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LWEC TH phase 1 - Accelerated detection and diagnosis of invasive alien pests and pathogens in imported plants - TH0122

This project lies in the “Detection” theme. Our ability to detect potentially invasive pests and pathogens at ports of entry is a major focus of phytosanitary regulation. Despite many interceptions by the authorities, the number of invasive pests and pathogens coming into the UK is increasing at an alarming rate. Many of these invasive organisms are establishing in our forests and woodlands, resulting in high rates of damage and threatening entire ecosystems. These problems illustrate the urgent need for more stringent techniques to detect invasive pests and pathogens in consignments of plants during import into both sea and airports.
Current methods of detection, relying on visual and/or molecular (DNA)-based detection techniques, are extremely useful, but have certain serious constraints to their effectiveness:
1. Both methods must be highly targeted to be successful
a. Inspectors cannot examine (visually) more than a very small proportion of imported plants;
b. The molecular approach has similar constraints, as the detection of pests and pathogen depends on sampling tissues that contain DNA of the pest or pathogen.
2. Both visual and molecular methods are labour intensive and require highly trained personnel.
3. Both methods are expensive to implement.
Chemical methods are available that can detect specified compounds such as illicit drugs or dangerous explosives in tiny quantities. These techniques are widely deployed for security measures at ports of entry into countries for people and goods; they are also being developed to detect medically important pathogens. The routinely used machines are based on highly sensitive ion mobility spectrometry (IMS), which utilizes ionization of target molecules, e.g. by static charge, and identification of the ionized products following separation in an electric field. The method is sensitive to parts per billion concentrations. Both table-top and hand-held IMS instruments are available (e.g. Smith’s Sabre Centurion II or Sabre 5000).
The further development of such instrumentation to detect pests and pathogens in plant consignments requires an innovative, forward-thinking and interdisciplinary approach, utilizing the expertise of pathologists, entomologist, chemists, engineers, IT specialists and end-users. In addition, economic aspects of taking this approach rather than one focused solely on molecular methods must be considered.
The purpose of this working group is to examine the feasibility for modifying such machinery for the detection of invasive pests and pathogens in consignments of plants during import into the EU, and in the plants for planting pathway within the EU, focused on imports into the UK. In two meetings undertaken during this scoping project, therefore, we will critically examine the possibility of developing rapid chemical volatile detection-based instrumentation for use by the plant quarantine authorities.
Two approaches will be considered:
1. Detection of volatile metabolites of bacterial and fungal pathogens, and of pest invertebrates characteristic of the organisms (to family/genus level);
2. Detection of characteristic changes in the volatile components produced by affected plants following attack by pests and/or pathogens, including transformation of plant metabolites by pest and pathogen activities.
It may also be possible to utilize a combination of these two approaches to detect the presence of threatening organisms. As plants are shipped both inter and intra-continentally in containers, sometimes sealed, concentrations of volatiles will be higher in transit compared with ambient conditions. The discussions will, however, determine the utility of devices for capture and preliminary concentration of the volatiles to increase the sensitivity of the methods (e.g. field-portable Guard ion GC/MS; GasID [FTIR-based identification]).
The technique could be useful to detect individual species of certain pests and pathogens, but we are aware of the large numbers of currently unknown invasive agents threatening our forest ecosystems: it is important, therefore, that detection methods recognize signature metabolites of groups (e.g. by genus or family), rather than discriminating to the species level. Moreover, IMS and/or GC/MS or GasID will provide, initially, a technique to focus sampling for other diagnostic methods, such as molecular tools/lateral flow devices.
With such large numbers of plants imported into European countries, it will remain true that sampling will be imperfect; the study will therefore also include consideration of how different deployment strategies and sampling intensities would affect the rate of novel invasions and therefore the costs of management and eradication.
The outputs of this work will be (1) a full proposal for Phase II funding of the Tree Health programme and (2) a report detailing the potential of the IMS, FT-IR and / or MS-based methods for the rapid detection of invasive pests and pathogens in plant consignments in transit.
See project description
Project Documents
• FRP - Final Report : TH0122 Aberdeen Final Report   (1576k)
Time-Scale and Cost
From: 2013

To: 2013

Cost: £44,417
Contractor / Funded Organisations
University of Aberdeen
Plant health