Blackleg in potato crops – filling the knowledge gaps

Friday, 21 August 2020

Blackleg is one of the most damaging bacterial plant diseases in the UK, responsible for annual losses of £50m for the potato industry. We are supporting and funding multiple projects researching this disease. A project which started three years ago, looking at how to achieve better control of blackleg, will be completed this summer, while another one which will also last for three year is just starting.

Completed trials

A large project which was co-funded by AHDB & Scottish Government is due to finish this summer.

This project has been investigating how improved seed management can minimise losses due to Pectobacterium species. Using a volume of over 50 years of research, the scientists involved in this project have put together a factsheet that can be used to reduce the risk of Blackleg disease in potato crops.

The factsheet summarizes some of the most important strategies which can be used to control Blackleg such as an efficient irrigation  (too much water can lead to diseases but not enough can result in common scab), condensation in stores and rapid haulm destruction.

New trials 2020-2023

Scientists at the James Hutton Institute together with AHDB and other partner organisations are working to understand the interactions between pathogen Pectobacterium atrosepticum (Pba) and free-living nematodes (FLN) in the development of Blackleg.

The project, ‘Building a Decision Support Tool for Blackleg Disease (DeS-BL), which secured funding via the BBSRC call for work on Bacterial Plant Diseases, will begin in September 2020. AHDB supported the application and will provide an ‘in-kind’ contribution to deliver Knowledge Exchange through our Farm Excellence Platform.

This project is looking at identifying how and where on the plant infection takes place, and if the management of nematodes might help to reduce blackleg infection but also the role of other soil microbes, insects, cover crops, irrigation and agronomic factors.

The main genera are Pectobacterium and Dickeya. Pectobacterium atrosepticum (Pba) is by far the most important species in the UK, and will be tackled by this project. Disease is caused when these bacteria from infected tubers enter growing stems. >50% of seed of all classes has some level of blackleg infection; the main cause of seed downgrading and failure by a factor of 10. Blackleg has become more common in the UK over the last 8-10 years, for unknown reasons. 

The project aims to develop new methods to control Pba and to make a major impact on the potato industry by combining data from the project into a new decision support tool. 

This project consists of five working projects:

  • Vectors and transmission 

Free living nematodes (FLN) species and insects will be tested as vectors of Pba in glasshouse trials. Diagnostics for the key FLN species will be developed and used as risk indicators. 

  • Current management practices

The team will investigate the effects of irrigation on Pba.  An irrigation regime will be developed to control both blackleg and common scab, which require opposing water regimes.  At the same time the effect of irrigation regimes on FLN will be measured.

  • The rhizosphere environment

Cover crops will be compared for the ability of Pba to colonise their rhizospheres, with changes in natural bacterial communities investigated in the presence of the different root exudates, and how changing communities might be used to protect against the disease.  

  • Modelling and decision support 

Modelling will be used to describe trends and drivers of Pba incidence in order to produce predictive models that could be used in decision support tools. 

  • Implementation and practical application

 Knowledge Exchange and uptake of the Decision support tool will be implemented via our Farm Excellence programme, Scottish Agronomy, SASA, Bayer conference, Soil Essentials and other industry opportunities to co-construct ideas with policy and industry.