bluuebunny/crossref_metadata_2025_split huggingface dataset:
The currant clearwing moth (Aegeria tipuliformis (Clerck)) as a pest of black currants
Authors: BROCK A. M. , COLLINGWOOD C. A. , WHITE J. H. 
Published: February 2008

SUMMARYThe bionomics of the currant clearwing moth in a heavily infested Lincolnshire black currant plantation were investigated from 1951 to 1960. 95% of overwintered larvae pupate in May; the remainder, chiefly in the older wood, carry over until the following season. The mean number of eggs laid per bush was ninety and the mean number of larvae surviving until winter was forty‐nine (59,000/acre). Pruning, parasitism and predation by tits reduced this to twenty by May, giving an overall loss of about 80% from egg to adult due to natural causes.Parathion, dipterex or gusathion, acting ovicidally, reduced surviving larvae by 80% compared with untreated controls, but a large‐scale experiment showed no crop increase in the year following successful treatment and the net economic effect of high larval infestation was negligible.
Estimation of slug populations
Authors: SOUTH A. 
Published: February 2008

SUMMARYIt is impracticable to count slugs per unit area in the field, but both slugs and their eggs are recovered efficiently by soil washing in the laboratory. A less laborious method is described in which slugs (only) are expelled from turves progressively immersed in cold water. This method, used with samples of twelve 12×12×4 in. units of substratum, gives satisfactory estimates for Agriolimax reticulatus and Arion intermedim at population densities above I per sq.ft.
On the systematic position of the coliform bacteria responsible for stalk rot of maize
Authors: SABET K. A. , SAMRA A. S. , EL‐SHAFEY H. A. 
Published: February 2008

SUMMARYComparative studies were made of two isolates of the Egyptian strain of the maize stalk‐rot bacterium (Erwinia carotovora f. zeae Sabet), one isolate of the Indian strain of the same pathogen, two isolates of the cause of stalk rot in U.S.A. named E. maydis, and several isolates of E. carotovora from different hosts and different parts of the world. It was shown that these pathogens are closely related in their cultural and morphological characters but somewhat variable in certain biochemical reactions. They agree in their pathogenicity and relation to environment. The differences between E. maydis of Kelman, Person & Hebert (1957) and E. carotovora were found to be well within strain variation and do not justify the creation of a new species. The stalk‐rot bacteria from U.A.R., India and U.S.A. are distinguished by their ability to attack certain graminaceous plants which no other strain of E. carotovora can infect. It is concluded on this ground that the name originally adopted by Sabet (1954), i.e. E. carotovora f. zeae should be maintained and applied to the organism causing stalk rot in U.S.A.
Necrotic ring spot and prune dwarf viruses in Prunus and in herbaceous indicators
Authors: CROPLEY R. , GILMER R. M. , POSNETTE A. F. 
Published: February 2008

SUMMARYWhen scions from sweet cherry trees with tatter‐leaf disease were used to infect a range of Prunus species they induced necrotic leaf spot and stunt in peach, prune dwarf in Italian Prune and necrotic leaf spot and yellows in sour cherry. Inoculum prepared from such infected sweet cherry leaves caused two types of lesions on inoculated cucumber cotyledons from which single‐lesion cultures yielded two viruses differing in physical properties and herbaceous host ranges.One of these viruses reacted with antiserum prepared against a North American isolate of necrotic ring spot virus and, when returned from cucumber to Prunus, it caused tatter‐leaf in sweet cherry, necrotic leaf spot in peach and sour cherry, and no symptoms in Italian Prune. The other virus, which reacted with antiserum prepared against a North American isolate of prune dwarf virus, caused prune dwarf in Italian Prune, stunt in peach and only slight leaf necrosis in sweet cherry. Sour cherry trees developed yellows only when infected with both viruses, but in sweet and sour cherry infection with one virus reduced the severity of the necrotic shock symptoms induced by the other.
Further studies on European rasp‐leaf and leaf‐roll diseases of cherry trees
Authors: CROPLEY R. 
Published: February 2008

SUMMARYCherry leaf‐roll, raspberry ringspot and arabis mosaic viruses occurred in high concentration in cherry sap extracted from buds or from young leaves in the spring. The viruses could be detected serologically in crude cherry sap which was highly infective to herbaceous test plants. During summer and autumn infectivity of leaf‐roll virus decreased in cherry sap, while a virus inhibitor increased.Each virus was transmitted by inoculation with sap from herbaceous host plants to young Prunus seedlings and from these to mazzard F12/1 and Bing sweet cherry plants by grafting. Cherry leaf‐roll virus caused leaf rolling and a few very small enations on the undersurfaces of Bing leaves. Raspberry ringspot virus and one strain of arabis mosaic virus induced small enations characteristic of mild rasp‐leaf disease. When plants infected with these viruses were also infected with Prunus necrotic ringspot virus, the symptoms were only slightly enhanced whereas they were very severe when prune dwarf virus was added.Rasp‐leaf disease may increase by the spread of prune dwarf virus in orchards where latent infection with raspberry ringspot virus had occurred previously. In other orchards, trees may develop the disease as raspberry ringspot virus spreads into trees already infected with prune dwarf virus.
The toxicity to fish of mixtures of poisons: II. Copper‐ammonia and zinc‐phenol mixtures
Authors: HERBERT D. W. M. , VANDYKE JENNIFER M. 
Published: February 2008

SUMMARYTests with rainbow trout in mixtures of ammonium chloride with copper sulphate and of phenol with zinc sulphate have shown that the threshold of toxic concentration for a 50% mortality occurs in solutions for which a value of I is obtained by summing the concentrations of the individual poisons expressed as fractions of their individual threshold concentrations. With ammonia‐copper mixtures this method of predicting the threshold concentration becomes progressively less adequate as lower percentage mortalities are considered.
Glasshouse experiments on apple scab I. Foliage infection in relation to wet and dry periods
Authors: MOORE M. H. 
Published: February 2008

SUMMARYA technique of investigating apple scab infection periods using MM 109 rootstocks in the glasshouse is fully described. Inoculation by ascospores in aqueous suspension was less reliable than that by sedimenting the spores direct from source leaves on to the host plants, but fresh conidia in aqueous suspension consistently gave high levels of infection under optimum conditions.Ascospores required a shorter period of continuous wetness (6 hr.) than conidia (7–9 hr.) for infection at near‐optimum temperatures. Maximum infection from both sources was reached after about 18 hr. continuous wetness; much longer periods were sometimes inimical. With discontinuous wetness, most ascospores tolerated a dry interval of 24 hr. on the host leaves, although infection was somewhat reduced if the dry period began when the spores were starting to germinate. Conidia were more inhibited than ascospores by 24 hr. drying during minimal infection periods, but many survived and produced lesions.Some ascospores survived dry periods of at least 96 hr., but mature leaves had acquired resistance during the interval and thus infection was reduced. The reduction was partly offset by greater infection of the youngest leaves, which meantime had expanded and were thus easier to wet. No infection resulted, however, when the dry interval was extended to 10 days.The implications of the results are discussed in relation to the interpretation of infection periods in the field.
Genotype‐environment interactions and developmental rate in the flour beetles Tribolium castaneum and T. confusum (Coleoptera, Tenebrionidae)
Authors: DAWSON P. S. 
Published: February 2008

SUMMARYDevelopmental rates of a number of strains of the flour beetles, Tribolium castaneum and T. confusum, were measured at 40, 60 and 70% relative humidity. Significant genotype‐environment interactions, as well as strain and humidity effects, were observed. The results indicate that the response to different humidities of some strains depends on their genetic composition.
Aspects of trapping slugs with metaldehyde and bran
Authors: WEBLEP D. 
Published: February 2008

SUMMARYIn trapping slugs, 1 part of 30% Sevin (carbaryl) (1‐naphthyl‐N‐methylcarbamate) to 40 parts of standard metaldehyde‐and‐bran mixture gave an improved catch over standard biscuits. The fungicides dazomet or zineb incorporated in biscuits repelled slugs. It was shown that the fall‐off in the attraction of metaldehyde and bran did not occur until 4 days after biscuit exposure, and that black glass plates placed over pelleted baits masked their effect, the same catch being obtained with one or with sixteen pellets. Even without glass plates there was evidence to suggest that the catch of Agriolimax reticulatus was similar with one or sixteen pellets. The implications of these results on control measures are discussed and it is recommended that metaldehyde sprays be used for epidemics, and the baits only as long‐term measures to keep down infestations already partly controlled.
Resistance to zinc sulphate of the zebrafish (Brachydanio rerio Hamilton‐Buchanan) at different phases of its life history
Authors: SKIDMORE J. F. 
Published: February 2008

SUMMARYZebrafish of eleven age groups were exposed to four concentrations of zinc sulphate (5, 10, 20 and 40 p.p.m. Zn) in soft water (CaCO3 10 p.p.m.) at 25d̀ C. In all four concentrations, newly laid eggs generally survived the longest time. Survival time decreased with age until hatching on the fourth day. Newly hatched fish (4–13 days old) survived the shortest time. Forty‐day‐old fish and adults (100 days old) survived slightly longer in the two highest concentrations. In the two lowest concentrations, 40‐day‐old fish survived as long as newly laid eggs, and many adults survived indefinitely. The threshold concentration of zinc was approximately 10 p.p.m. for adults and 1.3 p.p.m. for 40‐day‐old fish.
Biological control of Fusarium wilt of peas by organic soil amendments
Authors: KHALIFA O. 
Published: February 2008

SUMMARYPure chitin added to soil significantly lessened the severity of pea wilt caused by Fusarium oxysporum f. pisi (Linf.) Snyder & Hansen. Pectin, glucose, cellulose and laminarin had less effect. In the glasshouse the wilt index was diminished by 12 % when chitin was added to inoculated soil the same day pea seedlings were planted in the soil, and by 25 and 45 % when it was added 3 and 8 weeks before transplanting. In the field, applying chitin to naturally infested soil when peas were sown decreased wilt index by 82 and by 75 % when applied 4 weeks earlier.Chitin did not affect the growth of healthy pea seedlings, suggesting that it affects wilt indirectly by changing the soil microflora. Both in the glasshouse and the field chitin greatly increased the numbers of actinomycetes, fungi and bacteria in the rhizosphere, whereas it decreased the population of P. oxysporum f. pisi. Similar microbial changes occurred in ‘wilt‐sick’ soil without plants, indicating that root exudates and debris intensified rather than determined these changes.Micro‐organisms isolated from the rhizosphere soil treated with chitin were more antagonistic towards F. oxysporum f. pisi race I, and the sterile rhizosphere extracts were also more inhibitory to its spore germination in vitro, than were those from the rhizosphere in soil without chitin. Chitin therefore seems to diminish wilt by stimulating micro‐organisms that antagonize and/or lyse the pathogen.
The growth of Botrytis fabae and B. cinerea into leaves of bean (Vicia faba L.)
Authors: PURKAYASTHA R. P. , DEVERALL B. J. 
Published: February 2008

SUMMARYThe nature of the reactions underlying the success of Botrytis fabae and the failure of B. cinerea to colonize the leaves of bean (Vicia faba L.) have been studied.Damage to or removal of cuticle before inoculation failed to enable B. cinerea to cause spreading lesions. Nutrients including those which support good growth in vitro failed to stimulate B. cinerea to spread through leaves.The germination of spores of B. cinerea in water was more rapid and complete than of B. fabae on both glass and leaf surfaces. B. cinerea grew more rapidly than B. fabae in nutrient media, but germ tubes of B. fabae grew at a higher constant rate than those of B. cinerea in water drops on glass. In water drops on leaves, germ tubes of B. fabae grew at a constant rate but those of B. cinerea slowed after 8 hr. and then grew little more. Germ tubes of B. fabae were the same length after 24 hr. both over and away from lesions, but those of B. cinerea were markedly shorter over lesions than away from them at this time.Similar observations on pathogenicity and relative growth of the two fungi were made on six bean varieties.
Bacterial canker of stone‐fruits
Authors: CROSSE J. E. 
Published: February 2008

SUMMARYOn two different plots of cherry trees, the bacterial canker organism (Pseudomonas mors‐prunorum) outnumbered all other gram‐negative bacteria on the leaf surfaces in the approximate proportions of 4:1 and 3:1, respectively. The saprophytic flora was dominated by an organism having affinities with Erwinia spp. In mixed‐infection experiments this was shown to be capable of reducing the incidence and/or severity of leaf‐scar infection. The inhibitory activity of the saprophyte in different experiments was related to the amount of disease, and its general effect was similar to that which would have been expected from reducing the concentration of the pathogen in the inocula. Spraying bacterial suspensions on to trees substantially increased populations of the saprophyte, but these rapidly decayed and the natural equilibrium on the leaf surfaces was re‐established within a few days.
Studies on induced mutants of Corynebacterium fascians and on their pathogenicity in comparison with that of ‘natural’ strains
Authors: JACOBS S. E. , HABISH H. A. , DADD A. H. 
Published: February 2008

SUMMARYColony‐type, non‐pigmented and nutritional (auxotrophic) mutants of Corynebacterium fascians were isolated after ultraviolet irradiation of a highly virulent strain. The auxotrophs had single requirements for glycine, aspartic acid, arginine, methionine, creatine or adenine and the amount of their growth in a minimal medium adequate for the parent strain was controlled by the amount of the respective nutrients added.Preliminary results indicated that the pathways by which C. fascians synthesises the substances (with the exception of methionine) required by the mutants were those already known for other micro‐organisms.The induced auxotrophic mutants were examined, in comparison with ‘natural’ or wild strains, for ability to infect sweet pea seedlings and to grow in the environment provided by the host. The mutants were avirulent or weakly virulent unless the specific nutrient was added, and this was correlated with the amount of growth made by the mutants in an aqueous extract of the host tissue. Addition of the specific nutrient improved the growth of the mutant, thus suggesting that avirulence was due, at least in part, to the inability of the pathogen to grow sufficiently in the host environment.
The biology of Sclerotinia trifoliorum Erikss. and other species of sclerotium ‐forming fungi
Authors: WILLIAMS G. H. , WESTERN J. H. 
Published: February 2008

SUMMARYIn studies of the behaviour of sclerotia of Sclerotinia trifoliorum, S. sclerotiorum, Sclerotium delphinii and S. rolfsii it was established that S. trifoliorum and S. sclerotiorum formed apothecia in the field, S. sclerotiorum mainly in spring and S. trifoliorum almost exclusively in autumn. Apothecia were formed from sclerotia down to 2 in. in the soil, the number diminishing with increasing depth. At 6 in., sclerotia developed apothecial stipes up to 21/2 in. long: this limitation was not due to exhaustion of the food reserves of the sclerotia.In S. trifoliorum, apothecial formation was abundant in August, then steadily declined, and ceased in November. Broad red clover was exceptional in stimulating the initial flush in both S. trifoliorum and S. sclerotiorum, but very few apothecia formed subsequently.Mycelial growth from sclerotia of S. trifoliorum and S. sclerotiorum was much sparser, even in sterilized soil, than that from sclerotia of Sclerotium delphinii and S. rolfsii.
Mercury residues in apples from trees receiving organomercurial fungicide in the previous autumn and winter
Authors: TEW R. P. , SILLIBOURNE JOAN M. 
Published: February 2008

SUMMARYMercury residues have been measured in apples from trees receiving experimental applications of phenylmercury chloride in the previous autumn and/or in the dormant season. In the absence of organomercurial sprays in the succeeding summer, mercury could not be found in the fruit at harvest. Even when post‐harvest or dormancy applications preceded conventional summer schedules of an organomercurial fungicide, residues of mercury at harvest were not increased.
Studies on plant cuticle
Authors: SILVA FERNANDES A. M. S. 
Published: February 2008

SUMMARYSurfaces of apple, banana, blackcurrant, broad bean, cabbage, coffee, hydrangea, pea, rose, Eucalyptus, Exochordia and Rhus leaves and apple fruit are classified by a standardized wetting test into those that are water‐repellent, those that are easily wetted and those over which water spreads without wetting. The affinity of a surface for water is influenced by the amount and chemical composition and especially by the physical configuration of the wax present on the surface.
Effect of CCC (chlorocholine chloride) on growth and yield of spring wheat in the field
Authors: HUMPHRIES E. C. , WELBANK P. J. , WITTS K. J. 
Published: February 2008

SUMMARYSpring wheat, var. ‘Phoebus’, drilled at 11/2 times the usual rate and grown with three rates of nitrogen was treated with 2.5 or 5 lb. CCC per acre at the sixth‐leaf stage. At maturity, the height of treated plants was only 60% of that of untreated plants, but the percentage shortening was less as nitrogen increased. Although untreated plants did not lodge, CCC increased mean grain yield by 5% by increasing the number of ears and number of grains per ear. Grain weight per ear and thousand‐grain weight were decreased by CCC. The explanation of the increase in shoot number by CCC is not known, but possibly less light was intercepted by the shorter plants, so that later‐formed shoots survived to produce ears.CCC decreased assimilatory area by shortening stems and hence leaf sheath area; lamina area was little affected. It delayed ear emergence by up to 8 days, Leaf‐area index was decreased by CCC and as it increased, net assimilation rate decreased. CCC did not affect nitrogen uptake per unit area of land but it increased nitrogen as percentage of dry matter because it decreased dry‐matter yields.
The infectivity of soils containing Phytophthora infestans
Authors: LACEY J. 
Published: February 2008

SUMMARYInfectivity of soil was measured by incubating samples on potato tuber slices during and after outbreaks of potato blight in three years. Surface soil was always more infective than deeper soil, the most infective surface soil containing the equivalent of 2100 sporangia of P. infestans per ml. Infectivity usually diminished rapidly with increasing depth, and only occasionally did infectivity below 2 in. exceed the equivalent of 100 sporangia per ml. Exceptionally large infectivity was once found at all depths sampled after heavy rain, but rain did not consistently affect infectivity. The surface soil remained infective for at least 32 days after the haulm was killed with acid, but the concentration of viable spores declined to a small value during the first week after treatment. In the laboratory infectivity persisted for 11 weeks after sporangia were mixed with unsterilized soil originally with a moisture content of 20%. P. infestans mycelium grew only in sterilized soils, perhaps because some soil micro‐organisms inhibit its growth, and others (e.g. Trichoderma viride) parasitize it or lyse it (e.g. by Rhizoctonia solani). The three soils tested all contained substances that inhibit the germination of sporangia.
Infection of hop rootstocks by downy mildew Pseudoperonospora humuli (Miy. & Tak.) Wilson and its control by early‐season dusts
Authors: COLEY‐SMITH J. R. 
Published: February 2008

SUMMARYInfection of hop rootstocks by Pseudoperonospora humuli has been shown to occur as a result of inoculation of the tips of shoots 15 cm. or less in length. No rootstock infection developed when shoots were more than 17.5 cm. long at the time of inoculation. Infection via the base of shoots can occur at any time during the growing season and is thought to be the main source of rootstock disease under natural conditions. The importance of direct infection of hop rootstocks by zoospores of P. humuli, which occurs readily under laboratory conditions, is not known.Application of Bordeaux (6.5% Cu) and captan (15% a.i.) dusts to the crowns and shoot bases of field plants retarded development of rootstock disease and shoot infection (basal spikes) in originally disease‐free plantings of Golding hops.
Investigations on fungicides
Authors: HEYNS A. J. , CARTER G. A. , ROTHWELL K. , WAIN R. L. 
Published: February 2008

SUMMARYThe fungicidal properties of thirty‐three N‐substituted S‐esters derived from dithiocarbamic acid were examined. Several compounds inhibited the germination of spores of Botrytis fabae in vitro at concentrations below 100 p.p.m., but activity against Erysiphe graminis was considerably lower. In greenhouse tests the compounds were not effective against B. fabae when sprayed on broad bean seedlings but several gave more than 80% reduction of mildew infection when sprayed on wheat seedlings. Some compounds also showed a marked eradicant action against wheat mildew.The effect of pH, plant sap and amino acids upon their fungitoxicity was also studied and the degree of activity shown by the compounds is discussed in relation to these and other factors.
The respiration of leaves showing necrotic local lesions following infection by tobacco mosaic virus
Authors: SUNDERLAND D. W. , MERRETT M. J. 
Published: February 2008

SUMMARYAt 25°C. the respiration rate of leaves ofNicotiana tabacum L. var. Xanthi infected with tobacco mosaic virus increased before the appearance of local lesions. The increase was directly proportional to lesion number at low, but not at higher, lesion densities. With temperatures at which the infected leaf showed necrotic lesions the difference in respiration rates between healthy and infected leaves was greater than at 35°C., at which temperature infected leaves do not develop necrotic lesions. The concentration of 2,4‐dinitrophenol (DNP) that gave maximum stimulation of the respiration of the healthy leaf was 10‐5M, but even this respiration rate was less than that of the infected leaf showing local lesions. DNP had no effect on the respiration of the infected leaf showing a dense lesion cover. At 35°C., DNP increased the respiration rate of infected leaves and the maximum respiration rates for healthy and infected leaves in the presence of DNP were similar.