Rubio S.,Fera |
Barnes A.,Fera |
Webb K.,Fera |
Annals of Applied Biology | Year: 2017
Cryphonectria parasitica, an ascomycete fungus, is the causal agent of chestnut blight. This highly destructive disease of chestnut trees causes significant losses, and is therefore a regulated pathogen in Europe. Existing methods for the detection of C. parasitica include morphological identification following culturing, or PCR; however, these are time-consuming resulting in delays to diagnosis. To allow improved detection, a new specific real-time PCR assay was designed to detect C. parasitica directly from plant material and fungal cultures, and was validated according to the European Plant Protection Organisation (EPPO) standard PM 7/98. The analytical specificity of the assay was tested extensively using a panel of species taxonomically closely related to Cryphonectria, fungal species associated with the hosts and healthy plant material. The assay was found to be specific to C. parasitica, whilst the analytical sensitivity of the assay was established as 2pgμL-1 of DNA. Comparative testing of 63 samples of naturally infected plant material by the newly developed assay and traditional morphological diagnosis demonstrated an increased diagnostic sensitivity when using the real-time PCR assay. Furthermore the assay is able to detect both virulent and hypovirulent strains of C. parasitica. Therefore the new real-time PCR assay can be used to provide reliable, rapid, specific detection of C. parasitica to prevent the accidental movement of the disease and to monitor its spread. © 2017 Association of Applied Biologists.
Dorne J.L.,Unit on Contaminants |
Doerge D.R.,U.S. Food and Drug Administration |
Vandenbroeck M.,Unit on Contaminants |
Fink-Gremmels J.,University Utrecht |
And 6 more authors.
Toxicology and Applied Pharmacology | Year: 2013
Melamine can be present at low levels in food and feed mostly from its legal use as a food contact material in laminates and plastics, as a trace contaminant in nitrogen supplements used in animal feeds, and as a metabolite of the pesticide cyromazine. The mechanism of toxicity of melamine involves dose-dependent formation of crystals with either endogenous uric acid or a structural analogue of melamine, cyanuric acid, in renal tubules resulting in potential acute kidney failure. Co-exposure to melamine and cyanuric acid in livestock, fish, pets and laboratory animals shows higher toxicity compared with melamine or cyanuric acid alone. Evidence for crystal formation between melamine and other structural analogs i.e. ammelide and ammeline is limited. Illegal pet food adulterations with melamine and cyanuric acid and adulteration of milk with melamine resulted in melamine-cyanuric acid crystals, kidney damage and deaths of cats and dogs and melamine-uric acid stones, hospitalisation and deaths of children in China respectively. Following these incidents, the tolerable daily intake for melamine was re-evaluated by the U.S. Food and Drug Administration, the World Health Organisation, and the Scientific Panel on Contaminants in the Food Chain of the European Food Safety Authority (EFSA). This review provides an overview of toxicology, the adulteration incidents and risk assessments for melamine and its structural analogues. Particular focus is given to the recent EFSA risk assessment addressing impacts on animal and human health of background levels of melamine and structural analogues in animal feed. Recent research and future directions are discussed. © 2012 Elsevier Inc.
Ioos R.,Laboratoire Of La Sante Des Vegetaux |
Fourrier C.,Laboratoire Of La Sante Des Vegetaux |
Wilson V.,Laboratoire Of La Sante Des Vegetaux |
Webb K.,FERA |
And 2 more authors.
Phytopathology | Year: 2012
Plasmopara halstedii, the causal agent of downy mildew of sunflower, is an oomycete listed as a quarantine pathogen. This obligate parasite resides in a quiescent state in seeds of sunflower and can be spread from seed production areas to areas of crop production by international seed trade. To prevent the spread or the introduction of potentially new genotypes or fungicide-tolerant strains, an efficient method to detect P. halstedii in sunflower seed is required. This work reports the optimization of a real-time detection tool that targets the pathogen within sunflower seeds, and provides statistically validated data for that tool. The tool proved to be specific and inclusive, based on computer simulation and in vitro assessments, and could detect as few as 45 copies of target DNA. A fully optimized DNA extraction protocol was also developed starting from a sample of 1,000 sunflower seeds, and enabled the detection of <1 infected seed/1,000 seeds. To ensure reliability of the results, a set of controls was used systematically during the assays, including a plant-specific probe used in a duplex quantitative polymerase chain reaction that enabled the assessment of the quality of each DNA extract. © 2012 The American Phytopathological Society.
Cuthbertson A.G.S.,Fera |
Vanninen I.,Natural Resources Institute Finland
Insects | Year: 2015
The sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a major pest of economically important crops worldwide. Both the United Kingdom (UK) and Finland hold Protected Zone status against this invasive pest. As a result B. tabaci entering these countries on plants and plant produce is subjected to a policy of eradication. The impact of B. tabaci entering, and becoming established, is that it is an effective vector of many plant viruses that are not currently found in the protected zones. The Mediterranean species is the most commonly intercepted species of B. tabaci entering both the UK and Finland. The implications of maintaining Protected Zone status are discussed. © 2015 by the authors; licensee MDPI, Basel, Switzerland.
Cook R.T.A.,30 Galtres Avenue |
Braun U.,Martin Luther University of Halle Wittenberg |
Mycoscience | Year: 2011
Modes of branching of appressoria on conidial germ tubes of 36 Erysiphe spp. were studied. Only unlobed appressoria, termed alobatus pattern, were seen in E. lonicerae, E. magnifica and E. symphoricarpi. Viewed from above with light or scanning electron microscopes, other species had ± irregular lobing, but from below in the plane of contact with the substrate successive dichotomous branchings at 120° were seen to produce a five-lobed appressorium within 6 h. Each division produced a temporarily dormant outward-facing lobe and an inward limb that continued growth and division to form the axis of curved, hooked, single- or double-headed symmetrical or asymmetrical structures in a helicoid cyme-like pattern. Outlines of extracellular material after removal of germinated conidia confirmed this manner of branching. After 36 h some lobes re-divided forming botryose or jigsaw patterns even extending with extra appressoria to form candelabra-like structures. Conidia developed only one true germ tube; rarely secondary unswollen tubes emerged from spare shoulders or ends. The same true germ tubes developed initially on host surfaces, where secondary tubes and/or extensions from appressorial lobes grew into colony-forming hyphae. Lobed appressoria of Neoerysphe and Phyllactinia also branched at 120°. Podosphaera xanthii exhibited a simpler branching pattern. © 2010 The Mycological Society of Japan and Springer.
Cuthbertson A.G.S.,Fera |
Insects | Year: 2016
Drosophila suzukii populations remain low in the UK. To date, there have been no reports of widespread damage. Previous research demonstrated that various species of entomopathogenic fungi and nematodes could potentially suppress D. suzukii population development under laboratory trials. However, none of the given species was concluded to be specifically efficient in suppressing D. suzukii. Therefore, there is a need to screen further species to determine their efficacy. The following entomopathogenic agents were evaluated for their potential to act as control agents for D. suzukii: Metarhizium anisopliae; Isaria fumosorosea; a non-commercial coded fungal product (Coded B); Steinernema feltiae, S. carpocapsae, S. kraussei and Heterorhabditis bacteriophora. The fungi were screened for efficacy against the fly on fruit while the nematodes were evaluated for the potential to be applied as soil drenches targeting larvae and pupal life-stages. All three fungi species screened reduced D. suzukii populations developing from infested berries. Isaria fumosorosea significantly (p < 0.001) reduced population development of D. suzukii from infested berries. All nematodes significantly reduced adult emergence from pupal cases compared to the water control. Larvae proved more susceptible to nematode infection. Heterorhabditis bacteriophora proved the best from the four nematodes investigated; readily emerging from punctured larvae and causing 95% mortality. The potential of the entomopathogens to suppress D. suzukii populations is discussed. © 2016 by the authors; licensee MDPI, Basel, Switzerland.
Audsley N.,Fera |
Insect Biochemistry and Molecular Biology | Year: 2015
There is an on-going need for the discovery and development of new pesticides due to the loss of existing products through the continuing development of resistance, the desire for products with more favourable environmental and toxicological profiles and the need to implement the principles of integrated pest management. Insect G protein coupled receptors (GPCRs) have important roles in modulating biology, physiology and behaviour, including reproduction, osmoregulation, growth and development. Modifying normal receptor function by blocking or over stimulating its actions may either result in the death of a pest or disrupt its normal fitness or reproductive capacity to reduce pest populations. Hence GPCRs offer potential targets for the development of next generation pesticides providing opportunities to discover new chemistries for invertebrate pest control. Such receptors are important targets for pharmaceutical drugs, but are under-exploited by the agro-chemical industry. The octopamine receptor agonists are the only pesticides with a recognized mode of action, as described in the classification scheme developed by the Insecticide Resistance Action Committee, that act via a GPCR. The availability of sequenced insect genomes has facilitated the characterization of insect GPCRs, but the development and utilization of screening assays to identify lead compounds has been slow. Various studies using knock-down technologies or applying the native ligands and/or neuropeptide analogues to pest insects in vivo, have however demonstrated that modifying normal receptor function can have an insecticidal effect.This review presents examples of potential insect neuropeptide receptors that are potential targets for lead compound development, using case studies from three representative pest species, Tribolium castaneum, Acyrthosiphon pisum, and Drosophila suzukii.Functional analysis studies on T. castaneum suggest that GPCRs involved in growth and development (eclosion hormone, ecdysis triggering hormone and crustacean cardioacceleratory peptide receptors) as well as the dopamine-2 like, latrophilin-like, starry night, frizzled-like, methuselah-like and the smoothened receptors may be suitable pesticide targets.From in vivo studies using native ligands and peptide analogues, receptors which appear to have a role in the regulation of feeding in the pea aphid, such as the PISCF-allatostatin and the various "kinin" receptors, are also potential targets.In Drosophila melanogaster various neuropeptides and their signalling pathways have been studied extensively. This may provide insights into potential pesticide targets that could be exploited in D. suzukii. Examples include the sex peptide receptor, which is involved in reproduction and host seeking behaviours, and those responsible for osmoregulation such as the diuretic hormone receptors.However the neuropeptides and their receptors in insects are often poorly characterized, especially in pest species. Although data from closely related species may be transferable (e.g. D. melanogaster to D. suzukii), peptides and receptors may have different roles in different insects, and hence a target in one insect may not be appropriate in another. Hence fundamental knowledge of the roles and functions of receptors is vital for development to proceed. © 2015 Elsevier Ltd.
Ramwell C.T.,Fera |
Kah M.,Fera |
Pest Management Science | Year: 2014
BACKGROUND: It is necessary to understand the extent to which different sources of pesticides contribute to surface water contamination in order to focus preventive measures appropriately. The extent to which glyphosate use in the home and garden sector may contribute to surface water contamination has not previously been quantified. The aim of this study was to quantify the widely used herbicide glyphosate and its degradation product aminomethylphosphonic acid (AMPA) in surface water drains (storm drains) that could be attributed to amateur, non-professional usage alone. RESULTS: Maximum glyphosate and AMPA concentrations in surface water drains were 8.99 and 1.15 μg L-1 respectively after the first rain event following the main application period, but concentrations rapidly declined to <1.5 and <0.5 μg L-1. The AMPA:glyphosate ratio was typically 0.35. Less than 1% of the applied glyphosate was recovered in drain water. CONCLUSION: Glyphosate and AMPA losses from urban areas that arise solely from amateur usage have been quantified. In spite of overdosing occurring, glyphosate concentrations in drain flow were lower than concentrations reported elsewhere from professional use in urban areas. © 2014 Society of Chemical Industry.
Mumford R.A.,Fera |
Macarthur R.,Fera |
Food Security | Year: 2016
Pest and pathogens pose a major threat to food security and the natural environment, and these threats are moving around the globe. Trade, travel and transport have major roles to play in this and thus to improve plant biosecurity, we need enhanced phytosanitary inspection systems. In order to achieve this, there is a role for the more effective use of diagnostic technology, such as field-based testing or the use of next generation sequencing technology. In this review we examine the opportunities and challenges posed by using new technology within a plant biosecurity context, but in contrast to previous reviews, here we focus on practical challenges associated with deployment and routine use, rather than specific technical issues. These key challenges include the need to accelerate the development and deployment of new technologies into the field, the accelerated discovery of new pathogens and the need for new risk assessment approaches, and improvements to our understanding of how best to deploy and use new diagnostic tools for maximum impact. Throughout we focus on how interdisciplinary approaches are important to help us improve our understanding and achieve our goals. © 2015, Springer.
Elston C.,Imperial College London |
Thompson H.M.,Fera |
Walters K.F.A.,Imperial College London
Apidologie | Year: 2013
This study investigated whether field-realistic exposure to a neonicotinoid insecticide and a fungicide affected nest building or brood production in queenless Bombus terrestris micro-colonies in the laboratory. Bees were exposed to honey water and pollen paste containing field-realistic mean or field-maximum exposure rates of thiamethoxam (1, 10 μg/kg) or propiconazole (23, 230 mg/kg) for 28 days. Thiamethoxam: Both doses reduced consumption of honey water solution and resulted in fewer wax cells. At 10 μg/kg, nest building initiation was delayed, fewer eggs were laid and no larvae produced. Propiconazole: Both doses reduced consumption of honey water solution. At 23 mg/kg, fewer wax cells were produced. Thus, at realistic (mean) exposure rates of these pesticides, no adverse impacts on brood production were found. Pesticide-free alternative forage will reduce field exposure by dilution and thus the impact of maximum rates. © 2013 INRA, DIB and Springer-Verlag France.