Work Package Lead: Mark Stalham (NIAB CUF)

Objective 2.1 - Effects of irrigation on P. atrosepticum

Team: Simon Alexander (SA Consulting); Eric Anderson (Scottish Agronomy); Roy Neilson (James Hutton Institute); Amy King (Bayer Crop Science)

Seed crops are rarely irrigated, although ware crops are to: i) reach desired tuber size and yield; and ii) prevent common scab disease caused by the bacterial pathogen Streptomyces species, which develops under dry soil conditions. As soil moisture level impacts on blackleg disease, prevention of common scab (often by over-irrigating) frequently leads to increased blackleg. Irrigation therefore has a direct impact on how these two diseases develop. Anecdotal evidence from industry suggests that timing of irrigation influences FLN-related issues. However, such an event has not previously been correlated with blackleg.

This objective will determine the optimal irrigation regimes to prevent or reduce blackleg under treatments aimed at common scab control; the effect that irrigation has on FLN presence around potato plants; to what extent FLN are responsible for blackleg development; and whether nematicide treatment (Velum Prime by Bayer Crop Science) can be used to control blackleg.

Objective 2.2 - Role of cover crops on P. atrosepticum multiplication and spread

Team: Eric Anderson (Scottish Agronomy); Simon Alexander (SA Consulting); Roy Neilson, Ian Toth (James Hutton Institute)

Cover crops are increasingly used in the UK during crop rotations to help with soil structure, soil biology, soil erosion and nutrient management, with >60% of growers using them on c. 20% farm area. Our preliminary confocal microscopy data shows that, in addition to potato, Pectobacterium atrosepticum (Pba) colonises the roots of other plants, as an indigenous member of different rhizosphere communities, with a clear preference for some plants e.g. brassicas were more readily colonised than cereals. Cover crops, are now a major part of arable farming yet differences between them to support Pba colonisation and subsequent numbers in soil remains unknown.

This objective will determine whether Pba colonises the rhizosphere of different cover crops to different extents and to use this knowledge for future cover crop selection in rotations prior to potato planting.