North Dakota State University * Dickinson Research Extension Center
1089 State Avenue, Dickinson, ND 58601-4642 Voice: (701) 483-2348 FAX:
(701) 483-2005
HERBICIDE COMBINATIONS FOR BROADLEAF WEED CONTROL IN WHEAT
John Nalewaja, NDSU Crop and Weed Sciences
Stoa' hard red spring wheat was seeded April 13. Treatments were applied
to 5- to 6-leaf wheat, 1- to 2-inch wild buckwheat, 2-inch redroot pigweed, 2- to 4-inch
common lambsquarters, and 2- to 3-inch Russian thistle on May 26 with 60 F, clear sky, and
0- to 5-mph wind. Treatments were applied with a bicycle wheel type plot sprayer
delivering 8.5 gpa at 35 psi throught 8001 flat fan nozzles to a 7 ft wide area the length
of 10 by 28 ft plots. The experiment was a randomized complete block design with four
replicates. Weed densities were wild buckwheat 5 plants/M2, redroot pigweed 11
small plants/ft2, common lambsquarters 1 plant/ft2, and Russian
thistle less than 1 plant/M2.
| Treatment | Rate |
7/14 |
8/12 | Test weight lb/bu | ||||
| Wht | Wibw | Rrdw | Colq | Ruth | ||||
| Yield bu/a | ||||||||
| oz/A | % |
|||||||
| Metsulfuron+2.4-Dbee+NIS | 0.0625+4.0+0.125% | 0 | 73 | 95 | 99 | 99 | 52 | 59 |
| Mets+MSPA-ioe+NIS | 0.0625+4.0+0.125% | 0 | 61 | 99 | 99 | 99 | 55 | 59 |
| Mets+2.4-DbeeDica-dma+NIS | 0.0625+4.0+1.0+0.125% | 2 | 65 | 99 | 99 | 99 | 51 | 59 |
| Mets+MCPA-ioe+Dica-dma+NIS | 0.0625+4.0+1.0+0.125% | 1 | 66 | 99 | 99 | 98 | 51 | 59 |
| Tribenuron+2.4-Dbee+NIS | 0.09375+4.0+1.125% | 0 | 54 | 92 | 97 | 99 | 52 | 59 |
| Trib+MCPA-ioe+NIS | 0.09375+4.0+1.125% | 3 | 49 | 74 | 99 | 65 | 46 | 59 |
| Trib+2.4-Dbee+Dica-dma+NIS | 0.09375+4.0+1.0+0.125% | 1 | 61 | 89 | 99 | 97 | 46 | 59 |
| Trib+MCPA-ioe+Dica-dma+NIS | 0.09375+4.0+1.0+0.125% | 1 | 57 | 77 | 97 | 96 | 49 | 59 |
| Tribenuron+Brox&MCPA+NIS | 0.09375+5.0+0.125% | 1 | 70 | 90 | 99 | 94 | 49 | 59 |
| Trib+Brox&MCPA+NIS | 0.09375+6.0+0.125% | 0 | 71 | 84 | 96 | 79 | 49 | 59 |
| Trib+2.4-Dbee+Picloram+NIS | 0.09375+4.0+0.1875+0.125% | 1 | 87 | 88 | 99 | 99 | 47 | 59 |
| Trib+2.4-Dbee+Picloram+NIS | 0.09375+4.0+0.25+0.125% | 0 | 91 | 98 | 99 | 99 | 47 | 59 |
| 2.4-Dbee+Dicamba-dma | 4.0+1.0 | 0 | 58 | 86 | 99 | 98 | 46 | 59 |
| MCPA-ioe+Dica-dam | 4.0+1.0 | 3 | 61 | 86 | 97 | 55 | 47 | 59 |
| 2.4-Ddma+Picloram | 4.0+0.1875 | 1 | 83 | 80 | 97 | 99 | 46 | 59 |
| Brox&MCPA | 5 | 1 | 64 | 70 | 92 | 86 | 47 | 59 |
| Metsulfuron+2.4-Dbee | 0.0625+6.0 | 0 | 69 | 97 | 98 | 98 | 48 | 59 |
| Mets+2.4-Dbee+Picloram+NIS | 0.0625+4.0+0.1875+0.125% | 0 | 58 | 97 | 99 | 99 | 50 | 59 |
| Mets+2.4-Dbee+Picloram+NIS | 0.0625+4.0+0.25+0.125% | 0 | 88 | 93 | 99 | 99 | 46 | 59 |
| Brox&MCPA | 8 | 0 | 73 | 90 | 99 | 95 | 52 | 59 |
| Untreated | 0 | 0 | 0 | 0 | 0 | 0 | 44 | 59 |
| C.V. % | 237 | 29 | 12 | 4 | 15 | 11 | 1 | |
| LSD 5% | ns | 26 | 14 | 6 | 18 | ns | ns | |
| # OF REPS | 4 | 4 | 4 | 4 | 4 | 4 | 4 | |
SUMMARY:
Wheat yield was not significantly increased by herbicide treatments, but tended to be greater than for nontreated wheat. The lack of yield response probably reflected a low weed density and vigorous wheat growth. Herbicide treatments gave greater than 90% control of most weeds, except wild buckwheat. Wild buckwheat control only exceeded 88% when picloram at 0.25% oz/A was a component of the herbicide treatment. MCPA with tribenuron or bromoxynil tended to be less effective than the other treatments in controlling redroot pigweed. MCPA with dicamba or tribenuron only gave 55 and 65% Russian thistle control, respectively. The data indicate that combinations of various herbicides can provide excellent broadspectrum broadleaf weed control without injury to wheat.