Understanding of the principal drivers of pest and disease incidence, severity, and spread in Scotland, and the factors currently limiting effective disease control

Challenges

Plants sustain life, mitigate climate change, enrich landscapes, and underpin our rural industries.  However, they are subject to an ever-increasing range of pest and disease threats. The drivers of these threats are travel, the globalisation of trade, and the effects of climate change.

It is vital to protect the health and quality of Scotland’s major crops (barley, potatoes, and soft fruit) from the wide range of endemic diseases. We need to reduce our dependency on crop protection chemicals due to pesticide resistance and concerns around impacts on biodiversity. We must develop innovative and effective non-chemical controls that support sustainable ecosystem management and agricultural reform.

Phytophthora species (Potato late blight) infect plant species across agriculture, horticulture, forestry, and the natural environment. Blight infections are difficult to manage, making them one of Scotland’s key plant health threats. Potato Cyst Nematode (PCN) causes significant yield losses, and the amount of infested agricultural land increases every year. If the current loss of land continues, our £100 million seed potato industry will be in jeopardy in the next 30 years.

Scotland’s soft fruit industry supports the rural economy. There is also a need to future-proof the sector in the face of many plant disease challenges. There are considerable threats to the sector posed by Spotted Winged Drosophila, Brown Marmorated Stink Bug, and Phytophthora root rot, to name a few. It has never been more important that we better understand, detect, and manage these diseases to support the sector produce high-quality, healthy, and marketable crops.

Questions

Solutions

Our comprehensive project is quantifying the abundance, diversity, and spatiotemporal dynamics of key Scottish crop pests and pathogens. We are also exploring the ecology of pest and pathogen-host-environment-management interactions and the potential impacts of climate change. Discussions with growers and stakeholder groups identified the need for new knowledge on the underlying causes of key pests and disease spread in key environments and new predictive tools for scenario analyses and decision-making.

Analysing Restrospectively Outbreaks of Endemic Potato Diseases

National-scale datasets on outbreaks of endemic potato diseases have been collected over many years. Despite this, there are gaps in our understanding of the epidemiology of these diseases. We are conducting an exhaustive analysis of this data together with existing national-scale datasets on other risk factors.

Exploring the Epidemiology and Management of Potato late blight

Routine fungicide applications remain the principal means of managing Blight. However, product withdrawals and pressures to minimise environmental impacts continue to shift the focus onto enhancing host plant resistance. We are monitoring changes in the population of P. infestans to:

• Examine the sensitivity of the contemporary population to changing environmental conditions
• Track the virulence of the new populations against key resistance genes
• Monitor the sensitivity to commonly used active ingredients

Tracking Pectobacterium Strains in the Environment

Previous work has shown that Pectobacterium atrosepticum (Potato Blackleg) resides on the roots of non-potato plants and that even first-generation plants grown from mini tubers can develop the disease. This suggests an environmental rather than seed-borne source of the pathogen. We are exploring different plant types and habitats where blackleg disease is found to determine whether some are more likely to harbour the pathogen, and to what extent these isolates are responsible for causing disease.

Assessing the Impact of Local and Landscape Factors on Spotted Wing Drosophila (SWD) Epidemiology

SWD is a priority pest threatening the survival of the UK soft and stone fruit industries. We are predicting which soft fruit areas may support a higher abundance of SWD and relating this to local and landscape-scale factors. This research is complemented by work on the role that differences in crop varieties have in relation to pest susceptibility and habitat and landscape factors regarding the stability of populations.

Monitoring  Potato Cyst Nematode (PCN) Decline Rates under Scottish Conditions

We are monitoring and comparing the decline of PCN in different soil types and under current and projected overwintering conditions. This is examining the impact of soil amendments on decline rates, providing information on the mode of action of these practices.

Developing Decision Support Tools for Barley Diseases

This activity is developing predictive algorithms that can identify crops where fungicide interventions can be reduced, and exploring long-term data sets on disease development in barley for Ramularia leaf spot and Rhynchosporium. This is determining how drought, water logging, wetter winters, and growing conditions at tillering and stem extension affect disease risk and link to the risk associated with other altered management practices, such as cover cropping, tillage, and soil management in general.