ABSTRACT

Field experiments conducted in 1991 and 1992 at Tifton, GA evaluated Staple alone and in combination with other herbicides in a systems approach. Staple efficacy was evaluated both as a PRE application and when applied as a POST treatment following various PRE applications. All rates are expressed as lb ai ac^-1. PRE treatments included 1) Cotoran 1.5, 2) Staple 0.07, 3) Cotoran 1.5+ Staple 0.07, 4) Cotoran 1.5 + Dual 2.0, and 5) Cotoran 1.5 + Reflex 0.375. POST treatments were either 1) none or 2) Staple at 0.04 plus a nonionic surfactant at 0.25% (v/v). Early cotton injury ratings were taken approximately 12 days after the PRE application and mid-season injury ratings were taken 18 days after POST application. Weed species evaluated included Florida beggarweed (Desmodium tortuosum), an Ipomoea morningglory complex of red, pitted, and entireleaf (ipomia coccinea, lacunosa, and hederacea var integriuscula respectively), small flower morningglory (Jacquemontia tamnifolia), and sicklepod (Cassia obtusifolia). Seed cotton yield was also determined. Cotton yield was yield was also determined.

Cotton from PRE treatments was approximately 15% from Cotoran 1.5+Dual 2.0 and Cotoran 1.5 + Reflex 0.375. Mid season injury was less than 5 %. Other PRE treatments were not injurious. Effective Florida beggarweed and smallflower morningglory control (> 85 %) was obtained with all PRE treatments and the addition of Staple as a POST application gave complete control (100%). Staple PRE at 0.07 did not control Florida beggarweed and controlled smallflower morningglory 80%. PRE and POST Staple applications completely controlled both weeds. Cotoran 1.5 + Staple 0.07 and Cotoran 1.5 + Dual 2.0 controlled sicklepod comparable to the standard (90%) of Zorial + Cotoran. Staple at 0.04 POST did not improve sicklepod control for any PRE treatment. Staple PRE did not adequately control sicklepod (55 %), PRE followed by Staple POST increased control to 75 %. The systems that utilized Staple as a POST in combination with any PRE treatment increased seed cotton yield and were always greater than yield (2050 lb ac^-1) from Zorial + Cotoran PRE. When used PRE alone, Cotoran 1.5 or Staple 0.07 yielded 1600 and 1290 lb ac^-1, respectively. When used as a tank mixture PRE, the combination improve yield to 2260 lb ac^-1.