US: Blackleg disease reported in some Michigan potato fields

Blackleg symptoms in stem of potato plant.Aerial blackleg can look like stem and petiole late blight and is being reported in some potato crops in the southern growing areas of Michigan. The bacterium tends to affect single stems and can be distinguished from late blight by the absence of a disease focus, so usually only a single stem on an isolated plant is obvious. The margin between the disintegrated and sound tissue is clear and nearly odorless. However, secondary rots, such as Clostridium spp. andPseudomonas spp., invade the damaged and diseased tissue, causing the rot to progress quickly through the stem and possibly develop into a chalky-white, foul-smelling, slimy mass. More