FMC Overwatch Trial

Evaluation of new and pipeline herbicides, for the pre-emergent control of Annual Ryegrass in Wheat.

Hines Hill, WA, 2019

EXECUTIVE SUMMARY

A trial site was established in Hines Hill WA on the 30th of April 2019, to demonstrate and evaluate to the extended David Grays network, the efficacy and crop safety of FMC’s Overwatch. With the active constituent Bixlozone(group Q molecule), for the pre-emergent control of Annual Ryegrass (Loliummultiflorum) (ARG), when applied pre-emergent in Scepter wheat (Triticum aestivum). The trial was established in a commercial field with a known population of uniform annual ryegrass. Previous trials had raised suspicion of Trifluralin (group D) resistant Ryegrass, however; no formal testing had been conducted prior to trial commencement.

Assessment dates 84 and 91 showed crop phytotoxicity of below 5% leafarea affected for Overwatch and Overwatch + TriflurX.

Vigour ratings during the season saw no difference when compared to the control. However; by the last assessment in conjunction with the rapid ripening off of the crop Overwatch treatments both standalone and in combination had improved vigour responses compared to the control by approximately 10%.

The highest average yield was seen in plots treated with Overwatch stand alone at 819.7kg/ha. Closely followed by Avadex 2.5 + TriflurX 2, 655.7kg/ha. A one-way ANOVA found there was significant difference between treatments yield (P<0.05). Thus, a post-hoc Tukey HSD test was conducted to decipher where the differences lie. Results found 17 between treatment significant differences (P<0.05). Overwatch stand alone and with TriflurX were significantly different to the control (P>0.001).

INTRODUCTION

Objectives

Evaluate efficacy of annual ryegrass control, and subsequent crop effects of emerging chemistry, compared to existing products.
Compare crop safety to all treatments.

METHODOLOGY

RESULTS

Figure 1. Average percentage (%) ARG weed control

Figure 2. Percentage of leaf area affected by phytotoxicity, at each assessment date.

Figure 3. Percentage of crop vigour, relative to the untreated control = 100.

Figure 4. Average yield data per treatment, expressed as kg/ha. Return on investment calculated as input/output.

One way ANOVA found significant difference between treatments (P>0.05).

Table 1. Post-hoc Tukey HSD test for between treatment differences.

DISCUSSION/CONCLUSION

All treatments applied IBS achieved an acceptable level of annual ryegrass control.

Overwatch stand alone as well as with TriflurX both had ARG control of above 75% at 63 DAS. There was slight decline in control at assessment’s 84, 91, 133 DAS, however; weed control maintained above 70%. The highest average control was seen in Sakura standalone, Sakura + TriflurX and Avadex at 63 DAS, with controls of 82.5% across these treatments. Gradual efficacy incline was seen in Sakura stand alone at 84, 91 and 133 DAS with percentages of 89.5%, 89.5% and 94.5% respectively. As well as Avadex + Sakura with an incline of 90%, 90% and 97% respectively.

Assessment dates 84 and 91 showed crop phytotoxicity of below 5% leaf area affected for Overwatch and Overwatch +TriflurX.

It should be noted that due to the lower than average rainfall and late start to the season, yields were lesser than previous years. With water being a limiting factor.

APPENDICES

63 DAS

91 DAS