British Crop Production Council (BCPC) Virtual Diseases Review (October 2021): Exploring Alternatives to Enhance Plant Health

This online conference opened with a particular instruction to delegates – arrive with an open mind. No doubt this arose from the common perception that biological alternatives to synthetic pesticides are a less reliable and hence more risky means of crop protection. In her Introduction the Chairperson Kate Storer (ADAS) emphasized the need for, and growing interest in, alternative approaches to plant health, given the current challenges facing agriculture. While definitions of plant health vary there is a consensus that the genetic potential of crops cannot be realized by a single means, and a more holistic concept is required if we are to achieve sustainable production systems with a lower carbon footprint. The yield of some crops such as wheat have plateaued in recent years, and there is evidence for higher annual variability in yield, in spite of the usual inputs of fertilizers and fungicides. This may be a result of a more volatile climate, as well as the erosion of efficacy of some crop protection chemicals due to the development of resistance in target pests, weeds and pathogens. Increasing the resilience of crops is now a high priority. There is a renewed focus on the plant-microbial interactions influencing crop performance, from the well-known mutualistic associations such as mycorrhizas, to the complex communities of microbes colonizing plant surfaces and tissues (the microbiome). These have a range of potential effects on plant health, including improved nutrition, inhibition of pathogens, and priming plant defence. Optimizing these associations is one aim of current research, and they may also be a potentially rich source of biologically active metabolites. Understanding the impact of management practices, such as ploughing and crop rotations, on beneficial interactions is also important to maximize their benefits.