To determine the effects of adjuvants with Biffo (Glufosinate) on control of large flowering feathertop Rhodes grass plants.

• An estimate of % burndown was made 7 days after treatment application. Treatment with Biffo alone resulted in an average Burndown score of 78%. Addition of adjuvants did not significantly impact burndown rating. Raising the rate of Biffo application to 10 L/ha increased the burndown score to 93%, a significant improvement.
• The site was accidently over-sprayed by the grower at 9DAA by a herbicide mixture of Glyphosate 450 @ 2L/ha + Amicide 700 @ 500mL/ha. It was considered that this treatment would have had little effect on the trial as there was very little green leaf material present in most plots and neither of the products sprayed are very effective against FTR.
• The trial needed to be terminated earlier then ideal on April 28th as the grower began planting the paddock to wheat. Consequently, a visual estimate of % control of feathertop Rhodes grass was made for each plot. Regrowth was evident in every plot.
• Water volume had a significant impact on efficacy. On average % control where Biffo was sprayed at a volume of 75 L/ha was 61%. This increased to 82% where the application volume was increased to 150 L/ha.
• Increasing the rate of Biffo application to 10 L/ha increased % control from 64% (at 3.75/ha) to 93%. Where Biffo was applied at 5L/ha (not included in the factorial) % control was rated at 83%
• None of the adjuvants affected % control compared to Biffo alone. On Course appeared to give a poorer result than treatments containing AMS, Liase or Outright.
• In this trial the effect of water volume and rate were much more important than choice of adjuvant.

Trial design: Factorial