Precision diagnostics and next-generation decision support systems

The UK wheat crop is valued at £2 billion p.a., approximately 12% of which is lost to disease. Septoria leaf blotch (Zymoseptoria tritici) is the most prevalent and fungicide sprays estimated at £82million p.a. (GFK-Kynetec 2013) are used for control. Resistance is a significant problem, caused by continued overuse of chemicals with similar modes of action. Better control requires more precision in terms of spray timing as well as more careful selection of fungicides. Linking this information with risk prediction by use of disease forecasting systems is also critical. We have been developing an in-field, self-reporting, automated spore detection system, to monitor ingress of inoculum into fields. Based on cyclone air sampling technology linked to isothermal DNA amplification (LAMP) the system will sample and test air within crops, transferring data on inoculum movement wirelessly to the laboratory. In addition to inoculum, identifying resistant genotypes of a pathogen is critical to enable effective spray decisions to be made. Work has started on the development of LAMP assays to discriminate the SNPs (single nucleotide polymorphisms) responsible for azole resistance in the CYP51 gene of Septoria. The assays will be deployed on the handheld Genie III instrument, enabling decisions to be made rapidly in the field. Ultimately the two developments will converge, telling us not just when we should spray crops but also what active chemistry will be most effective.