bluuebunny/crossref_metadata_2025_split huggingface dataset:
STUDIES ON THE BEAN APHID (APHIS FABAE SCOP.) AND ITS CONTROL ON FIELD BEANS
Authors: WAY M. J. , SMITH P. M. , POTTER C. 
Published: February 2008

Field trials on chemical control of Aphis fabae Scop, attacking spring‐sown field beans were carried out during the years 1950–2. The insecticide sprays were applied once only, soon after primary aphid migration into the bean crop had ceased. Destruction of the few aphids present at this early date stops build‐up of the big populations that often develop later.An 0.02% (w/v) parathion spray was used in all three field trials. This gave excellent control of A. fabae as did the systemic insecticides Isopestox and Systox at 0.05% (w/v) active ingredient, and nicotine at 0.1% (w/v). Sprays containing allethrin (0.05% (w/v) pure material), pyrethrins (0.05% and 0.02% (w/v) total pyrethrins plus piperonyl butoxide) and an 0.1 (w/v) DDT emulsion gave moderate control. A. fabae was not controlled in plots treated with an 0.1% (w/v) DDT crystalline suspension, and the aphid population reached a higher peak than in the untreated plots; the suspension is not only relatively ineffective against the aphid, but is more toxic than the DDT emulsion to its Coccinellid predators.On the bean plant the 0.05% (w/v) Systox spray showed some residual toxicity to A. fabae for at least 5 days after application, but stopped causing 100% kill within 24 hr. 0.02% (w/v) parathion and 0.1 (w/v) DDT emulsion had slight, and 0.02% (w/v) pyrethrins and 0.1% (v/v) nicotine, no residual toxicity.In the year 1950, aphid attack on the field plots was slight and damage insignificant. In 1951, there was a moderate attack and the yield of bean seed was significantly increased by all insecticidal treatments; where aphid control was most efficient (parathion and Isopestox treatments) the yield (16.7–17.1 cwt./acre) was about × 2.7 that of the untreated control (6.3 cwt./acre). In 1952, there was severe aphid attack, and the mean seed yield of the untreated control plots was 1.4 cwt./acre. Plots treated with the DDT suspension yielded 1.3 cwt. seed/acre, but all other insecticides, including the DDT emulsion, increased the seed yield to 10.3–14.8 cwt./acre.All preparations used in 1952, except nicotine, were destructive to adult Coccinellid predators of A. fabae; Adalia bipunctata was more susceptible than Coccinella septempunctata. However, in 1952, predators on the experimental area were too uncommon to be economically important.
EXPERIMENTS ON SPRAYING WITH DDT TO PREVENT THE FEEDING OF SCOLYTUS BEETLES ON ELM AND CONSEQUENT INFECTION WITH CERATOSTOMELLA ULMI
Authors: PEACE T. R. 
Published: February 2008

Experiments were done for three years on street elms at Folkestone and Aldenham to repeat American work on the use of insecticidal sprays to prevent feeding by Scolytus beetles, which carry Ceratostomella ulmi, the cause of elm disease. Although the fungus can remain alive in the older annual rings of an infected tree, active disease usually results from fungus freshly introduced by Scolytus. Thus spraying is of value on infected, as well as uninfected elms.The results of the experiments supported American conclusions that DDT was superior to benzene hexachloride. A 1.5% solution of DDT in miscible oil gave reasonably good, but not perfect, control, and was much superior to solutions made from DDT in the form of a dispersible powder.Spraying of trees 20–30 ft. high cost over £1 per tree per year, which is considered prohibitive, except for small trees of special amenity or sentimental value.
THE DIFFERENT DISTRIBUTION OF TWO BRASSICA VIRUSES IN THE PLANT AND ITS INFLUENCE ON SPREAD IN THE FIELD
Authors: BROADBENT L. 
Published: February 2008

Previous knowledge provided no explanation for the greater prevalence of cauliflower mosaic than of cabbage black ring spot in field crops of cauliflower. Both viruses are spread principally by Myzus persicae and Brevicoryne brassicae, and both are transmitted equally readily from infected seedlings. Cabbage black ring spot virus has a much wider host range, and sap from infected leaves has a higher dilution end‐point than sap from leaves infected with cauliflower mosaic virus.At least part of the difference between the rate at which the two viruses spread in the field may be accounted for by the different manner in which they are distributed in old infected plants, and the effect this has on transmission by aphids. Cauliflower mosaic virus occurs in high concentration in all the new leaves produced by infected plants. Cabbage black ring spot virus, on the other hand, occurs mainly in the older leaves, and even there is localized in parts that show symptoms. Only in recently infected plants does cabbage black ring spot virus occur in young leaves.After flying, most aphids alight on the upper parts of plants; they are therefore less likely to acquire cabbage black ring spot virus than cauliflower mosaic virus. It may be significant that cabbage, a host in which old leaves are in a more favourable position for alighting aphids than are those of cauliflower, is also often extensively infected with cabbage black ring spot virus.
THE SYSTEMIC INSECTICIDAL ACTION OF CERTAIN COMPOUNDS OF FLUORINE AND OF PHOSPHORUS ON PHAEDON COCHLEARIAE FAB.
Authors: DAVID W. A. L. , GARDINER B. O. C. 
Published: February 2008

Four compounds—bisdimethylaminophosphonous anhydride (schradan), bis(dimethylamino)fluorophosphine oxide (dimefox), diethyl paranitrophenyl phosphate (paraoxon) and sodium fluoroacetate (acetate)—have been tested against the mustard beetle, Phaedon cochleariae Fab. When the four compounds are compared by a direct contact technique in which insects can also imbibe some of the test solutions, or the insects are caged with foliage which has been dipped and then dried, the order of toxicity to adults and larvae was found to be Paraoxon > acetate ≏ dimefox > schradan.The paraoxon is very much more toxic than the other compounds. In all cases the adults are more resistant than the larvae.When the insecticides are applied systemically the order of toxicity changes to Paraoxon > dimefox > acetate ≏ schradan because the acetate causes the plants to wilt and less of it is absorbed. Both paraoxon and dimefox give complete kills of adult Phaedon which is the most resistant stage, at practical concentrations.When the insecticides were applied to the outer leaves and translocated to the inner untreated leaves an effect was observed with the dimefox and paraoxon after numerous application, but with a single application very inconsistent results were obtained.It is concluded that schradan and the acetate are ineffective systemically against Phaedon. The dimefox and paraoxon are very effective, but because of their high mammalian toxicity they would require very careful handling in practice.
STUDIES IN THE ANTAGONISM BETWEEN BLASTOMYCES LUTEUS AND SPECIES OF VERTICILLIUM
Authors: ISAAC IVOR 
Published: February 2008

Blastomyces luteus has been shown to be antagonistic in culture to both Verticillium albo‐atrum and V. dahliae over a wide range of temperature and irrespective of the pH value of the medium. When B. luteus is grown on Dox's and potato‐dextrose solutions it produces an exudate which, added to agar media, has an inhibiting effect upon the growth of these two species of Verticillium. The effectiveness of this inhibiting material is slightly reduced by boiling for 15 min.When ‘spent’ Dox's liquid medium, which has supported the growth of B. luteus, is injected into tomato and antirrhinum seedlings inoculated with Verticillium no control of the disease is effected, but when B. luteus mycelium is added to soil infected with Verticillium, marked reduction in the incidence of disease results when the antagonistic organism and the pathogens have co‐existed in the soil a sufficient length of time for the exudate of the former to be effective upon the development of the latter.
THE EFFECT OF TIME OF APPLICATION OF NITROGENOUS FERTILIZER ON POWDERY MILDEW OF WINTER WHEAT
Authors: LAST F. T. 
Published: February 2008

Applying nitrogenous fertilizer (N) to wheat plants of different ages affected the incidence of powdery mildew, Erysiphe graminis DC, differently. When N was applied before the flag leaf had emerged, the infection‐index (number of pustules per 100 sq.cm. of leaf blade) increased to a maximum and then declined. If N was applied after the flag leaf had emerged, the infection‐index increased steadily without reaching a peak, and the increased susceptibility was not associated with an increased relative leaf growth rate as when N was applied earlier.The integral of the number of pustules per unit area with time, and the number of perithecia on the leaves of the main stem, both increased with increasing delay in the application of N. Plants given N in either April or May had at least three times as many pustules as those given N in January. The time when N was applied did not affect the date when perithecia appeared.After adding N to nitrogen‐deficient plants, the already mature leaves which had resisted mildew infection, became susceptible. This change is not associated with changes in the epidermal wall.
INVESTIGATIONS ON RESISTANCE TO DISEASE AMONG SPECIES OF THE GENUS AVENA
Authors: WILLIAMS WATKIN , VERMA U. N. 
Published: February 2008

Fifty‐three samples representing species of the genus Arena were tested for resistance to infection by Ustilago avenae and U. kolleri following artificial inoculation. Among the diploid and tetraploid species tested, eleven out of thirty‐seven samples of Arena strigosa subsp. strigosa showed complete resistance to all the cultures with which they were inoculated. Avena strigosa subsp. barbata (three samples), and Avena strigosa subsp. abyssinica (one sample), also proved to be resistant to all the available races.Variation in morphological and physiological characteristics within species and samples (varieties?) of the lower chromosome groups of Avena were observed and its consequences in breeding and race identification discussed.Race identification was carried out on the eight Ustilago cultures and the existence of at least six races established. The tester varieties used in the present study proved inadequate for the complete separation of the smut races.
DRY‐ROT DISEASE OF THE POTATO
Authors: McKEE R. K. 
Published: February 2008

Inoculation of wounded tubers at intervals throughout the storage season showed that, after harvesting, resistance to infection by F. avenaceum was maintained for a longer period than resistance to F. caeruleum, although eventually the tubers became equally susceptible to both fungi. Tubers were less readily infected through clean‐cut than through scarified wounds. Resistance to infection was greater when an interval elapsed between wounding and inoculation than when the wound was inoculated immediately; this was related to an increase in the intrinsic ability of the cells near the wound to resist infection rather than to suberization of the wounded surface or wound periderm formation.Histological studies showed that F. caeruleum grew through the intercellular spaces and that the adjacent host cells remained alive, often for considerable periods, whereas F. avenaceum killed and penetrated the cells with which it came into contact. Restriction of incipient or established lesions caused by F. caeruleum and of incipent lesions caused by F. avenaceum was associated with suberin deposition on the host cell walls and in the intercellular spaces; in established lesions caused by F. avenaceum, restriction was attributed to an increase in the intrinsic resistance of the adjacent host cells, similar to that found near a wounded surface.
HEAT‐THERAPY OF VIRUS‐INFECTED PLANTS
Authors: KASSANIS B. 
Published: February 2008

Virus‐free plants were produced from parents systemically infected with the following five viruses: tomato bushy stunt, carnation ring spot, cucumber mosaic, tomato aspermy and Abutilon variegation. The leaves formed while the infected plants were kept at 36°C. were free from symptoms, and test plants inoculated from these remained uninfected. When cuttings were taken from the infected plants at the end of the treatment most grew into healthy plants. The treated plants themselves usually developed symptoms after varying lengths of time at 20°C, but some that before treatment were infected with tomato aspermy, cucumber mosaic or Abutilon variegation viruses, remained permanently healthy.The same method failed to cure plants infected with tomato spotted wilt, potato virus X and tobacco mosaic virus, although it decreased their virus content. Heat‐therapy seems not to be correlated with the thermal inactivation end point of the virus in vitro.
THE ABSORPTION, TRANSLOCATION AND BREAKDOWN OF SCHRADAN APPLIED TO LEAVES, USING 32P‐LABELLED MATERIAL
Authors: BATT R. F. , BENNETT S. H. , THOMAS W. D. E. 
Published: February 2008

The methods of propagation of plant material for experimental use, the procedure for preparing the radioactive solution, and its application to leaves either by dipping or spraying are described.A description is given of the conditions under which the plants were kept, the procedure adopted at sampling involving leaching of the treated leaves, subdivision of the plant and preparation of samples for determination of ‘schradan’ and ‘schradan equivalent’ by liquid counting.The methods of compiling results to determine the distribution and status of the applied schradan in or on the leaves at harvest, are outlined.
THE BIOLOGY AND CONTROL OF OTIORRHYNCHUS CLAVIPES BONSD. (RHYN. COLEOP.), A PEST OF STRAWBERRIES
Authors: IBBOTSON ALAN , EDWARDS C. A. T. 
Published: February 2008

Otiorrkynchus clavipes Bonsd. is a serious pest of strawberries around Cheddar, Somerset. The weevils nibble the foliage, the larvae eat the roots of the plants, and burrow into the rootstock.The beetles appear in two waves, pupating in the autumn and emerging en masse in the spring, or pupating in the late spring and summer and emerging in succession between mid‐June and the end of August. Both sexes are found and can be distinguished by the posterior thoracic sterna, which are concave in males and convex in females. Mating is alternated with egg‐laying and the beetles lay between 100 and 300 eggs per female. On emergence the beetles eat voraciously, and roughly one egg is laid for every 10 sq.mm. of leaf consumed. Both parthenogenetic and fertile eggs are laid and hatch in between 17 and 24 days.The larvae burrow rapidly when hatched and can only penetrate soil spaces which will admit their head capsules. The distribution of head capsule widths in mixed populations of larvae of all ages shows there are five instars. While feeding, the larvae are clustered within the root range of the plants and find their way to their food from plant to plant, guided by the exudates from the strawberry roots. As the larvae grow older they descend in the soil and turn to white soft pupae in smooth earthen cells 6–8 in. below the plants.Adult damage to foliage is unimportant but larval damage to roots is serious and has been largely responsible for restricting the effective life of the strawberry beds to at most 2 years. Although weevil attack can be avoided by growing the crop in a 1‐year rotation, control is difficult owing to the intensive cropping, which creates the most suitable conditions for the spread of the infestations. The adults are killed with 10% DDT dust; and the larvae by DDT and BHC preparations poured on to the soil, at a pint per plant, or by DD injection. The limitations and possibilities of various methods of control are discussed.
A SURVEY OF WILD OATS (AVENA FATUA AND A. LUDOVICIANA) IN ENGLAND AND WALES IN 1951
Authors: THURSTON JOAN M. 
Published: February 2008

In 621 samples of wild oats, collected in England and Wales by N.A.A.S. and N.I.A.B. Officers, only two species (Avena fatua and A. ludoviciana) were found but both were very variable. A. fatua occurred in all wheat‐ and barley‐growing areas, in both winter and spring corn and on all soil types. A. ludoviciana occurred (with two exceptions) only within approximately 80 miles radius of Oxford, mainly on heavy soila and chiefly in winter corn.The amount of wild oats present appeared to depend on the frequency in the rotation of corn or other crops in which wild oats would shed seed. Deep ploughing often increased the infestation. The data did not show whether a field could be freed of wild oats by grassing down for a number of years, nor what is the maximum period of survival of buried wild oat seeds.
STUDIES ON THE SYNERGISTIC EFFECT OF PIPERONYL BUTOXIDE AND ISOBUTYLUNDECYLENEAMIDE ON PYRETHRINS AND ALLETHRIN
Authors: NASH RUTH 
Published: February 2008

Experiments are described to compare the toxicity of natural pyrethrins and allethrin, the completely synthetic homologue of cinerin I, and to show the effect of the two synergists, piperonyl butoxide and iaobutyl undecyleneamide (IN 930) on both these active ingredients, using a measured‐drop technique with Mucca domestiur L. the housefly, and a residual‐film technique with Cimex lectularius L. the bed bug. In the conditions of the experiment, pyrethrins were shown to be twice as toxic as allethrin to flies, and 5.5 times as toxic as allethrin to bugs. The two synergists were tested at several ratios to the two insecticides, ranging from 1 : 1 to 20 : 1. The results were plotted as series of log. concentration/probit regression linea. These were parallel for the bug tests; but in the fly tests, the slope of the line increased with a rise in the proportion of Synergist to insecticide. The estimated median lethal concentrations indicated, in all cases, that the toxicity increased with a rise in the ratio of synergist to insecticide, at least up to 20 : 1. However, the enhancement of toxicity was greatest for the smaller ratios and fell off as the ratio increased. Piperonyl butoxide was the more powerful synergist, increasing the potency of pyrethrins 5 times and allethrin 4 times to flies, and pyrethrins twice and allethrin 3 times to bugs, whereas IN 930 did not increase the potency of either ingredient more than twice to either test insect.The addition of piperonyl butoxide to residual films of pyrethrins greatly prolonged their effectiveness; but an experiment designed to investigate the effect of the synergist on the stability of this insecticide showed that this action, if it exists, must be slight.
PRELIMINARY STUDIES ON POTATO APHIDS IN NORTH AND NORTH‐EAST SCOTLAND
Authors: SHAW M. W. 
Published: February 2008

Studies of potato aphids made in the potato seed‐growing areas of north and north‐east Scotland during 1950‐3 showed that potato plants were first infested during July, but with few aphids; maximum populations did not develop until mid‐late August or early September, which is the period of potato haulm destruction in seed crops. Myzus persicae (Sulzer) was scarce in rural districts and most numerous near urban areas. The main influx of alatae occurred in early August. Aulacorthum solani (Kltb.) was the predominant species north of Inverness. Macrosiphum euphorbiae (Thomas) was present in small numbers in many potato fields, but Aphis nasturtii (Kltb.) was extremely scarce.Because of the small numbers of aphids found during two years by examining two or three compound leaves per haulm, it was preferable to count the aphids on one main stem and all its leaves.Stove‐pipe sticky traps provided information complementary to complete stem/leaf examination, but are considered to be of doubtful use in an area where aphids are few.
THE DEVELOPMENT OF LARGE SUCTION TRAPS FOR AIRBORNE INSECTS
Authors: JOHNSON C. G. , TAYLOR L. R. 
Published: February 2008

Small suction traps for estimating the density of airborne insects, and its fluctuations, in relatively sheltered situations, e.g. in crops, have already been designed and used.Larger, more powerful traps have now been developed for use in more exposed situations where insect densities are very low, or where winds are relatively strong, e.g. high in the air. Because of the large sample obtained they also enable very short‐term density fluctuations to be followed.The radical modifications of design and the special problems encountered in the operation of very large traps are described.
THE LOSS OF WEIGHT OF PYRETHRIN‐TREATED FLOUR BEETLES, TRIBOLIUM CASTANEUM (HERBST), AND ITS APPLICATION TO BIOASSAY
Authors: HEWLETT P. S. , GOSTICK K. G. 
Published: February 2008

Pyrethrin‐treated flour beetles, Tribolium castaneum (Herbst), lose weight rapidly. The weight lost by batches of beetles, a readily determined graded response, has been investigated with a view to its use in bioassay. Strong evidence was obtained that (1) in pyrethrum extracts only the pyrethrins cause the loss, and that (2) the other extractives do not modify the loss caused by the pyrethrins. Allethrin also caused a rapid weight loss; piperonyl butoxide, by itself producing little loss, greatly increased the loss caused by pyrethrum solutions and by allethrin, paralleling its effects on toxicity. The pyrethrin content of solutions appeared to account quantitatively for their weight‐reducing activities; irradiation of pyrethrum solutions that destroyed their toxicity also destroyed their weight‐reducing properties; and neither pyrethrum oleoresin heat‐treated to destroy the pyrethrins, nor irradiated solutions, modified the weight loss due to allethrin.Factors influencing weight loss were investigated. Beetles were exposed, mostly for 3 hr. at 25°C., on hard filter‐papers treated with solutions of pyrethrins in a non‐volatile oil (Shell Risella oil 17, formerly called P31). At fixed deposit the loss rose sigmoidally with increasing pyrethrin concentration from about 0.7 % for zero concentration to an upper limit of about 6.5 % of initial beetle weight. A log‐logit transformation made the sigmoid curve linear. The carrier oil and the length and temperature of the exposure to the pyrethrins influenced the weight loss. At 25°C, the rate of air movement and the relative humidity between 40 and 90% did not. Pyrethrins in Risella oil 17 could be applied satisfactorily to the filter‐papers by means of a spraying tower, or by pipette if the solutions were first diluted with a volatile solvent, which was allowed to evaporate subsequently. Deposits of given pyrethrin content were about 1.3 times as active in producing a weight loss if prepared by spraying than if prepared by solvent evaporation.The technique, design, and analysis of results, for bioassays based on weight loss are described. The most elaborate method of analysis ever likely to be needed is given, with a worked example, but a considerably simpler method, only slightly longer than the probit analysis for quantal‐response assays, would probably suffice normally.For a given number of beetles used, the weight loss method of assay has about the same inherent precision as the film method of Parkin & Green (1943), but is less precise than the direct spray method of Hewlett (1947). However, larger numbers of beetles can be used in the new method, the assessment of the insecticidal effect is more objective, and results are obtained more quickly y‐BHC and DDT cause T. castaneum to lose weight less rapidly than do pyrethrins.
A FURTHER STUDY OF THE TOXICITY OF POTASSIUM CYANIDE TO RAINBOW TROUT (SALMO GAIRDNERII RICHARDSON)
Authors: HERBERT D. W. M. , DOWNING KATHLEEN M. 
Published: February 2008

The distributions of the periods of survival of individual rainbow trout in solutions of potassium cyanide are asymmetrical and approximately log‐normal within the range of concentration where the relation between log time and log concentration is linear, whereas they are symmetrical and approximately normal at higher concentrations.Some inherent, persistent features possessed by the fish influence survival time in both the higher and lower ranges of concentration, but other such features exert a significant influence only in the lower concentrations.Some of the features influencing survival time in the lower concentration range only, are associated with body size.