STP1460: Effect of Adjuvant on the Efficacy of Glyphosate Applied at Different Times of Day

    Young, BG
    Associate Professor and Researcher, Soil, and General Agriculture, Southern Illinois University, Carbondale, IL

    Young, JM
    Associate Professor and Researcher, Soil, and General Agriculture, Southern Illinois University, Carbondale, IL

    Pages: 7    Published: Jan 2005


    Abstract

    Glyphosate was applied alone and with either ammonium sulfate (AMS) or RUSA 703 (a premix of hydroxypropyl guar and AMS). Herbicide treatments were applied at 3-h intervals starting at 6:00 am and ending at 9:00 pm. The efficacy of glyphosate was dependent on the application time of day for all weed species tested, except for common waterhemp in the greenhouse. In general, applications at 6:00 am and 9:00 pm resulted in the least control of all weed species. The efficacy of glyphosate was often improved with the addition of AMS when glyphosate was applied at a suboptimal time of day. RUSA 703 did not result in any benefit in glyphosate efficacy beyond AMS. The addition of RUSA 703 to glyphosate improved the efficacy of glyphosate as often as AMS in greenhouse studies, but not in field studies.

    Keywords:

    glyphosate, application time of day, ammonium sulfate, hydroxypropyl guar, giant foxtail, velvetleaf, common cocklebur, common waterhemp


    Paper ID: STP11983S

    Committee/Subcommittee: E35.22

    DOI: 10.1520/STP11983S


    CrossRef ASTM International is a member of CrossRef.