DIFFERENT ADJUVANT TYPES AND GLYPHOSATE EFFICACY ON SOME WEEDS

摘要

The effect of adjuvant types on glyphosate phytotox-icity to four annual weeds was evaluated in a greenhouse study. Glyphosate was used at a.i. rates of 0.25,0.38 and 0.5 kg ha1 and different adjuvants were formulated with glyphosate at 0.25 kg ha1. The application of glyphosate with adjuvants, e.g., with ammonium sulfate (AS) or X-77 or Agri-dex to black nightshade (Soianum nigrum L); with AS, Agri-Dex, AN, Kinetic, or X-77 to wild mustard (Sinapis arvensis L); with Kinetic, X-77, Volt, urea, or methylated seed oil (MSO) to large crabgrass (Digitaria sanguinalis L); and with all the adjuvants except CN and urea to barnyardgrass (Echinochloa crus-galli L.), significantly increased the percent control compared with glyphosate alone. Application of glyphosate (+AS) with X-77, L-77 or MSO to black nightshade or with either test adjuvant to wild mustard resulted in percent control more than or equal to glyphosate alone at an a.i. rate of 0.50 kg ha~(-1). Application of glyphosate (±AS) with L-77 to barnyardgrass showed some antagonistic effects, indicated by lateral shoot growth compared with the untreated plants. Glyphosate (+AS) with X-77, Kinetic or MSO applied to large crabgrass, or with Kinetic or MSO to barnyardgrass produced a further increasein percent control over glyphosate (+ AS) treatment alone. The addition of adjuvant to glyphosate reduced the necessary application rate and also improved the bioefficacy of glyphosate. The improvement in bio-efficacy depends on type of adjuvant and type of plant species.