Pest and disease resistance

We have been breeding raspberry varieties for Scotland, UK and Europe for > 40 years.  A key trait (conferred by one or more major resistance genes) is for resistance to the main aphid pest, the large raspberry aphid. This strategy has been very successful but over decades the pest has co-evolved resistance-breaking biotypes. We are now at a ‘tipping point’ where the pest can overcome resistance genes in the crop faster than plant breeders can introduce new types of resistance (typically taking  10+ years).

Bacterial pathogens pose a serious threat to either plant health or to food safety.  This has the consequence of financial impacts on crop production for pathogens that causes disease on plants, or human health impacts for food-borne pathogens transmitted into the food chain by plants.  One of the main challenges to producers is that there are few control options available for reducing or removing bacterial pathogens from plants, and growers have to resort to a limited set of biocides that can cause environmental damage, such as the active ingredient copper oxychloride.  This means that a pre-emptive approach is a more sustainable option, e.g. by reducing the risk of pathogens introduction from seeds or transplants and in irrigation water, or for endemic pathogens, using alternative strategies to keep their numbers at manageable, non-harmful levels.  These approaches require a degree of monitoring to ensure that the control levels are adequate, since the aim is to keep pathogen levels sufficiently low that they do not cause visible damage to crop plants, or for the food-borne pathogens, that they do not pose a food safety issue.