Post-emergent Herbicides for the Control of Wild Radish

Evaluation of various broadleaf herbicides in the control of Wild Radish. Comparison of Frequency to Velocity and Talinor.

Hines Hill, WA, 2018

Summary

Wild radish (Raphanusraphanistrum) is an extremely competitive broadleaf weed (BLW), with the potential to cause yield losses of up to 90%. A trial site was established in Hines Hill WA, on the 30th of July at a location with a heavy and even population of wild radish.

The trial aimed to demonstrate various BLW post emergent herbicide combinations, by examining the efficacy, speed of brownout and crop safety in wheat. Additionally, BASF’s new herbicide Frequency was compared to existing group H herbicides Velocity and Talinor.

Velocity + Tigrex provided the greatest control with Frequency + LVE, Tigrex and Howitzer close behind. The rates used for the group H chemistry were at the lower end of the spectrum for 6-8 leaf radish. This was done deliberately to stress test the products and piece out any differences in performance. In addition, spray conditions were not ideal for group H chemistry with an afternoon application and 60% cloud cover. Hence this trial provided challenging conditions for the Velocity, Talinor and Frequency treatments

Methodology

Herbicide Treatments

Trial Design

Site, Crop and Application Details

Assessment Methods

Data Analysis

All data analysis in this report was conducted using Microsoft Excel. Simple means, analysis of variance was used to determine statistical significance using the least significant difference method with a 95% confidence interval.

Results

% Control Ratings

Figure 1: Mean percentage brownout of radish in wheat, at 14, 28 & 76 DAT.

Howitzer and Velocity + Tigrex, indicated the most rapid brownout of 76% & 79% at 14 DAT (Fig. 1). This followed through to 74 DAT where Velocity + Tigrex provided greatest control (93%) with Howitzer and Frequency + LVE close behind (85%).

Frequency had a slower start, however finished off strong as an effective group H, I combination. This season conditions favoured brews with MCPA in the mix.

The level of control provided by high rates of DFF & MCPA is indicative of weak resistance. Emphasizing the need for MOA combinations for effective control.

The Gallery + Bromoxynil treatment was intended to be applied EPE, however we missed the opportunity and applied it at the same timing as the other treatments. Hence the level of control was poor as Gallery has no knockdown effect.

Application conditions were undesirable with an afternoon application and 60% cloud cover reduced the efficacy of Group H herbicides. Due to the requirement of light intensity for optimal uptake and expression of herbicide in the target weed. Weed density and size had advanced past an optimal size at spraying, with some out-growing the effects of the herbicide at these rates. Higher rates of Velocity, Talinor and Frequency should have been used, however we wanted to push the chemistry to piece out any differences.

Control for BASF’s new group H herbicide Frequency in combination eith Bromoxynil performed on par with its competitors Talinor and Velocity.

As expected, treatments containing Diflufenican exhibited slight levels of transient phytotoxicity with no reduction in vigor observed.

Conclusion

In this trial, Velocity + Tigrex was the most effective herbicide combination for Radish control, followed closely by Frequency + MCPA, Tigrex and Howitzer. Phytotoxicity 28 DAT was transient, with the crop able to grow through it. Of the group H + bromoxynil treatments, Velocity provided the greatest control followed closely by Talinorand Frequency.

Frequency provides agronomists and growers an exciting opportunity to be able to cost effectively tank mix Frequency with arange of herbicides. Howitzer + Frequency would compare with Velocity + Tigrex and provide 4 modes of action. If priced competitively the adoption ofFrequency will be rapid.

Mixing/rotating alternate modes of action will delay the onset of herbicide resistance, as well as improve efficacy. The importance of application timing along with adequate rates was highlighted in this trial. Where herbicides applied outside the optimum window at inadequate rates failed to achieve the expected level of control.

Appendix

Rainfall

Photos

Follow Dropbox link for all pre and post spray images and assessment DAT:

https://www.dropbox.com/sh/duj5tkjoxohuc7s/AABdCI8YA9Y-mt6ahZrrTkNDa?dl=0