bluuebunny/crossref_metadata_2025_split huggingface dataset:
EMBRYONIC DEVELOPMENT AND ESTERASE ACTIVITY OF EGGS OF PIERIS BRASSICAE IN RELATION TO TEPP POISONING
Authors: POTTER C. , LORD K. A. , KENTEN J. , SALKELD E. H. , HOLBROOK D. V. 
Published: February 2008

The embryological development of eggs of Pieris brassicae was studied in relation to the occurrence of enzymes hydrolysing phenyl acetate and acetylcholine. Phenyl acetate is hydrolysed at a high rate at all stages of development of the embryo. Hydrolysis of acetylcholine only becomes appreciable in the later stages of development. The first significant level of hydrolysis of acetylcholine can be correlated with the development of a nervous system in the embryo to a stage where it may be functional.Aqueous solutions of TEPP were applied to eggs soon after they were laid. Low doses of TEPP allowed a high percentage of eggs to develop to the point of hatching before death occurred. Most fully developed embryos became active before they died. As the dose was increased less development took place and with very high doses little development occurred.The significance of these results is discussed. The available evidence does not indicate that the poison penetrates slowly nor that it is ‘locked up’ and later released. The explanation that seems to fit the evidence best is that the poison penetrates rapidly and reacts irreversibly with, probably phosphorylates, one or more components of the egg, the extent of subsequent development depending upon the proportion of a biochemical system or the number of systems inactivated. Whilst inhibition of cholinesterase may play a part in the poisoning process, at least under some conditions, the evidence indicates that the death of the embryo may result from some other cause.
THE INFLUENCE OF THE pH OF THE NUTRIENT SOLUTION AND THE FORM OF IRON SUPPLY ON THE COUNTERACTION OF IRON DEFICIENCY IN PEAS, SOYBEAN AND FLAX BY HIGH CONCENTRATIONS OF MOLYBDENUM
Authors: WARINGTON KATHERINE 
Published: February 2008

The prevention of chlorosis in flax by high concentrations of molybdenum in a nutrient solution was associated with a delay in the precipitation of iron from ferric citrate, a slower drift of pH towards alkalinity and an increase in the iron content of the root. These effects were greater with ammonium than with sodium molybdate and occurred with solutions started at pH 4.6 but not at pH 6.6.When FeEDTA was the source of iron, a similar delay in pH drift in the solution and accumulation of iron in the root occurred, but there was no chlorosis or precipitation of iron in the control treatment, so the effect of high molybdenum could not be fully determined.When ferric chloride was used, high molybdenum did not prevent chlorosis nor delay iron precipitation or cause accumulation of iron in the root, though the rate of pH drift resembled that of solutions containing the organic forms of iron.Similar results were obtained with peas and soybeans receiving high molybdenum treatment, but suppression of chlorosis was only temporary.It is suggested that the capacity of molybdenum to offset chlorosis is due to the formation, in acid solution, of a complex with phosphorus which renders iron more available by delaying the formation of ferric phosphate. This seems to occur only when iron is supplied in the organic form.
SOME EFFECTS OF NITROGEN SUPPLY ON THE INFECTION OF TOMATO PLANTS WITH TOMATO SPOTTED WILT VIRUS
Authors: SELMAN I. W. , GRANT SHEILA A. 
Published: February 2008

The susceptibility of tomato plants to systemic infection by tomato spotted wilt virus was increased by increasing nitrogen supply to levels above that optimal for growth. The virus content, estimated by local‐lesions counts, was also raised by increasing nitrogen. The period between inoculation and the appearance of systemic symptoms was decreased by increasing nitrogen to a point slightly greater than the optimal level for growth, but increased by additional applications.Infected plants receiving more nitrate or ammonium compounds than were needed for optimal growth showed abnormal leaf symptoms and no bronzing. N, P and Mg analyses showed that these symptoms were related primarily to nitrogen content. Such leaves contained more virus than bronzed leaves.
ARREST OF THE SWOLLEN‐SHOOT VIRUS DISEASE OF CACAO IN THE GOLD COAST BY CONTROLLING THE MEALYBUG VECTORS WITH THE SYSTEMIC INSECTICIDE, DIMEFOX
Authors: HANNA A. D. , HEATHERINGTON W. 
Published: February 2008

A 13‐acre plot of cacao, in an area devastated by swollen shoot, was treated by dimefox applied to the soil nine times. The plot was examined every month and trees recorded as they showed symptoms. The number of such trees decreased very rapidly a year after the first treatment and remained low for the 3 years that the experiment was continued. This suggests that the time between infection and symptom development can extend to about I year. The cause of the continued appearance of a few diseased trees could not be determined.As cacao farms differ from one another, it was difficult to find suitable control plots. Three farms in the neighbourhood of the chemically treated area were selected. The initial percentage of diseased trees in each was lower than on the chemically treated plot. The three farms were inspected every month and newly discovered trees with symptoms were felled. The number of such trees decreased 12 months after the initial cutting out and then increased abruptly until it again reached a high level.Chemical treatment combined with cutting out was more efficient than cutting out alone in arresting the advance of the disease.
SOME ASPECTS OF THE EFFECT OF THE SOLVENT ON THE TOXICITY OF SOLUTIONS OF INSECTICIDE
Authors: HADAWAY A. B. , BARLOW F. 
Published: February 2008

The effect of varying the solvent upon the contact toxicities of solutions of insecticides to mosquitoes and flies has been investigated using DDT, prolan, dieldrin, endrin and malathion. The insects were allowed to walk for a limited time on filterpapers impregnated with the solutions. Chemical structure of the solvents had a general influence upon the biological activity of the solutions. Providing that the physical properties of the solvents were similar, insecticides were more effective in paraffinic hydrocarbons than in aliphatic long‐chain esters and related compounds, and were least effective in aromatic esters. Physical properties of the solvents were of importance in determining the effectiveness of insecticides dissolved in a group of solvents of similar chemical structure. Viscosity was an especially reliable guide as it presumably controlled the rate at which the solution could pass from the paper and be absorbed by the insects during the exposure period.The order in which the solvents could be arranged with regard to their ability to influence biological action was the same for all the insecticides used, but the ratios of the median lethal concentrations in different solvents varied greatly from one insecticide to another. Consequently, the relative toxicities of the insecticides depended upon the solvent in which they were dissolved.When some of the solutions used in filter‐paper tests were applied topically to the insects the differences in effectiveness were greatly reduced, showing that an important influence of the solvents had been upon pick‐up of insecticide from the papers. However, even with topical applications there were still some differences in median lethal concentrations and especially in rates of action between the solvents, thus providing further evidence that the solvent is also concerned with passage of insecticides through the insect cuticle.The relative toxicities of the solutions bore no relationship to the solubilities of the insecticides in the solvents, and it was concluded that in these experiments chemical potential was not likely to be a controlling factor.
BACTERIAL BOLL ROT OF COTTON (XANTHOMONAS MALVACEARUM (E. F. SMITH) DOWSON)
Authors: LOGAN C. 
Published: February 2008

Two inoculation techniques were compared for their value in assessing resistance of cotton to bacterial boll rot. In the first method, bacterial suspensions were applied with a fine brush to the outsides of young bolls immediately after corolla drop. In the second, suspensions were inoculated into the wall tissue of bolls 3–4 weeks old with a fine needle. The second method is the simpler and produces infections in all weather conditions; other advantages are that bolls are inoculated after the period of natural shedding and the circular lesions are easily measured, but a disadvantage compared with the brush method is that the puncture method does not satisfactorily indicate damage to the lint.Results from the two methods of inoculation suggest that resistance lies in some component of the boll‐wall tissue that affects bacterial growth and not in a physical factor that prevents the bacteria entering the boll. Variability in resistance occurs in local strains of cotton, and this could probably be exploited to give high resistance without the need of a large crossing programme to introduce new genes.
METHODS FOR THE STUDY OF BLOWFLY POPULATIONS
Authors: DONNELLY JOSEPH 
Published: February 2008

1. A simple method of radioactive labelling of L. sericata larvae is described.2. More uniform count levels are obtained in individuals which have fed entirely on radioactive foods than in those which first feed on non‐active food.3. The radioactive count rates of the larvae are correlated with larval live weight and the counting rates of resulting imagines correlated both with corresponding larval counting rates and with imaginal live weight.4. The loss of 32P in the larvae due to causes other than decay of the isotope is traced from the prepupal stage to 3 weeks after emergence. The first and major loss occurs at emergence, when about 10% of the original 31P is shed as empty puparium and meconium. Adults lose about 1.5% per day.5. The distribution of 32P in the adult body of L. sericata labelled in the larval stage has been determined. The abdominal tissues have a lower activity than the rest of the body.
EXPERIMENTS ON THE MOVEMENT OF STREPTOMYCIN IN CHERRY TREES
Authors: CROSSE J. E. , GARRETT CONSTANCE M. E. 
Published: February 2008

Systemic activity of streptomycin in cherry trees was investigated by studying the penetration of the antibiotic into leaves and its subsequent translocation.Antibiotic penetration appreciably suppressed infection with Pseudomonas morsprunorum. In detached leaves the uptake of the antibiotic was progressive with time.Widespread and rapid distribution of the antibiotic in the transpiration stream resulted from petiolar injection. Immersion of the laminae of intact leaves in the antibiotic resulted in a much slower translocation, possibly occurring in the transpiration stream.Evidence suggests that the antibacterial activity detected in fruiting spurs after field spraying is not dependent on the presence of leaves, but results from direct penetration of the antibiotic through the dermal tissues of the spur.It was concluded that foliar sprays at field concentrations were unlikely to result in significant systemic distribution of the antibiotic, but that localized activity might be an important factor in the control of bacterial canker.
STEM INFECTION OF COTTON BY XANTHOMONAS MALVACEARUM (E. F. SM.) DOWSON
Authors: LAST F. T. 
Published: February 2008

Varying the position of stem inoculation, the concentration of inoculum and the age of plant affected the reaction of cotton, Gossypium sp., to infection with Xanthomonas malvacearum (E. F. Sm.) Dowson.The extent of stem discoloration, internal and external, and the probability of disease ocurring in leaves by bacteria moving within the plant increased (a) the nearer the point of stem inoculation was to the apex, and (b) the higher the concentration of inoculum. The leaf symptoms were not the angular spots typical of primary leaf infection. Instead, bacteria seemed to lodge in, discolour and blacken sections of leaf veins. Then tissue next to the affected veins became water‐soaked and leaf sectors dependent upon these veins died and dried. These symptoms usually developed 14 to 55 days after inoculation in the expanding leaves.The amounts of stem discoloration and the probabilities of leaf symptoms developing were less when hypocotyls of old plants were inoculated than when hypocotyls of young plants were inoculated. The probabilities of leaf symptoms developing were similar, however, when young tissues in young and old plants were inoculated.American cotton, Gossypium hirsutum, was less affected by stem inoculation than Egyptian cotton, G. barbadense. Of the resistance factors against primary leaf infection only B6m gave appreciable stem resistance.
STUDIES ON SEED HEALTH
Authors: MUSKETT A. E. 
Published: February 2008

An account is given of the survey made in 1940‐55 to determine the incidence of the seed‐borne fungal parasites of flax. It was shown that fibre flax seed produced in eastern and south‐eastern England was relatively free from contamination with Colletotrichum linicola, Polyspora lini and Phoma sp. and that there was no build‐up of infection in seed stocks in these areas. In the wetter and cooler regions west and north of the Pennines, conditions were more favourable for these fungi, and seed contamination tended to increase.Seed contamination with Botrytis cinerea was general throughout the United Kingdom, with a tendency to be higher in coastal and upland areas. The incidence of Fusarium lini and Alternaria linicola in fibre flax seed produced in the United Kingdom was negligible.The examination of seed samples from other countries indicated the possible importance of P. lini in Denmark, of B. cinerea and C. linicola in the Netherlands, of A. linicola as a contaminant of oil flax seed in Sweden, and of C. linicola in parts of Canada.Seed disinfection, using a thiram product, proved useful for the control of flax diseases in general, but should be used as an ancillary to the method of avoiding seed infection by limiting the production of seed flax to areas where the risk of contamination is slight or absent. Where there is any risk of a build‐up of contamination, seed disinfection should be carried out as a routine practice each season.
EXPERIMENTS WITH A VIRUS DISEASE OF THE COTTON BOLLWORM HELIOTHIS ARMIGERA (HBN.)
Authors: COAKER T. H. 
Published: February 2008

Laboratory tests with a nuclear polyhedral virus disease of Heliothis armigera indicated that it was more infective and had a shorter incubation period in the younger instars than in the older larvae.Larvae on cotton plants sprayed with an aqueous suspension of the virus became infected; mortality depended on the number of polyhedra applied to the plant irrespective of the concentration in the suspension. Spraying with the virus seems unlikely to control bollworm in Uganda, but might do so where it is not already endemic and where bollworm numbers fluctuate more during the year.
CROOK ROOT OF WATERCRESS
Authors: TOMLINSON J. A. 
Published: February 2008

The discovery, occurrence and symptoms of crook‐root disease (Spongospora subterranea (Wallr.) Lagerh. f.sp. nasturtii Tomlinson) are described.Assessment of crook root in commercial watercress beds indicated that the disease increased with increasing distance from the water source, was more severe from October to April than from May to September, and affected brown more than green watercress.The healthier condition of plants near the fresh‐water inlets, compared with those growing further down the bed, was associated with the low concentration of zoospores.Water from the river Dene, Wellesbourne, contained a factor inhibiting crook root, which was shown to be calcium bicarbonate. In laboratory tests, increasing concentrations of calcium bicarbonate from 62 to 540 p.p.m. gave an increasing degree of control of the disease. The same effect was shown in a small field test.The combined (Ca + Mg) bicarbonate content in eighty‐seven spring and artesian waters supplying diseased watercress beds in various counties varied, with one exception, from 282 to 401 p.p.m. The only bed fed by water with a higher total bicarbonate content (525 p.p.m.) was free from crook root.It was shown that solutions containing 350–750 p.p.m. calcium bicarbonate had no effect on the germination of zoosporangia or the activity of zoospores.Certain resemblances are noted between the control of crook root by calcium bicarbonate and the control of club root of brassicas by lime.
OBSERVATIONS ON THE INFECTION OF COX'S ORANGE PIPPIN APPLES BYGLOEOSPORIUM PERENNANSZELLER & CHILDS
Authors: EDNEY K. L. 
Published: February 2008

Conidia ofGloeosporium perennansgerminating on the surface of Cox's Orange Pippin apples in the orchard, produce a germ tube which generally swells to form a thick‐walled appressorium. If the underlying tissues are not suberized the appressorium then produces an infection thread which penetrates the wall of the epidermal cell. If the underlying tissue is suberized no infection thread is formed. Subsequent rotting takes place either by penetration via a point of weakness in the suberized layer of cells across the lenticel as in Cox's Orange Pippin or by direct invasion of this layer as in the variety Sunset. Some lenticels have been observed where the suberized layer has not formed.Fruit infected in August and September rots at a greater rate than fruit infected in June and July of the same year. In years when susceptibility to rotting is high, infections initiated in July may develop more rapidly than those initiated later in the season in a year when susceptibility to rotting is relatively low. The rate of rotting has been found to increase with the size of fruit.
THE ADAPTATION OF FUNGI TO FUNGICIDES: ADAPTATION TO CAPTAN
Authors: PARRY K. E. , WOOD R. K. S. 
Published: February 2008

In sucrose‐nitrate liquid media Botrytis cinerea was able to grow from spores when the media contained captan at concentrations up to three‐quarters of the saturation value. Because of this, and the low water solubility of the fungicide (< 1 p.p.m.) all attempts to produce resistant strains were made with agar media.Spores did not germinate when applied as a suspension in water to the surface of a sucrose‐nitrate agar containing 500 p.p.m. captan; about 1% germinated when the concentration was 250 p.p.m. Similar results were obtained when an agar extracted with water and pyridine was used. There was some growth from spores on agar containing 250 p.p.m. captan; this always started at the edge of the agar.Resistant strains were produced when disks were transferred from cultures growing on agar containing low concentrations of captan to agar containing higher concentrations. By repeating this process over a period of months a strain was produced eventually which grew slowly but continuously, and sporulated on agar containing 250,000 p.p.m. captan. However, the very low solubility of the fungicide made it difficult to assess quantitatively the degree of adaptation. Although agar disk inocula from resistant strains retained their resistance on transfer to captan agar, inocula consisting of suspensions of spores only, or of hyphae and spores, were no more resistant than the parent strain. The resistant strain retained the first type of resistance after it had been grown on fungicide‐free media for four periods of 2 weeks.Spores from the resistant strain were more resistant than spores from the parent strain in germination tests with drops on glass slides; a concentration of 0·6 p.p.m. captan prevented germination of parent spores, but one or two spores out of a total of some 4000 spores of the resistant strain germinated at concentrations of 100 p.p.m. This type of resistance, transmissible by spores, was reduced when the resistant strain was grown on fungicide‐free agar.Spores from resistant strains had a very low viability, although they were produced normally and were normal in size and appearance; when obtained directly from a culture on a captan medium only 2% germinated whereas in similar conditions there was 100% germination of parent spores. Viability was increased to 13% after one transfer on a fungicide‐free medium but was no more than 52% after four transfers.Preliminary attempts to obtain strains of Venturia inaequalis resistant to captan were unsuccessful.The significance of the results obtained is discussed.
BROWN ROOT ROT OF TOMATOES: II. THE FUNGAL FLORA OF THE RHIZOSPHERE
Authors: EBBEN M. H. 
Published: February 2008

The fungal populations of soil and of the rhizosphere of tomatoes in steamed, fallowed and unsteamed plots were compared. Steaming greatly reduced the numbers of fungi in the soil, but fallowing had little effect. Soil bacteria were greatly reduced by steaming but increased to the level in the unsteamed plots after heavy watering. Outer rhizosphere fungal populations in unsteamed plots in July were larger than in the steamed plots, but by October this difference had disappeared, although roots in the unsteamed soil showed the greater development of disease.Root surface counts indicated that the populations on actively growing roots in July in steamed and unsteamed plots reached similar levels, and there was a slight fall in numbers in both types of plot in October. Fungal infection of roots increased noticeably in unsteamed plots between July and October, although root surface numbers showed a decrease.Of the fungal species isolated Colletotrichum atramentarium showed a distribution between soil and root surface which suggested that it was a root inhabiting fungus. Cephalosporium spp. were also found on the root surface and in roots, especially those from steamed soil.
SOME PROPERTIES OF THREE VIRUSES ISOLATED FROM A DISEASED PLANT OF SOLANUM JASMINOIDES PAXT. FROM INDIA
Authors: BADAMI R. S. , KASSANIS B. 
Published: February 2008

Three mechanically transmissible viruses were isolated from a diseased Solanum jasminoides plant obtained from India. One is a strain of potato virus Y, which in some potato varieties produces symptoms resembling those caused by potato virus C, but unlike potato virus C it is readily transmitted by Myzus persicae. The second, named tobacco wilt virus, is also transmitted by M. persicae but much less readily, whereas the third, named datura necrosis virus, is not. All three have a wide host range, but neither tobacco wilt nor datura necrosis viruses infects potato plants. All three have long flexuous particles and similar general properties.Simultaneous infection with datura necrosis virus usually decreases the concentration reached by potato virus Y in tobacco plants but not in Nicotiana glutinosa.
SUSCEPTIBILITY OF LARVAE OF THE LARGE WHITE BUTTERFLY (PIERIS BRASSICAE L.) TO TWO VIRUS DISEASES
Authors: SIDOR Ć. 
Published: February 2008

A cytoplasmic polyhedral virus ex Phalera bucephala (L.) induces a polyhedrosis in some stocks of Pieris brassicae (L.). Larvae from different localities vary in their susceptibility to their own viruses and the stock of Pieris brassicae larvae most susceptible to its granulosis is also more susceptible to the polyhedrosis.Polyhedra obtained from Pieris brassicae, infected from Phalera bucephala, did not cause a cytoplasmic polyhedrosis in larvae of Plutella maculipennis (Curtis) and Pseudaletria unipuncta (Haw.), but did do so in the larvae of Lymantria monacha (L.).