Table 2.2-12. Maximum corn and weed sizes for delayed preemergence/early postemergence herbicide applications.
See specific herbicide label(s) for additional information on application.
- This type of application generally is used when weather conditions preclude use of standard preemergence program.
- For most products, do not apply in liquid fertilizer if corn has emerged.
- Poor control from residual herbicides may result if annual grasses such as foxtail and panicum have emerged at time of application; tank-mix with product that controls emerged grasses.
- Delayed preemergence/early postemergence programs can work well with herbicide-resistant corn hybrids now available (e.g., Roundup Ready, Liberty Link, Clearfield-CL or IMI)
- When tank-mixing with other pesticides, follow the most restrictive product label.
| Herbicide | Maximum corn size | Maximum weed size |
|---|---|---|
| Atrazine | 12 inches | 1.5 inches |
| Axiom | before emergence | before emergence |
| Balance Pro / Radius | before emergence | before emergence |
| Bicep II Magnum, Cinch ATZ + Prowl | 4-leaf or 2 collars | 1- to 2-leaf |
| Bullet or Micro-Tech + atrazine | 5 inches | 2-leaf |
| Clarity or Marksman + Dual or Lasso EC | 3 inches | 2-leaf grass |
| Clarity or Marksman + Outlook | 8 inches | 1-inch grass |
| Define / Radius | before emergence | before emergence |
| Dual + Marksman | 3 inches | 2-leaf |
| Dual II Magnum (Dual + atrazine), Bicep II Magnum, Bicep Lite II Magnum, Cinch ATZ Lite | 5 inches | 2-leaf |
| Dual II Magnum + Clarity | 5 inches | 3-inch pigweed |
| Dual or Micro-Tech + atrazine, Bullet | 5 inches | 2-leaf |
| Guardsman Max/G-Max Lite | 12 inches | 1.5 inches broadleaves; before grass emergence |
| Harness, Harness Xtra2, Degree, or Degree Xtra | 11 inches or by tank-mix partner | before broadleaf emergence, 2-leaf grasses or by tank-mix partner |
| LeadOff | 8 inches | 1.5 inches |
| Lexar | 12 inches | 5-inch broadleaves, before grass emergence |
| Lumax, Camix | 12 inches | 3-inch broadleaves; inconsistent on emerged grasses |
| Marksman + Prowl | 2-leaf | 1-inch grass |
| Outlook | 12 inches | before emergence or by tank-mix partner |
| Princep | before emergence | before emergence |
| Prowl + Accent1 or Prowl + Accent + Beacon1 | 6-leaf | before broadleaf emergence, 2-leaf grasses or by tank-mix partner |
| Prowl + Atrazine, or Prowl + Banvel | 12 inches | see herbicide labels |
| Prowl + Beacon1 | 12 inches | 1 inch |
| Prowl H2O | 30 inches | before weed emergence |
| Python WDG | 2 inches | before weed emergence |
| Resolve | 12 inches | 2 inch grasses; 3-inch broadleaves (in general) |
| Surpass, FulTime, TopNotch, or Keystone3 | 11 inches or by tank-mix partner | before emergence or by tank-mix partner |
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