bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of the ant Lasius niger (L.) on insects preying on small populations of Aphis fabae Scop. on bean plants
Authors: BANKS C.J. 
Published: February 2008

SUMMARYSmall populations of Aphis fabae were wholly or partially protected by the ant Lasius niger which drove most predators away. Predators eliminated whole colonies of unprotected aphids or persistently restricted their numbers. Protection of the aphid against predators is probably more important than hitherto thought, and may be more important than the other ways in which ants affect the multiplication rate of A. fabae.
The efficiency of cylindrical sticky insect traps and suspended nets
Authors: TAYLOR L.R. 
Published: February 2008

SUMMARYThe efficiency with which the 5 in. diameter, white, cylindrical sticky trap and suspended tow‐net catch insects was assessed using Johnson's (1950) field comparison of the two with the suction trap recently standardized by Taylor (1962). The aerodynamic efficiency of the sticky trap was also calculated from Gregory's (1951) results. Comparing these two results shows that small insects behave very like inert particles during capture. Efficiency of the sticky trap is almost constant in winds from 2 to 10 m.p.h. Tables are given converting catch of small insects to aerial density in winds from 1 to 10 m.p.h.
Resistance of oats to cereal root eelworm (Heterodera avenae Woll.)
Authors: DAVIES T. GLYN , GRIFFITHS D.J. 
Published: February 2008

SUMMARYTests of cultivated and wild oats for resistance to the cereal root eelworm (Heterodera avenae Woll.) were based on reaction to eelworm attack in the field and examination of root systems for eelworm cysts. Some resistance was found in Avena sativa var. Heine's Silber II: a higher level of resistance occurred in the wild species A. sterilis, which bore no cysts, and in three forms of A. abyssinica, which bore few or none.
The effect of water‐table on beet eelworm, Heterodera schachtii Schm., in a sandy soil
Authors: MORIARTY F. 
Published: February 2008

SUMMARYThe failure of beet eelworm to develop on host plants in microplots filled with a sandy soil from an infested field at Cantley, Norfolk, was studied. Using artificial water‐tables it was found that by the time the plants were large enough for many eel‐worms to develop on them, soil conditions were too dry for larval hatch and invasion. Hatched larvae invaded and developed when added to microplots, presumably because they were able to survive the dry conditions until wet weather enabled them to invade the roots.Some areas may be too dry for development of beet eelworm. Conversely, irrigation may encourage beet eelworm.These experiments showed that the uses of microplots are limited, because conditions in them may differ from those in fields, and they are less manageable than pots.
Tests of spray materials for use against Gloeosporium spp. in apple orchards
Authors: CORKE A.T.K. 
Published: February 2008

SUMMARYFive out of six fungicides, applied to apple trees during dormancy, reduced the viability of conidia of Gloeosporium perennans passing in rainwater over the sprayed bark, and suppressed spore production on the acervuli. While mercury greatly reduced spore viability, it was less effective than the other materials in reducing sporulation over a long period; consequently, in the period from treatment to mid‐July, almost as many viable spores were washed from the mercury‐treated trees as from those which had received the less toxic sprays.On trees treated with mercury in the dormant season, mercury was found throughout the tissues, including the leaves and buds, six months after treatment.
The biological effects of synthetic detergents in the River Lee, Hertfordshire
Authors: HYNES H.B.N. , ROBERTS F.W. 
Published: February 2008

SUMMARYThe fauna and flora of the River Lee, which consists primarily of sewage effluent, were studied between 1950 and 1961. During this period the detergent content of the effluent rose from about 1 p.p.m. to between 3 and 4 in 1958, after which, because of the introduction of new types of detergent which are destroyed by sewage treatment, it fell steeply to about 2 p.p.m. in 1960. No marked biological changes which could be correlated with the changes in detergent concentration were found, but experiments indicate that the absence or paucity of some plant species from the river may be due to these substances.
Greenhouse evaluation of chemicals for control of powdery mildews
Authors: KIRBY A. H. M. , FRICK E. L. 
Published: February 2008

SUMMARYA method is described for the artificial inoculation of large numbers of potted apple rootstocks or barley seedlings with conidia of the appropriate powdery mildew, using settling towers large enough to hold 100 pots, and blowing spores via a central pipe into the upper part of the tower and allowing them to settle on the foliage.Plants are put in the tower some 24 hr. before introducing the spores, left enclosed for a further 24 hr., and then placed on the bench in a greenhouse with forced ventilation until lesions are clear enough for recording, usually 9 days after inoculation for apple mildew and 7 for barley mildew.Rooted shoots from stoolbeds of M. III apple rootstock provided suitable material for apple mildew experiments. The largest numbers of lesions per leaf were usually found on the third and fourth leaves down the shoots; records were usually taken on leaves 3 to 5.For barley mildew, the variety Plumage Archer was found to be suitable. Conidia can be collected and weighed as required, facilitating control over the inoculum load applied in each test. Seedlings are preferred before the second leaf emerges, i.e. before bending or twisting interferes with inoculation.The method is successful for the study of both the protective and curative effects of chemicals applied by a dipping technique.
Greenhouse evaluation of chemicals for control of powdery mildews
Authors: KIRBY A. H. M. , FRICK E. L. 
Published: February 2008

SUMMARYApple rootstocks placed in the settling‐tower 24 hr. before introduction of spores of Podosphaera Zeucotricha developed more lesions than those placed in position immediately before inoculation; a period of 24 hr. in the tower after introduction of spores induced more infections than one of 48 hr.Rootstocks kept at high temperature for a few hours immediately on removal from the tower (24 hr. after inoculation) developed only half as many lesions as those maintained at normal temperatures. This effect declined steadily as the heating was applied on successively later days until the 8th day when such heating had no effect.Plants kept at about 20°C. and a relative humidity not exceeding 70% grew satisfactorily and developed very similar numbers of lesions to those inoculated in the same tower but subsequently incubated in a greenhouse where R.H. reached saturation every night. High humidity therefore is unnecessary for the inoculation and development of apple mildew.The leaves initially produced by rootstocks potted in John Innes No. I compost and watered daily with ammonium nitrate solution, were no more susceptible to powdery mildew than those on similar plants given water only. However, when such rootstocks were grown for several weeks, cut back to a few buds, and allowed to break again, the leaves were larger and more susceptible if ammonium nitrate was given as a 0·005 to 0·015 M solution.The susceptibility of leaves on M. III rootstocks decreased with age by about 50% per leaf‐position down to the fourth and even faster below that position, so that the youngest leaf that is just unrolling is by far the most susceptible.
Host range and properties of grapevine fanleaf and grapevine yellow mosaic viruses
Authors: DIAS H. F. 
Published: February 2008

SUMMARYSap‐transmissible viruses were obtained from grapevines affected by fanleaf, yellow mosaic, distorting mosaic, witches' broom or fasciation diseases. Virus isolates from American, Australian, French and Portuguese grapevines did not differ with country of origin but those from any one country varied in virulence. Herbaceous hosts of isolates originally obtained from grapevines with fanleaf or with yellow mosaic included thirty‐two species in five plant families; yellow mosaic isolates usually caused distinctive symptoms in systemically infected leaves of Chenopodium amaranticolor, but in many other hosts could not be distinguished from fanleaf isolates. Yellow mosaic and fanleaf diseases were each reproduced by transmitting the respective isolates back to grapevine from C. amaranticolor. Grapevine fanleaf and grapevine yellow mosaic viruses were both transmitted through seed of C. amaranticolor; both were precipitated without inactivation by ethanol, by acetone, by ammonium sulphate and at pH 5. Preparations of each, partially purified from systemically infected leaves of Nicotiana clevelandii, contained polyhedral particles about 30 mp in diameter. Phenol‐disrupted virus was 1–5% as infective as its parent virus suspensions.
The relationship between grapevine fanleaf, grapevine yellow mosaic and arabis mosaic viruses
Authors: DIAS H. F. , HARRISON B. D. 
Published: February 2008

SUMMARYPlant protection and serological tests showed that the viruses causing the grapevine fanleaf and grapevine yellow mosaic diseases occurring in Portugal, Switzerland and the United States are closely related strains. These strains and arabis mosaic virus cause similar symptoms in many herbaceous species, but arabis mosaic virus is more virulent and more often becomes systemic. Attempts to transmit arabis mosaic virus to grapevine failed. Arabis mosaic virus shares only few antigenic determinants with the viruses obtained from grapevine, and these viruses do not protect plants against it. In a virus classification, the grapevine virus isolates and arabis mosaic virus can be considered two distinct serotypes of one virus.The nematode Xiphinema diversicaudatrim acquired arabis mosaic virus and transmitted it to herbaceous plants but did not transmit the grapevine viruses. As X. index is known to transmit grapevine fanleaf virus and probably transmits grapevine yellow mosaic virus, this suggests specific transmission of virus serotypes by different species of nematodes.
Investigations on fungicides
Authors: CARTER G. A. , GARRAWAY J. L. , SPENCER D. M. , WAIN R. L. 
Published: February 2008

SUMMARYThe structure/anti‐fungal relationships of a group of 137 sulphur‐containing compounds were studied by observation of their effects on the mycelial growth of six fungi, Pythium ultimum, Sclerotinia fructigena, Verticillium albo‐atrum, Alternaria solani, Botrytis cinerea and Aspergillus niger, and the germination of spores of Botrytis cinevea. These compounds consist of (a) salts and (b) carboxy‐alkyl and ‐alkenyl esters of both alkyl‐ and aryl‐substituted dithiocarbamic and hydroxydithioformic acids, (c) certain cyclic derivatives of (b), and (d) alkyl and aryl isothiocyanates. Short homologous series were selected to assess the importance of physico‐chemical properties in fungitoxicity, whilst certain aryl‐substituents were used on the basis of their contrasting electronic effects.Derivatives of alkoxydithioformic acids showed higher toxicity than those of N‐alkyl‐substituted dithiocarbamic acids, except for a series of β‐(N‐alkylthio‐carbamoylthio)acrylic acids. The fungitoxicity of esters of alkyl‐substituted dithiocarbamic or hydroxydithioformic acids showed little change on increasing the size of the alkyl substituent or ester grouping. The fungitoxicity of compounds derived from N‐aryldithiocarbamic acids varied considerably with the nature of the N‐substituent.
Investigations on fungicides
Authors: BATES ANGELA N. , SPENCER D. M. , WAIN R. L. 
Published: February 2008

SUMMARYFour series of aliphatic nitro compounds have been synthesized and examined for their fungistatic effects in mycelial growth tests. On the basis of the results nine compounds were selected for further study in spore germination tests and as fumigants. They were also examined for protectant and systemic fungicidal activity using broad bean seedlings. A special method was adopted in assessing activity as systemic fungicides whereby fumigant action could be avoided.
Studies on plant growth‐regulating substances: XVII. S‐esters of dithiocarbamates derived from amino acids
Authors: ROTHWELL K. , WAIN R. L. 
Published: February 2008

SUMMARYA further study of plant growth‐regulating activity in compounds not possessing a ring structure has been carried out. For this purpose a range of N‐substituted S‐esters of dithiocarbamates derived from amino acids was synthesized and their activities were assessed in the wheat cylinder, pea segment and pea curvature tests. The highest activity in all tests was shown by S‐methyl‐N‐methyl‐N‐carboxymethyl dithiocarbamate, CH3N(CH2COOH)C(: S)SCH3. N‐substituents other than methyl reduced the activity, whereas a group other than methyl attached to the sulphur atom destroyed activity.The infra‐red spectra of the compounds have been used to study the nature of the N‐C bonding within the molecules and this and other factors are discussed in relation to growth‐regulating activity.
A method of isolating Pythium spp. and Fusarium oxysporum from soil
Authors: BUXTON E. W. , KENDRICK J. B. 
Published: February 2008

SUMMARYWeighed amounts of lightly pulverized soil were drawn through a perforated aluminium plate and impacted on agar media in Petri dishes. This was done by placing the dishes in an Andersen air sampler, through which air was drawn at 14 l./min. The sampler was operated so that the soil was dispersed uniformly into 400 equally sized units/dish, each unit weighing 0·125 mg. These were transferred either to water‐agar medium to detect Pythium spp., or to Dox‐yeast‐agar medium for Fusarium oxysporum. The amount of each fungus in the soil was estimated from the frequency it was recovered from the transferred soil units. Results were more reproducible than by the usual soil‐dilution methods, and the method gave more uncontaminated cultures of Fusaria and Pythia.
Reactions of tomato leaves to species of Verticillium
Authors: GRIFFITHS D. A. , ISAAC IVOR 
Published: February 2008

SUMMARYMycelium developing from germinating spores of Verticillium tricorpus, supplied with an adequate source of carbohydrate, penetrated healthy but not wounded tomato leaves, whereas V. dahliae, originally isolated from Brussels sprouts, invariably failed to enter a living leaf. Colonization by V. tricorpus ceased when the lamina became chlorotic and was followed quickly by premature leaf‐fall. Whereas leaves killed by immersing in boiling water were quickly invaded by V. tricorpus and V. dahliae, fallen leaves which had died naturally appeared to have on their surfaces a substance which had an inhibiting effect upon the germination of conidia of both fungi.Expressed sap from living leaves contained a water‐soluble thermolabile substance which inhibited the germination of, but was not lethal to, conidia suspended in distilled water, but its action was suppressed by the presence of sucrose.It is suggested that this inhibitor, probably in a bound state in the living leaf, on death passed out through the now completely permeable cell membranes on to the surface in a sufficient concentration to prevent the germination of the conidia.
Abacá mosaic virus and its relationship to sugar‐cane mosaic
Authors: ELOJA A. L. , TINSLEY T. W. 
Published: February 2008

SUMMARYAbacá mosaic virus (AMV), which is readily transmissible between maize seedlings by inoculation with sap, has properties suggesting that it is a strain of sugar‐cane mosaic virus. Antisera to AMV precipitated specifically with sap from plants infected with the strain of sugar‐cane mosaic virus found, in Puerto Rico. Partially purified preparations of AMV contained flexuous rods 680 mμ long similar to those recorded for sugar‐cane mosaic virus.No evidence was found to support the widely held view that AMV is a strain of cucumber mosaic virus. Cucumber mosaic may infect abacá, but it is certain that other viruses can cause typical symptoms of abacá mosaic.
The behaviour of populations of potato‐root eelworm (Heterodera rostochiensis Woll.) towards some resistant tuberous and other Solanum species
Authors: JONES F. G. W. , PAWELSKA KRYSTYNA 
Published: February 2008

SUMMARYForty‐seven British populations of potato‐root eelworm (Heterodera rostochiensis) were tested for ability to form cysts on plants with resistance derived from Solanum tuberosum ssp. andigena, S. multidissectum, S. vernei, S. sanctae‐rosae, S. famatinae and S. × juzepczukii, and on S. nigrum, S. sarachoides and Nicotiana spp.The potato variety Arran Banner was used as the standard susceptible host and the number of cysts formed on the resistant plants in pot tests was expressed as a percentage of those formed on Arran Banner or assessed visually from the cysts observed on the outside root mat. Cyst production on andigena hybrids ranged from less than 1% of those on Arran Banner to slightly over 100%. About half of the populations produced 10% or less, and populations of this type, against which andigena resistance would be effective, were especially common in south‐east England and Northern Ireland. Cyst production on famatinae hybrids, a race of S. nigrum from East Germany, S. miniatum and S. sarachoides, resembled that on andigena hybrids. Cyst production on multidissectum hybrids varied less and only a few populations produced less than 10% and none less than 3% of the number on Arran Banner. S. vernei was highly resistant to all but about 5% of populations and a race of S. nigrum from Rothamsted was resistant to all tested.In selection experiments the proportion of females able to complete development increased when andigena hybrids, S. vernei or S. nigrum, were grown repeatedly in the same inoculum. Increase on S. vernei was slow, the pattern of increase on andigena hybrids suggested recessive inheritance but this could not be confirmed and increase on S. nigrum was more rapid, suggesting that the genetic mechanisms concerned in plant resistance and those concerned in the production of resistance‐breaking nematode biotypes differ for the three types of plant.The tests revealed much variability between populations of potato‐root eelworm from different localities despite the fact that they have undergone much selection on one type of host plant, cultivated Solanum tuberosum ssp. tuberosum. No cysts were seen on Nicotiana spp. Nevertheless, H. tabacum may prove to be little more than a recognizable biotype of H. rostochiensis.
The effect of restricted air supply on some insects which infest grain
Authors: OXLEY T. A. , WICKENDEN GLORIA 
Published: February 2008

SUMMARYIf insect pests of grain develop in a strictly airtight container all are killed by exhaustion of oxygen when the concentration of this gas falls to approximately 2%. If the walls of the container permit limited access of oxygen from the atmosphere by diffusion, at a rate dependent on the difference between the internal and external concentrations, the insect population may also be killed, but this will depend on the amount of diffusion and on the level of the original population. A method for investigating this in the laboratory using polythene diaphragms to admit oxygen is described. A population of six adult Sitophilus granarius per pound of wheat in a container admitting 7·5 mg. of oxygen per litre per day at zero internal concentration will not be killed immediately but will be reduced to a very low level and may eventually die out after many months. In the same container a smaller number of insects may survive sufficiently long to increase in numbers to a level at which they also are killed. At a critical population level (about twelve adults per pound) there may occur sharp fluctuations in oxygen concentration, and presumably of insect activity, which may or may not lead to death. A population initially much greater than twelve adults per pound will certainly be killed although this may take a little longer than in an airtight container.If the container is substantially full of wheat having a moisture content near 14% the apparent respiratory quotient of the insects is about 0·69 but if the proportion of the air space occupied by wheat is reduced, the apparent respiratory quotient is increased until it is approximately unity when the volume of wheat is about 5% of the volume of the container. It is concluded that carbon dioxide is adsorbed by wheat in proportion to the concentration of the gas.
A diffusion technique for assessing antifouling activity
Authors: CHRISTIE A. O. , CRISP D. J. 
Published: February 2008

SUMMARYA diffusion method for measuring the antifouling effectiveness of chemicals is described. The chemicals under test are allowed to diffuse through a porous container which is suspended in the sea under natural fouling conditions. These tests showed both tri‐n‐butyltin oxide and atrazine to have considerable antifouling activity. The test method is discussed in relation to conventional laboratory tests against single organisms.
Assessments of the infection of guineacorn (Sorghum vulgare) by covered smut (Sphacelotheca sorghi (Link) Clint.) in Northern Nigeria in 1957 and 1958
Authors: HARRIS K. M. 
Published: February 2008

SUMMARYA survey of the guineacorn (Sorghum vulgare) crop in Northern Nigeria in 1957 and 1958 indicated that, in both years, about 1% of all guineacorn spikelets were infected by covered smut (Sphacelotheca sorghi). This level of infection represents the annual loss of about £500,000 worth of grain or the unrewarded cultivation of at least 70,000 acres. There is evidence that the levels of infection are highest in those areas where temperatures at sowing time are relatively low.
Some graminicolous fungi associated with spotting of banana leaves in Jamaica
Authors: MEREDITH D. S. 
Published: February 2008

SUMMARYA dense spotting of leaves of young Lacatan banana plants is reported; the diameter of individual lesions rarely exceeds 2 mm. The disease is common near grassland or sugar‐cane but rare in grass‐free areas removed from sugar‐cane. Although widespread throughout Jamaica, it appears to be of negligible economic importance. Direct microscopic examination of lesions, spore‐trapping, isolation work and pathogenicity tests show that Cochliobolus sp. (?C. heterostrophus), Curvularia lunata and C. geniculata, and several species of Helminthosporium are associated with the disease and that spores of these fungi are regular components of the air‐spora in the vicinity of spotted banana leaves. The evidence suggests that grasses and sugar‐cane are major sources of inoculum. Other spots are caused by Detghtoniella torulosa which sporulates abundantly on decaying banana leaves.
The control of Gloeosporium album rot of stored apples by orchard sprays which reduce sporulation of wood infections
Authors: BURCHILL R. T. , EDNEY K. L. 
Published: February 2008

SUMMARYThe number of conidia of Gloeosporium album released from infections on the wood of Cox's Orange Pippin apple trees has been measured over a period of 21 months. The application of phenyl mercuric chloride at 0·10 and 0·05% in March 1960 reduced the amount of inoculum dispersed in the period May‐July and there was less rotting of the fruit in store. A similar reduction in sporulation occurred following the application of sprays in autumn 1960 and spring 1961, but spore production was enhanced when the effect of the sprays had disappeared. After an initial application of dichlorophen (5,5‐dichloro‐2,2‐dihydroxy‐diphenyl‐methane) at 0·25% in June 1961, two subsequent sprays were applied, when the records of spores trapped indicated that the previous spray was no longer effective. This treatment also reduced losses from rotting in store.