Towards a sustainable whole-farm approach to the control of ergot

Summary

Description
Concern has been mounting in recent years about the increasing problem of ergot contamination in wheat. This has resulted in greater numbers of grain loads being rejected for milling and in seed failing to reach the certification standards.
Recent changes in farming systems have been implicated, in particular the introduction of grass margins in arable fields, encouraged by CAP reform. The risk is that flowering grasses in the margins will become infected by ergot and act as a source of inoculum for the adjacent wheat crop as well as adding to the reservoir of ergots available to initiate the next season’s infection cycle. Other trends contributing to the increased ergot problem may include poor control of grass weeds because of increased herbicide resistance, shorter rotations, and earlier sowing.
The aim of this project is to develop an integrated package of measures aimed at reducing the risk of ergot infection in wheat crops whilst retaining the environmental benefits of grass margins. The importance of grass field margins as a source of ergot inoculum will be assessed and means of reducing this risk will be explored. These will include low risk’ grass species that are unlikely to act as a source of infection for wheat and margin management regimes that reduce the risk of ergot infection spreading to the crop. The resistance of wheat varieties to ergot will be investigated in order to identify low risk varieties with flowering characteristics that confer escape from infection or with resistance that is effective at a later stage once infection has occurred.
The research will combine monitoring of farm and experimental field margins, artificially inoculated and naturally infected field and glasshouse experiments, spore trapping and epidemiological studies and will use quantitative PCR diagnostics for pathogen detection.
Objective
Objective(s)
11.1 Scientific objective(s)
1. Establish the ergot status of representative country stewardship field margins in relation to their grass species composition and management
2. Determine whether populations of Claviceps purpurea supported by different margin grass species differ consistently in their pathogenicity for wheat
3. Determine the extent to which field margins contribute to ergot infection in cereal crops (using wheat as a model).
4. Quantify spatial distributions of C. purpurea resulting from primary spread (ascospores) and secondary spread (condia).
5. Examine variation in ‘field resistance’ to ergot amongst current UK wheat varieties. Determine the degree to which this is attributable to ‘escape’ (as conferred by flowering biology) or to post infection resistance.
6. Develop a PCR diagnostic for quantitative detection of C. purpurea.
Further details regarding these objectives may be found on the linked web pages.