bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some factors affecting the rotting of stored apples by Gloeosporium spp
Authors: EDNEY K. L. 
Published: February 2008

SUMMARYThe susceptibility to rotting by Gloeosporium spp. of fruit from sixty‐two Cox's Orange Pippin apple trees on two plots has been found to vary from tree to tree and from year to year. There are indications that the level of inoculum released each year also varies. Examination of pruning snags and old fruiting spurs from one of these plots showed that 6% were infected with either G. perennans or G. album. Of 650 pruning cuts made in the winter of 1957‐58, 19 % subsequently became infected with Gloeosporium spp. Changes in the susceptibility of apples during a 2‐week period at harvest time markedly affected the incidence of rotting in store. No differences were found in the rates of spread of G. perennans in the cortical tissues of Cox's Orange Pippin apples of different sizes following inoculation.Germination of G. album on the surface of the apples is followed by a slight swelling of the tip of the tube germ, but no evidence has been obtained that this swollen tip functions as an appressorium. Inoculations of single lenticels with suspensions of spores of G. album in apple juice were relatively more successful than inoculations using aqueous suspensions, but little more than half of the inoculations were successful. Inoculations of the cortical tissues were also only partly successful and, for either method, the ease of infection was not found to increase with increasing maturity of the fruit.
Studies on the application of a copper fungicide for the control of coffee leaf rust
Authors: PARK P. O. , BURDEKIN D. A. 
Published: February 2008

SUMMARYA proprietary cuprous oxide fungicide was applied to unshaded single‐stem coffee as both a high‐ and a low‐volume spray. Initial deposition of fungicide was not affected by the volume of application. An improved sampling method, used in the second year of the trial, showed that despite efforts to direct the spray on to the under leaf surface, more fungicide was applied to the upper.The deposits arising from high‐volume applications were more susceptible to weathering and this weathering was most marked from the upper leaf surfaces. It was noted that irrigation within 48 hr. of spraying caused a considerable reduction in fungicide deposit.A visual scoring technique indicated that a large proportion of the leaves received no fungicide at all and it was concluded that subsequent redistribution may occur.The biological assessments indicated that high‐ and low‐volume application of copper fungicide gave equally good leaf rust control and leaf retention. Reducing the fungicide application from 5 to I lb./acre resulted in reduced fungicidal efficiency.A ‘disease control index’ was developed to show the relationship between the level of fungicide deposit and the degree of leaf rust control. A mean total deposit of approximately 60 mg./m.2 leaf area was required for satisfactory protection.
Transmission of beet yellows virus by alate and apterous aphids
Authors: HEATHCOTE G. D. , COCKBAIN A. J. 
Published: February 2008

SUMMARY Myxus pusicae alatae and apterae were consistently better vectors than Aphis fabae of beet yellows virus, but there was little difference between the ability of alatae and apterae of each species to transmit.Alatae born and reared on infected plants transmitted no more readily than alatae that had fed on infected plants for only one day. No individual became infective after feeding on the plants for only 5 min., and few were infective after feeding for 30–60 min. Alatae and apterae were about equally infective after similar feeding times on infected plants.Apterae kept from feeding and at various temperatures up to 30°C. for 4 hr. after their infection feed, all transmitted equally often. Alatae transmitted as readily after a 4 hr. flight as after a 15 min. one. Some alatae of M. persicae remained infective longer than apterae, but most individuals of both ceased to be infective within 2 days of leaving infected plants. Most alatae ceased to fly 3–5 days after the final ecdysis because their flight muscles autolysed. A. fabae and Rhopalosiphoninus staphyleae transmitted BYV rather less than half as often as did M. persicae. Macrosiphum euphorbiae and Aulacorthum solani transmitted only rarely and transmissions were not obtained with Megoura viciae, Metopolophium festucae and Rhopalosiphoninus latysiphon.
Death of maiden apple trees caused by Phytophthora syringae Kleb. and a comparison of the pathogen with P. cactorum (L. & C.) Schroet
Authors: SEWELL G. W. F. , WILSON J. F. 
Published: February 2008

SUMMARY Phytophthora cactorum and the closely related (but only recently implicated) species, P. syringae, cause collar rot of mature apple trees, but infection of young trees is uncommon. In a Kent orchard, 279 maiden trees of Cox's Orange Pippin, Worcester Pearmain and Tydeman's Early Worcester were infected by P. syringae whilst heeled‐in prior to planting, and subsequently killed.These two paragynous antheridial species can readily be distinguished in agar culture. P. cactorum grows best at 25° C. and forms a diffuse, azonate colony with abundant reproductive structures; sporangia are uniformly obpyriform, markedly papillate, and occur in terminal clusters on the sporangiophores. P. syringae grows best at 20° C., very slightly at 25°C., and forms a compact, radially zonate colony with sparse reproductive structures; sporangia are irregular in size and shape, have a broadly flattened apex, and occur singly on the simple sporangiophores.Inoculation studies demonstrated that young trees are particularly susceptible to P. syringae during the period of low temperature and tree dormancy: the rate of lesion extension for P. syringae was inversely related to the mean accumulated air temperature while the reverse was true for P. cactoriim.Measures recommended for the protection of young trees during the pre‐planting period aim at preventing contact of scion variety stems with wet soil.
Investigations on fungicides
Authors: CARTER G. A. , WAIN R. L. 
Published: February 2008

SUMMARYThe systemic therapeutic activity of eighty‐eight inorganic salts was assessed by determining their ability to protect broad bean seedlings from Botrytis fabae, tomato plants from Alternarin solani and wheat seedlings from Erysiphe graminis following root application to the host plants. Lithium sulphate, when applied to wheat seedlings, showed marked systemic activity against E. graminis. The toxicity of the salts towards Botrytis fabae was determined using the standard spore germination test and their toxicity towards broad bean and wheat seedlings was also assessed. Further tests were performed to ascertain the effect of bean sap upon the fungistatic activity of the salts. The degree of systemic activity shown by the salts is discussed in relation to such factors as their fungitoxicity, mode of action, fungitoxicity/phytotoxicity ratios, uptake by the plant and the degree to which plant sap inactivates them.
Hop line‐pattern virus in relation to the etiology and distribution of nettlehead disease
Authors: LEGG J. T. 
Published: February 2008

SUMMARYHop line‐pattern virus (HLPV) was transmissible by mechanical inoculation to hop plants; it induced characteristic severe symptoms in Humulus lupulus L. var. neo‐mexicanus Nels. & Cockerell and the commercial derivatives College Cluster and Keyworth's Midseason, but none in the traditional English varieties of H. lupulus (e.g. Fuggle).Mechanical transmission of hop nettlehead virus (HNV) was facilitated by the presence of HLPV in the test plants; hop seedlings and clonal plants escaped infection by sap inoculum that infected plants of two varieties already infected with HLPV. HNV was also transferred by stem contact and by knife cuts to plants carrying HLPV.Infection with HLPV was latent in twelve nettlehead‐diseased Fuggle plants from different fields, and in diseased and symptomless plants in a nettlehead outbreak in W.G.V., a variety that previously had escaped infection. It is suggested either that HLPV predisposes hop plants to infection with HNV or that nettlehead disease is caused by dual infection with both viruses.Localized and scattered patterns of nettlehead spread were observed in hop plantations; these two types are usually attributed to different modes of spread which would be compatible with a complex etiology of the disease.
The uptake of phorate, a systemic insecticide, applied as a slurry to wheat and mustard seeds
Authors: BARDNER R. 
Published: February 2008

SUMMARYThe absorption by plants of wheat and mustard of a systemic organophosphorus insecticide (phorate), applied as a slurry seed dressing, was studied by caging the aphid Rhopalosiphum padi (L.) on the foliage of wheat, and the aphid Brevicoryne brassicae (L.) and the Chrysomelid beetle Phaedon cochleariae (F.) on white mustard, grown from phorate‐treated seed.Wheat and mustard plants quickly lost their toxicity to insects when they were transplanted, suggesting that most of the insecticide from a slurry seed treatment passes into the soil and is picked up by the roots. That phorate or its derivatives occur in the soil was shown by tests of anticholinesterase activity. Insecticide can also pass into the seed of wheat and move to the growing embryo. Phorate becomes closely bound to the testa of mustard, but does not penetrate it to reach the cotyledons or other parts of the embryo. Mustard cotyledons can become contaminated by insecticide as they emerge through the soil.Young and old leaves of both wheat and mustard depend on continued absorption of insecticide from the soil to maintain their toxicity. No insecticide moves from old to young leaves. Old leaves lose their toxicity to insects more slowly than young ones. When treated seeds are sown close together, the overlapping zones of insecticide round each seed can increase strength and persistence of insecticidal effect. This happens more with dimethoate, which readily dissolves in water, than with phorate, which is almost insoluble. At normal sowing rates the zones of insecticide round each seed would rarely overlap.Roots of wheat and mustard from treated seed did not excrete insecticide, and the roots did not carry insecticide through the soil.
The effects of rates of supply of nitrogen, phosphorus, potassium and magnesium on leaf and stem growth, flowering and ‘topple’ of Golden Harvest and Elmus tulip
Authors: CHEAL W. F. , HEWITT E. J. 
Published: February 2008

SUMMARYIn factorial nutrition experiments with three rates of nitrogen, phosphorus and potassium—with some additional treatments with magnesium—on two bulb sizes of Golden Harvest and Elmus tulip, the effect of nitrogen was outstanding. Flowering was retarded by low and high rates of nitrogen supply. Increased nitrogen decreased the length of the first internode of Elmus. Mineral deficiency symptoms in leaf and stem showed minor varietal differences.Elmus tulips receiving amounts of calcium normally considered adequate developed ‘topple’ when given no nitrogen especially when combined with high potassium: these treatments also induced stem contortion in Golden Harvest, which appeared to be an analogous disorder to ‘topple’.
The structure of the egg‐shell of the cabbage root fly, Erioischia brassicae
Authors: HINTON H. E. , COLE S. 
Published: February 2008

SUMMARYThe structure of the egg‐shell of Erioischia brassicae (Bouché) (Muscidae, Anthomyiinae) has been investigated with the aid of an electron‐microscope. The shell outside the hatching lines consists of three layers. The middle layer is a coarse meshwork, the struts of which are about 1–2μ thick. The upper layer consists of vertical columns that arise from the middle layer. These vertical columns or struts branch and anastomose at their apices in the plane of the shell and form a network that is the outermost wall of the shell. The struts of this outermost network are 0.01‐0.1μ thick and thus little of the outermost wall of the shell can be resolved with the light microscope. The inner layer consists of vertical columns usually 2–5μ long. These branch and anastomose at their apices in the plane of the shell and form a network that is the innermost wall of the shell. The median strip between the hatching lines lacks an outer network. The meshworks of the shell offer little protection against desiccation, and water, alcohols, and relatively mobile oils pass readily through the shell.
Further experiments on the effect of beetle predators on the numbers of the cabbage root fly, Erioischia brassicae (Bouché), attacking brassica crops
Authors: COAKER T. H. 
Published: February 2008

SUMMARYFurther experiments to determine the importance of beetle predators were carried out at Wellesbourne during the three years 1960‐62. By using barriers to restrict the movement of adult carabids into and out of plots of brassica crops it was shown that the survival of the immature stages of the root fly was inversely related to the population level of predatory carabids. After excluding adult carabids almost entirely from the plots it was estimated that they had been responsible for up to one‐third of the total egg mortality, although this varied with the species composition of the carabid population. Initial differences in egg survival resulting from predation by carabids were reduced as the cabbage root fly life‐cycle progressed and were due to other losses of which predation by adult Staphylinidae was important. Such differences in egg survival, however, led to substantial crop yield reductions, particularly in dry weather.
The genetic relationships of pathotypes of Heterodera rostochiensis Woll. which reproduce on hybrid potatoes with genes for resistance
Authors: JONES F. G. W. , PARROTT DIANA M. 
Published: February 2008

SUMMARYThe hypothesis is advanced that the major genes for resistance to Heterodera rostochiensis in potatoes bred from Solanum tuberosum ssp. andigena (Ab), from S. multidissectum (aB) and from both (AB) are matched by recessive genes in the nematodes able to overcome resistance, The hypothesis postulates the existence of a pathotype that multiplies only on ab plants (susceptible commercial potatoes) and of one that multiplies on plants with both genes (AB). Evidence for the first is of a negative kind but there is positive evidence for the second. When the results of pot tests were combined with tests previously made by Jones & Pawelska (1963), and the forty populations were divided into four groups, the proportions of pathotypes in two groups fitted expectation. Proportions also fitted expectation for the other two groups and for the means of all forty populations when an adjustment was made to allow for the excessive number of cysts formed on plants ex andigena (Ab). The three groups of populations with appreciable numbers of the pathotype able to reproduce on AB plants discriminated between AB plants with and without an additional factor for resistance derived from S. multidissectum. This indicates the existence of yet another pathotype. AB plants with the additional resistance were about equally as resistant as S. vernei to all forty populations.Assuming that males of all genetic constitutions (AA, Aa, aa) can mature in the roots of resistance plants but only recessive females (aa) can mature, the proportion of aa progeny should rise to 50 % at the end of the second generation. Pot experiments fit expectation but, in field plots, persistence of the old population delays increase in the proportions of recessive individuals. The growing of plants with one dominant gene for resistance increases the proportions of the pathotype that can reproduce upon them and also that which can reproduce on plants with both genes.The hypothesis parallels the gene‐for‐gene theory advanced to explain the inheritance of the ability of certain rust fungi to overcome the resistance of their hosts but, when applied to Heterodera rostochiensis, has to take into account the faculty of larvae to become either male of female according to circumstances.
Growth of Cucumis sativus, variety Butcher's Disease Resister, with two concentrations of carbon dioxide
Authors: NEWTON PETER 
Published: February 2008

SUMMARYSupplementary carbon dioxide increased the growth rate of cucumber (Cucumis sativus, variety Butcher's Disease Resister) in pots in a glasshouse, by increasing both net assimilation rate and leaf expansion. It increased areas of individual leaves by increasing their growth rate before they emerged from the terminal bud. Growth rate after emergence was unaffected by CO2 concentration. When the pots became full of roots, increasing CO2 concentration had less effect on leaf growth, probably because of indirect effects of restricted root growth.
Investigation of carnation viruses
Authors: HOLLINGS M. , STONE OLWEN M. 
Published: February 2008

SUMMARYCarnation ringspot virus (CRSV) was isolated from twenty‐three carnation cultivars, was readily transmitted by grafting and sap‐rubbing inoculation, and was spread among carnations by handling. CRSV was cultured in Nicotiana clevelandii or carnation and assayed in Chenopodium amaranticolor; Gomphrena globosa was the best diagnostic indicator plant.CRSV was not transmitted by Myzus persicae or through seed of Dianthus barbatus. The virus infected sixty‐two out of ninety‐six plant species tested, but carnation is the only plant likely to be a virus source for commercial stocks. The concentration of CRSV decreased greatly in the terminal 1–2 mm. of the carnation shoot apex and, unlike carnation mottle, CRSV was not detected in the meristem dome; it was, however, present in some first leaf primordia. Clones free from the virus were obtained by aseptic culture of excised meristem‐tips, but more easily by growing infected carnations at 38–40d̀ C. for 4 weeks, followed by striking small cuttings or culturing meristem‐tips. N. clevelandii sap was infective after dilution to 1/100,000, heating for 10 min. to 85d̀ C. but not 90d̀ C., and storage for 16 days at 20d̀ C. or 3 months at 0d̀ C. Purified and concentrated preparations of CRSV from carnation, D. barbatus or N. clevelandii were highly infective, contained polyhedral particles about 29 mμ diameter, were antigenic, and produced a specific light‐scattering zone in density‐gradient centrifugation. The S20, w at infinite dilution was 140. CRSV shares many in vitro properties with eleven other viruses having similar particle shape, but it was not serologically related to any of them.
Some properties of clover yellow vein, a virus from Trifolium repens L.
Authors: HOLLINGS M. , NARIANI T. K. 
Published: February 2008

SUMMARYA virus differing from those previously described from leguminous plants was obtained from Trifolium repens in Surrey, and named clover yellow vein virus. It was transmitted by Myzus persicae and Acyrthosiphon pisum (not by Aphis fabae) in the non‐persistent manner, but not through seed. The virus infected nineteen out of sixty‐one plant species inoculated with sap: it was cultured in Nicotiana clevelandii, which reacted diagnostically and developed intracellular inclusions, and assayed in N. tabacum or Chenopodium quinoa. N. clevelandii sap was still infective after dilution to 1/10,000, heating for 10 min. at 55d̀ C. but not 60° C., and storing for 8 days at 18° C. or 75 days at 0° C. Infectivity, but not serological activity, was abolished by 0.2 or 2.0 % formaldehyde.Symptoms of clover yellow vein virus (CIYVV) were suppressed, and the virus was not detected, in infected N. clevelandii plants grown for 4 weeks at 38° C. Symptoms and detectable virus returned 5–6 weeks after heat‐treatment ceased. The virus had particles of normal length 670 mμ, and was partially purified and concentrated by several methods. Virus preparations gave specific zones when centrifuged in density gradients. CIYVV shares many properties with the aphid‐transmitted, slightly flexible rod‐shaped viruses in group 8 of Brandes & Wetter, but no relationship was detected serologically to those tested or to four other viruses with particles of similar dimensions.
Studies on parsnip canker
Authors: CHANNON A. G. 
Published: February 2008

SUMMARYCankers of parsnips growing in the East Anglian fens were caused by a species of Centrospora. Comparison of the morphology and pathogenicity of isolates from infected roots with those of isolates from carrot and celery and also with published information, indicated that the fungus from parsnips was C. acerina. One of the parsnip isolates saltated to give sectors resembling a culture received from the Centraalbureau voor Schimmelcultures, Baarn as C. macrospora, confirming that, as reported previously, this fungus is a form of C. acerina.The foliage of a wide range of seedling hosts was susceptible to artificial infection.In a laboratory test, wounding of parsnip roots before inoculation with Centrospora did not increase lesion development. Lines of parsnip bred for resistance to Itersonilia and Phoma were also resistant to attack by Centrospora.In view of the susceptibility of parsnips, carrots and celery to infection by C. acerina, adequate rotation on fen soils, where these crops are frequently grown, is advisable.