In-field detection

New or improved diagnostics have been developed for key pests and pathogens for which in field detection is an essential component of an IPM approach to controlling disease in potato, cereals and soft fruits. New sensor technologies continued to be evaluated on potato and soft fruit crops. Previously developed software was updated for improved design of pathogen specific diagnostic assays. The framework for monitoring the potential for new threats for which diagnostics could be required was delivered through links to the Scottish Plant Health Centre.

Highlights:

An assay which had previously been validated for the detection of pathogenic Streptomyces spp. (a bacterial pathogen for which there are no chemical control options) in soil and on potato seed tubers was used to assess the relationship between pathogen detection and severity of disease in both glasshouse trials and in the field. This information will inform options for disease control.

Improved diagnostics for the detection and quantification of viruses affecting blueberry have been developed and are being deployed in pest and pathogen monitoring research, and in developing soft-fruit breeding programmes.

To understand the  threat of the invasive Spotted Wing Drosophila (SWD) to the Scottish fruit industry, molecular markers were used to analyse DNA from five SWD populations (four Scottish, one Slovenian)  providing a  baseline reference in the soft fruit IPM toolbox, against which researchers can monitor populations over time. This will have particular relevance should SWD numbers change dramatically in future years.

A diagnostic assay has been developed for B. sorokinia, a pathogen which appeared in cereal crops in 2018. The assay is being used to investigate the movement of the pathogen spores in summer months in Scotland. New pathogen testing for emerging cereal diseases were included in a presentation on "Integrated control of barley" at Crop Production Northern Britain.

Research to assess the use of sensor technologies for early disease detection focused on hyperspectral imaging in soft-fruit and multispectral imaging of potato. Hyperspectral imaging provided valuable data for abiotic stress in raspberry and blueberry and is being used to investigate biotic stress responses. Multispectral imaging associated with a fixed wing platform (drone) was used to assess key diseases in potato field trials supported by ground-truthing data e.g. disease/plant phenotype scoring.

New or improved diagnostics have been developed for key pests and pathogens for which in-field detection is an essential component of an IPM approach to controlling disease. For example, an assay to detect pathogenic Streptomyces spp. on seed and in soil was assessed for potential inclusion in a potato soil-pathogen testing package. A more efficient test for the detection of Spotted winged drosophila (SWD) was developed. SWD poses a threat to soft fruit production and awareness of its potential impacts and how to do the test have been demonstrated widely to stakeholders within the soft-fruit industry. An SWD testing clinic was made available to growers. In response to potential /suspected outbreaks of blueberry virus infections, a strategy to produce blueberry scorch control material has been developed which is expected to improve our ability to do antibody testing of suspected infected blueberry material. Ramularia collo-cygni is the pathogen responsible for the barley disease Ramularia leaf spot (RLS). New tests have been designed for the detection of Ramularia and are undergoing validation. This new assay will be used to test samples for seed infection. Additionally, to ensure diagnostic developments continue to remain fit for the future: new sensor technologies were evaluated; new software was developed for improved design of pathogen specific diagnostic assays; and the potential for new threats for which diagnostics could be required were evaluated.

Highlights:

• Spotted Winged Drosophila (SWD) is an emerging pest in Scotland potentially affecting the soft fruit industry. A more efficient test for the detection of SWD in fruit was developed. Stakeholder events were held, where attendees were reminded to remain vigilant for the presence of SWD and given advice on identification and testing methods they could use on their farms to look for the pest in traps and fruit to help the fruit industry with early detection of the pest in the crop. A free SWD clinic was also offered to growers.
• Blueberry production has recently emerged as a new and rapidly growing industry in Scotland. As part of the development of a toolkit of diagnostic virus tests for new and emerging blueberry diseases a nucleic acid-based test for the detection of Blueberry scorch virus was produced and a novel approach to produce positive control material to ensure that ELISA-based virus detection tests was developed.