By John Kruse, Ph.D.
As Isaac passes through the heart of Louisiana, we can expect that the winds and torrential rains from the storm may cause some or even extensive injury to the cotton crop. The high, sustained wind speeds in particular will leave the leaves wrinkled and injured – something akin to what we cause when we apply tribufos. The plant will respond to stress with increased ethylene production and the whole process will likely result in some natural defoliation in the days after the storm passes through. Some cotton fields will be physically flattened or pushed over, but we hope that many of the plants will eventually stand back up. However, defoliation strategies may require aerial applications instead of ground rigs to prevent mechanical damage. One common misconception is that the crop damage results from all the salt water that the storm dumped on the crop. In truth, rain from the storm started out as ocean water evapotranspiration – in effect purifying the salts from it. No doubt the coast will be affected by salt water that is blown in by the storm surge, but once the storm is inland by a few miles, the deluge from above is fresh water. The best defoliation strategy at this point is to wait out the storm and let the leaves on the plant protect the cotton from the winds as best it can. Inspect the crop after the storm and make the appropriate plans. Even with some natural defoliation caused by the storm, defoliation strategies should take into account the current temperatures and crop condition, rather than trying to guess rate changes based on already defoliated leaves. We hope your cotton avoids serious injury from the storm, and are here to assist you.
Cotton and Feedgrain Specialist