Dewar A.M.,Dewar Crop Protection Ltd |
Dewar A.M.,Brooms Barn Research Center |
Foster S.,Rothamsted Research
Outlooks on Pest Management | Year: 2017
Recent epidemics of barley yellow dwarf virus (BYDV) in the UK in the springs of 2012 and 2016 have been associated with, perhaps even caused by, the grain aphid, Sitobion avenae, that is resistant to pyrethroids. Over-use of pyrethroids in the last decade or more, encouraged by their low cost, has resulted in up to 50% of this aphid species in the eastern region of England containing the kdr resistance mutation. The recent withdrawals of alternative insecticides such as pirimicarb and chlorpyrifos have left growers with only pyrethroids approved as sprays for autumn use. The neonicotinoid insecticide clothianidin is approved as a seed treatment, and is especially useful in early sown crops of wheat or barley (before end of October), but its long-term availability is threatened by a restriction due to be implemented by the French government in September 2018, that may be adopted in other countries across Europe, including the UK. It is essential that growers now employ integrated pest management schemes to minimize exposure of cereal aphids to pesticides, and thus reduce the selection pressure, now and when new insecticides are introduced in the future. Cereal aphids have been pests of cereals as long as man has grown the crop. In the UK three species are more abundant than others-the grain aphid, Sitobion avenae, the rose-grain aphid, Metopolophium dirhodum, and the bird-cherry-oat aphid, Rhopalosiphum padi. One or more of these important species can cause serious yield losses in some years, either by direct feeding damage, or by spreading plant viruses, especially barley yellow dwarf virus (BYDV). BYDV comes in several strains, but one in particular, the PAV strain, is transmissible by two of the three main species of aphid, namely R. Padi and S. Avenae, and has been more prevalent in recent years in the UK. This article examines changes in the ecology of cereal aphids and their associated crops over the last 40 years, and explains how over-use of insecticides applied to control them has inadvertently exacerbated the incidence of BYDV-the law of unintended consequences. © 2017 Research Information Ltd.
West J.S.,Rothamsted Research |
Townsend J.A.,Rothamsted Research |
Stevens M.,Rothamsted Research |
Stevens M.,Brooms Barn Research Center |
And 2 more authors.
European Journal of Plant Pathology | Year: 2012
This review describes environmental factors that influence severity of crop disease epidemics, especially in the UK and north-west Europe, in order to assess the effects of climate change on crop growth and yield and severity of disease epidemics. While work on some diseases, such as phoma stem canker of oilseed rape and fusarium ear blight of wheat, that combine crop growth, disease development and climate change models is described in detail, climate-change projections and predictions of the resulting biotic responses to them are complex to predict and detailed models linking climate, crop growth and disease development are not available for many crop-pathogen systems. This review uses a novel approach of comparing pathogen biology according to 'ecotype' (a categorization based on aspects such as epidemic type, dissemination method and infection biology), guided by detailed disease progress models where available to identify potential future research priorities for disease control. Consequences of projected climate change are assessed for factors driving elements of disease cycles of fungal pathogens (nine important pathogens are assessed in detail), viruses, bacteria and phytoplasmas. Other diseases classified according to 'ecotypes' were reviewed and likely changes in their severity used to guide comparable diseases about which less information is available. Both direct and indirect effects of climate change are discussed, with an emphasis on examples from the UK, and considered in the context of other factors that influence diseases and particularly emergence of new diseases, such as changes to farm practices and introductions of exotic material and effects of other environment changes such as elevated CO 2. Good crop disease control will contribute to climate change mitigation by decreasing greenhouse gas emissions from agriculture while sustaining production. Strategies for adaptation to climate change are needed to maintain disease control and crop yields in north-west Europe. © 2012 KNPV.
Zhang L.,University of Nottingham |
Zhang L.,King's College London |
Clarke M.L.,University of Nottingham |
Steven M.D.,University of Nottingham |
Jaggard K.W.,Brooms Barn Research Center
Precision Agriculture | Year: 2011
Precision irrigation requires the mapping of within-field variations of water requirement. Conventional remote sensing techniques provide estimates of water status at only shallow soil depths. The ability of a water sensitive crop, sugar beet, to act as an intermediate sensor providing an integrated measure of water status throughout its rooting depth is tested here. Archive aerial photographs and satellite imagery of Eastern England show crop patterns resulting from past periglacial processes. The patterns were found to be spatially and temporally consistent. Field sampling of soil cores to 1 m depth established that the within-field wilting zones were significantly associated with coarser or shallow soils. The stress classes, determined by classification of the digitised images, were weakly correlated with total available water (Pearson correlation r=0.588,P<0.05).These results suggest that wilting in sugar beet can be used as an intermediate sensor for quantifying potential soil water availability within the root zone. Within-field stress maps generated in 1 year could be applied as a strategic tool allowing precision irrigation to be applied to high-value crops in following years, helping to make more sustainable use of water resources. © 2010 Springer Science+Business Media, LLC.
Abou-Elwafa S.F.,University of Kiel |
Buttner B.,University of Kiel |
Chia T.,Brooms Barn Research Center |
Schulze-Buxloh G.,University of Kiel |
And 5 more authors.
Journal of Experimental Botany | Year: 2011
The transition from vegetative growth to reproductive development is a complex process that requires an integrated response to multiple environmental cues and endogenous signals. In Arabidopsis thaliana, which has a facultative requirement for vernalization and long days, the genes of the autonomous pathway function as floral promoters by repressing the central repressor and vernalization-regulatory gene FLC. Environmental regulation by seasonal changes in daylength is under control of the photoperiod pathway and its key gene CO. The root and leaf crop species Beta vulgaris in the caryophyllid clade of core eudicots, which is only very distantly related to Arabidopsis, is an obligate long-day plant and includes forms with or without vernalization requirement. FLC and CO homologues with related functions in beet have been identified, but the presence of autonomous pathway genes which function in parallel to the vernalization and photoperiod pathways has not yet been reported. Here, this begins to be addressed by the identification and genetic mapping of full-length homologues of the RNA-regulatory gene FLK and the chromatin-regulatory genes FVE, LD, and LDL1. When overexpressed in A. thaliana, BvFLK accelerates bolting in the Col-0 background and fully complements the late-bolting phenotype of an flk mutant through repression of FLC. In contrast, complementation analysis of BvFVE1 and the presence of a putative paralogue in beet suggest evolutionary divergence of FVE homologues. It is further shown that BvFVE1, unlike FVE in Arabidopsis, is under circadian clock control. Together, the data provide first evidence for evolutionary conservation of components of the autonomous pathway in B. vulgaris, while also suggesting divergence or subfunctionalization of one gene. The results are likely to be of broader relevance because B. vulgaris expands the spectrum of evolutionarily diverse species which are subject to differential developmental and/or environmental regulation of floral transition. © 2011 The Author(s).
Burlakoti P.,North Dakota State University |
Rivera V.,North Dakota State University |
Secor G.A.,North Dakota State University |
Qi A.,Brooms Barn Research Center |
And 2 more authors.
Plant Disease | Year: 2012
In all, 98 isolates of three Fusarium spp. (18 Fusarium oxysporum, 30 F. graminearum, and 50 Fusarium sp. nov.) obtained from sugar beet in Minnesota were characterized for pathogenicity and virulence on sugar beet in the greenhouse by a bare-root inoculation method. Among the 98 isolates tested, 80% of isolates were pathogenic: 83% of the F. oxysporum isolates, 57% of the F. graminearum isolates, and 92% of the Fusarium sp. nov. isolates. Symptoms varied from slight to moderate wilting of the foliage, interveinal chlorosis and necrosis, and vascular discoloration of the taproot without any external root symptoms. Among the pathogenic isolates, 14% were highly virulent and 12% were moderately virulent. Most of the highly virulent isolates (91%) and moderately virulent isolates (89%) were Fusarium sp. nov. All pathogenic isolates of F. graminearum and most pathogenic isolates (87%) of F. oxysporum were less virulent. In general, more-virulent isolates induced first foliar symptoms earlier compared with lessvirulent isolates. This study indicates that both F. oxysporum and Fusarium sp. nov. should be used in greenhouse and be present in field studies used for screening and developing sugar beet cultivars resistant to Fusarium yellows complex for Minnesota and North Dakota. © 2012 The American Phytopathological Society.
Jaggard K.W.,Brooms Barn Research Center |
Zhao F.-J.,Rothamsted Research
Journal of Agricultural Science | Year: 2011
Six field experiments were carried out in eastern England between 2003 and 2005 to test the effect of sulphur (S) fertilizer on the yield of sugar beet (Beta vulgaris L.). The experiments were undertaken at sites where there had previously been a positive response to S in other crops or where no S-containing materials had been applied for more than 20 years. No individual experiment produced a significant positive response to S application, but the treatments that received no S fertilizer produced the smallest yield in five of the six experiments. Analysis across years using restricted maximum likelihood (REML) procedures showed that there was a positive and significant sugar yield response in beet of 0.56 t/ha where positive responses had previously been recorded in other crops grown on these loamy sand soils. Beet crops grown in soils of this type should receive S fertilizer that can be applied conveniently as sufficient ammonium sulphate to supply the first dressing of N. Copyright © 2010 Cambridge University Press.
Champion G.,Brooms Barn Research Center
Journal fur Verbraucherschutz und Lebensmittelsicherheit | Year: 2011
When the farm scale evaluations (FSE) of GMHT crops were initiated in the UK there was very little information in the UK on the variability of many farmland species within fields to inform the design of such trials. The original assumptions used in the calculations of site replication were tested using data collected in year 1 and 2. At this time the possibility of increasing site numbers in year 3 remained, but site replication was found to be sufficient. Upon completion of the trials, analyses of the data collected have validated the site replication and the power of the study to detect biologically important differences between conventional and GMHT management systems. Sub-samples of data corresponding to reduced sampling protocols at each site were analysed to investigate ways to reduce in-field sampling time whilst retaining the same precision as in the original scheme. The relative costs of the various protocols employed, both in staff time and financially have been published, as this too is an important constraint when planning any project. Besides producing the data necessary to test the null hypothesis, the FSE has also provided a significant body of information on the UK experience with the variability of farmland plants and invertebrates with a change in management practices, which is a key resource for future researchers in designing other field-based studies. © 2011 Bundesamt für Verbraucherschutz und Lebensmittelsicherheit (BVL).
May M.,Brooms Barn Research Center
Issues in Environmental Science and Technology | Year: 2010
Beet was first developed as a sugar producing crop in the late 16 th century. During the Napoleonic wars the naval blockade of France forced European countries to develop the crop. However, it was not until the 19th century that beet was finally established for sugar production in areas such as Europe, Scandinavia and North America. Sugar beet factories are generally efficient at produce a wide range of products as well as sugar. These include animal feed, medical products, foods and agricultural fertilisers. Sucrose production from sugar beet has always been subject to political influences and most countries operate under production quota systems. The fermentation of ethanol in beet factories helps to provide a partial solution to the problem of what to do with any excess sugar production. Sugar beet can also be a good substrate for biogas. The energy used per hectare to produce beet for biofuel is less than that for wheat or corn, but the main problem with beet is the difficulty of storage of the roots and, hence, provision of allyearround substrate for biofuel production. A limited amount of research is being undertaken to improve the opportunities for beet as a biofuel crop. © 2011 Royal Society of Chemistry.
Dodd I.C.,Lancaster University |
Whalley W.R.,Rothamsted Research |
Ober E.S.,Brooms Barn Research Center |
Parry M.A.J.,Rothamsted Research
Journal of Experimental Botany | Year: 2011
Faced with the challenge of increasing global food production, there is the need to exploit all approaches to increasing crop yields. A major obstacle to boosting yields of wheat (an important staple in many parts of the world) is the availability and efficient use of water, since there is increasing stress on water resources used for agriculture globally, and also in parts of the UK. Improved soil and crop management and the development of new genotypes may increase wheat yields when water is limiting. Technical and scientific issues concerning management options such as irrigation and the use of growth-promoting rhizobacteria are explored, since these may allow the more efficient use of irrigation. Fundamental understanding of how crops sense and respond to multiple abiotic stresses can help improve the effective use of irrigation water. Experiments are needed to test the hypothesis that modifying wheat root system architecture (by increasing root proliferation deep in the soil profile) will allow greater soil water extraction thereby benefiting productivity and yield stability. Furthermore, better knowledge of plant and soil interactions and how below-ground and above-ground processes communicate within the plant can help identify traits and ultimately genes (or alleles) that will define genotypes that yield better under dry conditions. Developing new genotypes will take time and, therefore, these challenges need to be addressed now. © 2011 The Author.
PubMed | Brooms Barn Research Center
Type: | Journal: AoB PLANTS | Year: 2012
Bolting, the first visible sign of reproductive transition in beets (Beta vulgaris), is controlled by the dominant bolting gene B (B allele), which allows for flowering under long days (LDs, >14 h light) without prior vernalization. The B-locus carries recessive alleles (bb) in sugar beet (Beta vulgaris L. spp. vulgaris), so that vernalization and LDs are required for bolting and flowering. Gibberellin growth hormones (GAs) control stem elongation and reproductive development, but their role during these processes in sugar beet is not defined. We aimed to investigate the involvement of GAs in bolting and flowering in sugar beet, and also its relationship with the vernalization requirement as defined by the B-gene.Plants segregating for the B allele were treated with exogenous GA(4) under inductive (16 h light) and non-inductive (8 h light) photoperiods, with and without prior vernalization treatment. A co-dominant polymerase chain reaction (PCR) marker was used to genotype the B-gene locus. Bolting and flowering dates were scored, and bolt heights were measured as appropriate. Analysis of variance was used to determine the effects and interactions of GAs, the B allele and vernalization on bolting and flowering. The effects of the B allele on bolting were also verified in the field.Application of GAs or the B allele could initiate bolting independently. When the B allele was absent, the applied GAs promoted stem growth, but did so only in vernalized plants, irrespective of photoperiod. Under LDs, bolt height before flowering in plants carrying the B allele (BB; Bb) was not significantly influenced by GAs. The timing and frequency of flowering were influenced by the B allele without interactive effects from GAs.In sugar beet, GA acts independently of the B allele and photoperiod to induce bolting. Vernalization enables GA action independently of the B allele; hence, the dominant B allele may not directly participate in vernalization-induced bolting.