ABSTRACT

Studies were conducted in central Texas and Arkansas in 2002 to evaluate 2,4-D (ester and salt formulations), Clarity (dicamba), and Harmony Extra for effectiveness in post-harvest cotton stalk destruction. Treatments included 2,4-D ester and amine formulations (1.0 and 1.5 lbs. a.i./acre – 32 and 48 oz. product), Clarity (0.5 lbs. a.i./acre – 16 oz. product), and Harmony Extra (0.028 lbs. a.i./acre – 0.6 oz. product) applied at shredding, and one, three, and five days post-shredding. The Texas location included an additional application timing of 21 days post-shredding. At both locations, herbicide application timing following shredding (0, 1, 3, and 5 days post-shredding) did not affect regrowth control. Similarly, at the Texas location root mortality also was not affected by herbicide application timing, except in the 21 days post-shredding treatment. Also, at both locations, the 2,4-D ester and amine formulations applied at 1.5 lbs. a.i./acre provided the best overall performance. Clarity and Harmony Extra showed the least regrowth control at both locations. Regardless of regrowth/root mortality ratings, all treatments rendered cotton non-hostable at both locations. Due to liability issues associated with ester formulations, 2,4-D amine (1.5 lbs. a.i../acre) appears to be the best choice for chemical stalk destruction. Due to significant environmental influences, additional research is necessary to develop standard recommendations.