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Title: EFFECT OF AMMONIUM SULFATE, POTASSIUM PHOSPHATE, AND ETHEPHON ON CGA 276854COTTON DEFOLIANT

Author
item WILLS, G - DREC
item Hanks, James
item JONES, E - DREC

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Abstract Only
Publication Acceptance Date: 1/6/2002
Publication Date: 1/6/2002
Citation: Wills, G.D., Hanks, J.E., Jones, E.J. 2002. Effect of ammonium sulfate, potassium phosphate, and ethephon on cga 276854cotton defoliant. National Cotton Council Beltwide Cotton Conference. 1:676-677.

Interpretive Summary: Abstract, not required.

Technical Abstract: A field study was conducted to determine the effect of CGA-276854 cotton defoliant at 10 oz in 10 gpa applied with Dyne-Amic adjuvant at 0.5% v/v alone in combination with the fertilizer salts, ammonium sulfate and potassium phosphate each at 1 lb/A, and with the growth regulator, ethephon at 1.33 pt/A both separately and together. Other research has indicatedr that the nonionic organosilicone based adjuvant, Dyme-Amic, which is most effective with oil-based formulations, increased the efficacy of CGA-276854 more than the crop oil surfactant, Agri-Dex, or siloxane based adjuvant, Kinetic, which is a more effective adjuvant with water-based formulations. It has been further shown that the addition of these same fertilizer salts and of ethephon will increase the efficacy of other cotton defoliating chemicals. All the results with CGA-276854 include the addition of the adjuvant, Dyne-Amic at 0.5% v/v. CGA-276854 with only Dyne-Amic resulted in 77 and 80% defoliation at 7 and 14 DAT. The addition of ammonium sulfate increased defoliation to 96 and 98% at 7 and 14 DAT. Other combinations of these adjuvants with CGA-276854 increased the percent defoliation but less than that with ammonium sulfate alone. Potassium phosphate was the next most effective adjuvant resulting in 93% and 95% defoliation at 7 and 14 DAT. The remaining combinations of the adjuvants resulted in defoliation between 85 and 90% except with the combination of all three adjuvants which resulted in only 85% defoliation at both 7 and 14 DAT. Percent foliar regrowth at 14 DAT was 5 to 15% with CGA-276854 with and without the addition of fertilizer salts. Further addition of ethephon increased the regrowth to 22 to 43% with the greatest percent regrowth resulting from the addition of all three adjuvants.