There are several problems (and combinations of problems) that can cause tobacco to be “up and down” in the field. A few that come to mind are certain nematodes, fertilizer injury, herbicide injury, and fumigant injury. In the situation pictured below, it was a possible combination of two problems; herbicide injury and some fertilizer injury.
When looking closely at the root tips, occasionally one would have a burned/brown appearance.
A total of 1100 lbs of 8-6-18 had been applied per acre, with approximately 700 lbs applied just before setting, and 400 lbs 2 weeks later. 700 lbs of 8-6-18 contains 56 lbs of nitrogen per acre, which could have easily injured the young tender roots of the tobacco transplants in the right conditions. However, I don’t think this was the primary issue.
Prowl was incorporated at a rate of 1.5 pints/acre and then bedded up. When bedding after incorporating, Prowl was pulled from both sides of the row which nearly doubled its concentration. When looking at the image above, you can see that the only viable roots left on the plant are up near the crown and had no sign of nematode damage. Another clue indicating herbicide injury was the fact that the “up and down” appearance only occurred in the sandier soil types. This is typical of herbicide injury. Stiffer soil types are usually higher in organic matter and “tie up” the herbicide, therefore causing less injury to the plants.
Take-home Message: “The main symptom to look for is restricted and nubby roots which may cause stunting. Symptoms are more common when plants roots are transplanted into the treated zone. Incorporation of the herbicide deeper than 2 inches, excessive application, and cool soils can contribute. Tobacco has good tolerance and should recover” (UK extension: Dealing with Chemical Injury in Tobacco). Hopefully a rainfall event will help turn it around.