Failed cotton stand…can I replant to soybeans?

• Dr. Charlie Cahoon Jr. and Wesley Everman •

Unfortunately, last week’s rain proved too much for many North Carolina cotton fields. For those pondering their replant options, here are some points to consider:

1. Regardless of replant crop, you must first deal with your existing cotton stand. This is best accomplished with paraquat applied prior to replanting while the existing cotton is still small. Tillage is also an option where feasible. Alternatively, switching herbicide traits is a viable option for dealing with existing cotton.

For example, if you initially planted XtendFlex cotton (dicamba-tolerant), replanting Enlist cotton would allow you to easily deal with volunteers with Enlist One (2,4-D choline) applied preplant or over-the-top. The exact opposite could be done if you originally planted Enlist cotton (2,4-D-tolerant).

If you plan to replant cotton and decide to use the same herbicide trait, it becomes paramount to deal with your existing stand before replanting. If not, dust off the hooded sprayer, as paraquat or Aim (carfentrazone) applied with a hood become the only options to deal with the existing stand.

Success of the aforementioned tactics hinges on cotton size; chemical and mechanical control of larger cotton (> 4 leaf) is variable. Note: If you can precisely replant cotton into your existing row, you should be able to manage both plantings for a crop.

failed cotton stand
Consider how to deal with your existing cotton stand before replanting cotton or soybean — photo courtesy North Carolina State University

2. Should you be concerned about replanting cotton into previously applied residual herbicides? Depends on what product(s) were initially used. Replanting cotton following Brake, Cotoran, Direx, Prowl, Reflex, and/or Staple will not be an issue. However, one residual herbicide is missing from this list, Warrant.

If Warrant was used preemergence on your first planting, research from North Carolina and Georgia says wait at least three weeks before replanting cotton. If willing to bring fresh soil into the planting zone via a ripper shank, the replant interval can be shorten to two weeks.

3. What if I want to plant soybeans? First, determine if soybeans can be planted. Where Brake, Cotoran, Direx or Staple were applied, DO NOT plant soybeans. Areas treated with Prowl, Reflex or Warrant can be planted to soybeans.

   1. Once you determine soybean are safe to plant, deal with the existing cotton stand using methods outlined above. In addition to paraquat, Sharpen can also effectively be used to take out cotton prior to planting.

   2. If cotton isn’t controlled prior to replant, several options are available. First, use different traits than those in cotton (dicamba versus 2,4-D). Aim, Cadet, ET or Resource may be applied over top of soybean to control cotton.

If dicamba-tolerant cotton was planted, 2,4-DB is an effective treatment; it will not be effective on 2,4-D tolerant cotton. Remember to follow label recommendations for rates and timing on soybeans for all products.

Dr. Charlie Cahoon Jr. is an Extension weed specialist and assistant professor with North Carolina State University. He may be reached at cwcahoon@ncsu.edu

Dr. Wesley Evermann is an Extension weed specialist and associate professor with North Carolina State University. He may be reached at wesley_everman@ncsu.edu.

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