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
Early-season Weed Control in Onion Using Micro-rates
H. Hatterman-Valenti and C. Auwarter
          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 standard pre-emergence treatment of DCPA (Dacthal) and ethofumesate (Nortron) in onion.  'Crockett', 'Patterson', 'Sedona', and 'Talon were planted April 25 with 16" centers and a planting population of 250,000 seeds/acre.  PRE treatments included 1 and 2 lb/ac ethofumesate and 13.33 lb/acre DCPA and were applied 11 days after planting (DAP).  Micro rate applications began between the flag-leaf and one-leaf stage, 27 DAP.  Bromoxynil and oxyfluorfen were applied at the 0.25 and 0.13 times the lowest labeled rate and applied in four of five sequential applications when weeds and onions were in seedling growth stages.  Petroleum oil-surfactant (Herbimax) (1 pt/acre) was tank mixed with the micro rate application.  All treatments received bromoxynil at 0.25 lb/acre and oxyfluorfen at 0.50 lb/acre when onions were around the 5 and 9-leaf stage.
Table 1.  Treatment Application Information. Table 4.  Crockett onion yield results.
Date: 5/6/14 5/22/14 5/29/14 6/4/14 6/13/14 6/20/14 6/30/14 7/23/14 Trt ------------Onion Bulb Counts in 6 row feet------------ ----------------------------CWT/A---------------------------
Time: A B C D E F G H No. <1" 1-2.25" 2.25-3" 3-4" >4" Total <1" 1-2.25" 2.25-3" 3-4" >4" Total
Sprayer: GPA: 20 20 20 20 20 20 20 20
PSI: 40 40 40 40 40 40 40 40 1 0.7b 4.7c 12.5abc 10.0ab 0a 0.0a 3.63a 34bcd 211abc 312a 0a 565abc
Nozzle: 8002 8002 8002 8002 8002 8002 8002 8002 2 0.3b 15.3ab 16.5ab 1.0d 0a 33.5a 2.42a 95abc 264ab 29bc 0a 388bcd
Air Temperature  (F): 48 72 87 81 59 69 75 79 3 0.1b 9.5abc 15.3abc 7.5abc 0a 32.8a 1.21a 62a-d 270ab 219a 0a 568abc
Relative Humidity (%): 76 37 24 37 63 83 45 43 4 0.1b 6.8bc 14.3abc 6.8abc 0a 28.3ab 1.21a 46a-d 247abc 200a 0a 501abc
Wind (MPH): 4.6 7 10 9 7 7.5 11.1 7 5 0.1b 20.0a 7.5cd 0.5d 0a 28.8ab 1.21a 125a 120cd 5c 0a 260de
Cloud Cover (%): 100 0 0 10 5 5 50 60 6 0.0b 5.9bc 19.8a 8.3ab 0a 34.0a 0.0a 44a-d 340a 244a 0a 634a
Onion Leaf Stage: PRE Flag 2-Jan 2 3 4 5 9 7 0.1b 12.0abc 13.0abc 2.0cd 0a 27.8ab 1.21a 78a-d 207abc 42bc 0a 346cde
8 0.6b 3.5c 14.3abc 8.8ab 0a 27.5ab 3.63a 22cd 258ab 276a 0a 566abc
Table 2.  Treatment details. 9 0.3b 19.2b 4.5de 0.0d 0a 24.3ab 2.42a 118ab 65de 0c 0a 184ef
Trt Trt Rate App Trt Trt Rate App 10 0.1b 7.3bc 11.0bcd 6.8abc 0a 25.8ab 1.21a 56a-d 186bc 201a 0a 451abc
No. Name Rate Unit Code   No. Name Rate Unit Code 11 0.2b 6.7bc 10.3bcd 10.5ab 0a 28.5ab 1.21a 41a-d 184bc 322a 0a 558abc
12 3.6a 12.5abc 1.3e 0.3d 0a 18.8b 6.05a 52a-d 22e 3c 0a 88f
1 Buctril 4 fl oz/ac B 10 Buctril 4 fl oz/ac B 13 0.7b 10.5abc 13.5abc 5.0a-d 0a 30.8a 3.63a 69a-d 247abc 114ab 0a 471abc
  Buctril 4 fl oz/ac C   Buctril 4 fl oz/ac C 14 0.4b 8.5abc 11.0bcd 7.5abc 0a 28.3ab 2.42a 59a-d 192bc 223a 0a 486abc
  Goal Tender 2 fl oz/ac D   Buctril 4 fl oz/ac D 15 0.1b 11.7abc 12.0bc 4.3bcd 0a 28.5ab 1.21a 107ab 213abc 123ab 0a 473abc
  Goal Tender 2 fl oz/ac E   Goal Tender 2 fl oz/ac D 16 0.1b 3.5c 12.8abc 10.8a 0a 27.5ab 1.21a 19d 225abc 346a 0a 594ab
2 Buctril 2 fl oz/ac B   Buctril 4 fl oz/ac E
Buctril 2 fl oz/ac C   Goal Tender 2 fl oz/ac E LSD (P=0.05) 0.5 1.0 4.7 3.8 0 6.2 3.32 3 81 5 0 138
Buctril 4 fl oz/ac D 11 Buctril 4 fl oz/ac B
Buctril 2 fl oz/ac E Buctril 4 fl oz/ac C Table 5.  Patterson onion yield results. 
Goal Tender 2 fl oz/ac E Buctril 4 fl oz/ac D Trt ------------Onion Bulb Counts in 6 row feet------------ ----------------------------CWT/A---------------------------
Buctril 2 fl oz/ac F Buctril 4 fl oz/ac E No. <1" 1-2.25" 2.25-3" 3-4" >4" Total <1" 1-2.25" 2.25-3" 3-4" >4" Total
Goal Tender 2 fl oz/ac F Goal Tender 2 fl oz/ac E
3 Buctril 2 fl oz/ac B Buctril 4 fl oz/ac F 1 0.4a 14.0ab 9.5ab 0.0a 0a 24.3a 2.42a 97ab 133abc 0a 0a 232abc
  Goal Tender 1 fl oz/ac B Goal Tender 2 fl oz/ac F 2 0.3a 18.3ab 2.0c 0.0a 0a 20.8ab 2.42a 94ab 27d 0a 0a 123de
Buctril 2 fl oz/ac C 12 Check       3 0.1a 17.5ab 9.0ab 0.3a 0a 27.0a 1.21a 115a 145ab 7a 0a 269ab
  Goal Tender 1 fl oz/ac C 13 Broclean 2 fl oz/ac B 4 2.8a 19.8ab 2.0c 0.3a 0a 25.0a 4.84a 98ab 28d 8a 0a 139cde
  Buctril 2 fl oz/ac D   Broclean 2 fl oz/ac C 5 0.1a 19.8ab 5.8abc 0.0a 0a 25.8a 1.21a 122a 85a-d 0a 0a 208a-d
  Goal Tender 1 fl oz/ac D Broclean 2 fl oz/ac D 6 0.0a 17.8ab 10.5ab 0.8a 0a 29.0a 0.0a 117a 156ab 19a 0a 293a
  Buctril 2 fl oz/ac E Broclean 2 fl oz/ac E 7 0.4a 16.8ab 5.3abc 0.5a 0a 23.3a 2.42a 81ab 76a-d 15a 0a 174bcd
  Goal Tender 1 fl oz/ac E Goal Tender 2 fl oz/ac E 8 0.3a 19.8ab 7.8abc 0.3a 0a 28.3a 2.42a 122a 121abc 8a 0a 254ab
  Buctril 2 fl oz/ac F Broclean 2 fl oz/ac F 9 0.0a 21.3a 4.8bc 0.0a 0a 26.0a 0.0a 120a 65bcd 0a 0a 185a-d
  Goal Tender 1 fl oz/ac F Goal Tender 2 fl oz/ac F 10 0.4a 12.5ab 8.5ab 1.3a 0a 23.0a 2.42a 85ab 136abc 35a 0a 258ab
4 Buctril 4 fl oz/ac B 14 Broclean 4 fl oz/ac B 11 0.1a 16.3ab 11.0a 0.3a 0a 27.8a 1.21a 107a 173a 8a 0a 289a
Buctril 4 fl oz/ac C   Broclean 4 fl oz/ac C 12 0.6a 9.3b 2.8c 0.0a 0a 13.3b 2.42a 35b 46cd 0a 0a 83e
Buctril 4 fl oz/ac D Broclean 4 fl oz/ac D 13 0.3a 14.5ab 10.5ab 0.8a 0a 26.3a 2.42a 90ab 165ab 18a 0a 275ab
Buctril 4 fl oz/ac E Broclean 4 fl oz/ac E 14 0.1a 16.5ab 4.5bc 0.5a 0a 21.8ab 1.21a 91ab 76a-d 13a 0a 182a-d
Buctril 4 fl oz/ac F Broclean 4 fl oz/ac F 15 0.1a 14.3ab 6.5abc 0.8a 0a 21.8ab 1.21a 79ab 100a-d 21a 0a 201a-d
5 Goal Tender 2 fl oz/ac B 15 Nortron 32 fl oz/ac A 16 0.1a 12.0ab 9.3ab 0.8a 0a 22.3ab 1.21a 74ab 146ab 22a 0a 243ab
  Goal Tender 2 fl oz/ac C 16 Broclean 4 fl oz/ac B
  Goal Tender 2 fl oz/ac D   Broclean 4 fl oz/ac C LSD (P=0.05) 0.5 6.4 3.6 0.9 0 6.5 3.38 41 58 24 0 66
  Goal Tender 2 fl oz/ac E Broclean 4 fl oz/ac D
  Goal Tender 2 fl oz/ac F Goal Tender 2 fl oz/ac D
6 Dacthal 10 lb/ac A Broclean 4 fl oz/ac E Table 6.  Sedona onion yield results. 
7 Nortron 32 fl oz/ac A   Goal Tender 2 fl oz/ac E Trt ------------Onion Bulb Counts in 6 row feet------------ ----------------------------CWT/A---------------------------
8 Nortron 64 fl oz/ac A No. <1" 1-2.25" 2.25-3" 3-4" >4" Total <1" 1-2.25" 2.25-3" 3-4" >4" Total
9 Buctril 2 fl oz/ac B Oakes Irrigation Research Site
  Buctril 2 fl oz/ac C Variety trials Crop index Home page Report 2014 1 0.2a 6.8cd 12.0a 7.4ab 0.0a 27.0a 1.21a 44bc 215a 258ab 0a 524a-d
Buctril 2 fl oz/ac D 2 0.3a 15.8ab 13.5a 1.0c 0.0a 31.0a 2.42a 107a 208a 21c 0a 353cde
Goal Tender 2 fl oz/ac D 3 0.1a 7.0cd 12.3a 10.1a 0.1a 30.0a 1.21a 41bc 229a 317a 15a 609ab
Buctril 2 fl oz/ac E 4 0.7a 14.3abc 9.8a 2.4bc 0.0a 27.8a 3.63a 82abc 172a 69bc 0a 341cde
  Goal Tender 2 fl oz/ac E 5 0.1a 7.8cd 13.5a 2.6bc 0.0a 25.0a 1.21a 57abc 217a 69bc 0a 378b-e
6 0.0a 4.0d 13.0a 9.7a 0.0a 26.8a 0.00a 33c 246a 332a 0a 611ab
7 0.1a 10.8a-d 17.3a 2.8bc 0.0a 31.5a 1.21a 84abc 306a 74bc 0a 488a-d
Table 3.  Stand counts, weed control and injury ratings. 8 0.0a 4.5d 13.8a 9.7a 0.1a 28.5a 0.00a 35bc 243a 323a 13a 623a
Stand Counts 9 0.4a 17.5a 11.5a 0.4c 0.0a 30.3a 2.42a 113a 180a 5c 0a 310de
29 DAA1-A2, 13 DAA-B2, 6 DAA-C2 in 3 row feet. Weed Control and Injury 38 DAA-A. 10 0.1a 3.3d 12.0a 7.6ab 0.0a 23.3a 1.21a 39bc 223a 235ab 0a 515a-d
Trt -----------------Variety------------------ -----% Control----- % 11 0.1a 6.3d 11.8a 8.1ab 0.1a 27.0a 1.21a 50bc 225a 272ab 17a 570abc
No. Crockett Sedona Patterson Talon Colq3 Pigw4 Injury 12 0.7a 16.3ab 5.8a 0.4c 0.0a 23.5a 3.63a 97ab 86a 9c 0a 201e
1 12.8a 12.8a 9.3a 7.8a 93.3a 100.0a 7.5ab 13 0.3a 9.8bcd 12.3a 6.1ab 0.1a 29.0a 2.42a 71abc 218a 193ab 13a 508a-d
2 12.3a 10.5a 12.0a 11.0a 70.0a 81.3ab 1.3c 14 0.4a 8.8cd 9.8a 5.4ab 0.1a 25.3a 2.42a 58abc 177a 169ab 15a 434a-d
3 11.5a 12.5a 9.8a 9.0a 86.7a 100.0a 8.8a 15 0.1a 6.3d 14.5a 5.8ab 0.0a 27.0a 1.21a 46bc 267a 181ab 0a 502a-d
4 10.3a 10.3a 10.8a 8.0a 85.0a 98.8a 3.8abc 16 0.1a 4.0d 10.3a 12.2a 0.1a 27.0a 1.21a 36bc 199a 416a 15a 667a
5 12.0a 9.5a 8.8a 9.8a 81.7a 100.0a 6.3ab
6 12.8a 8.3a 10.8a 8.3a 80.0a 62.5b 0.0c LSD (P=0.05) 0.5 4.9 5.0 7.9 0.2 6.2 3.45 36 92 90 25 143
7 10.5a 13.3a 10.8a 9.5a 11.7b 100.0a 0.0c
8 12.0a 12.3a 12.0a 11.0a 38.3b 98.8a 0.0c Table 7.  Talon onion yield results. 
9 11.5a 10.8a 11.0a 9.3a 80.0a 100.0a 7.5ab Trt ------------Onion Bulb Counts in 6 row feet------------ ----------------------------CWT/A---------------------------
10 10.5a 7.8a 9.5a 9.0a 95.0a 100.0a 6.3ab No. <1" 1-2.25" 2.25-3" 3-4" >4" Total <1" 1-2.25" 2.25-3" 3-4" >4" Total
11 8.0a 8.5a 10.8a 9.3a 90.0a 98.8a 2.5bc
12 7.8a 10.3a 10.8a 7.5a 0.0c 0.0c 0.0c 1 0.0a 5.0a 9.0a 5.8a-d 0.1a 20.0ab 0.00a 36a 153a 186a-d 17a 392abc
13 13.8a 10.8a 11.8a 9.5a 86.7a 100.0a 6.3ab 2 0.0a 10.5a 5.7a 2.5bcd 0.0a 18.8ab 0.00a 62a 88a 81bcd 0a 231cd
14 9.8a 10.3a 9.8a 7.3a 86.7a 100.0a 5.0abc 3 0.0a 5.8a 10.1a 5.8a-d 0.1a 22.3ab 0.00a 34a 173a 172a-d 18a 397abc
15 12.3a 13.8a 11.8a 9.3a 15.0c 100.0a 0.0c 4 0.0a 10.5a 6.7a 2.8a-d 0.0a 20.8ab 0.00a 61a 113a 82bcd 0a 255bcd
16 9.3a 11.5a 10.5a 9.5a 95.0a 100.0a 6.3ab 5 0.0a 7.0a 8.2a 4.8a-d 0.0a 20.0ab 0.00a 50a 130a 137a-d 0a 316a-d
6 0.0a 7.8a 7.7a 6.5abc 0.1a 22.3ab 0.00a 47a 125a 221abc 15a 408abc
LSD (P=0.05) 4.0 4.0 3.3 3.7   17.0 20.9 3.1 7 0.0a 12.0a 6.8a 3.8a-d 0.0a 23.3ab 0.00a 64a 130a 115a-d 0a 309a-d
8 0.0a 6.8a 10.5a 5.3a-d 0.1a 23.3ab 0.00a 42a 176a 185a-d 16a 419abc
1DAA = Days after application. 9 0.0a 9.5a 13.4a 3.0a-d 0.0a 26.0a 0.00a 59a 215a 88bcd 0a 363abc
2Time from table 1. 10 0.3a 7.0a 9.1a 7.3ab 0.1a 24.0a 1.21a 51a 146a 237ab 15a 450ab
3Colq = Common Lambsquarters. 11 0.0a 8.8a 9.4a 7.8a 0.0a 26.0a 0.00a 54a 166a 263a 0a 483a
4Pigw = Redroot pigweed. 12 0.3a 6.8a 4.1a 1.3d 0.0a 12.5b 1.21a 36a 68a 42d 0a 148d
13 0.0a 7.8a 8.7a 6.3a-d 0.0a 23.0ab 0.00a 52a 151a 209a-d 0a 413abc
14 0.0a 7.8a 7.9a 5.5a-d 0.1a 21.5ab 0.00a 48a 131a 197a-d 15a 391abc
15 0.5a 8.5a 6.3a 2.0cd 0.0a 17.5ab 2.42a 53a 108a 59cd 0a 223cd
16 0.3a 5.0a 7.0a 7.3ab 0.1a 20.0ab 1.21a 35a 121a 236ab 12a 405abc
RESULTS LSD (P=0.05) 0.4 4.4 7.8 3.0 0.3 6.5 1.77 28 77 98 30 126
          The pre-applications of DCPA and ethofumesate didn't injure onion (37 DAA), while the post-applications all had some injury after the third application.  Micro-rate treatments without oxyfluorfen at this time had less injury and bromoxynil at 0.031 lb/acre had less injury then 0.062 lb/acre.  The Buctril treatments had less injury than the Broclean treatments.  When comparing treatment 2 (Buctril) versus treatment 13 (Broclean), treatment 4 (Buctril) vs treatment 14 (Broclean), treatment 7 (Buctril) vs treatment 15 (Broclean) and treatment 10 (Buctril) vs treatment 16 (Broclean); the biggest difference in injury was shown between treatments 2 and 13.  Both received 0.031 lb/ acre bromoxynil for 2 applications, fb 0.0625 lb/acre with 6.3% onion injury for Broclean and only 1.3% onion injury for Buctril.  DCPA controlled COLQ better than ethofumesate, while ethofumesate had better control of RRPW than DCPA 37 DAA.  Stand counts were taken 40 DAP, just prior to the third application.  No differences were observed. 
          Sedona onions had the highest yield among the four cultivars fb Crockett, Talon, and Patterson.  Even though there was more onion injury in the Broclean treatments, these treatments had a higher yield overall than the Buctril treatments.  The highest yielding treatment over all four cultivars was treatment 16 with Sedona onions at 666 cwt/acre.  This treatment consisted of bromoxynil (Broclean) at 0.0625 lb/acre applied twice fb bromoxynil (Broclean) at 0.0625 lb/acre and oxyfluorfen at 0.0625 lb/acre applied twice.  This treatment resulted in a top seven yield among the four cultivars of onion.  In comparison, the Buctril treatment 10 ranked in the middle among all treatments for total onion yield averaged over all cultivars.  The most consistent treatment was treatment 6; pre-application of DCPA and two additional applications of the grower standard use rate of bromoxynil and oxyfluorfen at the 5- and 9-leaf stages.  The untreated consistently yielded at the bottom even though it received the two standard bromoxynil and oxyfluorfen applications at the 5- and 9-leaf stages, because the weeds were too big to fully control.
          Having oxyfluorfen mixed with bromoxynil in the first three applications compared to only bromoxynil increased yields with all four cultivars (treatments 3 vs 2). Comparing treatments 10 and 11, where an application of bromoxynil at 0.0625 lb/acre was added for treatment 11, showed a yield increase with all four cultivars.  Treatment 10 had 2 applications of bromoxynil at 0.0625 lb/ acre and 2 applications of bromoxynil at 0.0625 lb/acre plus oxyfluorfen at 0.0625 lb/acre.  Treatment 11 added a third application of bromoxynil at 0.0625 lb/acre in the middle fb 2 applications of bromoxynil at 0.0625 lb/acre plus oxyfluorfen at 0.0625 lb/acre.
Oakes Irrigation Research Site
Variety trials Crop index Home page Report 2014