Map of Brown Stem Rot Distribution in Minnesota
The preceeding map is the result of plant samples collected in the year 2000.
Root infection precedes discoloration of water conducting vessels and at mid-season the vascular elements and stem pith show a reddish-brown color. The brown color develops first at the stem base and moves up, often most evident at nodes. Yield reduction increases with greater discoloration. Leaf symptoms develop later in the season. Look for wilt, interveinal browning and green tissue over the vein, leaf drying, and early leaf drop. Plants do not mature normally, and appear to be frost damaged. This fungus survives in crop debris and increased inoculum levels are reported following tolerant varieties. Cool weather leads to more stem browning and warm dry conditions increase foliar symptoms, especially during the reproductive stage.