Several herbicides have been registered for cotton stalk destruction. Herbicides available include, but are not limited to, 2, 4-D (ester and amine formulations) and several dicamba products (Weedmaster, Clarity, Banvel). For these products to be legal for cotton stalk destruction, the label must contain a section addressing “crop stubble” or specify cotton as the target pest following harvest.

Based on most recent field research, it appears the low-volatile, amine salt formulations are equally as effective as the ester formulations for cotton stalk destruction, and minimize problems associated with off-target drift. The first application should be at the rate of one pound of active ingredient per acre (1 quart of a 4 pounds active ingredient per gallon formulation). Generally, a second application of 0.5 to 1.0 pound active ingredient per acre will be necessary to control any live stalks and emerged cotton seedlings.

To obtain optimum results, cotton stalks should be shredded (6- to 8-inch height) and the spray application should be made soon after shredding. Best results are achieved if the herbicide is applied the same day as shredding. To achieve optimum effectiveness, some growers have mounted spray booms directly on their flail shredders and are banding their herbicide during the shredding operation, and achieving excellent results.

 Note that thorough coverage is essential, and should be in the range of 5 to 10 gallons water per acre. Also, the addition of surfactant at the rate of 0.5 percent v/v (2 quarts per 100 gallons of water) is recommended. Research has shown essentially no difference in killing re-growing cotton plants with 2, 4-D between treating shredded stalks within one day, treating 2 weeks after shredding, or standing stalks.  However, other products are less effective on standing stalks.

If a hormone herbicide like 2, 4-D is used, remember there is always the potential for off-target drift that might affect other susceptible crops in the area. So, be careful and monitor local environmental conditions that could promote the off-target movement of the product.

With a lot of lint on the ground this year, a significant rain event will likely generate sprouting cotton seedlings in many fields, possibly allowing floating lint/seed to be washed into ditches and creeks, so we need to be aware of this potential problem and destroy these seedlings when they begin to emerge.

If we do not receive a good rain this summer or fall, we should expect to be fighting volunteer cotton in these fields next spring.  For additional information on managing volunteer cotton, refer to http://varietytesting.tamu.edu/cotton/#harvesting

At this web site scroll down to the Weed Section and then select the link for Managing Volunteer Cotton in Grain Crops. 

As we work to wrap up another cotton crop, it is important to remember that without an effective cotton stalk destruction program here, boll weevil eradication cannot be accomplished in South Texas.