Cacodylic acid, Quick Pick (QP), was introduced for cotton defoliation or dessication in the Cotton Belt with the exception of California and Arizona (1991). This organic arsenic compound has full E.P.A. registration, The environmental hazards of this organic compound is substantially less than the inorganic arsenic acid currently used for dessication. The same rate of cacodylic acid compared with inorganic arsenic acid would contribute 92% less elemental arsenic to the environment. The organic form also readily ties to the upper soil complex thus reducing possible leaching hazards. Recent research (1990) results from university test conducted across the Cotton Belt generally indicated that Quick Pick in combination with standard defoliation products could substantially improve defoliation results as compared with the singularly used products.

As a follow-up to these results, additional grower tests were conducted and Iimited sales of Quick Pick (GP) were initiated across the Cotton Belt (1991). Combinations of GP (Delta) with either Dropp(TM), Def or Prep(TM) was effective for cotton defoliation. Numerous field observations indicated that the addition of GP (cotton 60% open) with Dropp and Prep accelerated the defoliation rate. There was less of an increase when GP was added to Def(TM). However, there was a trend toward an increase in boll opening with QP for all combinations.

The rate of QP in combination with other harvest aid materials was dependent on plant growing conditions and stage of cotton development and maturity. The choice of spindle picking or stripper harvesting also influenced the rate of QP in the mixture. Combinations of QP with both Dropp and Def were used. The best combination for defoliation were Dropp (.1 - .2 lb/acre) plus QP or Def (1.5 pt. + 1 pt. QP). QP at 3/4 pt/acre rate affected die-back of the growing tip (terminal).

SOUTHEAST REGION: QP was used in combination with all of the defoliants and harvest aids typically used in the Southeast, but most commonly with Dropp, Def, Folex(TM) and Prep. Rates of QP ranged from 0.5 to 1.5 pints. We found that in general lower rates were better in higher temperatures and conversely, higher rates in lower temperatures. At higher temperatures, dessication of vigorous, immature foliage was occasionally seen. However, this was also seen with standard combinations, e.g. Dropp/Def, Dropp/Prep, and in some cases, with single ingredient treatments. Even though dessication was seen, "freezing" of the leaves did not usually occur if the rate of OP was 1.5 pints or less. Dessication and "freezing" were seen more frequently when three way combinations were used, whether they included GP or not. Best results were seen when OP was combined with Dropp or Prep. When combined with Dropp, GP was seen to both hasten and improve defoliation, and sometimes, to improve regrowth control and boll opening. When combined with Prep, defoliation was usually greatly improved and regrowth suppression was seen with this combination. Limited work also indicated sequential treatments, utilizing GP as one of the treatments, hold promise.

DELTA: GP in tank mix combinations with Dropp and Prep or Def and Prep plus GP was the most successful treatment in the Delta. Leaf stick with OP was considered as a potential problem. However, this was not a factor when treatments were applied at 50% boll opening. Defoliation was accelerated with the addition of four (4) ounces of Prep. If a second defoliation was required, Prep plus QP or Starfire(TM) plus QP did achieve excellent results. Harvade(TM) in combination with QP was successfully used for cotton in weedy fields.

HIGH PLAINS: In West Texas, QP was used in tank mixes with Cyclone(TM), Def, and Prep. In general, tank mixes with QP did a good job of preparing cotton for stripping. Boll opening was accelerated with the addition of QP. Tank mixes of QP with Dropp, and Def was primarily used in South, Central, and Coastal Bend of Texas. QP rates ranged from 1/2 pint to 1 pint/acre depending on cotton growth and maturity. QP was used at 3/4 pt/acre for late season canopy opening to avoid boll rot. One of the primary benefits of GP in Texas was terminal die back associated with 3/4 to 1 pint of OP/acre in the tank mix.

QP (1991) was observed to increase the performance of other defoliation materials. QP positively increased cost efficiency without jeopardizing the quality of either defoliation or lint.