Kochia and Wild Oat Control in Spring Wheat
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Objective:
To evaluate herbicide combinations on weed control performance in spring wheat in environments and cropping systems representative of northwestern Montana
Personnel:
Clint Beiermann, Lovreet Shergill, Jessica Pavelka 
Summary:
Spring wheat was planted on April 27th, 2021 and thirteen different herbicide treatments were applied throughout the spring of 2021, with a non-treated as a control (Tables 1 & 2).
The treatments (2) Sharpen followed by (fb) Axial Star, (4) Zidua fb Axial Star, (5) Anthem Flex fb Axial Star, (6) Prowl fb Axial Star, (7) Axial Star, and (8) Axial Star + Affinity TankMix all provided greater than 90% wild oat control. All herbicide treatments applied resulted in a high level of kochia control. This is likely due to a low presence of kochia in the study area.
Lambsquarters was controlled greater than 90% by the treatments (6) Prowl fb Axial Star, (8) Axial Star + Affinity TankMix, (9) Axial XL + Talinor, (10) Huskie + Axial XL, (11) Opensky, (12) Opensky + 2,4-D, (13) Varro + Starane Ultra, and (14) WideMatch + Affinity TankMix. Pennycress control was high with all herbicide treatments except for (3) Zidua, (4) Zidua fb Axial Star, and (7) Axial Star with the lowest control at 37.5% for the Zidua treatment (Table 3).
Weed density was assessed five weeks after the final post treatments were applied. Wild oat was only found in treatments (1) non-treated, (3) Zidua, and (14) WideMatch + Affinity Tankmix (Table 4). Kochia was only found at 1 plant per square meter in the non-treated control. Lambsquarter density was higher in treatments with poor control performance, including (1) non-treated, (2) Sharpen fb Axial Star, (3) Zidua, (4) Zidua fb Axial Star, (5) Anthem Flex fb Axial Star, and (7) Axial Start (Table 4).
Crop injury was low across all treatments, with the exception of treatment (9) Axial XL + Talinor; this treatment caused 16% injury at three weeks after treatment (Table 5). Spring wheat recovered from this injury as there was no effect on yield (Table 5). Herbicide treatment had no significant effect on spring wheat yield. Average yield was 109.4 bu/A across all herbicide treatments.
Table 1. Management information |
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|---|---|---|---|
| Seeding date: | 4/27/2021 | Field Location: | P2 |
| Julian date: | 117 | Harvest date: | 9/2/2021 |
| Seeding rate: | Julian date: | 245 | |
| Previous crop: | Barley | Soil type: | Silty Clay Loam |
| Herbicide: | Table 2 | Tillage: | Conventional |
| Insecticide: | None |
Soil residual nutrient (NO3-1, P, K lb/A): |
103-28-478 |
| Fungicide: | None |
Nutrient fertilizer applied (N, P2O5, K20 lb/A): |
110-30-25-10S |
Table 2. Herbicide Treatments |
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|---|---|---|
| Treatment # | Treatment Name | Application Timing |
| 1 | Non-treated | |
| 2 | Sharpen 4 FL OZ/A | Pre-Plant |
| Axial Star 16.4 FL OZ/A | Post-Emergence | |
| 3 | Zidua 1.5 OZ WT/A | Delayed Pre-Emergence |
| 4 | Zidua 1.5 OZ WT/A | Delayed Pre-Emergence |
| Axial Star 1.75 FL OZ/A | Post-Emergence | |
| 5 | Anthem Flex 2.75 FL OZ/A | Pre-Emergence |
| Axial Star 16.4 FL OZ/A | Post-Emergence | |
| 6 | Prowl 1.5 PT/A | Early Post-Emergence |
| Axial Star 16.4 FL OZ/A | Post-Emergence | |
| 7 | Axial Star 16.4 FL OZ/A | Post-Emergence |
| 8 | Axial Star 16.4 FL OZ/A | Post-Emergence |
| Affinity TankMix 1 OZ WT/A | Post-Emergence | |
| 9 | Axial XL 16.4 FL OZ/A | Post-Emergence |
| Talinor 13.7 FL OZ/A | Post-Emergence | |
| 10 | Huskie 11 FL OZ/A | Post-Emergence |
| Axial XL 16.4 FL OZ/A | Post-Emergence | |
| 11 | Opensky 1 PT/A | Post-Emergence |
| 12 | Opensky 1 PT/A | Post-Emergence |
| 2,4-Dester LV6 7 FL OZ/A | Post-Emergence | |
| 13 | Varro 6.85 FL OZ/A | Post-Emergence |
| Starane Ultra 0.3 PT/A | Post-Emergence | |
| 14 | WideMatch 1 PT/A | Post-Emergence |
| Affinity TankMix 1 OZ WT/A | Post-Emergence | |
Table 3. Weed Control (8 WAT*) |
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|---|---|---|---|---|
| Treatment | Wild Oat | Kochia | Lambsquarter | Pennycress |
| % | % | % | % | |
| 2 | 97.5 | 99.0 | 81.0 | 92.0 |
| 3 | 35.0 | 99.0 | 43.8 | 37.5 |
| 4 | 93.0 | 99.0 | 62.3 | 84.5 |
| 5 | 96.5 | 99.0 | 63.8 | 91.8 |
| 6 | 96.5 | 99.0 | 99.0 | 99.0 |
| 7 | 94.3 | 99.0 | 82.0 | 82.0 |
| 8 | 92.5 | 99.0 | 99.0 | 99.0 |
| 9 | 88.5 | 99.0 | 96.8 | 98.0 |
| 10 | 87.5 | 99.0 | 99.0 | 99.0 |
| 11 | 75.0 | 99.0 | 99.0 | 99.0 |
| 12 | 87.5 | 99.0 | 99.0 | 94.5 |
| 13 | 88.8 | 99.0 | 99.0 | 94.3 |
| 14 | 75.0 | 99.0 | 98.0 | 95.8 |
| Mean | 85.2 | 99.0 | 86.3 | 83.3 |
| CV | 11.6 | 0.0 | 13.2 | 11.5 |
| LSD | 14.1 | – | 16.4 | 13.7 |
| PR>F | <0.001 | 0.468 | <0.001 | <0.001 |
*Weeks after treatment
Table 4. Weed Density (5 WAT*) |
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|---|---|---|---|---|
| Treatment | Wild Oat | Kochia | Lambsquarter | Pennycress |
| plants/m2 | plants/m2 | plants/m2 | plants/m2 | |
| 1 | 17 | 1.0 | 3.5 | 0.5 |
| 2 | 0.0 | 0.0 | 2.5 | 0.0 |
| 3 | 18.5 | 0.0 | 1.5 | 0.0 |
| 4 | 0.0 | 0.0 | 4.0 | 0.5 |
| 5 | 0.0 | 0.0 | 0.5 | 0.5 |
| 6 | 0.0 | 0.0 | 0.0 | 0.0 |
| 7 | 0.0 | 0.0 | 3.5 | 0.5 |
| 8 | 0.0 | 0.0 | 0.0 | 0.0 |
| 9 | 0.0 | 0.0 | 0.0 | 0.0 |
| 10 | 0.0 | 0.0 | 0.0 | 0.0 |
| 11 | 0.0 | 0.0 | 0.0 | 0.0 |
| 12 | 0.0 | 0.0 | 0.0 | 0.0 |
| 13 | 0.0 | 0.0 | 0.0 | 0.0 |
| 14 | 16.0 | 0.0 | 0.0 | 0.0 |
| Mean | 3.7 | 0.1 | 1.1 | 0.1 |
| CV | 86.6 | 748.3 | 154.2 | 359.5 |
| LSD | 4.6 | – | 2.4 | – |
| PR>F | <0.001 | 0.47 | 0.002 | 0.624 |
*Weeks after treatment
Table 5. Crop Injury & Yield |
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|---|---|---|
| Treatment | Injury (%) | Yield |
| 2 WAT* | (bu/A) | |
| 1 | 0.0 | 108.7 |
| 2 | 0.0 | 115.6 |
| 3 | 0.0 | 112.5 |
| 4 | 2.5 | 103.5 |
| 5 | 0.0 | 118.0 |
| 6 | 2.8 | 108.8 |
| 7 | 0.8 | 111.9 |
| 8 | 2.5 | 118.5 |
| 9 | 16.3 | 106.9 |
| 10 | 1.3 | 106.0 |
| 11 | 5.0 | 99.3 |
| 12 | 2.5 | 108.7 |
| 13 | 6.3 | 119.5 |
| 14 | 3.8 | 94.3 |
| Mean | 3.1 | 109.4 |
| CV | 105.4 | 12.5 |
| LSD | 4.7 | – |
| PR>F | <0.001 | 0.2015 |
*Weeks after treatment