Take your pick; water logged soils, crusted soils, rotted seed, herbicide damage (see Dr. Steckel’s comments in this Blog),  Rhizoctonia, Black Root Rot, Pythium, or Ascochyta (wet weather blight). Some, all, or any combination of these have lead to lots of replant calls and visits this week. The good news is that we should know what damage has been done by this weekend. Warm temperatures have made most cotton fields progress to the point that we can keep them, or at least make it obvious that we should replant them as soon as possible.

It has been my observation from field visits this week that cotton planted May 10th-14th has been most effected by seed rot, soil crusting, and root disorders. Cotton planted May 17th-20th has been effected more by herbicide damage, loss of vigor from cold nights, wet soils and rhizotonia. Regardless of the situation the replants are making a late planted crop even later. Please refer to my comments on Managing Late Planted Cotton for tips on how to make this crop mature early and yield well.

Facts about cotton planting in cold wet conditions.
Cotton seed exposed to temperatures below 41F can result in seedling death. Even extended exposure to temperatures below 50F can lead to radical (root) abortion, or loss of taproot. Possibly the worst scenario is when cotton is exposed to cold water during the first few hours of imbibition (absorbing water). This would be of concern for cotton planted Thursday (5/12) or Friday (5/20) . Cotton that is in ‘early crook’ stage (just beginning to emerge from the soil) can be sensitive to chilling temperatures (low 40’s) that were experienced from May 16th-18th.

Heavy rainfall and saturated soil reduces soil oxygen content, increases pressure from seedling disease pathogens, and can cause soil crusting. Waterlogged conditions for 24 to 36 hours will prevent a supply of oxygen to the root system. After 36 hours of waterlogged conditions roots may die leading to the death of seedling plants.

When you compound the unseasonably cold temperatures, repeated rainfall, and some herbicide damage cotton seedlings will lose vigor and be more subject to diseases and stand loses. Please contact your consultant, local county Extension Agent, retail outlet, or me if questions arise around replant decisions. Most cotton seed companies have replant policies in effect when you purchase your seed. Contact your seed sales representative to find out details of these replant programs.