Objective:                  

To evaluate herbicide combinations applied pre planted and/or post planted on weed control performance in spring wheat in environments and cropping systems representative of northwestern Montana    

Personnel:                 

Clint Beiermann, Jessica Pavelka

Summary:

Spring wheat was planted on April 27th, 2022 and thirteen different herbicide combination were tested (Tables 1, 2).  

At four weeks after application there was 90% or greater control of wild oat in treatments (2) Axial Bold, (6) Prowl followed by (fb) Axial Bold, (7) Zidua SC fb Axial Bold, (8) Anthem Flex fb Axial Bold, (9) Prowl H2O + Axial Bold, (10) Zidua SC + Axial Bold, and (11) Anthem Flex + Axial Bold. Lambsquarters control was 88% or higher in treatments (3) Prowl H2O, (4) Zidua SC, (6) Prowl followed by (fb) Axial Bold, (7) Zidua SC fb Axial Bold, (8) Anthem Flex fb Axial Bold, (9) Prowl H2O + Axial Bold, and (11) Anthem Flex + Axial Bold (Table 3).

Weed density was assessed four weeks after the final POST treatments were applied. High amounts of wild oat were present in treatments (1) non-treated, (3) Prowl H2O, (4) Zidua SC, and (5) Anthem Flex. Lambsquarters density was higher in treatments with poor control, including (1) non-treated, (2) Axial Bold, and (10) Zidua SC + Axial Bold (Table 5).

There was a significant effect of herbicide treatment on crop injury. Treatments (2) Axial Bold, (6) Prowl H2O fb Axial Bold, (7) Zidua SC fb Axial Bold, and (8) Anthem Flex + Axial Bold ranged from 16-21.3% crop injury; however, spring wheat recovered from these injuries, as each of these treatments resulted in high yield. The highest yielding treatment was (8) Anthem Flex fb Axial Bold at 98.6 bu/A, while the non-treated yielded the lowest at 52.5 bu/A (Table 3). We cannot conclude that Prowl, Zidua, or Anthem Flex provided improved wild oat control beyond using Axial Bold as a POST treatment. Prowl, Zidua, and Anthem Flex did improve lambsquarters control compared to non-treated.

 

Table 1. Management Information

Seeding date: 4/27/2022 Field Location: R6
Julian date: 117 Harvest date: 8/23/2022
Seeding rate:   Julian date: 235
Previous crop: Alfalfa Soil type: Creston Silt Loam
Herbicide: Study Treatments Tillage: Conventional
Insecticide: NA Soil residual nutrient (NO3-1, P, K lb/A): 78.5-6-122-8s
Fungicide: NA Nutrient fertilizer applied (N, P2O5, K20 lb/A): 80-50-60-10s

 

 

Table 2. Spring Wheat Pre & Post Combinations

Trt No. Trt Name Form Concentration Form Unit Rate Rate Unit Appl Timing
1 Non-trt
2 Axial Bold 0.7 LBA/GAL 15.0 fl oz/a POST
3 Prowl H2O 3.8 LBA/GAL 2.0 pt/a Early POST
4 Zidua SC 4.2 LBA/GAL 2.5 fl oz/a PRE
5 Anthem Flex 4.0 LBA/GAL 3.0 fl oz/a PRE
6 Prowl H2O 3.8 LBA/GAL 2.0 pt/a Early POST
  Axial Bold 0.7 LBA/GAL 15.0 fl oz/a POST
7 Zidua SC 4.2 LBA/GAL 2.5 fl oz/a PRE
  Axial Bold 0.7 LBA/GAL 15.0 fl oz/a POST
8 Anthem Flex 4.0 LBA/GAL 3.0 fl oz/a PRE
  Axial Bold 0.7 LBA/GAL 15.0 fl oz/a POST
9 Prowl H2O 3.8 LBA/GAL 2.0 pt/a Early POST
  Axial Bold 0.7 LBA/GAL 15.0 fl oz/a Early POST
10 Zidua SC 4.2 LBA/GAL 2.5 fl oz/a Early POST
  Axial Bold 0.7 LBA/GAL 15.0 fl oz/a Early POST
11 Anthem Flex 4.0 LBA/GAL 3.0 fl oz/a Early POST
  Axial Bold 0.7 LBA/GAL 15.0 fl oz/a Early POST

 

 

Table 3. Crop Injury & Yield

Treatment Injury (%) Yield
  1 WAT (bu/A)
1 - 52.5
2 16.3 91.6
3 5.0 81.4
4 7.5 81.6
5 6.3 84.6
6 21.3 96.8
7 21.0 90.9
8 16.0 98.6
9 9.0 91.3
10 7.3 92.8
11 6.0 98.0
Mean 11.6 87.3
CV 38.4 8.4
LSD 6.4 10.6
PR>F <0.001 <0.001

WAT = weeks after treatment

 

Table 4. Weed Control (4 WAT)

Treatment Wild Oat Lambsquarters
  % %
2 99.0 10.0
3 16.3 99.0
4 18.8 89.5
5 22.5 68.5
6 99.0 99.0
7 99.0 89.5
8 99.0 88.3
9 99.0 99.0
10 96.8 32.5
11 99.0 99.0
Mean 74.8 77.4
CV 6.9 17.9
LSD 7.5 20.2
PR>F <0.001 <0.001

WAT = weeks after treatment

 

Table 5. Weed Density (4 WAT)

Treatment Wild Oat Lambsquarters
  plants/m2 plants/m2
1 18.5 19.0
2 0.0 20.0
3 18.5 0.0
4 11.5 4.0
5 17.0 3.5
6 0.5 0.0
7 0.5 5.0
8 0.0 1.5
9 0.0 0.5
10 0.0 10.0
11 0.0 2.0
Mean 6.0 6.0
CV 72.2 92.9
LSD 6.3 8.0
PR>F <0.001 <0.001

WAT = weeks after treatment