Oakes Irrigation Research Site
Carrington Research Extension Center * North Dakota State University
P.O. Box 531, Oakes, ND 58474-0531, Phone: (701) 742-2744, FAX: (701) 742-2700, E-mail: Blaine.Schatz@ndsu.edu
Leonard.Besemann@ndsu.edu
Fine Tuning Microrates for Early Season Broadleaf Weed Control in Onion
H. Hatterman-Valenti and C. Auwarter
       Weed control in onion is essential to produce marketable bulbs and is compounded by the crop’s notoriously competitive nature, especially during establishment when onion can take anywhere from 4-10 weeks to reach the 2-leaf stage.  Broadleaf weeds such as common lambsquarters and redroot pigweed gain a competitive advantage over the establishing onion crop if weed control methods are not implemented.  PRE and POST herbicide options prior to the 2-leaf stage are few, and often ineffective.  This study was conducted at the Oakes Irrigation Research Facility near Oakes, North Dakota to compare early-season weed control of bromoxynil (Buctril and Broclean) and oxyfluorfen (GoalTender) applied at micro rates to a standard pre-emergence treatment of DCPA (Dacthal) and ethofumesate (Nortron) in onion.  ‘Sedona’ and ‘Crocket’ onion were planted May 15 with 18” centers and a planting population of 175,000 seeds/ac.  PRE treatments included 1 and 2 lb/ac ethofumesate and 13.33 lb/ac DCPA and were applied 9 days after planting (DAP).  Micro rate applications began between the flag-leaf and one-leaf stage, 23 DAP.  Bromoxynil and oxyfluorfen were applied at the 0.25 and 0.13 times the lowest labeled rate along with 0.031 lb/ac clethodim (Select) and applied in four or five sequential applications when weeds and onion were in seedling growth stages.  Petroleum oil-surfactant (Herbimax) (1 pt/ac) was tank mixed with the micro rate application.  The pre-emergence treatments received Buctril at 1 pt and Goal at 2 pt/ac during the 5-leaf stage.
Table 1.  Treatment application information.        
Date:   5/24/2013 6/7/2013 6/14/2013 6/22/2013 7/1/2013 7/8/2013
Time:   A B C D E F
Sprayer: GPA: 20 20 20 20 20 20
PSI: 40 40 40 40 40 40
Nozzle: 11002 11002 11002 11002 8002 8002
Air Temperature (F): 62 62 77 77 82 80
Relative Humidity (%): 44 75 8156 71 34 54
Soil Moisture: Adequate Adequate Adequate Excessive Adequate Adequate
Wind (MPH): 14 10 11 8 4 5
Cloud Cover (%): 50 5 65 25 20 90
Onion Stage: Seed Cracking 1-leaf 2-leaf 3-leaf 4-leaf 5-leaf
Table 2.  Treatment details.
Trt Trt Rate App Trt Trt Rate App Trt Trt   Rate App Trt Trt   Rate App
No Name Rate Unit/ac Code No Name Rate Unit/ac Code No Name Rate Unit/ac Code No Name Rate Unit/ac Code
1 Buctril 4 floz B 4 Buctril 4 Floz B 9 Buctril 2 Floz B 13 Broclean 2 Floz B
Select Max 4 floz B Select Max 4 Floz B Select Max 4 Floz B Select Max 4 Floz B
Herbimax 1 pt B Herbimax 1 Pt B Herbimax 1 Pt B Herbimax 1 Pt B
Buctril 4 floz C Buctril 4 Floz C Buctril 2 Floz C Broclean 2 Floz C
Select Max 4 floz C Select Max 4 Floz C Select Max 4 Floz C Select Max 4 Floz C
Herbimax 1 pt C Herbimax 1 Pt C Herbimax 1 Pt C Herbimax 1 Pt C
Buctril 2 floz D Buctril 4 Floz D Buctril 2 Floz D Broclean 4 Floz D
Goal Tender 2 floz D Select Max 4 Floz D Goal Tender 2 Floz D Select Max 4 Floz D
Select Max 4 floz D Herbimax 1 Pt D Select Max 4 Floz D Herbimax 1 Pt D
Herbimax 1 pt D Buctril 4 Floz E Herbimax 1 Pt D Broclean 2 Floz E
Buctril 2 floz E Select Max 4 Floz E Buctril 2 Floz E Goal Tender 2 Floz E
Goal Tender 2 floz E Herbimax 1 Pt E Goal Tender 2 Floz E Select Max 4 Floz E
Select Max 4 Floz E Buctril 4 Floz F Select Max 4 Floz E Herbimax 1 Pt E
Herbimax 1 Pt E Select Max 4 Floz F Herbimax 1 Pt E Broclean 2 Floz F
2 Buctril 2 Floz B Herbimax 1 Floz F 10 Buctril 4 Floz B Goal Tender 2 Floz F
Select Max 4 Floz B 5 Goal Tender 2 Floz B Select Max 4 Floz B Select Max 4 Floz F
Herbimax 1 Pt B   Select Max 4 Floz B Herbimax 1 Pt B Herbimax 1 Pt F
Buctril 2 Floz C   Herbimax 1 Pt B Buctril 4 Floz C 14 Broclean 4 Floz B
Select Max 4 Floz C   Goal Tender 2 Floz C Select Max 4 Floz C Select Max 4 Floz B
Herbimax 1 Pt C   Select Max 4 Floz C Herbimax 1 Pt C Herbimax 1 Pt B
Buctril 2 Floz D   Herbimax 1 Pt C Buctril 4 Floz D Broclean 4 Floz C
Select Max 4 Floz D   Goal Tender 2 Floz D Goal Tender 2 Floz D Select Max 4 Floz C
Herbimax 1 Pt D   Select Max 4 Floz D Select Max 4 Floz D Herbimax 1 Pt C
Buctril 2 Floz E   Herbimax 1 Pt D Herbimax 1 Pt D Broclean 4 Floz D
Goal Tender 2 Floz E   Goal Tender 2 Floz E Buctril 4 Floz E Select Max 4 Floz D
Select Max 4 Floz E   Select Max 4 Floz E Goal Tender 2 Floz E Herbimax 1 Pt D
Herbimax 1 Pt E   Herbimax 1 Pt E Select Max 4 Floz E Broclean 4 Floz E
Buctril 2 Floz F   Goal Tender 2 Floz F Herbimax 1 Pt E Select Max 4 Floz E
Goal Tender 2 Floz F   Select Max 4 Floz F 11 Buctril 4 Floz B Herbimax 1 Pt E
Select Max 4 Floz F   Herbimax 1 Pt F Select Max 4 Floz B Broclean 4 Floz F
Herbimax 1 Pt F 6 Dacthal 10 Lb A Herbimax 1 Pt B Select Max 4 Floz F
3 Goal Tender 1 Floz B Buctril 1 Pt F Buctril 4 Floz C Herbimax 1 Pt F
Buctril 2 Floz B Goal 2 Pt F Select Max 4 Floz C 15 Nortron 2 Pt A
Select Max 4 Floz B Select Max 12 Floz F Herbimax 1 Pt C Broclean 1 Pt F
Herbimax 1 Pt B Herbimax 1 Pt F Buctril 4 Floz D Goal 2 Pt F
Goal Tender 1 Floz C 7 Nortron 2 Pt A Select Max 4 Floz D Select Max 12 Floz F
Buctril 2 Floz C Buctril 1 Pt F Herbimax 1 Pt D Herbimax 1 Pt F
Select Max 4 Floz C Goal 2 Pt F Buctril 4 Floz E 16 Broclean 4 Floz B
Herbimax 1 Pt C Select Max 12 Floz F Goal Tender 2 Floz E Select Max 4 Floz B
Goal Tender 1 Floz D Herbimax 1 Pt F Select Max 4 Floz E Herbimax 1 Pt B
Buctril 2 Floz D 8 Nortron 4 Pt A Herbimax 1 Pt E Broclean 4 Floz C
Select Max 4 Floz D Buctril 1 Pt F Buctril 4 Floz F Select Max 4 Floz C
Herbimax 1 Pt D Goal 2 Pt F Goal Tender 2 Floz F Herbimax 1 Pt C
Goal Tender 1 Floz E Select Max 12 Floz F Select Max 4 Floz F Broclean 4 Floz D
Buctril 2 Floz E Herbimax 1 Pt F Herbimax 1 Pt F Goal Tender 2 Floz D
Select Max 4 Floz E 12 Untreated       Select Max 4 Floz D
Herbimax 1 Pt E   Herbimax 1 Pt D
Goal Tender 1 Floz F   Broclean 4 Floz E
Buctril 2 Floz F   Goal Tender 2 Floz E
Select Max 4 Floz F   Select Max 4 Floz E
Herbimax 1 Pt F   Herbimax 1 Pt E
Table 3.  Weed and injury ratings.
Trt % CONTROL
No CHEAL1 AMARE2 Injury CHEAL AMARE Injury CHEAL AMARE Injury
---------6/25/2013--------- --------7/16/2013-------- --------8/16/2013--------
1 100 a3 100   a 10   a 98   ab 98   a 0 a 68  b 78  b 0 a
2 95   a 89 bcd 8 abc 98   ab 93   a 0 a 83 ab 85 ab 0 a
3 99   a 99   ab 10   a 99   ab 98   a 0 a 79 ab 93 ab 0 a
4 100 a 99   ab 6 a-d 100  a 99   a 0 a 84 ab 94 ab 0 a
5 100 a 99   ab 6 a-d 91   b 100 a 0 a 70 ab 94 ab 0 a
6 98   a 78     d 4 b-e 100  a 84   b 0 a 99  a 86 ab 0 a
7 59   c 96  abc 4 b-e 96   ab 95   a 0 a 86 ab 91 ab 0 a
8 80  b 94  abc 3 cde 96   ab 98   a 0 a 83 ab 96  a 0 a
9 94  a 100   a 6 a-d 93   ab 95   a 0 a 69 ab 86 ab 0 a
10 99  a 99   ab 9  ab 99   ab 99   a 0 a 75 ab 85 ab 0 a
11 100 a 99   ab 8 abc 100  a 99   a 0 a 95 ab 96  a 0 a
12 0     e 0      e 0    e 0     c 0     c 0 a 0    c 0   c 0 a
13 100 a 97 abc 10   a 100   a 95   a 0 a 96 ab 94 ab 0 a
14 100 a 99  ab 8 abc 99   ab 99   a 0 a 95 ab 95  a 0 a
15 53   d 86  cd 2  de 94   ab 95   a 0 a 93 ab 96  a 0 a
16 100 a 100  a 6 a-d 99   ab 99   a 0 a 76 ab 90 ab 0 a
LSD (P = 0.05) 4.53 9.87 3.23 4.84 4.96 0 17.17 10.17 0
1 CHEAL = Common lambsquarters.
2 AMARE = Redroot pigweed.
3 Data followed by different letters are significantly different at P < 0.05.
Table 4.  Crocket onion yield results.  
Trt 1 Double Row X 6'
No ----<1"---- --1" to 2.25"-- --2.25" to 3"-- --3" to 4" -- ----- >4" ----- -----Total-----
# lbs # lbs # lbs # lbs # lbs # lbs CWT/ac
1 2 a1 0 a 14 a 1.6 a 9 a 2.8 a 1.5 a 0.9 ab 0.0 a 0.0 a 25.8 a 5.28 a-e 511 a-e
2 1 a 0 a 5 bc 0.7 abc 9 a 2.9 a 5.8 a 4.1 ab 0.0 a 0.0 a 20.5 ab 7.7 a-d 748 a-d
3 0 a 0 a 7 abc 1    ab 9 a 2.9 a 1.5 a 0.8 ab 0.0 a 0.0 a 17.5 ab 4.7 a-e 453 a-e
4 2 a 0 a 10ab 1    ab 2 bc 0.4 b 0.3 a 0.1 b 0.0 a 0.0 a 13.3 b 1.6 de 152 de
5 0 a 0 a 6 bc 0.8 abc 9 a 3.2 a 4.8 a 3.1 ab 1.3 a 1.5 a 20.8 ab 8.5 abc 823 abc
6 1 a 0 a 4 bc 0.7 abc 8 ab 3.1 a 8.8 a 6.5 a 0.8 a 0.9 a 22.0 ab 11.1 a 1075 a
7 1 a 0 a 5 bc 0.6 abc 6 abc 2.0 ab 6.0 a 3.9 ab 0.5 a 0.6 a 17.3 ab 7.1 a-d 685 a-d
8 1 a 0 a 5 bc 0.8 abc 8 ab 2.6 a 8.0 a 5.5 ab 0.5 a 0.7 a 21.5 ab 9.6 ab 924 ab
9 1 a 0 a 8 ab 1.1 ab 8 ab 2.4 a 1.8 a 1.0 ab 0.0 a 0.0 a 18.8 ab 4.5 a-e 436 a-e
10 3 a 0 a 6 bc 0.6 abc 6 ab 1.9 ab 3.3 a 2.1 ab 0.0 a 0.0 a 18.5 ab 4.7 a-e 453 a-e
11 1 a 0 a 11ab 1.3 ab 5 abc 1.8 ab 4.0 a 2.7 ab 0.0 a 0.0 a 20.3 ab 5.8 a-e 561 a-e
12 0 a 0 a 0 c 0    c 0 c 0    b 0.0 a 0.0 b 0.0 a 0.0 a 0.0   c 0.0 e 0.0 e
13 1 a 0 a 4 bc 0.6 bc 8 ab 2.8 a 7.3 a 4.5 ab 0.8 a 0.8 a 20.8 ab 8.6 abc 835 abc
14 3 a 0 a 10ab 1.1 ab 2 bc 0.5 b 0.5 a 0.4 b 0.0 a 0.0 a 14.5 b 2.0 cde 194 cde
15 1 a 0 a 7 abc 1    ab 8 ab 2.9 a 6.8 a 4.3 ab 0.0 a 0.0 a 22.8 ab 8.2 abc 796 abc
16 2 a 0 a 6 bc 0.6 abc 5 abc 1.6 ab 2.0 a 1.0 ab 0.0 a 0.0 a 14.8 b 3.2 b-e 312 b-e
LSD (P = 0.05) 2.5 0 4.7 0.6 4 1.3 4.9 3.3 1.2 1.4 6 3.9 380
1 Data followed by different letters are significantly different at P < 0.05.
Table 5.  Sedona  onion yield results.  
Trt 1 Double Row X 6'
No ----<1"---- --1" to 2.25"-- --2.25" to 3"-- --3" to 4" -- ----- >4" ----- -----Total-----
# lbs # lbs # lbs # lbs # lbs # lbs CWT/ac
1 1 a1 0 a 0 a 1.5 a 9   ab 2.8 ab 1.3 b 0.7 b 0.0 a 0.0 a 22.8 a 5.0 bcd 486 bcd
2 1 a 0 a 7   ab 0.7 ab 8   ab 2.7 ab 4.0 ab 2.8 ab 0.3 a 0.4 a 20.0 ab 6.5 abc 629 abc
3 1 a 0 a 5   ab 0.7 ab 13 a 4.4 a 5.5 ab 3.5 ab 0.0 a 0.0 a 23.5 a 8.5 ab 818 ab
4 1 a 0 a 8   ab 0.9 ab 2   bc 0.7 bc 0.3 b 0.1 b 0.0 a 0.0 a 11.0 b 1.7 cd 165 cd
5 0 a 0 a 6   ab 0.9 ab 11 a 3.7 a 5.3 ab 3.8 ab 0.3 a 0.4 a 22.0 a 8.7 ab 842 ab
6 0 a 0 a 5   ab 0.7 ab 7   ab 2.5 abc 11.3 a 7.8 a 0.8 a 0.9 a 24.0 a 11.9 a 1150 a
7 1 a 0 a 5   ab 0.8 ab 7   ab 2.0 abc 3.5 ab 2.2 ab 0.0 a 0.0 a 16.0 ab 5.0 bcd 484 bcd
8 0 a 0 a 3   ab 0.5 ab 6  abc 2.0 abc 8.5 ab 5.9 ab 1.0 a 1.0 a 18.5 ab 9.4 ab 908 ab
9 1 a 0 a 8   ab 1.2 ab 9   ab 2.9 ab 1.8 b 1.0 b 0.0 a 0.0 a 19.8 ab 5.0 bcd 484 bcd
10 2 a 0 a 9   ab 1.1 ab 7   ab 2.0 abc 2.3 b 1.2 b 0.3 a 0.3 a 19.8 ab 4.6 bcd 448 bcd
11 2 a 0 a 7   ab 1.0 ab 8    ab 2.7 ab 5.3 ab 3.4 ab 0.0 a 0.0 a 21.8 ab 7.2 abc 692 abc
12 0 a 0 a 0   b 0.0 b 0    ab 0.0 c 0.0 b 0.0 b 0.0 a 0.0 a 0.0   c 0.0 d 0     d
13 1 a 0 a 5   ab 0.7 ab 10  ab 3.1 ab 7.0 ab 4.4 ab 0.3 a 0.4 a 22.5 a 8.6 ab 833 ab
14 2 a 0 a 9   ab 0.9 ab 6  abc 1.8 abc 0.3 b 0.1 b 0.0 a 0.0 a 17.0 ab 2.9 bcd 276 bcd
15 0 a 0 a 5   ab 0.7 ab 7   ab 2.3 abc 8.0 ab 5.3 ab 0.0 a 0.0 a 19.8 ab 8.3 ab 801 ab
16 1 a 0 a 7   ab 0.9 ab 6  abc 1.7 abc 3.8 ab 2.2 ab 0.0 a 0.0 a 17.8 ab 4.8 bcd 467 bcd
LSD (P = 0.05) 1.3 0 5.3 0.7 4.4 1.6 4.9 3.4 0.8 0.9 6.5 3.8 371
1 Data followed by different letters are significantly different at P < 0.05.
Table 6.  Crocket plus Sedona yield results.
Trt      
No <1" 1" to 2.25" 2.25" to 3" 3" to 4" >4" Total
---------------------------------CWT/ac---------------------------------
1 1.2 a1 152 a 271 abc 74   bc 0.0 a 499 bcd
2 2.4 a 69 bc 270 abc 330 abc 17 a 689 abc
3 0.0 a 80 ab 350 a 206 bc 0.0 a 635 abc
4 0.0 a 93 ab 53  de 12   c 0.0 a 159 cd
5 0.0 a 80 ab 333 ab 330 abc 90 a 833 ab
6 0.0 a 67 bc 271 abc 687 a 87 a 1112 a
7 1.2 a 65 bc 191 a-d 298 abc 29 a 584 abc
8 0.0 a 62 bc 226 abc 547 ab 81 a 916 ab
9 0.0 a 110 ab 254 abc 95   bc 0.0 a 460 bcd
10 3.6 a 85 ab 190 a-d 160 bc 0.0 a 450 bcd
11 3.6 a 111 ab 217 abc 295 abc 0.0 a 627 abc
12 0.0 a 0.0   c 0.0     e 0.0    c 0.0 a 0.0     d
13 1.2 a 59 bc 288 abc 426 abc 59 a 834 ab
14 4.8 a 94 ab 110 cde 25   c 0.0 a 235 cd
15 0.0 a 85 ab 250 abc 463 abc 0.0 a 799 ab
16 1.2 a 73 abc 159 bcd 157 bc 0.0 a 390 bcd
LSD (P = 0.05) 3.9 49 107 278 98 335
1 Data followed by different letters are significantly different at P < 0.05.
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