Poster Presentation Science Protecting Plant Health 2017

Utilising host and pathogen diversity to manage allium rust in gardens (#314)

Matthew G Cromey 1 , Rebekah Robinson 1
  1. Royal Horticultural Society, Woking, SURREY, United Kingdom

A garden environment is usually a more diverse ecosystem than that found in crops, providing both opportunities and complications for integrated disease and pest management. Allium rust (Puccinia spp.) affects a range of edible and ornamental Allium spp. There is considerable genetic and phenotypic variation amongst the rust pathogens, the hosts and their interactions. The potential to use the complexities of within- and between-species host-pathogen interactions to develop rust management strategies is hampered by a limited understanding of these very complexities. The UK allium rust population appears to be comprised of at least three species, with overlapping host ranges. Our results show that the two main rust populations can be split into those that infect chives but not leeks and vice versa. The role of other Allium spp. in disease epidemiology is not clear, although most collections of rust from ornamental alliums fit the ‘leek’ type, while garlic is susceptible to both. While rust is recorded on onions in the UK, it is seldom severe. At least one strain, common on an ornamental cultivar of A. vineale, appears to be particularly pathogenic on this host, while generally conforming to the ‘leek’ types. In this paper, we will present results of experiments on hosts, pathogens and the interactions between the two and discuss how this information can be used towards the integrated management of allium rust in garden. For example, it may be possible to alter planting and harvest times of host species to break the ‘green bridge’ which enables a rust species or strain to survive throughout the year in a home garden.