|Contributor||Northern Grower Alliance|
To evaluate the compatibility of Group A & Group G herbicides for summer grass control.
This trial was designed to evaluate the compatibility of mixtures of Group G and Group A herbicides for fallow control of feathertop Rhodes grass (FTR). Additional weeds present were liverseed grass (LSG) and peachvine. Treatments were applied to populations of FTR ~32/m2 at ~GS24 (early to mid-tillering), LSG ~51/m2 at ~GS25 (early to mid-tillering) and peachvine ~22/m2 at ~GS15 (5 leaf stage). Despite the large mean populations, there was a high degree of variability in weed density. One week after application the trial site was flooded. A second knock of Gramoxone was applied 17 days after the initial application. Burndown and final weed counts were assessed 24 and 45 days after the first knock application (7 and 28 days after the second knock). Verdict 150 mL/ha + Uptake oil alone provided very high levels of burndown at 24 days after the first knock application of both FTR and LSG (100 and 98% respectively). The addition of Valor to Verdict significantly reduced the level of burndown of FTR and trended to the poorest burndown of LSG. There was no significant antagonism from any Group G mixture with Verdict when a second knock of Gramoxone was applied on either weed. Shogun 500 mL/ha + Hasten alone provided significantly lower levels of burndown than Verdict (FTR 95% and LSG 77%). All Group G herbicides antagonised the level of FTR and LSG burndown when mixed with Shogun alone, however there was no significant reduction from any Group G and Shogun mixture when a second knock of Gramoxone was applied. In contrast to the Verdict result, the mixture of Shogun and Valor appeared to be significantly less antagonistic than other Group G mixtures against FTR. There were no clear differences between products for antagonism against LSG. Gp A E X 250 mL/ha + Hasten alone provided similar levels of burndown to Shogun (FTR 95% and LSG 70%). This product does not have a fallow registration. All Group G herbicides antagonised the level of FTR and LSG burndown when mixed with Gp A E X. There was no significant reduction from any Group G and Gp A E X mixture when a second knock of Gramoxone was applied. The mixtures of Gp A E X and either Nail or Cavalier were significantly less antagonistic than other Group G mixtures against FTR. There were no clear differences between products for antagonism against LSG. There were no significant differences in surviving FTR counts in this trial. Verdict did provide significantly greater levels of control of LSG than either Shogun or Gp A E X with the addition of Sharpen or Valor significantly reduced LSG control across all Group A herbicides. Sharpen alone, or in mixture with all Group A herbicides provided complete burndown of peachvine. Poor burndown activity was apparent from all other Group G herbicides. The second knock of Gramoxone provided a significant increase in peachvine burndown but did not provide complete burndown with any treatment other than Sharpen. Surviving peachvine counts showed a similar pattern with almost complete control from Sharpen treatments, however Valor also provided useful levels of suppression. The second knock of Gramoxone significantly improved peachvine control.
|Lead research organisation||
Northern Grower Alliance
|Host research organisation||N/A|
|Trial funding source||GRDC|
|Other trial partners||Not specified|