226 research outputs found

    Grain yield reductions in spring barley due to barley yellow dwarf virus and aphid feeding

    Get PDF
    peer-reviewedThe occurrence and control of barley yellow dwarf virus (BYDV) in spring barley was investigated, at Oak Park, in the periods 1990 to 1993 and 1996 to 2001. Barley was sown in March and April and treated with either organophosphorous or pyrethroid aphicide at various plant growth stages. The most common aphid encountered was Sitobion avenae and MAV the most common strain of BYDV. In untreated plots of March- and April-sown barley, 0.85% and 5.9%, respectively, of tillers had virus symptoms. Best control of symptoms, from a single aphicide in March- and April-sown crops, was a treatment at growth stage (g.s.) 14. This treatment contributed 77% of the reduction in symptoms recorded for multiple treatments in April-sown plots. The reduction in grain yield due to high, moderate and low BYDV infection in April-sown barley was 1.1 t/ha (20%), 0.65 t/ha (10%) and 0.36 t/ha (7%), respectively. In Marchsown barley, pyrethroid aphicide applied at g.s. 14 significantly improved grain yield by 0.26 t/ha (4%). In the season having the most severe BYDV outbreak, a pyrethroid aphicide at g.s. 14 was best in controlling yield loss. Pyrethroid aphicide gave better control of symptoms and better yields than organophosphorous aphicide. The estimated yield reductions in untreated April-sown barley due to feeding damage by Sitobion avenae was 0.71 t/ha and 0.83 t/ha (10.6% and 11.3%) in the two seasons in which this aphid was plentiful. In the three seasons in which Metopolophium dirhodum was recorded the estimated yield reductions were 0.32 t/ha, 0.48 t/ha and 0.43 t/ha (5.2%, 5.6% and 5.7%)

    An evaluation of seed-pellet insecticides in a precision drilled crop of sugar beet

    Get PDF
    peer-reviewedThe control of soil pests of sugar beet by means of seed-pellet insecticides was investigated on each of two farms in Co. Wexford from 2000 to 2002. The farms on which trials were conducted differed each season. A number of seed-pellet insecticides were compared with the standard methiocarb seed treatment, methiocarb supplemented with the in-furrow applied granule insecticide carbo furan-isofenphos and with an untreated control. Imidacloprid, Montur and thiamethoxam significantly reduced onychiurid numbers around seedlings compared with the untreated control and significantly reduced pest damage to seedlings compared with the standard methiocarb treatment. Imidacloprid gave best control of pest biting of seedlings and was as effective as the in-furrow incorporated granule insecticide in preventing pest damage and plant mortality at sites having moderate onychiurid infestations. Montur, while less effective than imidacloprid in controlling pest bites on seedling roots, gave consistently good plant establishment. Thiamethoxam was less effective than imidacloprid in some trials at reducing plant damage and mortality. The retardation of seedling growth and establishment recorded for insecticidepropamocarb combinations relative to insecticide-hymexazol combinations in some field and glasshouse trials could be overcome by replacing propamocarb with hymexazol

    An Investigation of Seed Treatments for the Control of Crow Damage to Newly-Sown Wheat

    Get PDF
    End of project reportSeed treatments for the control of crow damage to newly-sown winter and spring wheat were evaluated in field trials from 2004 to 2007. Treatments included six fungicides, three insecticides, a product marketed as a bird repellent and three possible repellents. Various rates of selected compounds were investigated. Winter wheat was sown in December and spring wheat in late-January to mid-February. Sowing depth was 2 to 4 cm while some selected treatments were also sown at 5 to 9 cm deep. Crow damage was assessed by recording plant density and grain yield. Severe damage by crows was recorded. The plant population for untreated spring wheat seed in 2004, 2005 and 2006 was reduced by 59%, 72% and 89%, respectively. The corresponding reductions caused by crows to winter wheat sown in December 2004, 2005 and 2006 was 97%, 89% and 96%. Best control of crow damage was provided by the fungicide Thiram. Increasing the rate of Thiram applied to seed improved the control of crow damage by increasing plant density in the range 42 to 70% and 36 to 57%, respectively, for spring and winter wheat when compared with untreated seed. Anchor, which contains the fungicides Thiram and Carboxin, also gave reasonably good control. The commonly used fungicide product panoctine gave poor control of crow damage. Other treatments investigated were ineffective in controlling damage. Increasing the sowing depth to more than 4.6 cm significantly reduced damage to both treated and untreated seed when compared with similar treatments sown less than this depth

    Control of insect transmitted virus diseases in cereals and sugar beet.

    Get PDF
    End of Project ReportThe objective of this investigation was to determine if, in a mild autumn when aphid numbers were high, the recommended aphicide treatments derived from earlier trial results were adequate to control BYDV in autumn-sown barley. Investigations on spring barley at Oak Park, 1990-1993, showed Barley Yellow Dwarf Virus (BYDV) can cause reductions in grain yield of up to 1.4 t/ha. These studies indicated that the risk of infection increased with lateness of sowing date. They also suggested that control of the disease might best be obtained by applying an aphicide at the 4-leaf stage of growth. The objectives of this investigation were to determine the growth stage at which aphicide should be applied in order to obtain best control of BYDV and to compare the effectiveness of systemic and contact aphicides in controlling the disease.Aphid numbers, species and infectivity with virus yellows were monitored in 20 beet crops between May and July over the period 1990-1999. Monitoring was undertaken to provide growers with an aphid-spray warning in order to minimise the risk of virus yellows and to establish aphid-thresholds which if exceeded would necessitate the spraying of crops with insecticide.Teagasc acknowledges the support of Irish Sugar, Sugar Beet Levy Farmer Funds and Cereals Levy Farmer Fund

    Effect of early sowing on the growth, yield and quality of sugar beet.

    Get PDF
    End of Project ReportExperiments have shown that yield of sugar is closely related to the amount of solar radiation intercepted by a sugar beet crop. Early sowing increases leaf area from May onwards when radiation is at its maximum and provides a basis for increasing yields. In the past, bolting has been an undesirable consequence of early sowing but some modern cultivars have good bolting resistance and can be sown early with a limited risk of bolting. This study, conducted from 1994 to 1998, compared the performance of two cultivars, Celt and Monofeb, at three sowing dates and three harvest dates. In replicated experiments, plant establishment, crop development, and root yield and quality were assessed. The effect of sowing date on solar radiation interception was studied. Effects of in-furrow pesticide application on pest numbers and plant damage were also measured. Plant establishment was influenced by sowing date with the early sowings generally giving lower plant numbers than the later ones. The cultivar Celt produced higher populations than Monofeb at all sowing dates. Early sowing increased the leaf area index (a measure of the ratio of leaf to land area) and consequently the amount of solar radiation intercepted. This was particularly so in June when solar radiation levels are highest. Early crop establishment provides the opportunity to exploit good weather conditions which may occur in April or May. Pest numbers generally were small at all the sites. Insecticide had a greater effect on pest numbers and plant damage than it had on plant establishment; the beneficial effects of pesticide were slightly more pronounced for the early and mid-season sowings than for later-sown beet. Seedling diseases were not a problem at any time of sowing. Poor emergence, where it occurred, was not associated with pre-emergence disease. Early to mid-March sowings produced significantly higher yields of roots and sugar than the early or late April sowings over the period of the experiment. Even in years when plant populations from the first sowings were much lower than subsequent sowings, yields tended to be at least equal to those of later sowings. Monofeb produced a slightly higher root yield than Celt, but because it had lower sugar contents there was no difference in sugar yields. Harvesting extended over the period from early October to mid-November and root growth and sugar production increased over that period irrespective of sowing date. Bolting was a problem in 1996 on the early-sown plots, particularly with the cultivar Celt.Teagasc acknowledges the support of Irish Sugar plc and Sugar Beet Levy Farmer Funds in the financing of this projec

    A study of cultivation and sowing systems for cereals.

    Get PDF
    End of Project ReportDue to the pressure on cereal margins growers are seeking ways of reducing their costs of production. Reduced cultivation may provide cheaper and faster crop establishment, but in the past has been subject to problems with (poor crop establishment) weeds and soil compaction. With modern cultivation and sowing technology and methodology it may be possible to overcome these difficulties. In addition reduced cultivation is considered to be more environmentally friendly and sustainable than the conventional plough-based system. With these considerations in mind it was decided to start an experiment in autumn 2000 to compare the conventional system (PL) with reduced cultivation (RC) for crop establishment, and to examine the effect of incorporating the straw into then soil or baling and removing it. The treatments were assessed on winter wheat, and winter and spring barley. The parameters assessed included – crop establishment, yield and quality effects on disease levels, invertebrate pests and beneficials (aphids, slugs, earthworms, beetles), and soil conditions. The work reported here was conducted on four trial sites at Oak Park, Carlow and Knockbeg, Co. Laois from 2000 to 2003. the objectives were to establish the efficacy of RC compared with PL and to its effects on the parameters outlined above. Plant establishment was lower after RC in most of the experiments. Winter wheat yields were good irrespective of the number of plants established and there were no significant differences between cultivation or straw disposal method. The relative yields of the PL and RC treatments in winter barley varied over the three years; in 2001 there was no difference, in 2002 PL yielded 1 t/ha more than RC, while in 2003 the PL area produced 2 t/ha extra. Spring barley yields were similar on the PL and RC treatments. Broadleaved weeds were not a problem on the PL or RC treatments but there were more annual grass weeds on the RC plots. This was particularly serious in the winter barley experiments where sterile brome (Bromus sterilis) had a big effect on yield by 2003. annual meadow grass (Poa annua) was a problem in both PL and RC areas if not controlled by timely herbicide application; this was particularly so on the headland areas in the spring barley field. Disease assessment on the winter wheat trail showed no significant differences in Take-all or Eyespot levels between cultivation or straw disposal methods, although Take-all levels tended to be lower on the RC plots. Soil strength as measured by cone penetrometer and shear vane was higher on the RC treatments. In the winter wheat there was no difference in slug numbers between any of the treatments. Leaf damage by slugs increased in RC relative to PL but not significantly, in 2003. No below ground slug damage was found. Earthworm numbers in the winter barley increased significantly on the RC treatment relative to the PL as the study progressed. Straw incorporation increased earthworm numbers on both PL and RC treatments. Allolobophora chlorotia was the most common species in 2004. In the winter wheat the RC and straw incorporation increased earthworm numbers. Cultivation method had a greater effect on ground beetle numbers than method of straw disposal. Large species (e.g. Pterostichies malanarius) were favoured by RC while smaller species (e.g. Bembidon species) were more numerous in the PL plots. Molecular studies on virus diseases, vectors and vector-predators are underway in progress. In the invertebrate pests and beneficials investigations the RC winter barley had 11% fewer aphids and 27% less BYDV than the PL. Incorporating straw reduced aphid numbers and virus incidence by 36% and 32% respectively; the comparable values for the PL + straw treatment were 15% and 15%. In the winter wheat there was less BYDV in the RC plots than the PL + less were the straw was incorporated than where the straw was removed. Aphid infestation of wheat ears was low in the three years of the experiment. The insecticide seed treatment imidacloprid significantly reduced aphid numbers and virus incidence in winter barley but was less effective than a single insecticide spray in controlling the disease. The seed treatment was more effective in controlling BYDV in RC than in the PL plots. Estimations of slug numbers in the winter barley showed that the dominant species was the grey field slug (Deroceras reticulatum). Slug numbers increased significantly on all treatments between 2001 and 2004. In November 2004, slugs were significantly more numerous in the RC treatments than in the PL areas. Leaf damage was proportional to slug populations, but the slugs did not damage the barely seed or reduce plant populations in continuous winter barley under RC. Root and stem diseases (Take-all and Eyespot) were not nay worse under RC than after PL. In fact there was a tendency towards lower disease levels on the RC areas and there was significantly less sharp eyespot on the RC treatment

    Relational Hidden Variables and Non-Locality

    Full text link
    We use a simple relational framework to develop the key notions and results on hidden variables and non-locality. The extensive literature on these topics in the foundations of quantum mechanics is couched in terms of probabilistic models, and properties such as locality and no-signalling are formulated probabilistically. We show that to a remarkable extent, the main structure of the theory, through the major No-Go theorems and beyond, survives intact under the replacement of probability distributions by mere relations.Comment: 42 pages in journal style. To appear in Studia Logic

    Functional skewing of the global CD8 T cell population in chronic hepatitis B virus infection

    Get PDF
    The inflamed liver in chronic hepatitis B virus (HBV) infection (CHB) is characterized by a large influx of non–virus-specific CD8 T cells. Little is known about the functional capacity of these lymphocytes, which could provide insights into mechanisms of failure of viral control and liver damage in this setting. We compared the effector function of total circulating and intrahepatic CD8 T cells in CHB patients and healthy donors. We demonstrated that CD8 T cells from CHB patients, regardless of their antigen specificity, were impaired in their ability to produce interleukin-2 and proliferate upon TCR-dependent stimulation. In contrast, these CD8 T cells had preserved production of the proinflammatory cytokines interferon-γ and tumor necrosis factor-α. This aberrant functional profile was partially attributable to down-regulation of the proximal T cell receptor signaling molecule CD3ζ, and could be corrected in vitro by transfection of CD3ζ or replenishment of the amino acid arginine required for its expression. We provide evidence for depletion of arginine in the inflamed hepatic microenvironment as a potential mechanism for these defects in global CD8 T cell signaling and function. These data imply that polarized CD8 T cells within the HBV-infected liver may impede proliferative antiviral effector function, while contributing to the proinflammatory cytokine environment

    Socially impaired robots: Human social disorders and robots’ socio-emotional intelligence

    Full text link
    © Springer International Publishing Switzerland 2014. Social robots need intelligence in order to safely coexist and interact with humans. Robots without functional abilities in understanding others and unable to empathise might be a societal risk and they may lead to a society of socially impaired robots. In this work we provide a survey of three relevant human social disorders, namely autism, psychopathy and schizophrenia, as a means to gain a better understanding of social robots’ future capability requirements.We provide evidence supporting the idea that social robots will require a combination of emotional intelligence and social intelligence, namely socio-emotional intelligence. We argue that a robot with a simple socio-emotional process requires a simulation-driven model of intelligence. Finally, we provide some critical guidelines for designing future socio-emotional robots

    Evidence for a narrow dip structure at 1.9 GeV/c2^2 in 3π+3π3\pi^+ 3\pi^- diffractive photoproduction

    Full text link
    A narrow dip structure has been observed at 1.9 GeV/c2^2 in a study of diffractive photoproduction of the  3π+3π~3\pi^+3\pi^- final state performed by the Fermilab experiment E687.Comment: The data of Figure 6 can be obtained by downloading the raw data file e687_6pi.txt. v5 (2nov2018): added Fig. 7, the 6 pion energy distribution as requested by a reade
    corecore