Survival of Pseudomonas syringae pv. pisi in soil and on pea trash and their importance as a source of inoculum for a following field pea crop

Abstract

Summary. The importance of soil and field pea trash as sources of Pseudomonas syringae pv. pisi for infection of field pea was investigated both in a controlled environment and in the field. Studies of the survival of P. syringae pv. pisi in soil using autoclaved and non-autoclaved soil found that P. syringae pv. pisi is unlikely to survive in soil from one season to the next suggesting that soil is an unlikely source of inoculum in the field. However, Pseudomonas syringae pv. pisiwas able to survive on buried pea trash for at least 29 weeks and on pea trash positioned on the soil surface for at least 78 weeks. In a field trial, the presence of pea trash naturally infected with P. syringae pv. pisi caused significant bacterial blight and reduced grain yield of a field pea crop by 25%. Therefore, pea trash is a potent source of inoculum and crop rotations which include 2 seasons free of field peas should be considered as part of a strategy to control bacterial blight.