bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE OLFACTORY BEHAVIOUR OF LUCILIA SPECIES (DIPTERA) UNDER NATURAL CONDITIONS
Authors: CRAGG J. B. 
Published: February 2008

Using an apparatus of the ‘two‐choice’ type under field conditions, it has been demonstrated that a wool‐factor forms an important part of the mechanism whereby female Lucilia sericata may be attracted to sheep. The ‘wool‐factor’ could not wholly be replaced by ammonium‐ or sulphydryl‐type attractants. L. sericata was strongly attracted by the combination of ammonium carbonate/indole with sheep wool but less strongly attracted when ethyl mercaptan/hydrogen sulphide was used with sheep wool. L. caesar and L. illustris, on the other hand, were not markedly responsive to the ammonium‐type attractants but were strongly attracted by the sulphydryl mixture used either alone or in combination with sheep wool.Temperature is an important element in the oviposition stimulus. The amount of oviposition by L. sericata was increased when substances known to induce oviposition were exposed at 30–40† C.Sheep wool kept moist and incubated at approx. 38† C. under field conditions for 3 weeks did not attract L. sericata and oviposition did not occur on such wool. This suggests that bacteria normally present on the wool fibre as distinct from the skin, do not play an important part in rendering sheep susceptible to blowfly attack.
LABORATORY STUDIES ON THE CHEMO‐SENSORY REACTIONS OF BLOWFLIES
Authors: CRAGG J. B. , COLE PATRICIA 
Published: February 2008

Attraction of various blowflies to sheep wool has been demonstrated under laboratory conditions using a choice‐chamber technique. The attractive factor in wool is intimately associated with the wool fibre for it does not disappear during storage and it is not completely removed by washing.Only female flies were attracted to wool. The highest degree of attraction was obtained from fertilized females which had daily access to meat. Even in the absence of fertilization and meat, attraction was not completely abolished.The species and strains tested can be placed in the following order in terms of strength of response to sheep wool: Lucilia sericata (British), L. cuprina (tested on damp floor)>L. sericata (Danish: country)> L. sericata (Danish: city), L. sericata (Australian) > L. illustris, L. caesar. No response was given by Calliphora vomitoria.The olfactory organs involved in the response to wool are mainly on the antennae but antennaeless L. sericata and L. cuprina with some tarsi removed were still able to show some response to wool provided that they were tested on a damp floor. In the course of testing the olfactory responses it was also shown that the main humidity receptors are present on the antennae.The existence of a ‘wool‐factor’ to which only certain strains of L. sericata and L. cuprina are specially sensitive offers a possible explanation for the greater efficiency of these species as myiasis‐producing forms.
SOME EFFECTS OF TANNIC ACID AND OF LEAF EXTRACTS WHICH CONTAIN TANNINS ON THE INFECTIVITY OF TOBACCO MOSAIC AND TOBACCO NECROSIS VIRUSES
Authors: THRESH J. M. 
Published: February 2008

The inhibition of infection by tobacco necrosis and tobacco mosaic viruses by tannic acid, and by extracts of raspberry and strawberry leaves, was associated with the precipitation of the viruses. Precipitation and inhibition were reversible, and infective virus was obtained from the precipitate formed between the viruses and tannins. Infectivity was fully restored by diluting mixtures of virus and tannin adequately and partially restored by adding alumina or nicotine sulphate.Viruses and tannins are thought to form non‐infective complexes, in which the virus and tannin components are held together by co‐ordinate linkages or hydrogen bonds.Macerating tobacco leaves infected with tobacco mosaic virus together with raspberry leaves greatly decreased the infectivity of the extracts; adding nicotine sulphate to the mixture of leaves before it was ground increased the infectivity, even though nicotine sulphate alone decreases the infectivity of tobacco mosaic virus. Even in the presence of nicotine sulphate, much of the virus was precipitated by substances from the raspberry leaves.Extracts of roots of Fragaria vesca plants, infected with a tobacco necrosis virus, were more infective when made by macerating the roots with four times their weight of buffer at pH 8 than when made without buffer. Various methods are suggested for facilitating the transmission of viruses from plants that contain tannin.
DETERMINATION OF THE RESISTANCE OF LOCUSTS TO DNC IN RELATION TO THEIR WEIGHT, AGE AND SEX
Authors: MacCUAIG R. D. 
Published: February 2008

Experiments have shown that the resistance of adults of the desert locust (Schistocerca gregaria) and the African migratory locust (Locusta migratoria migratorioides) to DNC applied as a contact poison to the ventral surface of the abdomen is directly related to their body weight, irrespective of age or sex.Varying the site of application of the insecticide had little effect on the susceptibility of the insects except when the dose was applied to the wings or femur, these being less effective sites of entry for the poison.Increasing the post‐treatment temperature from 25 to 36°C. had no noticeable effect on mortality, but the speed of action of the insecticide was much increased.
THE INFLUENCE OF STORED POLLEN AND OF COLONY SIZE ON THE BROOD REARING OF HONEYBEES
Authors: ALLEN M. DELIA , JEFFREE E. P. 
Published: February 2008

Four hundred and thirty records of the numbers of bees in honeybee colonies and of the amounts of brood and pollen present have been kept during various months of the years 1945‐53, and the data have been used to calculate total and partial regression coefficients showing the influence of stored pollen and of colony size on brood rearing throughout the year.It was found that pollen storage and colony size were correlated but that, even allowing for this, colony size and pollen both independently influenced brood rearing.The annual distribution of the total regression coefficients of brood on pollen was somewhat similar to the brood curve itself, rising from a minimum in October and November to a maximum in midsummer, while the partial regression coefficients showed less clearly marked but similar features.Both total and partial regression coefficients showing the influence of colony size on the amount of brood reared were also at a minimum in October and November, but reached their peaks in May.The quantities of brood present in these colonies at Aberdeen, Scotland, followed a pattern similar to that given by Nolan for colonies near Washington, D.C.
SOME SOIL FACTORS AFFECTING VERTICILLIUM WILT OF ANTIRRHINUM
Authors: ISAAC IVOR 
Published: February 2008

Variations in the application rates of chalk and superphosphate and the omission of all the fertilisers had no visible effect on the incidence of wilt caused by any of the five Verticillium species.he literature dealing with the influence of soil conditions upon the Verticillium wilt of a wide range of host plants is reviewed. It is shown that the species V. alboatrum, V. dahliae, V. nigrescens, V. nubilum and V. tricorpus vary inter se in their pathogenicity to Antirrhinum majus, and that their infectivity may be influenced by soil treatments. Thus, in pot cultures, the incidence of antirrhinum wilt induced by Verticillium dahliae and V. nigrescens was reduced by increasing sulphate of potash or ammonium sulphate; or by decreasing soil moisture. Very wet soil and heavy dressings of hoof‐and‐horn were the only conditions under which V. nubilunt and V. tricorpus induced wilt symptoms. Z7. albo‐atrunt was the most virulent species tested; none of the soil treatments decreased its pathogenicity.
FACTORS AFFECTING THE PATHOGENICITY OF BACTERIA TO POTATO TUBERS. I
Authors: MURANT A. F. , WOOD R. K. S. 
Published: February 2008

An isolate of Erwinia aroideae caused much more rotting of potato tubers than did isolates of Pseudomonas sp., Flavobacterium sp., and Pseudomonas syringae; filtrates from cultures of each of the bacteria in potato extract had about the same macerating activity. Pseudomonas sp. and P. syringae, but not Erwinia aroideae or Flavobacterium sp., were agglutinated in three different types of potato extract at the normal pH of potato tubers.Measurements of growth by turbidity and total count methods were compared. In undisturbed potato sap, Erwinia aroideae had grown much more after 12 hr. than had Flavobacterim sp. and Pseudomonas syringae. Erwinia aroideae also grew more rapidly than Pseudomonas sp., but in this case the difference was caused largely by a longer lag phase.The two species of Pseudomonas grew far less rapidly in potato sap cultures shaken hourly than in undisturbed cultures. Erwinia aroideae grew slightly more rapidly in disturbed culture. Measured by the total count method, growth of Flavobacterium sp. was better in undisturbed cultures, but the opposite result was obtained when growth was measured turbidimetrically.With a small inoculum, growth of Erwinia aroideae and of Pseudomonas sp. was delayed by as much as 3 days in potato sap sterilized by heat. This effect was not obtained with an inoculum twenty times bigger, with potato extract, or with sap sterilized by filtration.Potato sap reduced the macerating activity of preparations from each bacterium; oxidation of the sap had no further effect. Production of macerating enzymes by Flavobacterium sp. and Pseudomonas syringae, but not by Erwinia aroideae and Pseudomonas sp., was less in potato sap than in potato extract. Erwinia aroideae secreted macerating enzymes into potato sap much more rapidly during the first 12 hr. of growth than did Pseudomonas sp.The activities of filtrates from cultures of Erwinia aroideae and Pseudomonas sp. were higher at the pH of the culture at the time of sampling than at higher and lower values.The addition of CaCO3 to media apparently increased the pH optimum for macerating activity of Erwinia aroideae and, to a lesser extent, Pseudomonas sp. preparations.There was little difference in the toxicity of preparations of similar macerating activity from cultures of the four organisms.
MOULTING RHYTHM IN THE ALIENICOLAE OF APHIS FABAE SCOP. (HEMIPTERA: APHIDIDAE) IN THE FIELD
Authors: JOHNSON C. G. , HAINE E. , COCKBAIN A. J. , TAYLOR L. R. 
Published: February 2008

In a natural population of alienicolae of Aphis fabae Scop, on field beans in July 1952, the frequency of moulting of the last larval instar into the alate form was usually relatively high between about 04.00 and 08.00 hr. G. M. T. This high rate was followed by a decline to a lower fluctuating rate for the rest of the day. The moulting rate at night was usually very low.The high rate of moulting in the morning, just as the temperature is rising, may be due to acceleration of nymphal development which leads to a synchronization of moulting, much as teneral development of alatae, if accelerated, produces flight peaks during the day (Johnson, Taylor & Haine 1957): data on the relations of moulting and nymphal development to temperature are, however, insufficient for making a complete analysis along these lines.Changes in moulting rate during the rest of the day are correlated with temperature and with time, both independently. A rise of 1°C. ambient temperature is associated with an 11.6% rise in moulting rate: a fall of 1°C. with a drop of 10.5% and a lapse of 1 hr. in time by a 5.4% drop in the rate. Sunshine and humidity show no simple correlation with moulting rate.
THE PRODUCTION OF ANTIBIOTICS IN SOIL V. BREAKDOWN OF GRISEOFULVIN IN SOIL
Authors: WRIGHT JOYCE M. , GROVE JOHN FREDERICK 
Published: February 2008

When griseofulvin (I; R= Cl, R′= OCH3), a chlorine‐containing antibiotic produced by Penicillium nigricans, was added to fresh garden loam, after an initial lag it disappeared rapidly. When further griseofulvin was added it was inactivated from the start and at rates which increased with each successive addition, suggesting that it was degraded biologically. The numbers of one organism, a Pseudomonas sp., increased in the soil steadily after adding griseofulvin.When a little soil was added to a solution (pH 7·0) containing inorganic salts and griseofulvin as the sole carbon source, bioassays showed that the griseofulvin disappeared within 5 days. An organism isolated from the broth was identified as the Pseudomonas sp. thought to break down griseofulvin in soil. Griseofulvin also disappeared from a broth at pH 5·0 inoculated with soil, but at this lower pH value a dematiaceous fungus was responsible for its breakdown.The Pseudomonas sp. also degraded two derivatives of griseofulvin, dechlorogriseofulvin (I; R= H, R′= OCH3) and the amine (I; R= Cl, R′= NH2). Cl– was detected in the solutions after breakdown of griseofulvin by the Pseudomonas; the amount present agreed well with that calculated on the assumption that all the chlorine in the griseofulvin supplied was liberated as Cl–. Spectrophotometric examination of the solutions showed no metabolites with the aromatic ring intact, and confirmed the complete breakdown of griseofulvin suggested by the liberation of Cl‐.
THE PROPERTIES OF TOMATO ASPERMY VIRUS AND ITS RELATIONSHIP WITH CUCUMBER MOSAIC VIRUS*
Authors: GOVIER D. A. 
Published: February 2008

Chrysanthemum plants infected with tomato aspermy virus (TAV) produce severely distorted and discoloured flowers but show only slight leaf mottle.TAV infected twenty‐five of forty‐five species (belonging to seventeen genera) tested and was transmitted by the aphid species Aulacorthum solarti, Macrosiphoniella sanborni and Myzus persicae.Sap from infected tobacco leaves lost infectivity when diluted more than 1 in 10,000, when heated for 10 min. at above 65°C. and when stored for more than 42 hr. at 16–18°C.Partial protection was obtained between TAV and two strains of cucumber mosaic virus. Evidence was obtained that this was true protection between related viruses and serological tests confirmed the view that TAV is a strain of cucumber mosaic virus. Evidence was obtained that this was true protection between related viruses and serological tests confirmed the view that TAV is a strain of cucumber mosaic virus.
THE LINE‐PATTERN VIRUS DISEASE OF PLUMS
Authors: POSNETTE A. F. , ELLENBERGER CHRISTINA E. 
Published: February 2008

The disease, now usually called line‐pattern of plum, has been described under many names in most countries where plums are grown extensively.Naturally infected trees show widely differing Symptoms; this has two causes: (1) different varieties react differently to the same isolate of the virus, and (2) different isolates cause different symptoms in the same variety. Because the virus occurs in strains with different pathogenicities, the choice of indicator varieties is important when selecting virus‐free material by transmission tests. Peach seedlings and the mazzard clone, F 12/1, were the most sensitive types found.The line‐pattern virus does not become fully systemic in some varieties of plum. In this and other respects, it resembles the viruses that cause apple mosaic; three isolates obtained from plum and two from apple produced similar Symptoms in peach and apple. It is therefore suggested that plum line‐pattern and apple mosaic viruses are caused by strains of one virus.
OBSERVATIONS AND EXPERIMENTS ON THE HESSIAN FLY (MAYETIOLA DESTRUCTOR SAY)
Authors: STOKES BARBARA M. 
Published: February 2008

Experiments showed that a stem midge collected locally on couch grass (Agropyron repens) and similar midges collected on wheat, barley and rye were of the same species, i. e. the hessian fly, Mayetiola destructor Say. There were three main flights per year, with some overlapping of the generations. In experiments, Aegilops ovata, Triticum compactum, T. dicoccoides, T. durum, T. spelta and T. turgidum were successfully used as host plants besides wheat, barley, rye and couch grass. Individual female midges when moved from plant to plant gave rise to families on the different host plants; similarly, succeeding generations of midges were able to breed on various host plants other than those from which they themselves were reared. Oviposition also took place on plants on which larvae failed to establish themselves.Wheat seemed more favourable for the hessian fly than couch grass, and more midges were reared from young plants than from mature ones.Unisexual families occurred in about half the experiments. The following parasites were bred: Trichacis didas Walker, Eupteromalus? hemipterus Walker, Platygaster sp., Chrysocharis sp. and Tetrastichus sp.
PARTICLE SIZE OF INSECTICIDAL SUSPENSIONS AND THEIR CONTACT TOXICITY VI. EFFECT OF TEMPERATURE ON RELATIVE TOXICITY
Authors: McINTOSH A. H. 
Published: February 2008

Two aqueous suspensions, one containing crystals of uniform size and the other containing colloidal particles, were made with each of seven solid contact poisons (two DDT‐analogues, DDT, rotenone, 2‐bromomercurithiophen, dieldrin and endrin). The relative toxicity of each pair of suspensions was found in dipping or measured‐drop tests on as many as possible of the species Oryzaephilus surinamensis L., Tribolium castaneum Herbst and Tenebrio molitor L. In addition, some tests were made by injection of colloidal suspensions.In each test, insects were kept after treatment at two temperatures: 28°C. and 11, 17 or 20°C.; counts of kill were made after 24 hr. The tests measured three different kinds of temperature coefficient of insecticidal action.In the contact tests, the colloid was nearly always more toxic than the crystals. In all the tests, except those with dieldrin, the relative toxicity (colloid: crystals) was greater at the lower after‐treatment temperature, i. e. the temperature coeficient of the relative toxicity was negative. But in the case of dieldrin, the coefficient was positive.The DDT‐analogues, DDT, rotenone and endrin were more toxic at the lower after‐treatment temperature, i. e. they had negative temperature coefficients of kill by contact action. In all these cases the temperature coefficient of kill by contact action was greater for colloid than for crystals. Dieldrin and 2‐bromomercurithiophen had positive temperature coefficients of kill by contact action. With dieldrin, the temperature coefficient was greater for colloid than for crystals; but with 2‐bromomercurithiophen, the reverse was true.The temperature coefficient of kill by injection was negative for DDT, but positive for dieldrin and endrin; the other poisons were not tested by injection.A possible explanation for the results of the contact tests is given in an Appendix. The explanation is based on a number of assumptions about the penetration of insect cuticle by solid poisons. These assumptions lead to the conclusion that the effect of temperature on the relative toxicity depends on the temperature coefficient of kill by internal action of the poison on the insect. This can be measured by injection tests. If it is negative or zero, the ratio of toxicities (colloid: crystals) by contact action, measured quite soon after treatment of the insects, will be greater at a low temperature after treatment than at a high temperature after treatment; but if the coefficient is positive, the effect of temperature on relative toxicity cannot be foretold. The experimental results seem to confirm the assumptions.
THE DEVELOPMENT OF POTATO SKIN‐SPOT DISEASE
Authors: ALLEN J. D. 
Published: February 2008

A study of the development of skin spot in the potato variety Kerr's Pink has shown that humid conditions, both before and after infection by Oospora pustulans, increase the incidence of the disease. The results of inoculation experiments have indicated that infection of the tuber does not take place much before the normal time of lifting.It has been found that the pathogen may enter the tuber by way of the lenticels, and that invasion of the cortex and the production of a cork cambium takes place shortly after infection. Some damage to buds was observed within 16 days of inoculation. Although the affected pocket of cortical tissue soon dies, discoloration of the periderm is not apparent until much later. It is suggested that this may be the reason for the comparatively long period which elapses between infection and the appearance of skin‐spot symptoms.
PHYSIOLOGIC RACES OF PHYTOPHTHORA INFESTANS (MONT.) DE BARY IN NORTHERN IRELAND*
Authors: DOLING D. A. 
Published: February 2008

By using the detached‐leaf technique and Black's series of differential host varieties, seven physiologic races of Phytophthora infestans (Mont.) de Bary have been distinguished as occurring in Northern Ireland. Six were found at the Dunanney potato variety trial plots, namely: race 1; race 2; race 4; race I, 2; race 1,4; and race I, z, 4. The remaining race, race 0, was isolated from the commercial potato crop.In a survey, comprising seventy‐three isolates, of the physiologic races occurring in the commercial potato crop, only race o and race 4 were found (3 and 70 isolates respectively).Certain modifications to the detached‐leaf technique have given improved results, including the formation of normal lesions and the elimination of atypical infections showing sparse sporulation.The variation in the host‐parasite reaction of the detached leaves and the identity of the common race in commercial potato crops are discussed.
THE EFFECT OF INFECTION WITH TOBACCO ETCH VIRUS ON THE RATES OF RESPIRATION AND PHOTOSYNTHESIS OF TOBACCO LEAVES
Authors: OWEN P. C. 
Published: February 2008

Unlike tobacco mosaic virus, which increases the respiration of tobacco leaves within an hour of their being inoculated, a virulent strain of tobacco etch virus did not change respiration rates until leaves showed external symptoms. The respiration rates of inoculated or systemically infected leaves with symptoms rose to 40% above that of healthy leaves, three times the increase produced by tobacco mosaic virus. The increased respiration rate occurred at all times of the year and was maintained through the life of the leaves.Leaves infected with tobacco etch virus and showing symptoms had a photo‐synthetic rate 20% lower than that of healthy leaves.
STUDIES ON THE HOST RANGE, PROPERTIES AND MODE OF TRANSMISSION OF BEET RINGSPOT VIRUS
Authors: HARRISON B. D. 
Published: February 2008

An apparently undescribed mechanically transmissible virus has been named beet ringspot virus (BRV). It occurs naturally in Scotland in sugar‐beet, turnip, swede, potato and many kinds of weed plants. BRV is readily distinguished from raspberry ringspot virus by the symptoms produced in Chenopodium amaranticolor, French bean, tobacco and Petunia hybrida plants. BRV lost infectivity when heated for 10 min. at 63°C. but not at 60°C.: at 20°C. its longevity in vitro was about 3 weeks. BRV was precipitated by ammonium sulphate, ethanol and acetone.Protection experiments with tobacco plants, and serological tests, gave no evidence that BRV was related to tobacco ringspot, raspberry ringspot, potato bouquet or tobacco rattle viruses, but showed that viruses isolated from different host plants and from different localities were strains of BRV.BRV is soil‐borne: in glasshouse experiments sugar‐beet, beetroot, potato, turnip, swede, French bean, Fragaria vesca, oat and wheat plants often became systemically infected when grown in soil from the site of a disease outbreak, but the virus was restricted to the roots of many infected plants. When sugar‐beet seedlings were grown in virus‐containing soil, BRV was first detected in their roots, where its concentration increased, before progressively increasing amounts of virus were found in the shoots.Soils from five localities were found to contain BRV. BRV has been found only where the soil is light in texture, and often in fields where raspberry ringspot virus occurs.