bluuebunny/crossref_metadata_2025_split huggingface dataset:
Further investigations on the biology and control of the carrot fly (Psila rosae F.)
Authors: Petherbridge F. R. 
Published: February 2008

Records were obtained for the emergence of the first and second generation flies at Chatteris and Cambridge. There is a correlation between the age of the carrot crop and the commencement of the emergence of the second generation from it. The first generation was successfully controlled by killing the flies with a poison bait sprayed on the dikesides of the carrot fields. This treatment reduced the popúlation of second generation flies and also their attack. Spraying the dikesides and/or the headlands of eight maincrop carrot fields in August and September greatly reduced the second generation damage. Very high kills of carrot fly were obtained on the headlands of treated fields. Poor results were given by the treatment on three very weedy fields which were incompletely treated. A marked increase in attack occurred in three untreated areas in 1942 as compared with the previous year.Application of the poison bait spray in the field is discussed. Creosote‐treated string gave promising results in small‐scale experiments for the control of the second generation. Calomel dust (4°) with and without grass cuttings caused no reduction in attack.In hot sunny weather the flies shelter in the vegetation around carrot fields from about 10 a.m. until about 5 p.m. In the cooler conditions of early morning and evening there is a movement of flies into the field. This rhythm is not maintained in dull warm weatherSeedling carrots may be attacked in the field any time after the cotyledon stage. This enables the first generation of flies to propagate on main crop carrots. Soil sections about carrot rows showed that pupae of the overwintering generation are closely congregated around the carrots. Various insecticides were tested for the destruction of pupae in the soil. A creosote‐sawdust mixture gave the best results.Storage experiments showed that clamped carrots deteriorate much less than those unlifted. The population of flies is greatly increased by allowing attacked carrots to remain unlifted throughout the winter or by ploughing in.
Mould deterioration of feeding‐stuffs in relation to humidity of storage: Part I. The growth of moulds at low humidities
Authors: Snow D. , Crichton M. H. G. , Wright N. C. 
Published: February 2008

The literature relating to the growth of moulds at different humidities is surveyed.Observations were made on the development of mould growth on six widely different types of feeding‐stuffs for storage periods extending over some 3 1/2 years. The main factors controlling mould growth were found to be:1. The relative humidity rather than the moisture content of the food.2. The length of the storage period. Mould growth took place relatively quickly on all feeding‐stuffs stored at 100‐75% R‐H. Below 75% R.H. mould growth, while not prevented, only developed after a very prolonged latent period. Mould development was observed on locust beans exposed to a humidity as low as 65 % after a latent period of over 2 years.3. The balance and type of nutrients provided by the various feeding‐stuffs was shown to influence the latent period as well as the extent of mould deterioration. This was confirmed by experiments on artificially dried grass fractions and by experiments on starch, protein and fibre mixtures.4. The temperature of storage was found to affect the rate of mould development; mould growth developed sooner on samples stored at 22d̀C. than at 15.5d̀C.5. The type of mould species present. At high humidities all mould species grew rapidly: at low humidities, only a few types were capable of growth.
Mould deterioration of feeding‐stuffs in relation to humidity of storage: Part II. The water uptake of feeding‐stuffs at different humidities
Authors: Snow D. , Crichton M. H. G. , Wright N. C. 
Published: February 2008

The water uptake of a wide variety of feeding‐stuffs was determined over a range of fixed humidities. It was shown that the level and shape of the water uptake curves are closely related to the amounts of soluble carbohydrate and protein present. Fibre exerts a depressing effect on the water uptake, while the value is also lowered by the presence of inert fats and non‐hygroscopic ash constituents. These conclusions were confirmed by direct experiments on the water uptake of samples of pure starch, protein and fibre.The results of the investigations have enabled safe limits of moisture content to be laid down, for both short‐ and long‐period storage, below which mould growth will not normally take place. These limits vary for each individual feed, representative figures being included in the paper in tabular form.
Inert dust insecticides: Part I. Mechanism of action
Authors: Alexander P. , Kitchener J. A. , Briscoe H. V. A. 
Published: February 2008

The mode of action of inert dust insecticides on the grain weevil (Calandra granaria L.) has been investigated by determination of mortality‐time curves and by a detailed study of the influence of dusts on the water relations of the insects. It has been found that dusts do not depend for their action on any chemical reactivity, some highly inert substances such as diamond and carborundum being very effective. A physical process is therefore indicated.Dusts do not penetrate into the respiratory system, and although large amounts are ingested these seem to have little harmful effect.It has been demonstrated that effective dusts increase the rate of evaporation of water from insects to the air, and that the relative killing powers of different dusts run parallel with their capacities for promoting evaporation. The results are in harmony with the view (proposed by earlier workers) that inert dusts kill insects by inducing death by desiccation.
Factors influencing the development of cotton diseases
Authors: Ling Lee 
Published: February 2008

The observations and experiments reported in the present paper were carried out in Suinin, Szechuan Province, West China, through the period 1938‐41. Under local conditions, the incidence of most cotton diseases was observed to be influenced chiefly by air humidity. No matter whether it attacks the seedlings, mature plants, or bolls, such a disease requires a humid condition preceding the occurrence of an epidemic. For sore shin disease, soil moisture and soil temperature, however, have a more profound influence. Cyrtosis, which is a disorder caused by leafhopper injury, responds to the climatic factors in a different way. During the period of rapid reproduction of the leafhopper, higher temperatures result in the earlier appearance of the disease, while heavy rainfalls reduce the intensity.Modification of the environmental conditions by varying the time of sowing influences the incidence of diseases occurring in both the seedling and mature stages of the cotton plant. Among seedling diseases, anthracnose is further proved to be influenced chiefly by air humidity in its prevalence. Sore shin disease, on the other hand, requires a moist soil condition for its spread and development. In the mature plant, late sowing increases the intensity of cyrtosis but reduces that of bacterial blight and anthracnose.Modification of several cultural practices was also tested. Nitrogenous fertilizers generally increase the incidence of most diseases. Denser stand and closer spacing bring about a heavier infection in stem and leaf diseases but not in boll diseases. A mixed cropping system appears to have no effect on the fungal and bacterial diseases but reduces the intensity of cyrtosis when the crop interplanted with cotton is not susceptible to the infestation of leafhopper.
Diseases of the gladiolus: I. Control of hard rot, due to Septoria gladioli Passer., by fungicidal treatment of the corms
Authors: Hawker Lilian E. 
Published: February 2008

Losses from hard rot, measured by an arbitrary disease index, were reduced by treating the dehusked corms before planting with mercuric chloride (with or without the addition of 10% hydrochloric acid), mercurous chloride (calomel), three proprietary mercury compounds (Aretan, Uspulun and Ceresan) and one proprietary non‐mercury compound (Folosan). Calomel was the least effective. All the treatments were relatively less effective when corms with definite lesions were treated.The weight of clean corms produced per old corm planted (weight index) was usually increased by all the fungicides tried, but calomel and Ceresan were less satisfactory than the others.Mercuric chloride (3 hr. steep in a 0.1% solution) was not rendered more effective by the addition of hydrochloric acid nor by a preliminary dip in methylated spirits to facilitate wetting, while the addition of a proprietary wetting compound (Agral) was definitely harmful to the corms and usually less effective than mercuric chloride alone. Increase in time of steeping or concentration of mercuric chloride was not beneficial and was sometimes harmful. Reduction in time of steeping to 1 hr. gave promising results.Treatment in November had some advantages over treatment in March.All the mercury compounds tended to delay flowering, this being most marked in the presence of the wetting compound. Stunted foliage and poor quality flowers resulted from the use of Ceresan.
Dry rot of potato [Fusarium caeruleum (Lib.) Sacc.]. Investigation on the sources and time of infection
Authors: Small T. 
Published: February 2008

Inoculation with soil samples proved that the fungus causing dry rot is frequently present in field soils in Cheshire and in soil adhering to imported seed tubers. The fungus was viable in soils having a wide range of pH values and in fields which had not grown potatoes for 5‐6 years. Other sources of infection include lofts, used sacks, seed boxes, diseased tubers, and knives used for cutting seed potatoes.Bruised tubers stored in heavily contaminated boxes developed much dry rot; far less disease occurred in unbruised tubers. In boxes containing own‐saved seed, healthy tubers in contact with diseased ones remained sound. Bruised tubers in contact with, or contaminated by, diseased tubers contracted dry rot. Cutting seed with a contaminated knife increased the disease seven‐fold.Inoculation of tubers attached to the parent plant showed that little or no infection occurred before lifting. In field trials severe dry rot developed in several varieties 6‐8 weeks after lifting.The results are discussed in relation to seed treatment.
The ‘phloem necrosis’ virus disease of tea in Ceylon II. Field observations and effect on yield
Authors: Bond T. E. T. 
Published: February 2008

After a brief discussion of the methods and accuracy of diagnosis of the ‘phloem necrosis’ disease in the field, the results of plot records taken over a number of years are presented. These are compared with the figures supplied from estates for the removal of non‐productive diseased bushes, which is undertaken as a routine measure of control and regeneration of affected fields. Taking all the evidence together a frequency of at least 25% diseased bushes is suggested for the aggregate acreage of tea above 6000 ft. At lower elevations no reliable estimate is possible.Despite the pronounced effect on individual bushes there appears to be no general tendency for the yield of affected estates to decline. Two estates, believed to be representative, are dealt with in which a decline in yield occurred from 1929 to 1930, followed by a recovery some 4 or 5 years later. The fields judged to be most heavily affected in each of the two properties, respectively, show a decline in yield relative to the estate as a whole, not exceeding 19 1b. made tea per acre per annum, which is only 33% of the mean yield during the last 10 years. The great variability in individual bush yields is stressed, and the conclusion is drawn that the elimination of unproductive bushes and their replacement by supplies of a type which, so far, has remained unaffected (although possibly ‘carrying’ the virus) will more than counteract the effect of the continued and gradual deterioration of the necrotic bushes remaining.The distribution of diseased bushes in the field is irregular, and records from observation plots have mostly given positive results on examination by Cochran's geometric series ‘aggregation’ test and the X2 test for ‘neighbour infection’. The rate of spread of the disease in the different areas is highly variable, and doubling of the incidence of infection may occur in periods ranging from 3 1/2 to less than 1 year. Two ‘rogueing’ experiments are described, the results of which lend further emphasis to the importance of bush‐to‐bush spread. The course of the disease in these experiments has been expressed by means of the Verhulst‐Pearl logistic curve, whence it appears that complete rogueing of all ‘necrotic’ and ‘suspected’ bushes at 6‐monthly intervals has reduced the rate of spread to about one‐third of the value for the unrogued plots.
Influence of earthworms on larval emergence in the potato‐root eelworm, Heterodera rostochiensis Wollenweber
Authors: Ellenby C. 
Published: February 2008

Hatching experiments were carried out with potato‐root eelworm cysts (a) from plant pots containing different numbers of earthworms, and (b) from worm casts. Cysts from these sources differed from controls in the following ways: (1) more larvae emerged, per cyst; (2) the larvae emerged sooner; (3) more cysts produced larvae; (4) the number of emerging larvae, per cyst, increased with the number of earthworms.Examination of the contents of cysts isolated from worm casts showed that, compared with controls, 145% more eggs hatched; it also indicated some of the limitations of the ‘per‐cyst’ basis of expressing results.
The behaviour of mercury compounds in soil*
Authors: Booer J. R. 
Published: February 2008

The uses of inorganic compounds of mercury for the control of plant pests is reviewed, and a summary of the relevant chemical and physical properties of the compounds concerned is given. On chemical evidence a working hypothesis is propounded showing that all compounds may be expected to decompose into metallic mercury.A pot technique is described by means of which a correlation can be obtained between the effective mercury content of a given soil sample and the rate of growth of wheat seedlings. The mathematical treatment of the results is described, and the validity of the pot technique is verified by statistical analysis of results. Using the pot technique it is shown that volatilization losses are insignificant but that mercury is slowly rendered ineffective by the formation of mercuric sulphide. The effect of sulphur‐reducing bacteria is considered and the influence of Vibrio desulpkuricans on mercury is studied in detail.Experimental evidence obtained by the pot technique is produced to show that mercurous chloride slowly decomposes in the soil giving mercury and mercuric chloride, mercuric chloride rapidly decomposes into mercury and mercurous chloride, and other inorganic compounds decompose directly into mercury. The working hypothesis is substantiated in all major aspects.The uses and properties of the organo‐mercury compounds are then discussed. Type compounds selected are ethyl mercury phosphate, phenyl mercury acetate and methoxyethyl mercury acetate.Using the pot technique it is shown that the formation of organo‐mercury clays takes place and that these clays decompose giving metallic mercury. A mechanism is suggested.
Black scurf and stem canker of potato (Corticium Solani Bourd. & Galz.): Further field studies on the use of clean and contaminated seed potatoes and on the contamination of crop tubers
Authors: A.R.C.S. T. Small, Ph.D., 
Published: February 2008

Black scurf and stem canker of the potato were investigated in field trials in contaminated soil at Warburton, Cheshire, to determine the effect of planting clean and contaminated seed (vars. Arran Banner and Majestic) on crop yield and on the contamination of the crop tubers.Black‐scurf contamination was prevalent on crops grown from clean seed and was not significantly different from that occurring on plots planted with contaminated seed. It was severe on early‐dug tubers, but was more severe on late‐dug tubers. Produce grown with and without stable manure was heavily contaminated.Contaminated seed caused a check to tuber formation and an appreciable increase in stem canker and in the number of primary shoots killed. Nevertheless, the yields from the manured, contaminated seed plots were satisfactory and were not lower than those from the clean‐seed plots. There was no relation between the yield and the amount of black scurf on the produce.The results of a trial made in a field which had been in grass for at least 43 years, suggested that the soil contained little, if any, Corticium Solani. Heavy contamination occurred on tubers grown under relatively dry soil conditions.In all the trials misses and wilted shoots caused by Corticium were rare and there was no premature yellowing or death of the haulms on the clean or contaminated seed plots.The evidence obtained in the four seasons from 1941 to 1944 indicates that in this country satisfactory yields of early maincrop and maincrop varieties may be obtained despite the prevalence of C. Solani in the soil and on the seed, provided the soil and cultural conditions are reasonably good.
Experiments on the control of white rot (Sclerotium cepivorum Berk.) in onions
Authors: B.Sc. J. R. Booer, Ph.D., 
Published: February 2008

Experiments‐made during 1943 and 1944 on the use of mercurous chloride (calomel) for the control of Sclerotium cepivorum in spring‐sown onions are described. The application of 4% calomel dust to the seed drill at sowing time gave better results than seed treatment. 1 lb. of dust per 25 yd. of seed drill gave good disease control in bulb onions, and 1 lb./so yd. may suffice for salad onions.The relation between disease control and the effective mercury content of the treated soil is discussed.
The incidence and distribution of some diseases of the adult honeybee (Apis mellifera L.) in England and Wales
Authors: Butler C. G. 
Published: February 2008

Although epidemics of bee disease have been repoited in Europe for hundreds of years it was not until recent times that detailed notes on the incidence and distribution of one of these epidemics, the so‐called ‘Isle of Wight disease’ epidemic, were made.Since 1918 four complaints of the adult honeybee, acarine disease, Nosema disease, Amoeba disease and bee paralysis, have been recognized in this country.Surveys in England and Wales to determine the incidence and distribution of acarine disease, Nosema disease and Amoeba disease were carried out during the winters of 1941‐2 and 1943‐4. These surveys showed that none of these diseases is clearly confined to any definite areas of England and Wales. Acarine disease is, however, apparently more abundant in the west and south‐west; and Nosema disease appears to be most prevalent in Buckinghamshire, Hertfordshire, Middlesex and Surrey, and also has other areas of heavy infection in Leicestershire and Cumberland, Lancashire and Yorkshire.Sufficient cases of Amoeba disease have not yet been recorded for it to be possible to conclude that any one area is more heavily infected than another. It is estimated that approximately one out of every five or six of the colonies of bees in England and Wales is suffering from acarine disease. Less than 1% are likely to be suffering from Nosema or Amoeba disease. Bee paralysis is both common and widespread, but probably does little serious harm.
The prevention of seed‐borne diseases of flax III. The dusting, short wet and fixation methods of seed disinfection in relation to storage of the seed
Authors: Colhoun John 
Published: February 2008

Flax seed containing up to 10% of moisture was disinfected with a proprietary dry fungicide containing tetramethylthiuram disulphide (Nomersan) at the rate of 12 oz./cwt. of seed, and stored for periods of up to 18 months, without its germination being impaired.Experiments were made with samples of seed the moisture content of which, before treatment, varied within the range of 5‐8‐13‐2% and which were kept in a commercial store after disinfection. Treatments were carried out with an 8% solution of a soluble organo‐mercurial (Ceresan U. 564) at the rates of 0‐67 and 0‐9 gal./cwt. applied by the short wet method, and with an organo‐mercurial powder (Ceresan UT. 1875 A) at the rate of 12 oz./cwt. applied by the fixation method using 0‐9 gal. of separated milk per cwt. The results obtained show that treatment by either method has the effect of lowering the percentage of viable seeds during subsequent storage and that the higher the moisture content of the seed before treatment the earlier this effect becomes apparent. It is suggested that seed to be treated by the short wet method on a commercial scale should be dried to contain about 5% of moisture, that not more than 0‐67 gal./cwt. of liquid be applied and that the seed should not be stored for longer than 3 months after treatment. Following upon these suggestions, 10‐ton lots of seed were treated commercially by the short wet method using a Kontramix machine and no ill effects on the crop were observed.
Chemical changes in beech litter due to infection by Marasmius peronatus (Bolt.) Fr
Authors: Harris G. C. M. 
Published: February 2008

The chemical effect of Marasmius peronatus on beech litter is described, with particular reference to the ecological relation between fungus and substrate. Beech leaves, some infected, and others uninfected by this fungus, were analysed and the results compared.Analysis shows that a vital process involving loss of carbon is at work, and that the fungus decomposes lignin, converting it into soluble products by the action of exoenzymes. It is suggested that by this process it is contributing to conditions favourable for beech regeneration.The fact that this fungus can more successfully colonize hardwood litter (e.g. beech) than other types of substrate, is explained by consideration of its physiology.