1 / 76

Peter H. Sikkema University of Guelph

Weed Management in Corn Questions from Farmers. Peter H. Sikkema University of Guelph. Question # 1.

george
Download Presentation

Peter H. Sikkema University of Guelph

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Weed Management in Corn Questions from Farmers Peter H. Sikkema University of Guelph

  2. Question # 1 I was planning to plant soybeans next spring so I applied Guardian for perennial broadleaf weed control last fall. I changed my mind and I would like to plant corn this spring. Will the corn be OK?

  3. Fall Application of Guardian Corn Injury the Following Spring Visible Corn Injury (%) Sikkema, UG

  4. Fall Application of Guardian Corn Injury the Following Spring

  5. Fall Application of Guardian Corn Yield the following Fall Corn Yield (bu/ac) Sikkema, UG

  6. Fall Application of Guardian Conclusions • The fall application of Guardian results in visible injury in corn the following spring • Purple discolouration • Stunting • In our studies there was a trend (9 bu/ac) to reduced yield, but it was not statistically significant

  7. Question # 2 Is weed control reduced if the herbicide is in spray solution in the sprayer for an extended period of time?

  8. Length of Time Herbicide is in Spray Solution Introduction • Sometimes a herbicide already is in spray solution but it cannot be spray immediately due to: • Mechanical breakdown • Sudden and unexpected rain • High winds

  9. Time in Solution Experiments • Herbicides were mixed and held in solution for: • 7 days • 3 days • 1 day • 0 days

  10. Time in Solution Herbicides Tested

  11. Time in Solution (PRE) Converge Sikkema, UG

  12. Converge – Sprayed Immediately

  13. Time in Solution (PRE) Yield (bu/ac) Sikkema, UG

  14. Time in Solution (PRE) Primextra + Callisto Sikkema, UG

  15. Primextra + Callisto – Sprayed Immediately

  16. Time in Solution (PRE) Summary • When herbicides were held in spray solution for an extended period of time there was: • No difference in pigweed control • A decrease in lamb’s-quarters control with Converge • A decrease in velvetleaf control with Converge and Frontier + Marksman

  17. Time in Solution (PRE) Summary • When herbicides were held in spray solution for an extended period of time there was (continued): • No decrease in corn yield with Frontier + Marksman, Primextra + Callisto and Battalion • A decrease in corn yield with Converge

  18. Time in Solution Herbicides Tested

  19. Time in Solution (POST) Distinct Sikkema, UG

  20. Time in Solution (POST) Roundup Sikkema, UG

  21. Liberty – Sprayed Immediately

  22. Time in Solution (POST) Yield (bu/ac) Sikkema, UG

  23. Time in Solution (POST) Summary • When herbicides were held in spray solution for an extended period of time there was: • No decrease in weed control with Distinct, Callisto + atrazine, Roundup or Liberty • No decrease in corn yield • It is recommended to spray the herbicide held in solution • Monitor field closely and re-spray if necessary

  24. Question # 3 Is there a benefit of adding Crop Booster to glyphosate in RR corn?

  25. No effect on weed control Crop Booster – 6 studies Sikkema, UG

  26. Crop Booster on RR Corn Roundup

  27. No effect on RR corn yield Crop Booster – 6 studies Sikkema, UG

  28. Crop Booster Summary • No difference in weed control • No difference in RR corn yield

  29. Question # 4 My corn is at the 8-10 leaf stage and I have weed escapes. Which herbicides are safest to apply at this late stage?

  30. Late Herbicide Application in Corn Corn Injury – 7 studies Sikkema, UG

  31. Late Herbicide Application in Corn Distinct Injury in Corn

  32. Late Herbicide Application in Corn Decrease in Corn Height – 7 studies Sikkema, UG

  33. Late Herbicide Application in Corn Corn Yield – 7 studies Sikkema, UG

  34. Late Herbicide Application in Corn Summary • Option results in greater injury than Accent • Distinct and Shotgun result in greater injury than Callisto + atrazine, Pardner and PeakPlus • There was no effect on corn yield in these studies

  35. Question # 5 I heard about glyphosate-resistant weeds. What are my weed management options in RR corn?

  36. Roundup Ready Corn Introduction • There are many approaches to weed management in Roundup Ready corn • Yield was maximized when Roundup was applied before weeds were 10 cm in height 1 • Profitability was maximized with one early postemergence application of Roundup 2 • BUT, the over-reliance on Roundup has resulted in the selection of glyphosate resistant weed biotypes or weeds naturally tolerant to glyphosate in other jurisdictions 1 Nelson, 2007 2 Thomas et al. 2007

  37. Roundup Ready Corn Weed Management Strategies • One application of Roundup applied early postemergence (EP) • One application of Roundup applied late postemergence (LP) • A tankmix of Roundup plus a residual herbicide (Marksman) applied EP • A sequential application of a preemergence (PRE) residual herbicide (Converge) followed by Roundup applied LP • A sequential application of Roundup applied EP and LP

  38. Roundup Ready Corn Velvetleaf Control – 8 WAA Weed Control (%) Sikkema, UG Nurse, AAFC

  39. Roundup Ready Corn Sikkema, UG Roundup + Marksman EP

  40. Roundup Ready Corn Pigweed Control – 8 WAA Weed Control (%) Sikkema, UG Nurse, AAFC

  41. Roundup Ready Corn Lamb’s-quarters Control – 8 WAA Weed Control (%) Sikkema, UG Nurse, AAFC

  42. Roundup Ready Corn Sikkema, UG Converge PRE; Roundup LP

  43. Roundup Ready Corn Green Foxtail Control – 8 WAA Weed Control (%) Sikkema, UG Nurse, AAFC

  44. Roundup Ready Corn Yield (bu/ac) Yield (T/ha) Sikkema, UG Nurse, AAFC

  45. Roundup LP Sikkema, UG Roundup LP Sikkema, UG

  46. Roundup Ready Corn Profit Margins Profit Margin ($/ac) Vyn, UG

  47. Roundup Ready Corn Conclusions • Weed management is field specific • The most consistent weed control was provided by the two-pass programs • Residual herbicide (PRE) fb glyphosate (LP) • A sequential application of glyphosate applied EP fb LP

  48. Roundup Ready Corn Comments • Due to the possibility of glyphosate-resistant weeds or weed shifts, the following are recommended: • A diverse crop rotation • Inclusion of multiple herbicide modes-of-action • Preemergence residual followed by glyphosate postemergence • Postemergence tankmix of glyphosate + another effective herbicide

  49. Question # 6 When is the best time to apply glyphosate in RR corn?

  50. Roundup Ready Corn Application Timing There is a temptation to delay the application until all the weeds have emerged

More Related