Philp

The Apple. By Sir A. Daniel Hall and M. B. Crane. Pp. 235, 11 figs, and 12 plates. London: Martin Hopkinson, Ltd., 1933. 10s. 6d. net.

Elements of Agriculture. By the late R. Pream, LL.D. Ed. by Prof. Sir Rowland H. Biffen

Plant Parasitic Nematodes. By T. Goodey.

Phytopathological and Botanical Research Methods. By Thomas Elsworth Rawlins.
The Physiology of Virus Diseases in Plants: V. The Movement of the Virus Agent in Tobacco and Tomato
Authors: CALDWELL JOHN
Published: February 2008

Experiments on the movement of the virus of aucuba or yellow mosaic of the tomato in the host plant are described. It has been found that the presence of the virus in the tissues is not always associated with symptoms, and that the symptoms appear in those tissues which have developed after infection. It was also found that the distribution of the virus throughout the plant was not uniform. In the chlorotic tissues the virus content was higher than in the neighbouring green areas.

A large series of experiments has been carried out on the transmission of six different viruses in the seed of tomato or tobacco. In no instance was there any evidence of transmission, and it is suggested that the chance of seed transmission of these viruses is very slight.

The movement of the virus from an infected leaf and the possibility of its being carried with the food material were examined, and results are given which show that the virus can move independently of the food materials and that, under certain conditions, the virus apparently moves in the direction opposite to that of the metabolites.
Studies in Bacteriosis: Xx. The Spraing Disease of Potato Tubers
Authors: GRIEVE BRIAN JOHN
Published: February 2008

1. The disease symptoms generally grouped in England under the designation “spraing or internal rust spot” hare been segregated into two types, namely “arc” lesions constituting spraing disease and “blotch” lesions constituting internal rust spot disease.

2. Isolation experiments have been carried out to see if either of the organisms reputed to be the cause of these tuber necroses (B. solaniolens and B. rubefaciens) were constantly present in the lesions. The results show that neither organism occurs in spraing, but that there is some slight evidence that bacteria may be concerned in the production of internal rust spot.

3. Inoculation experiments have been carried out with B. solaniolens and B. rubefaciens. No infection has been produced by B. solaniolens, and though some slight evidence of infection with B. rubefaciens has been obtained the results are far from convincing.

4. Spraing has been transmitted by tuber grafting in three cases out of eighteen, so that the results of Atanasoff have to that extent been confirmed. Spraing was also transmitted in one instance by a ground‐up suspension of the arc lesions. This evidence, together with the absence of any constantly occurring bacterial organism in the lesions, inclines the writer to support Quanjer's view of the virus origin of spraing. Internal rust spot could not be transmitted by tuber grafting. The fact that organisms are more constantly present in the lesions, that B. rubefaciens apparently produced internal rust spot in one experiment, and the failure to transmit this disease by grafting suggest that internal rust spot is a distinct disease from spraing, and may possibly be bacterial in origin.

6. Attempts to isolate a possible infectious principle by leaching from soil after having buffered soil suspensions to different pH values have so far led to no success.
A study of the Compositton and Utilisation of Alberta Peats
Authors: NEWTON J. D.
Published: February 2008

1. The three elements commonly applied in the form of mineral fertilisers in farm practice did not produce rapid decomposition of filter paper cellulose in incubated cultures, whereas the addition of all “essential” elements produced rapid decomposition.

2. Fungi appeared to be more important than bacteria in the decomposition of the filter paper cellulose.

3. The numbers of ammonifying bacteria in cellulose fermentation cultures increased with each additional “essential” element or group of “essential” elements.

4. Different horizons or layers of the Alberta peats studied differ greatly in colour or stage of decomposition and in reaction or pH value.

5. The surface samples of peat usually contain less ash than the deeper samples.

6. The nitrogen content of the different samples varies rather widely, and the subsurface layer usually contains about twice as much nitrogen as the surface layer.

7. The total phosphorus content of the different samples does not vary as much as the nitrogen content.

8. The calcium oxide percentages and the pH values indicate that the Carnwood and Spruce Grove peats require liming and that the Winter burn and Stonyplain peats do not require liming for satisfactory crop production.

9. The cellulose content of the peats varies from none to about 47 per cent. of ash‐free cellulose, and the lignin from about 20 to 49 per cent. A decrease in cellulose content is usually accompanied by an increase in lignin.

10. Cellulose, lignin, and ash together nearly always make up about two‐thirds or more of the weight of the peat. Nitrogeneous organic matter would account for about 3–16 per cent., and petroleum‐ether‐soluble material for only 1 per cent. or less of the total peat.

11. Growth of oat seedlings and bacterial plate counts indicated that the fertility of Carnwood surface peat was not greatly increased or affected by the addition (about three to four months earlier) of ordinary applications of fertiliser salts.

12. At the end of an incubation period of 50 days appreciable losses of cellulose had occurred in the Carnwood peat cultures to which an abundant supply of fertiliser salts had been added; and bacterial numbers were increased by the addition of fertiliser salts. In the case of the Winterburn peat the losses of cellulose, if any, were within the experimental error of the determination.

13. After nineteen days' incubation at a relatively high temperature (55°C.) all of the cultures of Spruce Grove peat showed loss of cellulose, the largest loss occurring in the culture to which lime was given in addition to an abundant supply of the other nutrient salts.
Studies on Aphides Infesting the Potato Crop: Ii. Aphis Survey: Its Bearing Upon the Selection of Districts for Seed Potato Production
Authors: DAVIES W. MALDWYN
Published: February 2008

1. A comparative study has been made during 1928–1933 of the aphis infestation at successful seed potato producing centres, where there has been no increase in virus infection among the stocks, and also at unsuccessful centres, where the increase in virus infection has been large and rapid.

2. The technique developed for this study—one which is applicable for an aphis survey of prospective seed potato producing areas—is given. Identification, in the field, of the different species of aphides infesting potato is desirable in such a survey, and descriptions, with photographs, are presented.

3. Ecological notes on the development of the aphis infestation show that M. persicae—the species that is generally responsible for the spread of virus diseases among potatoes—hibernates as apterae in considerable quantity on winter Brassicae, particularly savoys. These plants constitute the main source of alate spring migrants in most rural districts. The main migration of alatae takes place, normally, in early June, and, in North Wales, is largely from the east. Alatae are not common during July and August and do not increase until the late September migration from potatoes.

4. The index figure of infestation at centres in which there was a rapid increase in virus diseases among the potato stocks always exceeded 100 M. persicae per 100 leaves, and attained such numbers as 1000 individuals per 100 leaves. At centres where there has been no increase in virus infection, the index figure of infestation has not exceeded 20 M. persicae per 100 leaves. The period at which this index figure should be obtained is important, and, with certain exceptions, mid‐July proved to be the most satisfactory. It is essential that the figure should be an index of the intensity of the initial infestation of alatae from outside Bources and their subsequent spread, and should not be simply an index of the rate of reproduction of aphides within the field.
A COMPARISON OF ENGLISH AND CANADIAN TOMATO VIRUS DISEASES
Authors: AIXSWORTH G. C. , BERKELEY G. H. , CADWELL J.
Published: February 2008

It has been found from a comparative study of English and Canadian tomato virus diseases that the commoner viruses which affect the tomato occur in both countries.

Tomato streak caused by the same single virus occurs in both countries, but streak due to a mixed‐virus infection appears to be more frequent in Canada than in England.

The following diseases with their causal viruses are described in this paper. Tomato mosaic (tobacco virus No. l), yellow mosaic of tomato (tobacco virus No. 6), single‐virus streak (tomato streak virus No. l), mixed‐virus streak (a tobacco virus + a potato virus) and spotted wilt (spotted wilt virus). The presence of the last‐named disease in Canada was not established.

Ring mosaic virus and tobacco virus No. 9, which have not been recorded in England, are also described.
A COMPARISON OF CERTAIN ENGLISH AND CANADIAN POTATO VIRUSES FOUND INFECTING TOMATOES
Authors: AINSWORTH G. C.
Published: February 2008

Potato viruses isolated from Canadian tomato material have been compared with standard English material.

The different viruses, which corresponded to the mild and virulent forms of the “latent” or “healthy potato” virus, were all considered to be strains of potato virus X which differed primarily in virulence.

It was found that immunity against a virulent strain of the virus was conferred on tomato plants by inoculation with a mild strain.

In conclusion I wish to thank Dr G. H. Berkeley to whom I am indebted for all the Canadian material.
THE LIFE HISTORY AND CULTURAL CHARACTERISTICS OF TYPHULA GYRANS (BATSCH) FRIES
Authors: MACDONALD J. A.
Published: February 2008

A description is given of the life history and cultural characteristics of Typhula gyrans (Batsch) Fries.

The parasitism of the fungus was investigated. Infection experiments yielded entirely negative results.

The fungus forms resting sclerotia. The mycelium is either pure white and rapidly growing or, under adverse conditions, dark brown and slow‐growing. The sporophore consists typically of a stalk and club‐shaped head. The hymenium is borne all over the surface of the head. The sporophore usually arises from a sclerotium.

The mycelium contains numerous clamp connections. Their function is doubtful.

The development of the sclerotium is traced with special reference to the limiting layer.

The sequence of nuclear changes in the basidium is suggested.

Various abnormal forms, intermediate in construction between sclerotium and sporophore, are described. It is suggested that a consideration of these, together with the resemblance in structure between normal sporophore and normal sclerotium, proves these latter to be fundamentally the same. The proportion of each formed at any time is governed by external conditions.

The fungus is heterothallic. Monospore strains fail to produce clamp connections, sclerotia, or sporophores. When monospore cultures are grown in pairs, in some cases mixing and fusion of the hyphae take place, with subsequent production of clamps, sclerotia, and sporophores; in others no fusions take place.
PRODUCTION OF AN ARTIFICIAL EPIDEMIC OF WHEAT STEM RUST IN KENYA COLONY
Authors: THOROLD C. A.
Published: February 2008

Four physiologic forms of wheat‐stem rust are known to occur in Kenya Colony. Only one or two of these forms may occur in any one year, and the work of selecting wheat varieties resistant to several forms is hampered on that account.

A method is described whereby an artificial rust epidemic has been produced. The hybrid wheats have thereby been subjected to infection by the four physiologic forms.

Certain susceptible varieties were planted as “surround rows” amongst the hybrids, and utilised for inoculations.

The inoculum consisted of uredospores, taken from inoculated plants grown in muslin cages, and was applied to leaves of plants in the surround rows. Afterwards these plants were covered for about 50–60 hours with bell‐jars or with large “cloches” described as “V” glasses.

Suggestions are made as to modifications in the methods of procedure which might be adopted in the production of future artificial field infections in Kenya Colony.
AN IMPROVED LABORATORY APPARATUS FOR FUMIGATION EXPERIMENTS
Authors: BOVINGDON H. H. S.
Published: February 2008

An account is given of a new type of laboratory apparatus for fumigation experiments with insects or other small animals, and the experimental procedure adopted is described. Reference is also made to appliances used by other investigators.
ON THE BIOLOGY OF ARAECERUS FASCICULATUS DE GEER (COL., ANTHRIBIDAE), WITH SPECIAL REFFERENCE TO THE EFFECTS OF VARIATIONS IN THE NATURE AND WATER CONTENT OF THE FOOD
Authors: SAYED M. TAHER EL.
Published: February 2008

Summary.

The time necessary for maize and cacao (the two important foods of Araecerus fasciculatus) to come in equilibrium with atmospheric humidities between 50 and 100 per cent. r.h. have been determined. The same determination has been made more roughly for nutmeg.

Under ideal conditions (maize at high, humidities) the sex ratio of A. fasciculatus is about 1:1. On nutmeg (which appears to be a less suitable food) more females than males are produced.

At 27d̀ C., the male is mature 3 days and the female 6 days, after emergence.

Fertilisation takes place at 6 days after emergence, and lasts 6.5–8 min., at 27d̀ C. Females are normally fertilised more than once, but once is enough to render all the eggs fertile.

Females in which fertilisation is delayed lay more rapidly when once they are fertilised. The effect gradually increases for delays of 1, 2 and 3 weeks and after that ceases.

Oviposition in maize is described. It takes on the average 8 min. (at 18d̀ C.) whether in light or darkness. Unfertilised eggs are laid loose and are not inserted into the food.

The incubation period is 5–8 days at 27d̀ C. at all humidities between 50 and 100 per cent. r.h.

The maximum number of eggs was laid by groups of 25 females on maize (at 27d̀ C.) at r.h. 90 and 100 per cent. At lower humidities the number laid was less and the viability smaller. 60 per cent. r.h. is about the limit at which the life cycle can be carried on with maize and nutmeg, 80 per cent. r.h. for cacao.

For maize and nutmeg, the minimum length of the total life cycle varies inversely with the relative humidity of the atmosphere, the period always being about 10 days less on the former. For cacao there is a similar relation, but the curve is not parallel to those for maize and nutmeg. On maize the minimum life cycle at 27d̀ C. varies from 57 days at 60 per cent. r.h. to 29 days at 100 per cent, r.h., the variation occurring only in the period spent as a larva.

The pupa is the only stage which can survive humidities lower than 60 per cent. r.h.

On maize, the adults live 27–28 days at 50 per cent. r.h. and 86–134 days at 90 per cent. r.h. (at 100 per cent, the food becomes mouldy). On cacao, few live more than 20 days at humidities less than 80 per cent. r.h. The reduction in length of life is principally due to failure to feed at lower humidities, for when starved, the beetles live about the same time at all humidities.
A VIRUS DISEASE OF PRIMULA OBCONICA AND RELATED PLANTS
Authors: SMITH KENNETH M.
Published: February 2008

Summary.

A virus disease of Primula obconica is described. The virus is shown to be transmissible to various Solanaceous plants on which it produces symptoms closely resembling those caused by cucumber virus I on the same host plants. Comparison of the virus from the Primula with a strain of cucumber virus I suggests that the two are very similar if not identical.
A VIRUS DISEASE OF CULTIVATED CRUCIFERS
Authors: SMITH KENNETH M.
Published: February 2008

Summary.

An account is given of an apparently undescribed virus disease affecting cultivated crucifers and other plants. The virus is sap‐transmissible and has been so transmitted to young cabbages and also to various members of the Solanaceae. On Nicotiana glutinosa it produces a disease which is usually fatal.

Preliminary tests with the virus differentiate it from the viruses of tomato spotted wilt and cabbage mosaic.
FURTHER SEROLOGICAL STUDIES OF PLANT VIRUSES
Authors: BIRKELAND JORGEN M.
Published: February 2008

Summary.

Precipitin reactions with several plant viruses propagated in serologically unrelated hosts offer additional evidence that the virus is, in itself, antigenic.

Reciprocal precipitin tests show that the viruses of cucumber mosaic, tobacco ringspot, and tobacco mosaic are serologically distinct; whereas tobacco mosaic virus, aucuba mosaic virus (green and yellow strains), and probably tomato streak virus remain serologically indistinguishable.

No soluble specific substance was isolated from the juice of virus diseased plants or of healthy tomato by the methods employed.
THE EFFECT ON THE TOMATO PLANT OF CARBON DIOXIDE PRODUCED BY COMBUSTION
Authors: BOLAS B. D. , MELVILLE R.
Published: February 2008

The effect of carbon dioxide on tomato plants growing in a small greenhouse has been studied, the gas being produced by burning paraffin in a pressure burner.

An increased yield of fruit of 23.9 per cent. for the first half of the season and 13.9 per cent. for the whole season was obtained.

A significant increase in the growth‐rate of tomato seedlings was brought about by the treatment.

The distribution of carbon dioxide in the glasshouse was investigated and the sources of loss of gas examined.

The economic bearing of the results is briefly discussed.
MOSAIC DISEASES OF THE CUCUMBER*
Authors: AINSWORTH G. C.
Published: February 2008

Three cucumber mosaic diseases of this country and the causal viruses are described.

The first disease, green‐mottle mosaic (cucumber virus3), and the second, yellow mosaic (cucumber virus4), are not transmissible to solanaceous plants.Cucumber virus3, on cucumber, causes a dark green mottle with blistering and distortion of the leaves, but the fruit is not usually marked; whilecucumber virus4 gives rise to a distinct type of leaf‐mottle, yellow to silver‐white in colour, and the fruit may be seriously marked. The third disease, yellow‐mottle mosaic (cucumber virus1), is characterised by a diffuse yellow mottle of cucumber leaves and fruit and is transmissible to solanaceous plants. Cucumber viruses 3 and 4 are described for the first time.

Notes are given on fern leaf of tomato, insect vectors and control measures.
STUDIES ON APHIDES INFESTLNG THE POTATO CROP
Authors: DAVIES W. MALDWYN
Published: February 2008

Contrasted differences in the intensity and nature of the infestation of aphides attacking the potato crop in certain districts in North Wales prompted a detailed study of the factors involved.

Migrating alatae are considerably more numerous in the Flintshire districts than in the south Caernarvon area. The mean monthly values for relative humidity are consistently and appreciably lower in the former district than in the latter.

Controlled laboratory experiments on the effect of variation in relative humidity upon the flight of M. persicae clearly demonstrate an inhibitive action of high humidities upon flight. The experiments were conducted at 0, 25, 50. 70, 85 and 100 per cent, relative humidities at the temperatures 55d̀ F., 70d̀ F., 80d̀ F. and 90°F.

The findings of the survey of aphis population at centres in North Wales during 1928–33 are discussed in the light of these results.
BIOLOGICAL STUDIES OF CERTAIN SPECIES OF CALIROA COSTA AND ENDELOMYIA ASHMEAD (HYMENOPTERA SYMPHYTA)
Authors: MILES HERBERT W.
Published: February 2008

Larvae of Caliroa Costa and Endelomyia Ashmead are well known as slugworms and leaf skeletonisers of many cultivated trees and shrubs.

C. limacina Retz. oviposits on the under sides of leaves of plum, pear and cherry and the eggs hatch in 11–14 days. The larvae are covered with dark slime and feed on the upper surface of the leaves. The feeding stage lasts 18–21 days. The larvae moult and shed their coating of slime before entering the soil to make cocoons. The cocoons are composed mainly of soil particles, lightly cemented with saliva. In the north‐west of England some individuals emerge the same season and give rise to a second generation, and others continue in the cocoons until the following year. Reproduction is mainly dependent on parthenogenesis.

C. annulipes Klug. oviposits on the upper surface of the leaves of Salix, Grategus, Prunus, etc. The incubation period is 13–15 days. The larvae, unlike those of C. limacina, are covered with transparent slime and feed on the under side of the leaves. The larval stage lasts 19–22 days and at maturity they lose their coating of slime and enter the soil to construct cocoons. C. annulipes is bivoltine in the north of England and the phenomenon of delayed development has not so far been observed.

E. aethiops Fab. appears confined to Rosa sp. The flight period is May–June and the females oviposit in the edges of rose leaves, preferring Rosa canina and R. arvensis. The incubation period is 9–14 days and the larval feeding period 20–27 days. The larvae are yellowish; the thorax is enlarged but not as much as in Caliroa sp., and the prothoracic glands and coating of slime are lacking. They feed on the under surfaces of the leaves and at maturity they moult and enter the soil to make cocoons. E. aethiops is univoltine and hibernation takes place in the contracted prepupal condition in the cocoon.

Endelomyia Ashm. can be separated from Caliroa Costa on antennal characters and wing venation. A key for the identification of the five recorded British species of Caliroa and Endelomyia is included.
SOME EFFECTS OF TOBACCO MOSAIC VIRUS ON THE GROWTH OF SEEDLING TOMATO PLANTS
Authors: AINSWORTH G. C. , SELMAN I. W.
Published: February 2008

A negative correlation has been shown to exist between the growth rate of seedling tomato plants and the length of the incubation period.

Evidence has been presented, which suggests that the relative effects of tobacco virus 1 on the growth rate of the plant subsequent to the appearance of symptoms is the same in both summer and winter.

The percentage water content of all parts of infected plants was found to be lower than that of the controls, during the early stages of the disease. Later the water content tended to rise above that of healthy plants.

In conclusion we wish to express our thanks to Mr B. D. Bolas for his interest and valuable advice.
STUDIES IN BACTEMOSIS. XXII
Authors: LACEY MARGARET S.
Published: February 2008

An organism has been isolated from fasciated sweet peas and found to reproduce the disease on inoculation into young seedlings.

Bacterial strains culturally similar to the sweet‐pea organism have been isolated from “leafy galls” on chrysanthemums, carnations and Schizanthus, and from “cauliflower” of strawberry. On inoculation all these strains produced marked fasciation in sweet‐pea seedlings, and also produced fasciation of sweet‐pea seedlings growing in inoculated sand cultures.

A preliminary description of the organism has been given.

REFERENCES
THE INSECTICTDAL PROPERTIES OF SOME EAST AFRICAN PLANTS
Authors: WORSLEY R. R. LE G.
Published: February 2008

Mundulecc bark from Moa district is as toxic to insects as Ammi Derris root containing 6.4 per cent. rotenone. That obtained from two other dietricts is only about half as toxic. The former tree may be a variety of the ordinary M. suberosa.

The powder dusted on cockroaches and flies, although having a much smaller initial effect than pyrethrum and not producing any rapid knock‐down, yet causes death in about half the time; Derris has the same action. The same remarks apply to paraffin extracts of these substances.

Mudulea seeds are about three‐quarters as toxic as the bark, but are unlikely to be of any commercial value on account of their scarcity. Experiments are in progress in the cultivation of M. suberosa from Moa seed, and it is hoped that the bark will h d a commercial outlet.
THE BIOLOGY OF LEPTOBYRSA RHODODENDRI HORVATH (HEMIPTERA, TINGITIDAE), THE RHODODENDRON LACEBUG
Authors: JOHNSON C. G.
Published: February 2008

A brief review of the literature dealing with the history of Lepto‐byrsa rhododendri Horvath as a pest is given. The original home and subsequent dispersal are discussed.

The distribution of the insect in Great Britain, as known to the author, is given.

The bionomics of the insect are dealt with.

Detailed descriptions of the structure of the egg and its position in the leaf tissue are made, together with a short description of the egg gall and an account of the hatching process.

The external appearance of each of the four instars is described in detail. Comments upon the descriptions of the immature stages of previous workers are given.

The list of references contains all the more important papers which deal with the insect mainly from general economic and bionomic aspects.
SOME NOTES ON THE BIOLOGY AND ECONOMICS OF SOME BRITISH CHAFERS
Authors: FIDLER J. HAVELOCK
Published: February 2008

Adult chafer beetles do not usually occur in very extensive swarms in the British Isles, and their general importance lies in the characters of the larvae which are notable for their voracity and large size. Another factor of importance is the tendency towards concentration, large numbers of beetles often ovipositing in one field while neighbouring crops remain free.

There are few crops which the larvae do not attack, but the damage done by the adult beetles in this country is not important.

The distribution, which is local, is shown to be controlled by the sparseness of suitable habitats and by the prevailing conditions of temperature and humidity.

The factors which control the varying lengths of the life cycle are also considered to be mainly temperature and humidity. Thus, although Serica always takes 2 years to develop, Amphimattus solstitialis may take either 2 or 3 and M. melolontha 3 or 4 years, according to the conditions controlled by these two factors.

Regular flight‐years are usual on the Continent, but are much less definite in the British Isles, and the numbers of beetles appearing are relatively small. It is suggested that the reason for this is the differences in climatic conditions, particularly in spring.
A STUDY OF FOMES FRAXINEUS AND ITS EFFECTS ON ASHWOOD
Authors: MONTGOMERY H. B. S.
Published: February 2008

An account is given of the occurrence and distribution of Fomes fraxineus.

The appearance of the fungus in culture and details of the hyphae are described.

Fruit bodies, in the form of pore surfaces bearing basidiospores on typical basidia, were obtained. Monosporous cultures derived from these spores were found to be heterothallic, sex appearing to be determined by two factors.

The formation of fructifications is favoured by certain media but does not seem to be influenced by light, temperature or moisture.

The optimum temperature for growth is 26o C, and the optimum hydrogen‐ion concentration is pH. 6.

The fungus was found to be moderately resistant to zinc chloride, sodium fluoride and coal‐tar creosote.

A list of enzymes found to be present is given and some preliminary experiments on the effect of nitrogen on the activity of diastase and oxidase produced by the fungus are outlined.

The growth of the fungus on ashwood and some other woods was investigated. The fungus grows well on ash, beech and elm and is able to attack oak, Scot's pine, Sitka spruce and Robinia pseudacacia. Ann Biol xxIII 32

A description of the hyphae in the cells of the wood and their effect upon the walls is given.
STUDIES ON EUROPEAN FOUL BROOD OF BEES
Authors: TARR H. L. A.
Published: February 2008

“European foul brood” has been initiated in healthy nuclei by feeding either the young larvae directly or the bees naturally infected material. The disease thus produced varied from a mild transient infection to a serious form depending upon whether the inoculation had been made early or late in the brood‐rearing season. In one experiment in which a nucleus very strong in bees was employed no disease resulted.

“European foul brood” has also been induced in healthy nuclei by suspending in them combs containing artificially infected larvae in which disease had been produced by feeding them pure cultures of Streptococcus apis or Bacillus alvei and then starving them under conditions favouring the growth of the bacteria. The susceptibility of nuclei to infection by this means seems to be governed by approximately the same conditions as pertain to inoculations made with material obtained from natural sources. The disease thus induced ultimately becomes a mixed bacterial infection of the brood.

Attempts to cause disease by feeding the bees or larvae (without starving them) relatively large numbers of S. apis or B. alvei organisms have as yet proved unsuccessful. Whether this is due to the fact that these bacteria become attenuated with respect to virulence by culturing them on artificial media, or that decomposing brood acts as a vehicle and that the relative inoculum is greater by this method, remains to be determined.

The failure to produce “European foul brood” by feeding sterile Pasteur‐Chamberland L 2 or L 3 filtrates prepared from naturally infected larvae to the bees or larvae of healthy nuclei, either with or without bacteria, may be taken as strong evidence in support of the view that a filterable virus is in no way implicated as an etiological agent in this type of disease. This conclusion is strengthened by the success which has attended the use of pure cultures of the bacteria associated with this disease employing the “starved larvae” technique described.

The introduction of queen bees from nuclei affected with “European foul brood” into healthy queenless nuclei has not caused any transmission of the disease under the conditions of the experiments.

Two species of S. apis Maassen have been isolated from affected larvae taken from several different cases of “European foul brood”; one of these hydrolyses both casein and gelatine, the other does not. In other respects these species appear to be identical.

The etiology of so‐called “European foul brood” is discussed in detail, and it is suggested from the evidence submitted in this and other papers that it may not be a single disease with one well‐defined etiological agent, as is American foul brood, but is, perhaps, a non‐specific mixed bacterial infection of the brood of bees, especially of the brood of weak colonies. This conclusion must be regarded as temporary pending further investigation.

My thanks are due to Mr D. M. T. Morland and to Mr A. Rolt, whose generous advice and assistance in connexion with the apiary work greatly facilitated the carrying out of the practical experiments.
ADELGES COOLEY1 GILLETTE (HEMIPTERA, ADELGIDAE) OF THE DOUGLAS FIR IN BRITAIN: COMPLETION OF ITS LIFE CYCLE
Authors: CAMERON A. E.
Published: February 2008

Adelges cooleyi is a pest of Sitka spruce, the primary host, and Douglas fir, the secondary host, on the latter of which it has been known in Britain since 1913.

Hitherto its life cycle in Britain has been regarded as incomplete because of the non‐viability of generation I (sexuales) on Sitka spruce and consequent absence of the subsequent generation II (fundatrix vera) and generation III (gallicolae).

Both of these generations have been discovered for the first time in Britain and their development followed.

The investigation began with the finding of the dead galls of A. cooleyi on Sitka spruce at Glen Tress in February 1935. Subsequently, dead galls were also found at Stobs, Melrose, Dreghorn and Murthly. At Melrose they were found on a new secondary host, the white spruce, Picea alba. Later the fundatrix vera of generation I was found.

The growth of the galls was followed on cut twigs in the laboratory and on growing shoots in the field; galls of the current season were found at Glen Tress, Dreghorn and Murthly.

The winged gallicolae of generation II were observed migrating to Douglas fir, where they settled and oviposited. From the eggs there hatched typical hibernating first‐instar nymphs (sistentes).

Generation III (colonici) was determined to be triple‐brooded, and this character has recently been noted in Adelges cooleyi in British Columbia.

The population of the sistentes on Douglas fir during any one winter was found to be composed of four categories, which hav* been designated.

The migration of generation IV (sexuparae) to Sitka spruce and white spruce was observed at Glen Tress and Melrose respectively. It was also verified in the laboratory.

Generation V (sexuales), for some cause or causes yet unknown, was practically exterminated during development. Only a few adults were observed. The solitary egg laid by the female of this generation was not discovered.

Further investigation is required concerning:

The causes of mortality of the sexuales.

The oviposition of the sexual female, and the sexually produced egg.

The extent of the distribution and establishment of the spruce generations in Britain.

The prospective status of A. cooleyi as a pest of Sitka spruce in Britain.

With regard to status, it would be unsafe, at the present juncture, to speculate, especially as the investigation has been conducted for only one year. I have, therefore, refrained from discussing possibilities of damage to the spruce host until more evidence is available.

The writer is indebted to Mr R. Carrick, B.Sc, Research Student in the Department of Entomology, for the photograph of the winged gallicollae reproduced in PI. XXV, fig. 4. Part of the expenses incurred in conducting the investigation were met by a grant from the Earl of Moray Endowment of the University of Edinburgh, and it is a pleasure to acknowledge this assistance.
THE BIOLOGY OF THE CHRYSANTHEMUM LEAF‐MINER, PHYTOMYZA ATRICORNIS MG. (DIPTERA: AGROMYZIDE)
Authors: COHEN MORRIS
Published: February 2008

The synonymy and distribution of the chrysanthemum leaf‐miner are discussed.

The host plants are enumerated, and it is shown that the attacks on chrysanthemums decrease by August, although the flies are still common on other Compositae.

A description and comparison of the morphology of the three larval instars is given, and the method of feeding of the larva is discussed.

The puparium and emergence of the adult fly are also described, together with an attempt to separate the puparia into sexes by measurement.

Some degree of natural control is secured by the parasitism of a braconid on which a chalcid is probably hyperparasitic.

A table is included comparing the developmental period of Phytomyza atricornis Mg. and P. chrysanthemi Kowarz.
DAMAGE TO WHEAT BY HELOPHORUS NUBILUS F
Authors: PETHERBRIDGE F. R. , THOMAS I.
Published: February 2008

Helophorus nubilus F. is recorded as a serious pest of wheat in East Anglia. No previous record of serious damage has been made, but slight injury was recorded iu 1922 and 1923. Observations in a number of widely separated fields show that the intensity of attack varies with the previous cropping and a serious attack occurs most frequently after rye grass and clover. The larva causes Tl most damage when the tilth is loose.

Observations on the life history suggest that the species has one generation per annum. Eggs were not found, and the earliest damage to wheat was observed in January. Pupae were found in late April and early May, and adults were bred out in the laboratory at the end of May. The larval and pupal stages are described.

The authors are indebted to Dr G. H. Bates and Mr J. C. Mann of the Norfolk County Agricultural Staff, and to Mr G. W. Channon, formerly of the Cambridgeshire County Agricultural Staff, who reported insect attacks on the wheat fields visited.
DAMAGE TO PANICLES OF ALOPECURUS PRATENSIS L. BY APAMEA SECALIS L
Authors: BAENES H. F. , MERCEE S. P.
Published: February 2008

A brief description of the moth, and caterpillar stages of Apamea (Trachea) secalis L. is given, as well as notes on its geographical distribution, life history, host plants and economic importance. The normal damage is the withering and death of the stems of the grasses owing to the caterpillars feeding within the sheaths.

An unusual type of damage is described and figured. This consists of the destruction of the flowering culms and head, exceedingly similar to that caused by the larvae of Amaurosoma flavipes and A. armiUatum. This damage has been observed over a number of years in Northern Ireland, and in 1935 at Harpenden, Hertfordshire.
A DISEASE OF CHERRY LAUREL CAUSED BY TROCHILA LAUROCERASI (DESM.) FR
Authors: GREGOR MARY J. F.
Published: February 2008

A leaf spot disease of cherry laurel is described. The infected areas eventually become occluded and fall out, leaving irregular holes in the foliage. The disease is caused by Trochila Laurocerasi (Desm.) Fr., the imperfect stage of which is proved to be Gloeosporium‐phacidiellum Grove. Infection takes place on the young leaves, most commonly through wounds, and a moist atmosphere is essential for the development and spread of the disease. Control can be effected by spraying with colloidal sulphur during spring and early summer, and by cutting back the bushes only in the autumn, not at short intervals during the summer as is frequently the practice.

The writer wishes to acknowledge her indebtedness to Dr G. H. Pethybridge for valuable suggestions during the course of this work, also to Dr C. E. Foister for the photographs reproduced on PL XXXI.